This is a note to let you know that I've just added the patch titled

x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stack

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: x86-entry-rename-sysenter_stack-to-cpu_entry_area_entry_stack.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@vger.kernel.org know about it.

From 4fe2d8b11a370af286287a2661de9d4e6c9a145a Mon Sep 17 00:00:00 2001

From: Dave Hansen dave.hansen@linux.intel.com Date: Mon, 4 Dec 2017 17:25:07 -0800 Subject: x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stack

From: Dave Hansen dave.hansen@linux.intel.com

commit 4fe2d8b11a370af286287a2661de9d4e6c9a145a upstream.

If the kernel oopses while on the trampoline stack, it will print "<SYSENTER>" even if SYSENTER is not involved. That is rather confusing.

The "SYSENTER" stack is used for a lot more than SYSENTER now. Give it a better string to display in stack dumps, and rename the kernel code to match.

Also move the 32-bit code over to the new naming even though it still uses the entry stack only for SYSENTER.

Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Andy Lutomirski luto@kernel.org Cc: Borislav Petkov bp@alien8.de Cc: Borislav Petkov bp@suse.de Cc: Brian Gerst brgerst@gmail.com Cc: Denys Vlasenko dvlasenk@redhat.com Cc: H. Peter Anvin hpa@zytor.com Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Juergen Gross jgross@suse.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/x86/entry/entry_32.S | 12 ++++++------ arch/x86/entry/entry_64.S | 4 ++-- arch/x86/include/asm/fixmap.h | 8 ++++---- arch/x86/include/asm/processor.h | 6 +++--- arch/x86/include/asm/stacktrace.h | 4 ++-- arch/x86/kernel/asm-offsets.c | 4 ++-- arch/x86/kernel/asm-offsets_32.c | 2 +- arch/x86/kernel/cpu/common.c | 14 +++++++------- arch/x86/kernel/dumpstack.c | 10 +++++----- arch/x86/kernel/dumpstack_32.c | 6 +++--- arch/x86/kernel/dumpstack_64.c | 12 +++++++++--- 11 files changed, 44 insertions(+), 38 deletions(-)

--- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -942,9 +942,9 @@ ENTRY(debug)

/* Are we currently on the SYSENTER stack? */ movl PER_CPU_VAR(cpu_entry_area), %ecx - addl $CPU_ENTRY_AREA_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx - subl %eax, %ecx /* ecx = (end of SYSENTER_stack) - esp */ - cmpl $SIZEOF_SYSENTER_stack, %ecx + addl $CPU_ENTRY_AREA_entry_stack + SIZEOF_entry_stack, %ecx + subl %eax, %ecx /* ecx = (end of entry_stack) - esp */ + cmpl $SIZEOF_entry_stack, %ecx jb .Ldebug_from_sysenter_stack

TRACE_IRQS_OFF @@ -986,9 +986,9 @@ ENTRY(nmi)

/* Are we currently on the SYSENTER stack? */ movl PER_CPU_VAR(cpu_entry_area), %ecx - addl $CPU_ENTRY_AREA_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx - subl %eax, %ecx /* ecx = (end of SYSENTER_stack) - esp */ - cmpl $SIZEOF_SYSENTER_stack, %ecx + addl $CPU_ENTRY_AREA_entry_stack + SIZEOF_entry_stack, %ecx + subl %eax, %ecx /* ecx = (end of entry_stack) - esp */ + cmpl $SIZEOF_entry_stack, %ecx jb .Lnmi_from_sysenter_stack

/* Not on SYSENTER stack. */ --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -154,8 +154,8 @@ END(native_usergs_sysret64) _entry_trampoline - CPU_ENTRY_AREA_entry_trampoline(%rip)

/* The top word of the SYSENTER stack is hot and is usable as scratch space. */ -#define RSP_SCRATCH CPU_ENTRY_AREA_SYSENTER_stack + \ - SIZEOF_SYSENTER_stack - 8 + CPU_ENTRY_AREA +#define RSP_SCRATCH CPU_ENTRY_AREA_entry_stack + \ + SIZEOF_entry_stack - 8 + CPU_ENTRY_AREA

ENTRY(entry_SYSCALL_64_trampoline) UNWIND_HINT_EMPTY --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -56,10 +56,10 @@ struct cpu_entry_area { char gdt[PAGE_SIZE];

/* - * The GDT is just below SYSENTER_stack and thus serves (on x86_64) as + * The GDT is just below entry_stack and thus serves (on x86_64) as * a a read-only guard page. */ - struct SYSENTER_stack_page SYSENTER_stack_page; + struct entry_stack_page entry_stack_page;

/* * On x86_64, the TSS is mapped RO. On x86_32, it's mapped RW because @@ -250,9 +250,9 @@ static inline struct cpu_entry_area *get return (struct cpu_entry_area *)__fix_to_virt(__get_cpu_entry_area_page_index(cpu, 0)); }

-static inline struct SYSENTER_stack *cpu_SYSENTER_stack(int cpu) +static inline struct entry_stack *cpu_entry_stack(int cpu) { - return &get_cpu_entry_area(cpu)->SYSENTER_stack_page.stack; + return &get_cpu_entry_area(cpu)->entry_stack_page.stack; }

#endif /* !__ASSEMBLY__ */ --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -336,12 +336,12 @@ struct x86_hw_tss { #define IO_BITMAP_OFFSET (offsetof(struct tss_struct, io_bitmap) - offsetof(struct tss_struct, x86_tss)) #define INVALID_IO_BITMAP_OFFSET 0x8000

-struct SYSENTER_stack { +struct entry_stack { unsigned long words[64]; };

-struct SYSENTER_stack_page { - struct SYSENTER_stack stack; +struct entry_stack_page { + struct entry_stack stack; } __aligned(PAGE_SIZE);

struct tss_struct { --- a/arch/x86/include/asm/stacktrace.h +++ b/arch/x86/include/asm/stacktrace.h @@ -16,7 +16,7 @@ enum stack_type { STACK_TYPE_TASK, STACK_TYPE_IRQ, STACK_TYPE_SOFTIRQ, - STACK_TYPE_SYSENTER, + STACK_TYPE_ENTRY, STACK_TYPE_EXCEPTION, STACK_TYPE_EXCEPTION_LAST = STACK_TYPE_EXCEPTION + N_EXCEPTION_STACKS-1, }; @@ -29,7 +29,7 @@ struct stack_info { bool in_task_stack(unsigned long *stack, struct task_struct *task, struct stack_info *info);

-bool in_sysenter_stack(unsigned long *stack, struct stack_info *info); +bool in_entry_stack(unsigned long *stack, struct stack_info *info);

int get_stack_info(unsigned long *stack, struct task_struct *task, struct stack_info *info, unsigned long *visit_mask); --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -97,6 +97,6 @@ void common(void) { /* 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); - OFFSET(CPU_ENTRY_AREA_SYSENTER_stack, cpu_entry_area, SYSENTER_stack_page); - DEFINE(SIZEOF_SYSENTER_stack, sizeof(struct SYSENTER_stack)); + OFFSET(CPU_ENTRY_AREA_entry_stack, cpu_entry_area, entry_stack_page); + DEFINE(SIZEOF_entry_stack, sizeof(struct entry_stack)); } --- a/arch/x86/kernel/asm-offsets_32.c +++ b/arch/x86/kernel/asm-offsets_32.c @@ -48,7 +48,7 @@ void foo(void)

/* Offset from the sysenter stack to tss.sp0 */ DEFINE(TSS_sysenter_sp0, offsetof(struct cpu_entry_area, tss.x86_tss.sp0) - - offsetofend(struct cpu_entry_area, SYSENTER_stack_page.stack)); + offsetofend(struct cpu_entry_area, entry_stack_page.stack));

#ifdef CONFIG_CC_STACKPROTECTOR BLANK(); --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -487,8 +487,8 @@ static DEFINE_PER_CPU_PAGE_ALIGNED(char, [(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]); #endif

-static DEFINE_PER_CPU_PAGE_ALIGNED(struct SYSENTER_stack_page, - SYSENTER_stack_storage); +static DEFINE_PER_CPU_PAGE_ALIGNED(struct entry_stack_page, + entry_stack_storage);

static void __init set_percpu_fixmap_pages(int idx, void *ptr, int pages, pgprot_t prot) @@ -523,8 +523,8 @@ static void __init setup_cpu_entry_area( #endif

__set_fixmap(get_cpu_entry_area_index(cpu, gdt), get_cpu_gdt_paddr(cpu), gdt_prot); - set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu, SYSENTER_stack_page), - per_cpu_ptr(&SYSENTER_stack_storage, cpu), 1, + set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu, entry_stack_page), + per_cpu_ptr(&entry_stack_storage, cpu), 1, PAGE_KERNEL);

/* @@ -1323,7 +1323,7 @@ void enable_sep_cpu(void)

tss->x86_tss.ss1 = __KERNEL_CS; wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0); - wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_SYSENTER_stack(cpu) + 1), 0); + wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1), 0); wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);

put_cpu(); @@ -1440,7 +1440,7 @@ void syscall_init(void) * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit). */ wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS); - wrmsrl_safe(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_SYSENTER_stack(cpu) + 1)); + wrmsrl_safe(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1)); wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat); #else wrmsrl(MSR_CSTAR, (unsigned long)ignore_sysret); @@ -1655,7 +1655,7 @@ void cpu_init(void) */ set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); load_TR_desc(); - load_sp0((unsigned long)(cpu_SYSENTER_stack(cpu) + 1)); + load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1));

load_mm_ldt(&init_mm);

--- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -43,9 +43,9 @@ bool in_task_stack(unsigned long *stack, return true; }

-bool in_sysenter_stack(unsigned long *stack, struct stack_info *info) +bool in_entry_stack(unsigned long *stack, struct stack_info *info) { - struct SYSENTER_stack *ss = cpu_SYSENTER_stack(smp_processor_id()); + struct entry_stack *ss = cpu_entry_stack(smp_processor_id());

void *begin = ss; void *end = ss + 1; @@ -53,7 +53,7 @@ bool in_sysenter_stack(unsigned long *st if ((void *)stack < begin || (void *)stack >= end) return false;

- info->type = STACK_TYPE_SYSENTER; + info->type = STACK_TYPE_ENTRY; info->begin = begin; info->end = end; info->next_sp = NULL; @@ -111,13 +111,13 @@ void show_trace_log_lvl(struct task_stru * - task stack * - interrupt stack * - HW exception stacks (double fault, nmi, debug, mce) - * - SYSENTER stack + * - entry stack * * x86-32 can have up to four stacks: * - task stack * - softirq stack * - hardirq stack - * - SYSENTER stack + * - entry stack */ for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) { const char *stack_name; --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -26,8 +26,8 @@ const char *stack_type_name(enum stack_t if (type == STACK_TYPE_SOFTIRQ) return "SOFTIRQ";

- if (type == STACK_TYPE_SYSENTER) - return "SYSENTER"; + if (type == STACK_TYPE_ENTRY) + return "ENTRY_TRAMPOLINE";

return NULL; } @@ -96,7 +96,7 @@ int get_stack_info(unsigned long *stack, if (task != current) goto unknown;

- if (in_sysenter_stack(stack, info)) + if (in_entry_stack(stack, info)) goto recursion_check;

if (in_hardirq_stack(stack, info)) --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -37,8 +37,14 @@ const char *stack_type_name(enum stack_t if (type == STACK_TYPE_IRQ) return "IRQ";

- if (type == STACK_TYPE_SYSENTER) - return "SYSENTER"; + if (type == STACK_TYPE_ENTRY) { + /* + * On 64-bit, we have a generic entry stack that we + * use for all the kernel entry points, including + * SYSENTER. + */ + return "ENTRY_TRAMPOLINE"; + }

if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST) return exception_stack_names[type - STACK_TYPE_EXCEPTION]; @@ -118,7 +124,7 @@ int get_stack_info(unsigned long *stack, if (in_irq_stack(stack, info)) goto recursion_check;

- if (in_sysenter_stack(stack, info)) + if (in_entry_stack(stack, info)) goto recursion_check;

goto unknown;

Patches currently in stable-queue which might be from dave.hansen@linux.intel.com are

queue-4.14/x86-entry-rename-sysenter_stack-to-cpu_entry_area_entry_stack.patch queue-4.14/x86-mm-put-mmu-to-hardware-asid-translation-in-one-place.patch queue-4.14/x86-vsyscall-64-explicitly-set-_page_user-in-the-pagetable-hierarchy.patch queue-4.14/x86-uv-use-the-right-tlb-flush-api.patch queue-4.14/x86-mm-dump_pagetables-check-page_present-for-real.patch queue-4.14/x86-ldt-prevent-ldt-inheritance-on-exec.patch queue-4.14/x86-microcode-dont-abuse-the-tlb-flush-interface.patch queue-4.14/x86-doc-remove-obvious-weirdnesses-from-the-x86-mm-layout-documentation.patch queue-4.14/init-invoke-init_espfix_bsp-from-mm_init.patch queue-4.14/x86-cpu_entry_area-move-it-to-a-separate-unit.patch queue-4.14/x86-vsyscall-64-warn-and-fail-vsyscall-emulation-in-native-mode.patch queue-4.14/x86-mm-create-asm-invpcid.h.patch queue-4.14/x86-mm-remove-superfluous-barriers.patch queue-4.14/x86-ldt-rework-locking.patch queue-4.14/arch-mm-allow-arch_dup_mmap-to-fail.patch queue-4.14/x86-cpu_entry_area-move-it-out-of-the-fixmap.patch queue-4.14/x86-mm-remove-hard-coded-asid-limit-checks.patch queue-4.14/x86-kconfig-limit-nr_cpus-on-32-bit-to-a-sane-amount.patch queue-4.14/x86-mm-add-comments-to-clarify-which-tlb-flush-functions-are-supposed-to-flush-what.patch queue-4.14/x86-mm-move-the-cr3-construction-functions-to-tlbflush.h.patch queue-4.14/x86-mm-dump_pagetables-make-the-address-hints-correct-and-readable.patch queue-4.14/x86-insn-eval-add-utility-functions-to-get-segment-selector.patch queue-4.14/x86-mm-use-__flush_tlb_one-for-kernel-memory.patch queue-4.14/x86-mm-64-improve-the-memory-map-documentation.patch