From: Mike Rapoport rppt@linux.ibm.com
On arm64, set_direct_map_*() functions may return 0 without actually changing the linear map. This behaviour can be controlled using kernel parameters, so we need a way to determine at runtime whether calls to set_direct_map_invalid_noflush() and set_direct_map_default_noflush() have any effect.
Extend set_memory API with can_set_direct_map() function that allows checking if calling set_direct_map_*() will actually change the page table, replace several occurrences of open coded checks in arm64 with the new function and provide a generic stub for architectures that always modify page tables upon calls to set_direct_map APIs.
Signed-off-by: Mike Rapoport rppt@linux.ibm.com --- arch/arm64/include/asm/Kbuild | 1 - arch/arm64/include/asm/cacheflush.h | 6 ------ arch/arm64/include/asm/set_memory.h | 17 +++++++++++++++++ arch/arm64/kernel/machine_kexec.c | 1 + arch/arm64/mm/mmu.c | 6 +++--- arch/arm64/mm/pageattr.c | 13 +++++++++---- include/linux/set_memory.h | 12 ++++++++++++ 7 files changed, 42 insertions(+), 14 deletions(-) create mode 100644 arch/arm64/include/asm/set_memory.h
diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild index ff9cbb631212..4306136ef329 100644 --- a/arch/arm64/include/asm/Kbuild +++ b/arch/arm64/include/asm/Kbuild @@ -4,5 +4,4 @@ generic-y += local64.h generic-y += mcs_spinlock.h generic-y += qrwlock.h generic-y += qspinlock.h -generic-y += set_memory.h generic-y += user.h diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h index d3598419a284..b1bdf83a73db 100644 --- a/arch/arm64/include/asm/cacheflush.h +++ b/arch/arm64/include/asm/cacheflush.h @@ -136,12 +136,6 @@ static __always_inline void __flush_icache_all(void) dsb(ish); }
-int set_memory_valid(unsigned long addr, int numpages, int enable); - -int set_direct_map_invalid_noflush(struct page *page, int numpages); -int set_direct_map_default_noflush(struct page *page, int numpages); -bool kernel_page_present(struct page *page); - #include <asm-generic/cacheflush.h>
#endif /* __ASM_CACHEFLUSH_H */ diff --git a/arch/arm64/include/asm/set_memory.h b/arch/arm64/include/asm/set_memory.h new file mode 100644 index 000000000000..ecb6b0f449ab --- /dev/null +++ b/arch/arm64/include/asm/set_memory.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef _ASM_ARM64_SET_MEMORY_H +#define _ASM_ARM64_SET_MEMORY_H + +#include <asm-generic/set_memory.h> + +bool can_set_direct_map(void); +#define can_set_direct_map can_set_direct_map + +int set_memory_valid(unsigned long addr, int numpages, int enable); + +int set_direct_map_invalid_noflush(struct page *page, int numpages); +int set_direct_map_default_noflush(struct page *page, int numpages); +bool kernel_page_present(struct page *page); + +#endif /* _ASM_ARM64_SET_MEMORY_H */ diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index a0b144cfaea7..0cbc50c4fa5a 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -11,6 +11,7 @@ #include <linux/kernel.h> #include <linux/kexec.h> #include <linux/page-flags.h> +#include <linux/set_memory.h> #include <linux/smp.h>
#include <asm/cacheflush.h> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 86be6d1a78ab..aa5ec08cb902 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -22,6 +22,7 @@ #include <linux/io.h> #include <linux/mm.h> #include <linux/vmalloc.h> +#include <linux/set_memory.h>
#include <asm/barrier.h> #include <asm/cputype.h> @@ -477,7 +478,7 @@ static void __init map_mem(pgd_t *pgdp) int flags = 0; u64 i;
- if (rodata_full || debug_pagealloc_enabled()) + if (can_set_direct_map()) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
/* @@ -1453,8 +1454,7 @@ int arch_add_memory(int nid, u64 start, u64 size, * KFENCE requires linear map to be mapped at page granularity, so that * it is possible to protect/unprotect single pages in the KFENCE pool. */ - if (rodata_full || debug_pagealloc_enabled() || - IS_ENABLED(CONFIG_KFENCE)) + if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
__create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index b53ef37bf95a..d505172265b0 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -19,6 +19,11 @@ struct page_change_data {
bool rodata_full __ro_after_init = IS_ENABLED(CONFIG_RODATA_FULL_DEFAULT_ENABLED);
+bool can_set_direct_map(void) +{ + return rodata_full || debug_pagealloc_enabled(); +} + static int change_page_range(pte_t *ptep, unsigned long addr, void *data) { struct page_change_data *cdata = data; @@ -156,7 +161,7 @@ int set_direct_map_invalid_noflush(struct page *page, int numpages) }; unsigned long size = PAGE_SIZE * numpages;
- if (!debug_pagealloc_enabled() && !rodata_full) + if (!can_set_direct_map()) return 0;
return apply_to_page_range(&init_mm, @@ -172,7 +177,7 @@ int set_direct_map_default_noflush(struct page *page, int numpages) }; unsigned long size = PAGE_SIZE * numpages;
- if (!debug_pagealloc_enabled() && !rodata_full) + if (!can_set_direct_map()) return 0;
return apply_to_page_range(&init_mm, @@ -183,7 +188,7 @@ int set_direct_map_default_noflush(struct page *page, int numpages) #ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { - if (!debug_pagealloc_enabled() && !rodata_full) + if (!can_set_direct_map()) return;
set_memory_valid((unsigned long)page_address(page), numpages, enable); @@ -208,7 +213,7 @@ bool kernel_page_present(struct page *page) pte_t *ptep; unsigned long addr = (unsigned long)page_address(page);
- if (!debug_pagealloc_enabled() && !rodata_full) + if (!can_set_direct_map()) return true;
pgdp = pgd_offset_k(addr); diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h index c650f82db813..7b4b6626032d 100644 --- a/include/linux/set_memory.h +++ b/include/linux/set_memory.h @@ -28,7 +28,19 @@ static inline bool kernel_page_present(struct page *page) { return true; } +#else /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */ +/* + * Some architectures, e.g. ARM64 can disable direct map modifications at + * boot time. Let them overrive this query. + */ +#ifndef can_set_direct_map +static inline bool can_set_direct_map(void) +{ + return true; +} +#define can_set_direct_map can_set_direct_map #endif +#endif /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */
#ifndef set_mce_nospec static inline int set_mce_nospec(unsigned long pfn, bool unmap)