December 2017 - Linux-stable-mirror

[Linux-stable-mirror] FAILED: patch "[PATCH] iw_cxgb4: when flushing, complete all wrs in a chain" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From d14587334580bc94d3ee11e8320e0c157f91ae8f Mon Sep 17 00:00:00 2001 From: Steve Wise <swise(a)opengridcomputing.com> Date: Tue, 19 Dec 2017 14:02:10 -0800 Subject: [PATCH] iw_cxgb4: when flushing, complete all wrs in a chain If a wr chain was posted and needed to be flushed, only the first wr in the chain was completed with FLUSHED status. The rest were never completed. This caused isert to hang on shutdown due to the missing completions which left iscsi IO commands referenced, stalling the shutdown. Fixes: 4fe7c2962e11 ("iw_cxgb4: refactor sq/rq drain logic") Cc: stable(a)vger.kernel.org Signed-off-by: Steve Wise <swise(a)opengridcomputing.com> Signed-off-by: Jason Gunthorpe <jgg(a)mellanox.com> diff --git a/drivers/infiniband/hw/cxgb4/qp.c b/drivers/infiniband/hw/cxgb4/qp.c index 21495f917bcc..d5c92fc520d6 100644 --- a/drivers/infiniband/hw/cxgb4/qp.c +++ b/drivers/infiniband/hw/cxgb4/qp.c @@ -858,6 +858,22 @@ static int complete_sq_drain_wr(struct c4iw_qp *qhp, struct ib_send_wr *wr) return 0; } +static int complete_sq_drain_wrs(struct c4iw_qp *qhp, struct ib_send_wr *wr, + struct ib_send_wr **bad_wr) +{ + int ret = 0; + + while (wr) { + ret = complete_sq_drain_wr(qhp, wr); + if (ret) { + *bad_wr = wr; + break; + } + wr = wr->next; + } + return ret; +} + static void complete_rq_drain_wr(struct c4iw_qp *qhp, struct ib_recv_wr *wr) { struct t4_cqe cqe = {}; @@ -890,6 +906,14 @@ static void complete_rq_drain_wr(struct c4iw_qp *qhp, struct ib_recv_wr *wr) } } +static void complete_rq_drain_wrs(struct c4iw_qp *qhp, struct ib_recv_wr *wr) +{ + while (wr) { + complete_rq_drain_wr(qhp, wr); + wr = wr->next; + } +} + int c4iw_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr, struct ib_send_wr **bad_wr) { @@ -913,7 +937,7 @@ int c4iw_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr, */ if (qhp->wq.flushed) { spin_unlock_irqrestore(&qhp->lock, flag); - err = complete_sq_drain_wr(qhp, wr); + err = complete_sq_drain_wrs(qhp, wr, bad_wr); return err; } num_wrs = t4_sq_avail(&qhp->wq); @@ -1061,7 +1085,7 @@ int c4iw_post_receive(struct ib_qp *ibqp, struct ib_recv_wr *wr, */ if (qhp->wq.flushed) { spin_unlock_irqrestore(&qhp->lock, flag); - complete_rq_drain_wr(qhp, wr); + complete_rq_drain_wrs(qhp, wr); return err; } num_wrs = t4_rq_avail(&qhp->wq);

6 years, 6 months

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[Linux-stable-mirror] [PATCH] arm64: Target aarch64elf emulation to allow bare-metal toolchains

by Paul Kocialkowski

This sets the LDFLAGS variable to target the aarch64elf emulation instead of aarch64linux, which is incompatible with bare-metal toolchains. This change allows the kernel to build with bare-metal toolchains again. Fixes: 3d6a7b99e3fa ("arm64: ensure the kernel is compiled for LP64") Cc: stable(a)vger.kernel.org Signed-off-by: Paul Kocialkowski <contact(a)paulk.fr> --- arch/arm64/Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index b481b4a7c011..a249233edcd8 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -64,14 +64,14 @@ KBUILD_CPPFLAGS += -mbig-endian CHECKFLAGS += -D__AARCH64EB__ AS += -EB LD += -EB -LDFLAGS += -maarch64linuxb +LDFLAGS += -maarch64elfb UTS_MACHINE := aarch64_be else KBUILD_CPPFLAGS += -mlittle-endian CHECKFLAGS += -D__AARCH64EL__ AS += -EL LD += -EL -LDFLAGS += -maarch64linux +LDFLAGS += -maarch64elf UTS_MACHINE := aarch64 endif -- 2.15.1

6 years, 6 months

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[Linux-stable-mirror] Patch "x86/pti: Put the LDT in its own PGD if PTI is on" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/pti: Put the LDT in its own PGD if PTI is on to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From f55f0501cbf65ec41cca5058513031b711730b1d Mon Sep 17 00:00:00 2001 From: Andy Lutomirski <luto(a)kernel.org> Date: Tue, 12 Dec 2017 07:56:45 -0800 Subject: x86/pti: Put the LDT in its own PGD if PTI is on From: Andy Lutomirski <luto(a)kernel.org> commit f55f0501cbf65ec41cca5058513031b711730b1d upstream. With PTI enabled, the LDT must be mapped in the usermode tables somewhere. The LDT is per process, i.e. per mm. An earlier approach mapped the LDT on context switch into a fixmap area, but that's a big overhead and exhausted the fixmap space when NR_CPUS got big. Take advantage of the fact that there is an address space hole which provides a completely unused pgd. Use this pgd to manage per-mm LDT mappings. This has a down side: the LDT isn't (currently) randomized, and an attack that can write the LDT is instant root due to call gates (thanks, AMD, for leaving call gates in AMD64 but designing them wrong so they're only useful for exploits). This can be mitigated by making the LDT read-only or randomizing the mapping, either of which is strightforward on top of this patch. This will significantly slow down LDT users, but that shouldn't matter for important workloads -- the LDT is only used by DOSEMU(2), Wine, and very old libc implementations. [ tglx: Cleaned it up. ] Signed-off-by: Andy Lutomirski <luto(a)kernel.org> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Dave Hansen <dave.hansen(a)intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Laight <David.Laight(a)aculab.com> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Kirill A. Shutemov <kirill(a)shutemov.name> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- Documentation/x86/x86_64/mm.txt | 3 arch/x86/include/asm/mmu_context.h | 59 ++++++++++++- arch/x86/include/asm/pgtable_64_types.h | 4 arch/x86/include/asm/processor.h | 23 +++-- arch/x86/kernel/ldt.c | 139 +++++++++++++++++++++++++++++++- arch/x86/mm/dump_pagetables.c | 9 ++ 6 files changed, 220 insertions(+), 17 deletions(-) --- a/Documentation/x86/x86_64/mm.txt +++ b/Documentation/x86/x86_64/mm.txt @@ -12,6 +12,7 @@ ffffea0000000000 - ffffeaffffffffff (=40 ... unused hole ... ffffec0000000000 - fffffbffffffffff (=44 bits) kasan shadow memory (16TB) ... unused hole ... +fffffe0000000000 - fffffe7fffffffff (=39 bits) LDT remap for PTI fffffe8000000000 - fffffeffffffffff (=39 bits) cpu_entry_area mapping ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks ... unused hole ... @@ -29,7 +30,7 @@ Virtual memory map with 5 level page tab hole caused by [56:63] sign extension ff00000000000000 - ff0fffffffffffff (=52 bits) guard hole, reserved for hypervisor ff10000000000000 - ff8fffffffffffff (=55 bits) direct mapping of all phys. memory -ff90000000000000 - ff9fffffffffffff (=52 bits) hole +ff90000000000000 - ff9fffffffffffff (=52 bits) LDT remap for PTI ffa0000000000000 - ffd1ffffffffffff (=54 bits) vmalloc/ioremap space (12800 TB) ffd2000000000000 - ffd3ffffffffffff (=49 bits) hole ffd4000000000000 - ffd5ffffffffffff (=49 bits) virtual memory map (512TB) --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -50,10 +50,33 @@ struct ldt_struct { * call gates. On native, we could merge the ldt_struct and LDT * allocations, but it's not worth trying to optimize. */ - struct desc_struct *entries; - unsigned int nr_entries; + struct desc_struct *entries; + unsigned int nr_entries; + + /* + * If PTI is in use, then the entries array is not mapped while we're + * in user mode. The whole array will be aliased at the addressed + * given by ldt_slot_va(slot). We use two slots so that we can allocate + * and map, and enable a new LDT without invalidating the mapping + * of an older, still-in-use LDT. + * + * slot will be -1 if this LDT doesn't have an alias mapping. + */ + int slot; }; +/* This is a multiple of PAGE_SIZE. */ +#define LDT_SLOT_STRIDE (LDT_ENTRIES * LDT_ENTRY_SIZE) + +static inline void *ldt_slot_va(int slot) +{ +#ifdef CONFIG_X86_64 + return (void *)(LDT_BASE_ADDR + LDT_SLOT_STRIDE * slot); +#else + BUG(); +#endif +} + /* * Used for LDT copy/destruction. */ @@ -64,6 +87,7 @@ static inline void init_new_context_ldt( } int ldt_dup_context(struct mm_struct *oldmm, struct mm_struct *mm); void destroy_context_ldt(struct mm_struct *mm); +void ldt_arch_exit_mmap(struct mm_struct *mm); #else /* CONFIG_MODIFY_LDT_SYSCALL */ static inline void init_new_context_ldt(struct mm_struct *mm) { } static inline int ldt_dup_context(struct mm_struct *oldmm, @@ -71,7 +95,8 @@ static inline int ldt_dup_context(struct { return 0; } -static inline void destroy_context_ldt(struct mm_struct *mm) {} +static inline void destroy_context_ldt(struct mm_struct *mm) { } +static inline void ldt_arch_exit_mmap(struct mm_struct *mm) { } #endif static inline void load_mm_ldt(struct mm_struct *mm) @@ -96,10 +121,31 @@ static inline void load_mm_ldt(struct mm * that we can see. */ - if (unlikely(ldt)) - set_ldt(ldt->entries, ldt->nr_entries); - else + if (unlikely(ldt)) { + if (static_cpu_has(X86_FEATURE_PTI)) { + if (WARN_ON_ONCE((unsigned long)ldt->slot > 1)) { + /* + * Whoops -- either the new LDT isn't mapped + * (if slot == -1) or is mapped into a bogus + * slot (if slot > 1). + */ + clear_LDT(); + return; + } + + /* + * If page table isolation is enabled, ldt->entries + * will not be mapped in the userspace pagetables. + * Tell the CPU to access the LDT through the alias + * at ldt_slot_va(ldt->slot). + */ + set_ldt(ldt_slot_va(ldt->slot), ldt->nr_entries); + } else { + set_ldt(ldt->entries, ldt->nr_entries); + } + } else { clear_LDT(); + } #else clear_LDT(); #endif @@ -194,6 +240,7 @@ static inline int arch_dup_mmap(struct m static inline void arch_exit_mmap(struct mm_struct *mm) { paravirt_arch_exit_mmap(mm); + ldt_arch_exit_mmap(mm); } #ifdef CONFIG_X86_64 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -82,10 +82,14 @@ typedef struct { pteval_t pte; } pte_t; # define VMALLOC_SIZE_TB _AC(12800, UL) # define __VMALLOC_BASE _AC(0xffa0000000000000, UL) # define __VMEMMAP_BASE _AC(0xffd4000000000000, UL) +# define LDT_PGD_ENTRY _AC(-112, UL) +# define LDT_BASE_ADDR (LDT_PGD_ENTRY << PGDIR_SHIFT) #else # define VMALLOC_SIZE_TB _AC(32, UL) # define __VMALLOC_BASE _AC(0xffffc90000000000, UL) # define __VMEMMAP_BASE _AC(0xffffea0000000000, UL) +# define LDT_PGD_ENTRY _AC(-4, UL) +# define LDT_BASE_ADDR (LDT_PGD_ENTRY << PGDIR_SHIFT) #endif #ifdef CONFIG_RANDOMIZE_MEMORY --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -851,13 +851,22 @@ static inline void spin_lock_prefetch(co #else /* - * User space process size. 47bits minus one guard page. The guard - * page is necessary on Intel CPUs: if a SYSCALL instruction is at - * the highest possible canonical userspace address, then that - * syscall will enter the kernel with a non-canonical return - * address, and SYSRET will explode dangerously. We avoid this - * particular problem by preventing anything from being mapped - * at the maximum canonical address. + * User space process size. This is the first address outside the user range. + * There are a few constraints that determine this: + * + * On Intel CPUs, if a SYSCALL instruction is at the highest canonical + * address, then that syscall will enter the kernel with a + * non-canonical return address, and SYSRET will explode dangerously. + * We avoid this particular problem by preventing anything executable + * from being mapped at the maximum canonical address. + * + * On AMD CPUs in the Ryzen family, there's a nasty bug in which the + * CPUs malfunction if they execute code from the highest canonical page. + * They'll speculate right off the end of the canonical space, and + * bad things happen. This is worked around in the same way as the + * Intel problem. + * + * With page table isolation enabled, we map the LDT in ... [stay tuned] */ #define TASK_SIZE_MAX ((1UL << __VIRTUAL_MASK_SHIFT) - PAGE_SIZE) --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -24,6 +24,7 @@ #include <linux/uaccess.h> #include <asm/ldt.h> +#include <asm/tlb.h> #include <asm/desc.h> #include <asm/mmu_context.h> #include <asm/syscalls.h> @@ -51,13 +52,11 @@ static void refresh_ldt_segments(void) static void flush_ldt(void *__mm) { struct mm_struct *mm = __mm; - mm_context_t *pc; if (this_cpu_read(cpu_tlbstate.loaded_mm) != mm) return; - pc = &mm->context; - set_ldt(pc->ldt->entries, pc->ldt->nr_entries); + load_mm_ldt(mm); refresh_ldt_segments(); } @@ -94,10 +93,121 @@ static struct ldt_struct *alloc_ldt_stru return NULL; } + /* The new LDT isn't aliased for PTI yet. */ + new_ldt->slot = -1; + new_ldt->nr_entries = num_entries; return new_ldt; } +/* + * If PTI is enabled, this maps the LDT into the kernelmode and + * usermode tables for the given mm. + * + * There is no corresponding unmap function. Even if the LDT is freed, we + * leave the PTEs around until the slot is reused or the mm is destroyed. + * This is harmless: the LDT is always in ordinary memory, and no one will + * access the freed slot. + * + * If we wanted to unmap freed LDTs, we'd also need to do a flush to make + * it useful, and the flush would slow down modify_ldt(). + */ +static int +map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot) +{ +#ifdef CONFIG_PAGE_TABLE_ISOLATION + bool is_vmalloc, had_top_level_entry; + unsigned long va; + spinlock_t *ptl; + pgd_t *pgd; + int i; + + if (!static_cpu_has(X86_FEATURE_PTI)) + return 0; + + /* + * Any given ldt_struct should have map_ldt_struct() called at most + * once. + */ + WARN_ON(ldt->slot != -1); + + /* + * Did we already have the top level entry allocated? We can't + * use pgd_none() for this because it doens't do anything on + * 4-level page table kernels. + */ + pgd = pgd_offset(mm, LDT_BASE_ADDR); + had_top_level_entry = (pgd->pgd != 0); + + is_vmalloc = is_vmalloc_addr(ldt->entries); + + for (i = 0; i * PAGE_SIZE < ldt->nr_entries * LDT_ENTRY_SIZE; i++) { + unsigned long offset = i << PAGE_SHIFT; + const void *src = (char *)ldt->entries + offset; + unsigned long pfn; + pte_t pte, *ptep; + + va = (unsigned long)ldt_slot_va(slot) + offset; + pfn = is_vmalloc ? vmalloc_to_pfn(src) : + page_to_pfn(virt_to_page(src)); + /* + * Treat the PTI LDT range as a *userspace* range. + * get_locked_pte() will allocate all needed pagetables + * and account for them in this mm. + */ + ptep = get_locked_pte(mm, va, &ptl); + if (!ptep) + return -ENOMEM; + pte = pfn_pte(pfn, __pgprot(__PAGE_KERNEL & ~_PAGE_GLOBAL)); + set_pte_at(mm, va, ptep, pte); + pte_unmap_unlock(ptep, ptl); + } + + if (mm->context.ldt) { + /* + * We already had an LDT. The top-level entry should already + * have been allocated and synchronized with the usermode + * tables. + */ + WARN_ON(!had_top_level_entry); + if (static_cpu_has(X86_FEATURE_PTI)) + WARN_ON(!kernel_to_user_pgdp(pgd)->pgd); + } else { + /* + * This is the first time we're mapping an LDT for this process. + * Sync the pgd to the usermode tables. + */ + WARN_ON(had_top_level_entry); + if (static_cpu_has(X86_FEATURE_PTI)) { + WARN_ON(kernel_to_user_pgdp(pgd)->pgd); + set_pgd(kernel_to_user_pgdp(pgd), *pgd); + } + } + + va = (unsigned long)ldt_slot_va(slot); + flush_tlb_mm_range(mm, va, va + LDT_SLOT_STRIDE, 0); + + ldt->slot = slot; +#endif + return 0; +} + +static void free_ldt_pgtables(struct mm_struct *mm) +{ +#ifdef CONFIG_PAGE_TABLE_ISOLATION + struct mmu_gather tlb; + unsigned long start = LDT_BASE_ADDR; + unsigned long end = start + (1UL << PGDIR_SHIFT); + + if (!static_cpu_has(X86_FEATURE_PTI)) + return; + + tlb_gather_mmu(&tlb, mm, start, end); + free_pgd_range(&tlb, start, end, start, end); + tlb_finish_mmu(&tlb, start, end); +#endif +} + /* After calling this, the LDT is immutable. */ static void finalize_ldt_struct(struct ldt_struct *ldt) { @@ -156,6 +266,12 @@ int ldt_dup_context(struct mm_struct *ol new_ldt->nr_entries * LDT_ENTRY_SIZE); finalize_ldt_struct(new_ldt); + retval = map_ldt_struct(mm, new_ldt, 0); + if (retval) { + free_ldt_pgtables(mm); + free_ldt_struct(new_ldt); + goto out_unlock; + } mm->context.ldt = new_ldt; out_unlock: @@ -174,6 +290,11 @@ void destroy_context_ldt(struct mm_struc mm->context.ldt = NULL; } +void ldt_arch_exit_mmap(struct mm_struct *mm) +{ + free_ldt_pgtables(mm); +} + static int read_ldt(void __user *ptr, unsigned long bytecount) { struct mm_struct *mm = current->mm; @@ -287,6 +408,18 @@ static int write_ldt(void __user *ptr, u new_ldt->entries[ldt_info.entry_number] = ldt; finalize_ldt_struct(new_ldt); + /* + * If we are using PTI, map the new LDT into the userspace pagetables. + * If there is already an LDT, use the other slot so that other CPUs + * will continue to use the old LDT until install_ldt() switches + * them over to the new LDT. + */ + error = map_ldt_struct(mm, new_ldt, old_ldt ? !old_ldt->slot : 0); + if (error) { + free_ldt_struct(old_ldt); + goto out_unlock; + } + install_ldt(mm, new_ldt); free_ldt_struct(old_ldt); error = 0; --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -52,12 +52,18 @@ enum address_markers_idx { USER_SPACE_NR = 0, KERNEL_SPACE_NR, LOW_KERNEL_NR, +#if defined(CONFIG_MODIFY_LDT_SYSCALL) && defined(CONFIG_X86_5LEVEL) + LDT_NR, +#endif VMALLOC_START_NR, VMEMMAP_START_NR, #ifdef CONFIG_KASAN KASAN_SHADOW_START_NR, KASAN_SHADOW_END_NR, #endif +#if defined(CONFIG_MODIFY_LDT_SYSCALL) && !defined(CONFIG_X86_5LEVEL) + LDT_NR, +#endif CPU_ENTRY_AREA_NR, #ifdef CONFIG_X86_ESPFIX64 ESPFIX_START_NR, @@ -82,6 +88,9 @@ static struct addr_marker address_marker [KASAN_SHADOW_START_NR] = { KASAN_SHADOW_START, "KASAN shadow" }, [KASAN_SHADOW_END_NR] = { KASAN_SHADOW_END, "KASAN shadow end" }, #endif +#ifdef CONFIG_MODIFY_LDT_SYSCALL + [LDT_NR] = { LDT_BASE_ADDR, "LDT remap" }, +#endif [CPU_ENTRY_AREA_NR] = { CPU_ENTRY_AREA_BASE,"CPU entry Area" }, #ifdef CONFIG_X86_ESPFIX64 [ESPFIX_START_NR] = { ESPFIX_BASE_ADDR, "ESPfix Area", 16 }, Patches currently in stable-queue which might be from luto(a)kernel.org are queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch queue-4.14/x86-mm-clarify-the-whole-asid-kernel-pcid-user-pcid-naming.patch queue-4.14/x86-mm-abstract-switching-cr3.patch queue-4.14/x86-mm-optimize-restore_cr3.patch queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch queue-4.14/x86-entry-align-entry-text-section-to-pmd-boundary.patch queue-4.14/x86-mm-64-make-a-full-pgd-entry-size-hole-in-the-memory-map.patch queue-4.14/x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch queue-4.14/x86-mm-pti-share-entry-text-pmd.patch queue-4.14/x86-ldt-make-the-ldt-mapping-ro.patch queue-4.14/x86-mm-dump_pagetables-check-user-space-page-table-for-wx-pages.patch queue-4.14/x86-pti-map-the-vsyscall-page-if-needed.patch queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch queue-4.14/x86-mm-dump_pagetables-allow-dumping-current-pagetables.patch queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch queue-4.14/x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch queue-4.14/x86-mm-use-invpcid-for-__native_flush_tlb_single.patch queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch queue-4.14/x86-mm-allow-flushing-for-future-asid-switches.patch queue-4.14/x86-mm-pti-add-kconfig.patch queue-4.14/x86-mm-pti-add-mapping-helper-functions.patch queue-4.14/x86-mm-pti-map-espfix-into-user-space.patch queue-4.14/x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch queue-4.14/x86-mm-pti-add-functions-to-clone-kernel-pmds.patch queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch queue-4.14/x86-events-intel-ds-map-debug-buffers-in-cpu_entry_area.patch queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch queue-4.14/x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch queue-4.14/x86-mm-pti-populate-user-pgd.patch queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch

6 years, 6 months

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[Linux-stable-mirror] Patch "x86/pti: Map the vsyscall page if needed" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/pti: Map the vsyscall page if needed to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-pti-map-the-vsyscall-page-if-needed.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 85900ea51577e31b186e523c8f4e068c79ecc7d3 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski <luto(a)kernel.org> Date: Tue, 12 Dec 2017 07:56:42 -0800 Subject: x86/pti: Map the vsyscall page if needed From: Andy Lutomirski <luto(a)kernel.org> commit 85900ea51577e31b186e523c8f4e068c79ecc7d3 upstream. Make VSYSCALLs work fully in PTI mode by mapping them properly to the user space visible page tables. [ tglx: Hide unused functions (Patch by Arnd Bergmann) ] Signed-off-by: Andy Lutomirski <luto(a)kernel.org> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Laight <David.Laight(a)aculab.com> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/entry/vsyscall/vsyscall_64.c | 6 +-- arch/x86/include/asm/vsyscall.h | 1 arch/x86/mm/pti.c | 65 ++++++++++++++++++++++++++++++++++ 3 files changed, 69 insertions(+), 3 deletions(-) --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -344,14 +344,14 @@ int in_gate_area_no_mm(unsigned long add * vsyscalls but leave the page not present. If so, we skip calling * this. */ -static void __init set_vsyscall_pgtable_user_bits(void) +void __init set_vsyscall_pgtable_user_bits(pgd_t *root) { pgd_t *pgd; p4d_t *p4d; pud_t *pud; pmd_t *pmd; - pgd = pgd_offset_k(VSYSCALL_ADDR); + pgd = pgd_offset_pgd(root, VSYSCALL_ADDR); set_pgd(pgd, __pgd(pgd_val(*pgd) | _PAGE_USER)); p4d = p4d_offset(pgd, VSYSCALL_ADDR); #if CONFIG_PGTABLE_LEVELS >= 5 @@ -373,7 +373,7 @@ void __init map_vsyscall(void) vsyscall_mode == NATIVE ? PAGE_KERNEL_VSYSCALL : PAGE_KERNEL_VVAR); - set_vsyscall_pgtable_user_bits(); + set_vsyscall_pgtable_user_bits(swapper_pg_dir); } BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) != --- a/arch/x86/include/asm/vsyscall.h +++ b/arch/x86/include/asm/vsyscall.h @@ -7,6 +7,7 @@ #ifdef CONFIG_X86_VSYSCALL_EMULATION extern void map_vsyscall(void); +extern void set_vsyscall_pgtable_user_bits(pgd_t *root); /* * Called on instruction fetch fault in vsyscall page. --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -38,6 +38,7 @@ #include <asm/cpufeature.h> #include <asm/hypervisor.h> +#include <asm/vsyscall.h> #include <asm/cmdline.h> #include <asm/pti.h> #include <asm/pgtable.h> @@ -223,6 +224,69 @@ static pmd_t *pti_user_pagetable_walk_pm return pmd_offset(pud, address); } +#ifdef CONFIG_X86_VSYSCALL_EMULATION +/* + * Walk the shadow copy of the page tables (optionally) trying to allocate + * page table pages on the way down. Does not support large pages. + * + * Note: this is only used when mapping *new* kernel data into the + * user/shadow page tables. It is never used for userspace data. + * + * Returns a pointer to a PTE on success, or NULL on failure. + */ +static __init pte_t *pti_user_pagetable_walk_pte(unsigned long address) +{ + gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO); + pmd_t *pmd = pti_user_pagetable_walk_pmd(address); + pte_t *pte; + + /* We can't do anything sensible if we hit a large mapping. */ + if (pmd_large(*pmd)) { + WARN_ON(1); + return NULL; + } + + if (pmd_none(*pmd)) { + unsigned long new_pte_page = __get_free_page(gfp); + if (!new_pte_page) + return NULL; + + if (pmd_none(*pmd)) { + set_pmd(pmd, __pmd(_KERNPG_TABLE | __pa(new_pte_page))); + new_pte_page = 0; + } + if (new_pte_page) + free_page(new_pte_page); + } + + pte = pte_offset_kernel(pmd, address); + if (pte_flags(*pte) & _PAGE_USER) { + WARN_ONCE(1, "attempt to walk to user pte\n"); + return NULL; + } + return pte; +} + +static void __init pti_setup_vsyscall(void) +{ + pte_t *pte, *target_pte; + unsigned int level; + + pte = lookup_address(VSYSCALL_ADDR, &level); + if (!pte || WARN_ON(level != PG_LEVEL_4K) || pte_none(*pte)) + return; + + target_pte = pti_user_pagetable_walk_pte(VSYSCALL_ADDR); + if (WARN_ON(!target_pte)) + return; + + *target_pte = *pte; + set_vsyscall_pgtable_user_bits(kernel_to_user_pgdp(swapper_pg_dir)); +} +#else +static void __init pti_setup_vsyscall(void) { } +#endif + static void __init pti_clone_pmds(unsigned long start, unsigned long end, pmdval_t clear) { @@ -319,4 +383,5 @@ void __init pti_init(void) pti_clone_user_shared(); pti_clone_entry_text(); pti_setup_espfix64(); + pti_setup_vsyscall(); } Patches currently in stable-queue which might be from luto(a)kernel.org are queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch queue-4.14/x86-mm-clarify-the-whole-asid-kernel-pcid-user-pcid-naming.patch queue-4.14/x86-mm-abstract-switching-cr3.patch queue-4.14/x86-mm-optimize-restore_cr3.patch queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch queue-4.14/x86-entry-align-entry-text-section-to-pmd-boundary.patch queue-4.14/x86-mm-64-make-a-full-pgd-entry-size-hole-in-the-memory-map.patch queue-4.14/x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch queue-4.14/x86-mm-pti-share-entry-text-pmd.patch queue-4.14/x86-ldt-make-the-ldt-mapping-ro.patch queue-4.14/x86-mm-dump_pagetables-check-user-space-page-table-for-wx-pages.patch queue-4.14/x86-pti-map-the-vsyscall-page-if-needed.patch queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch queue-4.14/x86-mm-dump_pagetables-allow-dumping-current-pagetables.patch queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch queue-4.14/x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch queue-4.14/x86-mm-use-invpcid-for-__native_flush_tlb_single.patch queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch queue-4.14/x86-mm-allow-flushing-for-future-asid-switches.patch queue-4.14/x86-mm-pti-add-kconfig.patch queue-4.14/x86-mm-pti-add-mapping-helper-functions.patch queue-4.14/x86-mm-pti-map-espfix-into-user-space.patch queue-4.14/x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch queue-4.14/x86-mm-pti-add-functions-to-clone-kernel-pmds.patch queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch queue-4.14/x86-events-intel-ds-map-debug-buffers-in-cpu_entry_area.patch queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch queue-4.14/x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch queue-4.14/x86-mm-pti-populate-user-pgd.patch queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch

6 years, 6 months

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[Linux-stable-mirror] Patch "x86/pti: Add the pti= cmdline option and documentation" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/pti: Add the pti= cmdline option and documentation to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-pti-add-the-pti-cmdline-option-and-documentation.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 41f4c20b57a4890ea7f56ff8717cc83fefb8d537 Mon Sep 17 00:00:00 2001 From: Borislav Petkov <bp(a)suse.de> Date: Tue, 12 Dec 2017 14:39:52 +0100 Subject: x86/pti: Add the pti= cmdline option and documentation From: Borislav Petkov <bp(a)suse.de> commit 41f4c20b57a4890ea7f56ff8717cc83fefb8d537 upstream. Keep the "nopti" optional for traditional reasons. [ tglx: Don't allow force on when running on XEN PV and made 'on' printout conditional ] Requested-by: Linus Torvalds <torvalds(a)linux-foundation.org> Signed-off-by: Borislav Petkov <bp(a)suse.de> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Andy Lutomirsky <luto(a)kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Dave Hansen <dave.hansen(a)intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Laight <David.Laight(a)aculab.com> Cc: Denys Vlasenko <dvlasenk(a)redhat.com> Cc: Eduardo Valentin <eduval(a)amazon.com> Cc: Greg KH <gregkh(a)linuxfoundation.org> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Will Deacon <will.deacon(a)arm.com> Cc: aliguori(a)amazon.com Cc: daniel.gruss(a)iaik.tugraz.at Cc: hughd(a)google.com Cc: keescook(a)google.com Link: https://lkml.kernel.org/r/20171212133952.10177-1-bp@alien8.de Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- Documentation/admin-guide/kernel-parameters.txt | 6 +++++ arch/x86/mm/pti.c | 26 +++++++++++++++++++++++- 2 files changed, 31 insertions(+), 1 deletion(-) --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3255,6 +3255,12 @@ pt. [PARIDE] See Documentation/blockdev/paride.txt. + pti= [X86_64] + Control user/kernel address space isolation: + on - enable + off - disable + auto - default setting + pty.legacy_count= [KNL] Number of legacy pty's. Overwrites compiled-in default number. --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -54,21 +54,45 @@ static void __init pti_print_if_insecure pr_info("%s\n", reason); } +static void __init pti_print_if_secure(const char *reason) +{ + if (!boot_cpu_has_bug(X86_BUG_CPU_INSECURE)) + pr_info("%s\n", reason); +} + void __init pti_check_boottime_disable(void) { + char arg[5]; + int ret; + if (hypervisor_is_type(X86_HYPER_XEN_PV)) { pti_print_if_insecure("disabled on XEN PV."); return; } + ret = cmdline_find_option(boot_command_line, "pti", arg, sizeof(arg)); + if (ret > 0) { + if (ret == 3 && !strncmp(arg, "off", 3)) { + pti_print_if_insecure("disabled on command line."); + return; + } + if (ret == 2 && !strncmp(arg, "on", 2)) { + pti_print_if_secure("force enabled on command line."); + goto enable; + } + if (ret == 4 && !strncmp(arg, "auto", 4)) + goto autosel; + } + if (cmdline_find_option_bool(boot_command_line, "nopti")) { pti_print_if_insecure("disabled on command line."); return; } +autosel: if (!boot_cpu_has_bug(X86_BUG_CPU_INSECURE)) return; - +enable: setup_force_cpu_cap(X86_FEATURE_PTI); } Patches currently in stable-queue which might be from bp(a)suse.de are queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch queue-4.14/x86-mm-pti-populate-user-pgd.patch queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch

6 years, 6 months

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[Linux-stable-mirror] Patch "x86/mm: Use INVPCID for __native_flush_tlb_single()" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/mm: Use INVPCID for __native_flush_tlb_single() to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-mm-use-invpcid-for-__native_flush_tlb_single.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 6cff64b86aaaa07f89f50498055a20e45754b0c1 Mon Sep 17 00:00:00 2001 From: Dave Hansen <dave.hansen(a)linux.intel.com> Date: Mon, 4 Dec 2017 15:08:01 +0100 Subject: x86/mm: Use INVPCID for __native_flush_tlb_single() From: Dave Hansen <dave.hansen(a)linux.intel.com> commit 6cff64b86aaaa07f89f50498055a20e45754b0c1 upstream. This uses INVPCID to shoot down individual lines of the user mapping instead of marking the entire user map as invalid. This could/might/possibly be faster. This for sure needs tlb_single_page_flush_ceiling to be redetermined; esp. since INVPCID is _slow_. A detailed performance analysis is available here: https://lkml.kernel.org/r/3062e486-3539-8a1f-5724-16199420be71@intel.com [ Peterz: Split out from big combo patch ] Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Denys Vlasenko <dvlasenk(a)redhat.com> Cc: Eduardo Valentin <eduval(a)amazon.com> Cc: Greg KH <gregkh(a)linuxfoundation.org> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Will Deacon <will.deacon(a)arm.com> Cc: aliguori(a)amazon.com Cc: daniel.gruss(a)iaik.tugraz.at Cc: hughd(a)google.com Cc: keescook(a)google.com Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/include/asm/cpufeatures.h | 1 arch/x86/include/asm/tlbflush.h | 23 ++++++++++++- arch/x86/mm/init.c | 64 +++++++++++++++++++++---------------- 3 files changed, 60 insertions(+), 28 deletions(-) --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -197,6 +197,7 @@ #define X86_FEATURE_CAT_L3 ( 7*32+ 4) /* Cache Allocation Technology L3 */ #define X86_FEATURE_CAT_L2 ( 7*32+ 5) /* Cache Allocation Technology L2 */ #define X86_FEATURE_CDP_L3 ( 7*32+ 6) /* Code and Data Prioritization L3 */ +#define X86_FEATURE_INVPCID_SINGLE ( 7*32+ 7) /* Effectively INVPCID && CR4.PCIDE=1 */ #define X86_FEATURE_HW_PSTATE ( 7*32+ 8) /* AMD HW-PState */ #define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */ --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -85,6 +85,18 @@ static inline u16 kern_pcid(u16 asid) return asid + 1; } +/* + * The user PCID is just the kernel one, plus the "switch bit". + */ +static inline u16 user_pcid(u16 asid) +{ + u16 ret = kern_pcid(asid); +#ifdef CONFIG_PAGE_TABLE_ISOLATION + ret |= 1 << X86_CR3_PTI_SWITCH_BIT; +#endif + return ret; +} + struct pgd_t; static inline unsigned long build_cr3(pgd_t *pgd, u16 asid) { @@ -335,6 +347,8 @@ static inline void __native_flush_tlb_gl /* * Using INVPCID is considerably faster than a pair of writes * to CR4 sandwiched inside an IRQ flag save/restore. + * + * Note, this works with CR4.PCIDE=0 or 1. */ invpcid_flush_all(); return; @@ -368,7 +382,14 @@ static inline void __native_flush_tlb_si if (!static_cpu_has(X86_FEATURE_PTI)) return; - invalidate_user_asid(loaded_mm_asid); + /* + * Some platforms #GP if we call invpcid(type=1/2) before CR4.PCIDE=1. + * Just use invalidate_user_asid() in case we are called early. + */ + if (!this_cpu_has(X86_FEATURE_INVPCID_SINGLE)) + invalidate_user_asid(loaded_mm_asid); + else + invpcid_flush_one(user_pcid(loaded_mm_asid), addr); } /* --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -203,34 +203,44 @@ static void __init probe_page_size_mask( static void setup_pcid(void) { -#ifdef CONFIG_X86_64 - if (boot_cpu_has(X86_FEATURE_PCID)) { - if (boot_cpu_has(X86_FEATURE_PGE)) { - /* - * This can't be cr4_set_bits_and_update_boot() -- - * the trampoline code can't handle CR4.PCIDE and - * it wouldn't do any good anyway. Despite the name, - * cr4_set_bits_and_update_boot() doesn't actually - * cause the bits in question to remain set all the - * way through the secondary boot asm. - * - * Instead, we brute-force it and set CR4.PCIDE - * manually in start_secondary(). - */ - cr4_set_bits(X86_CR4_PCIDE); - } else { - /* - * flush_tlb_all(), as currently implemented, won't - * work if PCID is on but PGE is not. Since that - * combination doesn't exist on real hardware, there's - * no reason to try to fully support it, but it's - * polite to avoid corrupting data if we're on - * an improperly configured VM. - */ - setup_clear_cpu_cap(X86_FEATURE_PCID); - } + if (!IS_ENABLED(CONFIG_X86_64)) + return; + + if (!boot_cpu_has(X86_FEATURE_PCID)) + return; + + if (boot_cpu_has(X86_FEATURE_PGE)) { + /* + * This can't be cr4_set_bits_and_update_boot() -- the + * trampoline code can't handle CR4.PCIDE and it wouldn't + * do any good anyway. Despite the name, + * cr4_set_bits_and_update_boot() doesn't actually cause + * the bits in question to remain set all the way through + * the secondary boot asm. + * + * Instead, we brute-force it and set CR4.PCIDE manually in + * start_secondary(). + */ + cr4_set_bits(X86_CR4_PCIDE); + + /* + * INVPCID's single-context modes (2/3) only work if we set + * X86_CR4_PCIDE, *and* we INVPCID support. It's unusable + * on systems that have X86_CR4_PCIDE clear, or that have + * no INVPCID support at all. + */ + if (boot_cpu_has(X86_FEATURE_INVPCID)) + setup_force_cpu_cap(X86_FEATURE_INVPCID_SINGLE); + } else { + /* + * flush_tlb_all(), as currently implemented, won't work if + * PCID is on but PGE is not. Since that combination + * doesn't exist on real hardware, there's no reason to try + * to fully support it, but it's polite to avoid corrupting + * data if we're on an improperly configured VM. + */ + setup_clear_cpu_cap(X86_FEATURE_PCID); } -#endif } #ifdef CONFIG_X86_32 Patches currently in stable-queue which might be from dave.hansen(a)linux.intel.com are queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch queue-4.14/x86-mm-clarify-the-whole-asid-kernel-pcid-user-pcid-naming.patch queue-4.14/x86-mm-abstract-switching-cr3.patch queue-4.14/x86-mm-optimize-restore_cr3.patch queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch queue-4.14/x86-entry-align-entry-text-section-to-pmd-boundary.patch queue-4.14/x86-mm-64-make-a-full-pgd-entry-size-hole-in-the-memory-map.patch queue-4.14/x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch queue-4.14/x86-mm-pti-share-entry-text-pmd.patch queue-4.14/x86-ldt-make-the-ldt-mapping-ro.patch queue-4.14/x86-mm-dump_pagetables-check-user-space-page-table-for-wx-pages.patch queue-4.14/x86-pti-map-the-vsyscall-page-if-needed.patch queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch queue-4.14/x86-mm-dump_pagetables-allow-dumping-current-pagetables.patch queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch queue-4.14/x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch queue-4.14/x86-mm-use-invpcid-for-__native_flush_tlb_single.patch queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch queue-4.14/x86-mm-allow-flushing-for-future-asid-switches.patch queue-4.14/x86-mm-pti-add-kconfig.patch queue-4.14/x86-mm-pti-add-mapping-helper-functions.patch queue-4.14/x86-mm-pti-map-espfix-into-user-space.patch queue-4.14/x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch queue-4.14/x86-mm-pti-add-functions-to-clone-kernel-pmds.patch queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch queue-4.14/x86-events-intel-ds-map-debug-buffers-in-cpu_entry_area.patch queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch queue-4.14/x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch queue-4.14/x86-mm-pti-populate-user-pgd.patch queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch

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[Linux-stable-mirror] Patch "x86/mm: Use/Fix PCID to optimize user/kernel switches" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/mm: Use/Fix PCID to optimize user/kernel switches to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 6fd166aae78c0ab738d49bda653cbd9e3b1491cf Mon Sep 17 00:00:00 2001 From: Peter Zijlstra <peterz(a)infradead.org> Date: Mon, 4 Dec 2017 15:07:59 +0100 Subject: x86/mm: Use/Fix PCID to optimize user/kernel switches From: Peter Zijlstra <peterz(a)infradead.org> commit 6fd166aae78c0ab738d49bda653cbd9e3b1491cf upstream. We can use PCID to retain the TLBs across CR3 switches; including those now part of the user/kernel switch. This increases performance of kernel entry/exit at the cost of more expensive/complicated TLB flushing. Now that we have two address spaces, one for kernel and one for user space, we need two PCIDs per mm. We use the top PCID bit to indicate a user PCID (just like we use the PFN LSB for the PGD). Since we do TLB invalidation from kernel space, the existing code will only invalidate the kernel PCID, we augment that by marking the corresponding user PCID invalid, and upon switching back to userspace, use a flushing CR3 write for the switch. In order to access the user_pcid_flush_mask we use PER_CPU storage, which means the previously established SWAPGS vs CR3 ordering is now mandatory and required. Having to do this memory access does require additional registers, most sites have a functioning stack and we can spill one (RAX), sites without functional stack need to otherwise provide the second scratch register. Note: PCID is generally available on Intel Sandybridge and later CPUs. Note: Up until this point TLB flushing was broken in this series. Based-on-code-from: Dave Hansen <dave.hansen(a)linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Laight <David.Laight(a)aculab.com> Cc: Denys Vlasenko <dvlasenk(a)redhat.com> Cc: Eduardo Valentin <eduval(a)amazon.com> Cc: Greg KH <gregkh(a)linuxfoundation.org> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Will Deacon <will.deacon(a)arm.com> Cc: aliguori(a)amazon.com Cc: daniel.gruss(a)iaik.tugraz.at Cc: hughd(a)google.com Cc: keescook(a)google.com Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/entry/calling.h | 72 ++++++++++++++++++---- arch/x86/entry/entry_64.S | 9 +- arch/x86/entry/entry_64_compat.S | 4 - arch/x86/include/asm/processor-flags.h | 5 + arch/x86/include/asm/tlbflush.h | 91 ++++++++++++++++++++++++---- arch/x86/include/uapi/asm/processor-flags.h | 7 +- arch/x86/kernel/asm-offsets.c | 4 + arch/x86/mm/init.c | 2 arch/x86/mm/tlb.c | 1 9 files changed, 162 insertions(+), 33 deletions(-) --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -3,6 +3,9 @@ #include <asm/unwind_hints.h> #include <asm/cpufeatures.h> #include <asm/page_types.h> +#include <asm/percpu.h> +#include <asm/asm-offsets.h> +#include <asm/processor-flags.h> /* @@ -191,17 +194,21 @@ For 32-bit we have the following convent #ifdef CONFIG_PAGE_TABLE_ISOLATION -/* PAGE_TABLE_ISOLATION PGDs are 8k. Flip bit 12 to switch between the two halves: */ -#define PTI_SWITCH_MASK (1<<PAGE_SHIFT) +/* + * PAGE_TABLE_ISOLATION PGDs are 8k. Flip bit 12 to switch between the two + * halves: + */ +#define PTI_SWITCH_PGTABLES_MASK (1<<PAGE_SHIFT) +#define PTI_SWITCH_MASK (PTI_SWITCH_PGTABLES_MASK|(1<<X86_CR3_PTI_SWITCH_BIT)) -.macro ADJUST_KERNEL_CR3 reg:req - /* Clear "PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */ - andq $(~PTI_SWITCH_MASK), \reg +.macro SET_NOFLUSH_BIT reg:req + bts $X86_CR3_PCID_NOFLUSH_BIT, \reg .endm -.macro ADJUST_USER_CR3 reg:req - /* Move CR3 up a page to the user page tables: */ - orq $(PTI_SWITCH_MASK), \reg +.macro ADJUST_KERNEL_CR3 reg:req + ALTERNATIVE "", "SET_NOFLUSH_BIT \reg", X86_FEATURE_PCID + /* Clear PCID and "PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */ + andq $(~PTI_SWITCH_MASK), \reg .endm .macro SWITCH_TO_KERNEL_CR3 scratch_reg:req @@ -212,21 +219,58 @@ For 32-bit we have the following convent .Lend_\@: .endm -.macro SWITCH_TO_USER_CR3 scratch_reg:req +#define THIS_CPU_user_pcid_flush_mask \ + PER_CPU_VAR(cpu_tlbstate) + TLB_STATE_user_pcid_flush_mask + +.macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI mov %cr3, \scratch_reg - ADJUST_USER_CR3 \scratch_reg + + ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID + + /* + * Test if the ASID needs a flush. + */ + movq \scratch_reg, \scratch_reg2 + andq $(0x7FF), \scratch_reg /* mask ASID */ + bt \scratch_reg, THIS_CPU_user_pcid_flush_mask + jnc .Lnoflush_\@ + + /* Flush needed, clear the bit */ + btr \scratch_reg, THIS_CPU_user_pcid_flush_mask + movq \scratch_reg2, \scratch_reg + jmp .Lwrcr3_\@ + +.Lnoflush_\@: + movq \scratch_reg2, \scratch_reg + SET_NOFLUSH_BIT \scratch_reg + +.Lwrcr3_\@: + /* Flip the PGD and ASID to the user version */ + orq $(PTI_SWITCH_MASK), \scratch_reg mov \scratch_reg, %cr3 .Lend_\@: .endm +.macro SWITCH_TO_USER_CR3_STACK scratch_reg:req + pushq %rax + SWITCH_TO_USER_CR3_NOSTACK scratch_reg=\scratch_reg scratch_reg2=%rax + popq %rax +.endm + .macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req ALTERNATIVE "jmp .Ldone_\@", "", X86_FEATURE_PTI movq %cr3, \scratch_reg movq \scratch_reg, \save_reg /* - * Is the switch bit zero? This means the address is - * up in real PAGE_TABLE_ISOLATION patches in a moment. + * Is the "switch mask" all zero? That means that both of + * these are zero: + * + * 1. The user/kernel PCID bit, and + * 2. The user/kernel "bit" that points CR3 to the + * bottom half of the 8k PGD + * + * That indicates a kernel CR3 value, not a user CR3. */ testq $(PTI_SWITCH_MASK), \scratch_reg jz .Ldone_\@ @@ -251,7 +295,9 @@ For 32-bit we have the following convent .macro SWITCH_TO_KERNEL_CR3 scratch_reg:req .endm -.macro SWITCH_TO_USER_CR3 scratch_reg:req +.macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req +.endm +.macro SWITCH_TO_USER_CR3_STACK scratch_reg:req .endm .macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req .endm --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -23,7 +23,6 @@ #include <asm/segment.h> #include <asm/cache.h> #include <asm/errno.h> -#include "calling.h" #include <asm/asm-offsets.h> #include <asm/msr.h> #include <asm/unistd.h> @@ -40,6 +39,8 @@ #include <asm/frame.h> #include <linux/err.h> +#include "calling.h" + .code64 .section .entry.text, "ax" @@ -406,7 +407,7 @@ syscall_return_via_sysret: * We are on the trampoline stack. All regs except RDI are live. * We can do future final exit work right here. */ - SWITCH_TO_USER_CR3 scratch_reg=%rdi + SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi popq %rdi popq %rsp @@ -744,7 +745,7 @@ GLOBAL(swapgs_restore_regs_and_return_to * We can do future final exit work right here. */ - SWITCH_TO_USER_CR3 scratch_reg=%rdi + SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi /* Restore RDI. */ popq %rdi @@ -857,7 +858,7 @@ native_irq_return_ldt: */ orq PER_CPU_VAR(espfix_stack), %rax - SWITCH_TO_USER_CR3 scratch_reg=%rdi /* to user CR3 */ + SWITCH_TO_USER_CR3_STACK scratch_reg=%rdi SWAPGS /* to user GS */ popq %rdi /* Restore user RDI */ --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -275,9 +275,9 @@ sysret32_from_system_call: * switch until after after the last reference to the process * stack. * - * %r8 is zeroed before the sysret, thus safe to clobber. + * %r8/%r9 are zeroed before the sysret, thus safe to clobber. */ - SWITCH_TO_USER_CR3 scratch_reg=%r8 + SWITCH_TO_USER_CR3_NOSTACK scratch_reg=%r8 scratch_reg2=%r9 xorq %r8, %r8 xorq %r9, %r9 --- a/arch/x86/include/asm/processor-flags.h +++ b/arch/x86/include/asm/processor-flags.h @@ -38,6 +38,11 @@ #define CR3_ADDR_MASK __sme_clr(0x7FFFFFFFFFFFF000ull) #define CR3_PCID_MASK 0xFFFull #define CR3_NOFLUSH BIT_ULL(63) + +#ifdef CONFIG_PAGE_TABLE_ISOLATION +# define X86_CR3_PTI_SWITCH_BIT 11 +#endif + #else /* * CR3_ADDR_MASK needs at least bits 31:5 set on PAE systems, and we save --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -10,6 +10,8 @@ #include <asm/special_insns.h> #include <asm/smp.h> #include <asm/invpcid.h> +#include <asm/pti.h> +#include <asm/processor-flags.h> static inline u64 inc_mm_tlb_gen(struct mm_struct *mm) { @@ -24,24 +26,54 @@ static inline u64 inc_mm_tlb_gen(struct /* There are 12 bits of space for ASIDS in CR3 */ #define CR3_HW_ASID_BITS 12 + /* * When enabled, PAGE_TABLE_ISOLATION consumes a single bit for * user/kernel switches */ -#define PTI_CONSUMED_ASID_BITS 0 +#ifdef CONFIG_PAGE_TABLE_ISOLATION +# define PTI_CONSUMED_PCID_BITS 1 +#else +# define PTI_CONSUMED_PCID_BITS 0 +#endif + +#define CR3_AVAIL_PCID_BITS (X86_CR3_PCID_BITS - PTI_CONSUMED_PCID_BITS) -#define CR3_AVAIL_ASID_BITS (CR3_HW_ASID_BITS - PTI_CONSUMED_ASID_BITS) /* * ASIDs are zero-based: 0->MAX_AVAIL_ASID are valid. -1 below to account * for them being zero-based. Another -1 is because ASID 0 is reserved for * use by non-PCID-aware users. */ -#define MAX_ASID_AVAILABLE ((1 << CR3_AVAIL_ASID_BITS) - 2) +#define MAX_ASID_AVAILABLE ((1 << CR3_AVAIL_PCID_BITS) - 2) + +/* + * 6 because 6 should be plenty and struct tlb_state will fit in two cache + * lines. + */ +#define TLB_NR_DYN_ASIDS 6 static inline u16 kern_pcid(u16 asid) { VM_WARN_ON_ONCE(asid > MAX_ASID_AVAILABLE); + +#ifdef CONFIG_PAGE_TABLE_ISOLATION /* + * Make sure that the dynamic ASID space does not confict with the + * bit we are using to switch between user and kernel ASIDs. + */ + BUILD_BUG_ON(TLB_NR_DYN_ASIDS >= (1 << X86_CR3_PTI_SWITCH_BIT)); + + /* + * The ASID being passed in here should have respected the + * MAX_ASID_AVAILABLE and thus never have the switch bit set. + */ + VM_WARN_ON_ONCE(asid & (1 << X86_CR3_PTI_SWITCH_BIT)); +#endif + /* + * The dynamically-assigned ASIDs that get passed in are small + * (<TLB_NR_DYN_ASIDS). They never have the high switch bit set, + * so do not bother to clear it. + * * If PCID is on, ASID-aware code paths put the ASID+1 into the * PCID bits. This serves two purposes. It prevents a nasty * situation in which PCID-unaware code saves CR3, loads some other @@ -95,12 +127,6 @@ static inline bool tlb_defer_switch_to_i return !static_cpu_has(X86_FEATURE_PCID); } -/* - * 6 because 6 should be plenty and struct tlb_state will fit in - * two cache lines. - */ -#define TLB_NR_DYN_ASIDS 6 - struct tlb_context { u64 ctx_id; u64 tlb_gen; @@ -146,6 +172,13 @@ struct tlb_state { bool invalidate_other; /* + * Mask that contains TLB_NR_DYN_ASIDS+1 bits to indicate + * the corresponding user PCID needs a flush next time we + * switch to it; see SWITCH_TO_USER_CR3. + */ + unsigned short user_pcid_flush_mask; + + /* * Access to this CR4 shadow and to H/W CR4 is protected by * disabling interrupts when modifying either one. */ @@ -250,14 +283,41 @@ static inline void cr4_set_bits_and_upda extern void initialize_tlbstate_and_flush(void); /* + * Given an ASID, flush the corresponding user ASID. We can delay this + * until the next time we switch to it. + * + * See SWITCH_TO_USER_CR3. + */ +static inline void invalidate_user_asid(u16 asid) +{ + /* There is no user ASID if address space separation is off */ + if (!IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION)) + return; + + /* + * We only have a single ASID if PCID is off and the CR3 + * write will have flushed it. + */ + if (!cpu_feature_enabled(X86_FEATURE_PCID)) + return; + + if (!static_cpu_has(X86_FEATURE_PTI)) + return; + + __set_bit(kern_pcid(asid), + (unsigned long *)this_cpu_ptr(&cpu_tlbstate.user_pcid_flush_mask)); +} + +/* * flush the entire current user mapping */ static inline void __native_flush_tlb(void) { + invalidate_user_asid(this_cpu_read(cpu_tlbstate.loaded_mm_asid)); /* - * If current->mm == NULL then we borrow a mm which may change during a - * task switch and therefore we must not be preempted while we write CR3 - * back: + * If current->mm == NULL then we borrow a mm which may change + * during a task switch and therefore we must not be preempted + * while we write CR3 back: */ preempt_disable(); native_write_cr3(__native_read_cr3()); @@ -301,7 +361,14 @@ static inline void __native_flush_tlb_gl */ static inline void __native_flush_tlb_single(unsigned long addr) { + u32 loaded_mm_asid = this_cpu_read(cpu_tlbstate.loaded_mm_asid); + asm volatile("invlpg (%0)" ::"r" (addr) : "memory"); + + if (!static_cpu_has(X86_FEATURE_PTI)) + return; + + invalidate_user_asid(loaded_mm_asid); } /* --- a/arch/x86/include/uapi/asm/processor-flags.h +++ b/arch/x86/include/uapi/asm/processor-flags.h @@ -78,7 +78,12 @@ #define X86_CR3_PWT _BITUL(X86_CR3_PWT_BIT) #define X86_CR3_PCD_BIT 4 /* Page Cache Disable */ #define X86_CR3_PCD _BITUL(X86_CR3_PCD_BIT) -#define X86_CR3_PCID_MASK _AC(0x00000fff,UL) /* PCID Mask */ + +#define X86_CR3_PCID_BITS 12 +#define X86_CR3_PCID_MASK (_AC((1UL << X86_CR3_PCID_BITS) - 1, UL)) + +#define X86_CR3_PCID_NOFLUSH_BIT 63 /* Preserve old PCID */ +#define X86_CR3_PCID_NOFLUSH _BITULL(X86_CR3_PCID_NOFLUSH_BIT) /* * Intel CPU features in CR4 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -17,6 +17,7 @@ #include <asm/sigframe.h> #include <asm/bootparam.h> #include <asm/suspend.h> +#include <asm/tlbflush.h> #ifdef CONFIG_XEN #include <xen/interface/xen.h> @@ -94,6 +95,9 @@ void common(void) { BLANK(); DEFINE(PTREGS_SIZE, sizeof(struct pt_regs)); + /* TLB state for the entry code */ + OFFSET(TLB_STATE_user_pcid_flush_mask, tlb_state, user_pcid_flush_mask); + /* Layout info for cpu_entry_area */ OFFSET(CPU_ENTRY_AREA_tss, cpu_entry_area, tss); OFFSET(CPU_ENTRY_AREA_entry_trampoline, cpu_entry_area, entry_trampoline); --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -855,7 +855,7 @@ void __init zone_sizes_init(void) free_area_init_nodes(max_zone_pfns); } -DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = { +__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = { .loaded_mm = &init_mm, .next_asid = 1, .cr4 = ~0UL, /* fail hard if we screw up cr4 shadow initialization */ --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -105,6 +105,7 @@ static void load_new_mm_cr3(pgd_t *pgdir unsigned long new_mm_cr3; if (need_flush) { + invalidate_user_asid(new_asid); new_mm_cr3 = build_cr3(pgdir, new_asid); } else { new_mm_cr3 = build_cr3_noflush(pgdir, new_asid); Patches currently in stable-queue which might be from peterz(a)infradead.org are queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch queue-4.14/x86-mm-clarify-the-whole-asid-kernel-pcid-user-pcid-naming.patch queue-4.14/x86-mm-abstract-switching-cr3.patch queue-4.14/x86-mm-optimize-restore_cr3.patch queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch queue-4.14/x86-entry-align-entry-text-section-to-pmd-boundary.patch queue-4.14/x86-mm-64-make-a-full-pgd-entry-size-hole-in-the-memory-map.patch queue-4.14/x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch queue-4.14/x86-mm-pti-share-entry-text-pmd.patch queue-4.14/x86-ldt-make-the-ldt-mapping-ro.patch queue-4.14/x86-mm-dump_pagetables-check-user-space-page-table-for-wx-pages.patch queue-4.14/x86-pti-map-the-vsyscall-page-if-needed.patch queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch queue-4.14/x86-mm-dump_pagetables-allow-dumping-current-pagetables.patch queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch queue-4.14/x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch queue-4.14/x86-mm-use-invpcid-for-__native_flush_tlb_single.patch queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch queue-4.14/x86-mm-allow-flushing-for-future-asid-switches.patch queue-4.14/x86-mm-pti-add-kconfig.patch queue-4.14/x86-mm-pti-add-mapping-helper-functions.patch queue-4.14/x86-mm-pti-map-espfix-into-user-space.patch queue-4.14/x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch queue-4.14/x86-mm-pti-add-functions-to-clone-kernel-pmds.patch queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch queue-4.14/x86-events-intel-ds-map-debug-buffers-in-cpu_entry_area.patch queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch queue-4.14/x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch queue-4.14/x86-mm-pti-populate-user-pgd.patch queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch

6 years, 6 months

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[Linux-stable-mirror] Patch "x86/mm/pti: Share entry text PMD" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/mm/pti: Share entry text PMD to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-mm-pti-share-entry-text-pmd.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 6dc72c3cbca0580642808d677181cad4c6433893 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner <tglx(a)linutronix.de> Date: Mon, 4 Dec 2017 15:07:47 +0100 Subject: x86/mm/pti: Share entry text PMD From: Thomas Gleixner <tglx(a)linutronix.de> commit 6dc72c3cbca0580642808d677181cad4c6433893 upstream. Share the entry text PMD of the kernel mapping with the user space mapping. If large pages are enabled this is a single PMD entry and at the point where it is copied into the user page table the RW bit has not been cleared yet. Clear it right away so the user space visible map becomes RX. Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Laight <David.Laight(a)aculab.com> Cc: Denys Vlasenko <dvlasenk(a)redhat.com> Cc: Eduardo Valentin <eduval(a)amazon.com> Cc: Greg KH <gregkh(a)linuxfoundation.org> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Will Deacon <will.deacon(a)arm.com> Cc: aliguori(a)amazon.com Cc: daniel.gruss(a)iaik.tugraz.at Cc: hughd(a)google.com Cc: keescook(a)google.com Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/mm/pti.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -288,6 +288,15 @@ static void __init pti_clone_user_shared } /* + * Clone the populated PMDs of the entry and irqentry text and force it RO. + */ +static void __init pti_clone_entry_text(void) +{ + pti_clone_pmds((unsigned long) __entry_text_start, + (unsigned long) __irqentry_text_end, _PAGE_RW); +} + +/* * Initialize kernel page table isolation */ void __init pti_init(void) @@ -298,4 +307,5 @@ void __init pti_init(void) pr_info("enabled\n"); pti_clone_user_shared(); + pti_clone_entry_text(); } Patches currently in stable-queue which might be from tglx(a)linutronix.de are queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch queue-4.14/x86-mm-clarify-the-whole-asid-kernel-pcid-user-pcid-naming.patch queue-4.14/x86-mm-abstract-switching-cr3.patch queue-4.14/x86-mm-optimize-restore_cr3.patch queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch queue-4.14/x86-entry-align-entry-text-section-to-pmd-boundary.patch queue-4.14/x86-mm-64-make-a-full-pgd-entry-size-hole-in-the-memory-map.patch queue-4.14/x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch queue-4.14/x86-mm-pti-share-entry-text-pmd.patch queue-4.14/x86-ldt-make-the-ldt-mapping-ro.patch queue-4.14/x86-mm-dump_pagetables-check-user-space-page-table-for-wx-pages.patch queue-4.14/x86-pti-map-the-vsyscall-page-if-needed.patch queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch queue-4.14/x86-mm-dump_pagetables-allow-dumping-current-pagetables.patch queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch queue-4.14/x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch queue-4.14/x86-mm-use-invpcid-for-__native_flush_tlb_single.patch queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch queue-4.14/x86-mm-allow-flushing-for-future-asid-switches.patch queue-4.14/x86-mm-pti-add-kconfig.patch queue-4.14/x86-mm-pti-add-mapping-helper-functions.patch queue-4.14/x86-mm-pti-map-espfix-into-user-space.patch queue-4.14/x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch queue-4.14/x86-mm-pti-add-functions-to-clone-kernel-pmds.patch queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch queue-4.14/x86-events-intel-ds-map-debug-buffers-in-cpu_entry_area.patch queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch queue-4.14/x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch queue-4.14/x86-mm-pti-populate-user-pgd.patch queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch

6 years, 6 months

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[Linux-stable-mirror] Patch "x86/mm/pti: Share cpu_entry_area with user space page tables" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/mm/pti: Share cpu_entry_area with user space page tables to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From f7cfbee91559ca7e3e961a00ffac921208a115ad Mon Sep 17 00:00:00 2001 From: Andy Lutomirski <luto(a)kernel.org> Date: Mon, 4 Dec 2017 15:07:45 +0100 Subject: x86/mm/pti: Share cpu_entry_area with user space page tables From: Andy Lutomirski <luto(a)kernel.org> commit f7cfbee91559ca7e3e961a00ffac921208a115ad upstream. Share the cpu entry area so the user space and kernel space page tables have the same P4D page. Signed-off-by: Andy Lutomirski <luto(a)kernel.org> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Laight <David.Laight(a)aculab.com> Cc: Denys Vlasenko <dvlasenk(a)redhat.com> Cc: Eduardo Valentin <eduval(a)amazon.com> Cc: Greg KH <gregkh(a)linuxfoundation.org> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Will Deacon <will.deacon(a)arm.com> Cc: aliguori(a)amazon.com Cc: daniel.gruss(a)iaik.tugraz.at Cc: hughd(a)google.com Cc: keescook(a)google.com Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/mm/pti.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -265,6 +265,29 @@ pti_clone_pmds(unsigned long start, unsi } /* + * Clone a single p4d (i.e. a top-level entry on 4-level systems and a + * next-level entry on 5-level systems. + */ +static void __init pti_clone_p4d(unsigned long addr) +{ + p4d_t *kernel_p4d, *user_p4d; + pgd_t *kernel_pgd; + + user_p4d = pti_user_pagetable_walk_p4d(addr); + kernel_pgd = pgd_offset_k(addr); + kernel_p4d = p4d_offset(kernel_pgd, addr); + *user_p4d = *kernel_p4d; +} + +/* + * Clone the CPU_ENTRY_AREA into the user space visible page table. + */ +static void __init pti_clone_user_shared(void) +{ + pti_clone_p4d(CPU_ENTRY_AREA_BASE); +} + +/* * Initialize kernel page table isolation */ void __init pti_init(void) @@ -273,4 +296,6 @@ void __init pti_init(void) return; pr_info("enabled\n"); + + pti_clone_user_shared(); } Patches currently in stable-queue which might be from luto(a)kernel.org are queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch queue-4.14/x86-mm-clarify-the-whole-asid-kernel-pcid-user-pcid-naming.patch queue-4.14/x86-mm-abstract-switching-cr3.patch queue-4.14/x86-mm-optimize-restore_cr3.patch queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch queue-4.14/x86-entry-align-entry-text-section-to-pmd-boundary.patch queue-4.14/x86-mm-64-make-a-full-pgd-entry-size-hole-in-the-memory-map.patch queue-4.14/x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch queue-4.14/x86-mm-pti-share-entry-text-pmd.patch queue-4.14/x86-ldt-make-the-ldt-mapping-ro.patch queue-4.14/x86-mm-dump_pagetables-check-user-space-page-table-for-wx-pages.patch queue-4.14/x86-pti-map-the-vsyscall-page-if-needed.patch queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch queue-4.14/x86-mm-dump_pagetables-allow-dumping-current-pagetables.patch queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch queue-4.14/x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch queue-4.14/x86-mm-use-invpcid-for-__native_flush_tlb_single.patch queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch queue-4.14/x86-mm-allow-flushing-for-future-asid-switches.patch queue-4.14/x86-mm-pti-add-kconfig.patch queue-4.14/x86-mm-pti-add-mapping-helper-functions.patch queue-4.14/x86-mm-pti-map-espfix-into-user-space.patch queue-4.14/x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch queue-4.14/x86-mm-pti-add-functions-to-clone-kernel-pmds.patch queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch queue-4.14/x86-events-intel-ds-map-debug-buffers-in-cpu_entry_area.patch queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch queue-4.14/x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch queue-4.14/x86-mm-pti-populate-user-pgd.patch queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch

6 years, 6 months

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[Linux-stable-mirror] Patch "x86/mm/pti: Prepare the x86/entry assembly code for entry/exit CR3 switching" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/mm/pti: Prepare the x86/entry assembly code for entry/exit CR3 switching to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 8a09317b895f073977346779df52f67c1056d81d Mon Sep 17 00:00:00 2001 From: Dave Hansen <dave.hansen(a)linux.intel.com> Date: Mon, 4 Dec 2017 15:07:35 +0100 Subject: x86/mm/pti: Prepare the x86/entry assembly code for entry/exit CR3 switching From: Dave Hansen <dave.hansen(a)linux.intel.com> commit 8a09317b895f073977346779df52f67c1056d81d upstream. PAGE_TABLE_ISOLATION needs to switch to a different CR3 value when it enters the kernel and switch back when it exits. This essentially needs to be done before leaving assembly code. This is extra challenging because the switching context is tricky: the registers that can be clobbered can vary. It is also hard to store things on the stack because there is an established ABI (ptregs) or the stack is entirely unsafe to use. Establish a set of macros that allow changing to the user and kernel CR3 values. Interactions with SWAPGS: Previous versions of the PAGE_TABLE_ISOLATION code relied on having per-CPU scratch space to save/restore a register that can be used for the CR3 MOV. The %GS register is used to index into our per-CPU space, so SWAPGS *had* to be done before the CR3 switch. That scratch space is gone now, but the semantic that SWAPGS must be done before the CR3 MOV is retained. This is good to keep because it is not that hard to do and it allows to do things like add per-CPU debugging information. What this does in the NMI code is worth pointing out. NMIs can interrupt *any* context and they can also be nested with NMIs interrupting other NMIs. The comments below ".Lnmi_from_kernel" explain the format of the stack during this situation. Changing the format of this stack is hard. Instead of storing the old CR3 value on the stack, this depends on the *regular* register save/restore mechanism and then uses %r14 to keep CR3 during the NMI. It is callee-saved and will not be clobbered by the C NMI handlers that get called. [ PeterZ: ESPFIX optimization ] Based-on-code-from: Andy Lutomirski <luto(a)kernel.org> Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Borislav Petkov <bp(a)suse.de> Reviewed-by: Thomas Gleixner <tglx(a)linutronix.de> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: David Laight <David.Laight(a)aculab.com> Cc: Denys Vlasenko <dvlasenk(a)redhat.com> Cc: Eduardo Valentin <eduval(a)amazon.com> Cc: Greg KH <gregkh(a)linuxfoundation.org> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Juergen Gross <jgross(a)suse.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Will Deacon <will.deacon(a)arm.com> Cc: aliguori(a)amazon.com Cc: daniel.gruss(a)iaik.tugraz.at Cc: hughd(a)google.com Cc: keescook(a)google.com Cc: linux-mm(a)kvack.org Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/entry/calling.h | 66 +++++++++++++++++++++++++++++++++++++++ arch/x86/entry/entry_64.S | 45 +++++++++++++++++++++++--- arch/x86/entry/entry_64_compat.S | 24 +++++++++++++- 3 files changed, 128 insertions(+), 7 deletions(-) --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -1,6 +1,8 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include <linux/jump_label.h> #include <asm/unwind_hints.h> +#include <asm/cpufeatures.h> +#include <asm/page_types.h> /* @@ -187,6 +189,70 @@ For 32-bit we have the following convent #endif .endm +#ifdef CONFIG_PAGE_TABLE_ISOLATION + +/* PAGE_TABLE_ISOLATION PGDs are 8k. Flip bit 12 to switch between the two halves: */ +#define PTI_SWITCH_MASK (1<<PAGE_SHIFT) + +.macro ADJUST_KERNEL_CR3 reg:req + /* Clear "PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */ + andq $(~PTI_SWITCH_MASK), \reg +.endm + +.macro ADJUST_USER_CR3 reg:req + /* Move CR3 up a page to the user page tables: */ + orq $(PTI_SWITCH_MASK), \reg +.endm + +.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req + mov %cr3, \scratch_reg + ADJUST_KERNEL_CR3 \scratch_reg + mov \scratch_reg, %cr3 +.endm + +.macro SWITCH_TO_USER_CR3 scratch_reg:req + mov %cr3, \scratch_reg + ADJUST_USER_CR3 \scratch_reg + mov \scratch_reg, %cr3 +.endm + +.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req + movq %cr3, \scratch_reg + movq \scratch_reg, \save_reg + /* + * Is the switch bit zero? This means the address is + * up in real PAGE_TABLE_ISOLATION patches in a moment. + */ + testq $(PTI_SWITCH_MASK), \scratch_reg + jz .Ldone_\@ + + ADJUST_KERNEL_CR3 \scratch_reg + movq \scratch_reg, %cr3 + +.Ldone_\@: +.endm + +.macro RESTORE_CR3 save_reg:req + /* + * The CR3 write could be avoided when not changing its value, + * but would require a CR3 read *and* a scratch register. + */ + movq \save_reg, %cr3 +.endm + +#else /* CONFIG_PAGE_TABLE_ISOLATION=n: */ + +.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req +.endm +.macro SWITCH_TO_USER_CR3 scratch_reg:req +.endm +.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req +.endm +.macro RESTORE_CR3 save_reg:req +.endm + +#endif + #endif /* CONFIG_X86_64 */ /* --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -164,6 +164,9 @@ ENTRY(entry_SYSCALL_64_trampoline) /* Stash the user RSP. */ movq %rsp, RSP_SCRATCH + /* Note: using %rsp as a scratch reg. */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp + /* Load the top of the task stack into RSP */ movq CPU_ENTRY_AREA_tss + TSS_sp1 + CPU_ENTRY_AREA, %rsp @@ -203,6 +206,10 @@ ENTRY(entry_SYSCALL_64) */ swapgs + /* + * This path is not taken when PAGE_TABLE_ISOLATION is disabled so it + * is not required to switch CR3. + */ movq %rsp, PER_CPU_VAR(rsp_scratch) movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp @@ -399,6 +406,7 @@ syscall_return_via_sysret: * We are on the trampoline stack. All regs except RDI are live. * We can do future final exit work right here. */ + SWITCH_TO_USER_CR3 scratch_reg=%rdi popq %rdi popq %rsp @@ -736,6 +744,8 @@ GLOBAL(swapgs_restore_regs_and_return_to * We can do future final exit work right here. */ + SWITCH_TO_USER_CR3 scratch_reg=%rdi + /* Restore RDI. */ popq %rdi SWAPGS @@ -818,7 +828,9 @@ native_irq_return_ldt: */ pushq %rdi /* Stash user RDI */ - SWAPGS + SWAPGS /* to kernel GS */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi /* to kernel CR3 */ + movq PER_CPU_VAR(espfix_waddr), %rdi movq %rax, (0*8)(%rdi) /* user RAX */ movq (1*8)(%rsp), %rax /* user RIP */ @@ -834,7 +846,6 @@ native_irq_return_ldt: /* Now RAX == RSP. */ andl $0xffff0000, %eax /* RAX = (RSP & 0xffff0000) */ - popq %rdi /* Restore user RDI */ /* * espfix_stack[31:16] == 0. The page tables are set up such that @@ -845,7 +856,11 @@ native_irq_return_ldt: * still points to an RO alias of the ESPFIX stack. */ orq PER_CPU_VAR(espfix_stack), %rax - SWAPGS + + SWITCH_TO_USER_CR3 scratch_reg=%rdi /* to user CR3 */ + SWAPGS /* to user GS */ + popq %rdi /* Restore user RDI */ + movq %rax, %rsp UNWIND_HINT_IRET_REGS offset=8 @@ -945,6 +960,8 @@ ENTRY(switch_to_thread_stack) UNWIND_HINT_FUNC pushq %rdi + /* Need to switch before accessing the thread stack. */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi movq %rsp, %rdi movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp UNWIND_HINT sp_offset=16 sp_reg=ORC_REG_DI @@ -1244,7 +1261,11 @@ ENTRY(paranoid_entry) js 1f /* negative -> in kernel */ SWAPGS xorl %ebx, %ebx -1: ret + +1: + SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg=%rax save_reg=%r14 + + ret END(paranoid_entry) /* @@ -1266,6 +1287,7 @@ ENTRY(paranoid_exit) testl %ebx, %ebx /* swapgs needed? */ jnz .Lparanoid_exit_no_swapgs TRACE_IRQS_IRETQ + RESTORE_CR3 save_reg=%r14 SWAPGS_UNSAFE_STACK jmp .Lparanoid_exit_restore .Lparanoid_exit_no_swapgs: @@ -1293,6 +1315,8 @@ ENTRY(error_entry) * from user mode due to an IRET fault. */ SWAPGS + /* We have user CR3. Change to kernel CR3. */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rax .Lerror_entry_from_usermode_after_swapgs: /* Put us onto the real thread stack. */ @@ -1339,6 +1363,7 @@ ENTRY(error_entry) * .Lgs_change's error handler with kernel gsbase. */ SWAPGS + SWITCH_TO_KERNEL_CR3 scratch_reg=%rax jmp .Lerror_entry_done .Lbstep_iret: @@ -1348,10 +1373,11 @@ ENTRY(error_entry) .Lerror_bad_iret: /* - * We came from an IRET to user mode, so we have user gsbase. - * Switch to kernel gsbase: + * We came from an IRET to user mode, so we have user + * gsbase and CR3. Switch to kernel gsbase and CR3: */ SWAPGS + SWITCH_TO_KERNEL_CR3 scratch_reg=%rax /* * Pretend that the exception came from user mode: set up pt_regs @@ -1383,6 +1409,10 @@ END(error_exit) /* * Runs on exception stack. Xen PV does not go through this path at all, * so we can use real assembly here. + * + * Registers: + * %r14: Used to save/restore the CR3 of the interrupted context + * when PAGE_TABLE_ISOLATION is in use. Do not clobber. */ ENTRY(nmi) UNWIND_HINT_IRET_REGS @@ -1446,6 +1476,7 @@ ENTRY(nmi) swapgs cld + SWITCH_TO_KERNEL_CR3 scratch_reg=%rdx movq %rsp, %rdx movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp UNWIND_HINT_IRET_REGS base=%rdx offset=8 @@ -1698,6 +1729,8 @@ end_repeat_nmi: movq $-1, %rsi call do_nmi + RESTORE_CR3 save_reg=%r14 + testl %ebx, %ebx /* swapgs needed? */ jnz nmi_restore nmi_swapgs: --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -49,6 +49,10 @@ ENTRY(entry_SYSENTER_compat) /* Interrupts are off on entry. */ SWAPGS + + /* We are about to clobber %rsp anyway, clobbering here is OK */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp + movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp /* @@ -216,6 +220,12 @@ GLOBAL(entry_SYSCALL_compat_after_hwfram pushq $0 /* pt_regs->r15 = 0 */ /* + * We just saved %rdi so it is safe to clobber. It is not + * preserved during the C calls inside TRACE_IRQS_OFF anyway. + */ + SWITCH_TO_KERNEL_CR3 scratch_reg=%rdi + + /* * User mode is traced as though IRQs are on, and SYSENTER * turned them off. */ @@ -256,10 +266,22 @@ sysret32_from_system_call: * when the system call started, which is already known to user * code. We zero R8-R10 to avoid info leaks. */ + movq RSP-ORIG_RAX(%rsp), %rsp + + /* + * The original userspace %rsp (RSP-ORIG_RAX(%rsp)) is stored + * on the process stack which is not mapped to userspace and + * not readable after we SWITCH_TO_USER_CR3. Delay the CR3 + * switch until after after the last reference to the process + * stack. + * + * %r8 is zeroed before the sysret, thus safe to clobber. + */ + SWITCH_TO_USER_CR3 scratch_reg=%r8 + xorq %r8, %r8 xorq %r9, %r9 xorq %r10, %r10 - movq RSP-ORIG_RAX(%rsp), %rsp swapgs sysretl END(entry_SYSCALL_compat) Patches currently in stable-queue which might be from dave.hansen(a)linux.intel.com are queue-4.14/x86-mm-pti-allow-nx-poison-to-be-set-in-p4d-pgd.patch queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch queue-4.14/x86-mm-clarify-the-whole-asid-kernel-pcid-user-pcid-naming.patch queue-4.14/x86-mm-abstract-switching-cr3.patch queue-4.14/x86-mm-optimize-restore_cr3.patch queue-4.14/x86-mm-pti-force-entry-through-trampoline-when-pti-active.patch queue-4.14/x86-entry-align-entry-text-section-to-pmd-boundary.patch queue-4.14/x86-mm-64-make-a-full-pgd-entry-size-hole-in-the-memory-map.patch queue-4.14/x86-cpu_entry_area-add-debugstore-entries-to-cpu_entry_area.patch queue-4.14/x86-mm-pti-share-entry-text-pmd.patch queue-4.14/x86-ldt-make-the-ldt-mapping-ro.patch queue-4.14/x86-mm-dump_pagetables-check-user-space-page-table-for-wx-pages.patch queue-4.14/x86-pti-map-the-vsyscall-page-if-needed.patch queue-4.14/x86-mm-pti-disable-global-pages-if-page_table_isolation-y.patch queue-4.14/x86-mm-dump_pagetables-allow-dumping-current-pagetables.patch queue-4.14/x86-mm-pti-add-infrastructure-for-page-table-isolation.patch queue-4.14/x86-cpufeatures-add-x86_bug_cpu_insecure.patch queue-4.14/x86-mm-use-fix-pcid-to-optimize-user-kernel-switches.patch queue-4.14/x86-mm-use-invpcid-for-__native_flush_tlb_single.patch queue-4.14/x86-mm-pti-prepare-the-x86-entry-assembly-code-for-entry-exit-cr3-switching.patch queue-4.14/x86-mm-allow-flushing-for-future-asid-switches.patch queue-4.14/x86-mm-pti-add-kconfig.patch queue-4.14/x86-mm-pti-add-mapping-helper-functions.patch queue-4.14/x86-mm-pti-map-espfix-into-user-space.patch queue-4.14/x86-mm-pti-share-cpu_entry_area-with-user-space-page-tables.patch queue-4.14/x86-mm-pti-add-functions-to-clone-kernel-pmds.patch queue-4.14/x86-pti-add-the-pti-cmdline-option-and-documentation.patch queue-4.14/x86-events-intel-ds-map-debug-buffers-in-cpu_entry_area.patch queue-4.14/x86-mm-pti-allocate-a-separate-user-pgd.patch queue-4.14/x86-pti-put-the-ldt-in-its-own-pgd-if-pti-is-on.patch queue-4.14/x86-mm-pti-populate-user-pgd.patch queue-4.14/x86-mm-dump_pagetables-add-page-table-directory-to-the-debugfs-vfs-hierarchy.patch

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Linux-stable-mirror December 2017