在 2024/1/30 18:31, Mark Rutland 写道:
On Mon, Jan 29, 2024 at 09:46:51PM +0800, Tong Tiangen wrote:Currently, many scenarios that can tolerate memory errors when copying page have been supported in the kernel[1][2][3], all of which are implemented by copy_mc_[user]_highpage(). arm64 should also support this mechanism. Due to mte, arm64 needs to have its own copy_mc_[user]_highpage() architecture implementation, macros __HAVE_ARCH_COPY_MC_HIGHPAGE and __HAVE_ARCH_COPY_MC_USER_HIGHPAGE have been added to control it. Add new helper copy_mc_page() which provide a page copy implementation with machine check safe. The copy_mc_page() in copy_mc_page.S is largely borrows from copy_page() in copy_page.S and the main difference is copy_mc_page() add extable entry to every load/store insn to support machine check safe. Add new extable type EX_TYPE_COPY_MC_PAGE_ERR_ZERO which used in copy_mc_page(). [1]a873dfe1032a ("mm, hwpoison: try to recover from copy-on write faults") [2]5f2500b93cc9 ("mm/khugepaged: recover from poisoned anonymous memory") [3]6b970599e807 ("mm: hwpoison: support recovery from ksm_might_need_to_copy()") Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx> --- arch/arm64/include/asm/asm-extable.h | 15 ++++++ arch/arm64/include/asm/assembler.h | 4 ++ arch/arm64/include/asm/mte.h | 5 ++ arch/arm64/include/asm/page.h | 10 ++++ arch/arm64/lib/Makefile | 2 + arch/arm64/lib/copy_mc_page.S | 78 ++++++++++++++++++++++++++++ arch/arm64/lib/mte.S | 27 ++++++++++ arch/arm64/mm/copypage.c | 66 ++++++++++++++++++++--- arch/arm64/mm/extable.c | 7 +-- include/linux/highmem.h | 8 +++ 10 files changed, 213 insertions(+), 9 deletions(-) create mode 100644 arch/arm64/lib/copy_mc_page.S diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h index 980d1dd8e1a3..819044fefbe7 100644 --- a/arch/arm64/include/asm/asm-extable.h +++ b/arch/arm64/include/asm/asm-extable.h @@ -10,6 +10,7 @@ #define EX_TYPE_UACCESS_ERR_ZERO 2 #define EX_TYPE_KACCESS_ERR_ZERO 3 #define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 4 +#define EX_TYPE_COPY_MC_PAGE_ERR_ZERO 5/* Data fields for EX_TYPE_UACCESS_ERR_ZERO */#define EX_DATA_REG_ERR_SHIFT 0 @@ -51,6 +52,16 @@ #define _ASM_EXTABLE_UACCESS(insn, fixup) \ _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)+#define _ASM_EXTABLE_COPY_MC_PAGE_ERR_ZERO(insn, fixup, err, zero) \+ __ASM_EXTABLE_RAW(insn, fixup, \ + EX_TYPE_COPY_MC_PAGE_ERR_ZERO, \ + ( \ + EX_DATA_REG(ERR, err) | \ + EX_DATA_REG(ZERO, zero) \ + )) + +#define _ASM_EXTABLE_COPY_MC_PAGE(insn, fixup) \ + _ASM_EXTABLE_COPY_MC_PAGE_ERR_ZERO(insn, fixup, wzr, wzr) /* * Create an exception table entry for uaccess `insn`, which will branch to `fixup` * when an unhandled fault is taken. @@ -59,6 +70,10 @@ _ASM_EXTABLE_UACCESS(\insn, \fixup) .endm+ .macro _asm_extable_copy_mc_page, insn, fixup+ _ASM_EXTABLE_COPY_MC_PAGE(\insn, \fixup) + .endm +This should share a common EX_TYPE_ with the other "kaccess where memory error is handled but other faults are fatal" cases.
OK, reasonable.
/* * Create an exception table entry for `insn` if `fixup` is provided. Otherwise * do nothing. diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 513787e43329..e1d8ce155878 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -154,6 +154,10 @@ lr .req x30 // link register #define CPU_LE(code...) code #endif+#define CPY_MC(l, x...) \+9999: x; \ + _asm_extable_copy_mc_page 9999b, l + /* * Define a macro that constructs a 64-bit value by concatenating two * 32-bit registers. Note that on big endian systems the order of the diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h index 91fbd5c8a391..9cdded082dd4 100644 --- a/arch/arm64/include/asm/mte.h +++ b/arch/arm64/include/asm/mte.h @@ -92,6 +92,7 @@ static inline bool try_page_mte_tagging(struct page *page) void mte_zero_clear_page_tags(void *addr); void mte_sync_tags(pte_t pte, unsigned int nr_pages); void mte_copy_page_tags(void *kto, const void *kfrom); +int mte_copy_mc_page_tags(void *kto, const void *kfrom); void mte_thread_init_user(void); void mte_thread_switch(struct task_struct *next); void mte_cpu_setup(void); @@ -128,6 +129,10 @@ static inline void mte_sync_tags(pte_t pte, unsigned int nr_pages) static inline void mte_copy_page_tags(void *kto, const void *kfrom) { } +static inline int mte_copy_mc_page_tags(void *kto, const void *kfrom) +{ + return 0; +} static inline void mte_thread_init_user(void) { } diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h index 2312e6ee595f..304cc86b8a10 100644 --- a/arch/arm64/include/asm/page.h +++ b/arch/arm64/include/asm/page.h @@ -29,6 +29,16 @@ void copy_user_highpage(struct page *to, struct page *from, void copy_highpage(struct page *to, struct page *from); #define __HAVE_ARCH_COPY_HIGHPAGE+#ifdef CONFIG_ARCH_HAS_COPY_MC+int copy_mc_page(void *to, const void *from); +int copy_mc_highpage(struct page *to, struct page *from); +#define __HAVE_ARCH_COPY_MC_HIGHPAGE + +int copy_mc_user_highpage(struct page *to, struct page *from, + unsigned long vaddr, struct vm_area_struct *vma); +#define __HAVE_ARCH_COPY_MC_USER_HIGHPAGE +#endif + struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma, unsigned long vaddr); #define vma_alloc_zeroed_movable_folio vma_alloc_zeroed_movable_folio diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile index 29490be2546b..a2fd865b816d 100644 --- a/arch/arm64/lib/Makefile +++ b/arch/arm64/lib/Makefile @@ -15,6 +15,8 @@ endiflib-$(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) += uaccess_flushcache.o +lib-$(CONFIG_ARCH_HAS_COPY_MC) += copy_mc_page.o+ obj-$(CONFIG_CRC32) += crc32.oobj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.odiff --git a/arch/arm64/lib/copy_mc_page.S b/arch/arm64/lib/copy_mc_page.S new file mode 100644 index 000000000000..524534d26d86 --- /dev/null +++ b/arch/arm64/lib/copy_mc_page.S @@ -0,0 +1,78 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2012 ARM Ltd. + */ + +#include <linux/linkage.h> +#include <linux/const.h> +#include <asm/assembler.h> +#include <asm/page.h> +#include <asm/cpufeature.h> +#include <asm/alternative.h> +#include <asm/asm-extable.h> + +/* + * Copy a page from src to dest (both are page aligned) with machine check + * + * Parameters: + * x0 - dest + * x1 - src + * Returns: + * x0 - Return 0 if copy success, or -EFAULT if anything goes wrong + * while copying. + */ +SYM_FUNC_START(__pi_copy_mc_page) +CPY_MC(9998f, ldp x2, x3, [x1]) +CPY_MC(9998f, ldp x4, x5, [x1, #16]) +CPY_MC(9998f, ldp x6, x7, [x1, #32]) +CPY_MC(9998f, ldp x8, x9, [x1, #48]) +CPY_MC(9998f, ldp x10, x11, [x1, #64]) +CPY_MC(9998f, ldp x12, x13, [x1, #80]) +CPY_MC(9998f, ldp x14, x15, [x1, #96]) +CPY_MC(9998f, ldp x16, x17, [x1, #112]) + + add x0, x0, #256 + add x1, x1, #128 +1: + tst x0, #(PAGE_SIZE - 1) + +CPY_MC(9998f, stnp x2, x3, [x0, #-256]) +CPY_MC(9998f, ldp x2, x3, [x1]) +CPY_MC(9998f, stnp x4, x5, [x0, #16 - 256]) +CPY_MC(9998f, ldp x4, x5, [x1, #16]) +CPY_MC(9998f, stnp x6, x7, [x0, #32 - 256]) +CPY_MC(9998f, ldp x6, x7, [x1, #32]) +CPY_MC(9998f, stnp x8, x9, [x0, #48 - 256]) +CPY_MC(9998f, ldp x8, x9, [x1, #48]) +CPY_MC(9998f, stnp x10, x11, [x0, #64 - 256]) +CPY_MC(9998f, ldp x10, x11, [x1, #64]) +CPY_MC(9998f, stnp x12, x13, [x0, #80 - 256]) +CPY_MC(9998f, ldp x12, x13, [x1, #80]) +CPY_MC(9998f, stnp x14, x15, [x0, #96 - 256]) +CPY_MC(9998f, ldp x14, x15, [x1, #96]) +CPY_MC(9998f, stnp x16, x17, [x0, #112 - 256]) +CPY_MC(9998f, ldp x16, x17, [x1, #112]) + + add x0, x0, #128 + add x1, x1, #128 + + b.ne 1b + +CPY_MC(9998f, stnp x2, x3, [x0, #-256]) +CPY_MC(9998f, stnp x4, x5, [x0, #16 - 256]) +CPY_MC(9998f, stnp x6, x7, [x0, #32 - 256]) +CPY_MC(9998f, stnp x8, x9, [x0, #48 - 256]) +CPY_MC(9998f, stnp x10, x11, [x0, #64 - 256]) +CPY_MC(9998f, stnp x12, x13, [x0, #80 - 256]) +CPY_MC(9998f, stnp x14, x15, [x0, #96 - 256]) +CPY_MC(9998f, stnp x16, x17, [x0, #112 - 256]) + + mov x0, #0 + ret + +9998: mov x0, #-EFAULT + ret + +SYM_FUNC_END(__pi_copy_mc_page) +SYM_FUNC_ALIAS(copy_mc_page, __pi_copy_mc_page) +EXPORT_SYMBOL(copy_mc_page)This is a duplicate of the existing copy_page logic; it should be refactored such that the logic can be shared.
OK, I'll think about how to do it.
diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S index 5018ac03b6bf..2b748e83f6cf 100644 --- a/arch/arm64/lib/mte.S +++ b/arch/arm64/lib/mte.S @@ -80,6 +80,33 @@ SYM_FUNC_START(mte_copy_page_tags) ret SYM_FUNC_END(mte_copy_page_tags)+/*+ * Copy the tags from the source page to the destination one wiht machine check safe + * x0 - address of the destination page + * x1 - address of the source page + * Returns: + * x0 - Return 0 if copy success, or + * -EFAULT if anything goes wrong while copying. + */ +SYM_FUNC_START(mte_copy_mc_page_tags) + mov x2, x0 + mov x3, x1 + multitag_transfer_size x5, x6 +1: +CPY_MC(2f, ldgm x4, [x3]) +CPY_MC(2f, stgm x4, [x2]) + add x2, x2, x5 + add x3, x3, x5 + tst x2, #(PAGE_SIZE - 1) + b.ne 1b + + mov x0, #0 + ret + +2: mov x0, #-EFAULT + ret +SYM_FUNC_END(mte_copy_mc_page_tags) + /* * Read tags from a user buffer (one tag per byte) and set the corresponding * tags at the given kernel address. Used by PTRACE_POKEMTETAGS. diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c index a7bb20055ce0..9765e40cde6c 100644 --- a/arch/arm64/mm/copypage.c +++ b/arch/arm64/mm/copypage.c @@ -14,6 +14,25 @@ #include <asm/cpufeature.h> #include <asm/mte.h>+static int do_mte(struct page *to, struct page *from, void *kto, void *kfrom, bool mc)+{ + int ret = 0; + + if (system_supports_mte() && page_mte_tagged(from)) { + /* It's a new page, shouldn't have been tagged yet */ + WARN_ON_ONCE(!try_page_mte_tagging(to)); + if (mc) + ret = mte_copy_mc_page_tags(kto, kfrom); + else + mte_copy_page_tags(kto, kfrom); + + if (!ret) + set_page_mte_tagged(to); + } + + return ret; +}The boolean 'mc' argument makes this painful to read, and I don't think it's necessary to have this helper anyway. It'd be clearer to have this expanded inline in the callers, e.g. // in copy_highpage(), as-is today if (system_supports_mte() && page_mte_tagged(from)) { /* It's a new page, shouldn't have been tagged yet */ WARN_ON_ONCE(!try_page_mte_tagging(to)); mte_copy_page_tags(kto, kfrom); set_page_mte_tagged(to); } // in copy_mc_highpage() if (system_supports_mte() && page_mte_tagged(from)) { /* It's a new page, shouldn't have been tagged yet */ WARN_ON_ONCE(!try_page_mte_tagging(to)); ret = mte_copy_mc_page_tags(kto, kfrom); if (ret) return -EFAULT; set_page_mte_tagged(to); }
OK, follow this idea in the next version.
Mark.+ void copy_highpage(struct page *to, struct page *from) { void *kto = page_address(to); @@ -24,12 +43,7 @@ void copy_highpage(struct page *to, struct page *from) if (kasan_hw_tags_enabled()) page_kasan_tag_reset(to);- if (system_supports_mte() && page_mte_tagged(from)) {- /* It's a new page, shouldn't have been tagged yet */ - WARN_ON_ONCE(!try_page_mte_tagging(to)); - mte_copy_page_tags(kto, kfrom); - set_page_mte_tagged(to); - } + do_mte(to, from, kto, kfrom, false); } EXPORT_SYMBOL(copy_highpage);@@ -40,3 +54,43 @@ void copy_user_highpage(struct page *to, struct page *from,flush_dcache_page(to); } EXPORT_SYMBOL_GPL(copy_user_highpage); + +#ifdef CONFIG_ARCH_HAS_COPY_MC +/* + * Return -EFAULT if anything goes wrong while copying page or mte. + */ +int copy_mc_highpage(struct page *to, struct page *from) +{ + void *kto = page_address(to); + void *kfrom = page_address(from); + int ret; + + ret = copy_mc_page(kto, kfrom); + if (ret) + return -EFAULT; + + if (kasan_hw_tags_enabled()) + page_kasan_tag_reset(to); + + ret = do_mte(to, from, kto, kfrom, true); + if (ret) + return -EFAULT; + + return 0; +} +EXPORT_SYMBOL(copy_mc_highpage); + +int copy_mc_user_highpage(struct page *to, struct page *from, + unsigned long vaddr, struct vm_area_struct *vma) +{ + int ret; + + ret = copy_mc_highpage(to, from); + + if (!ret) + flush_dcache_page(to); + + return ret; +} +EXPORT_SYMBOL_GPL(copy_mc_user_highpage); +#endif diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c index 28ec35e3d210..bdc81518d207 100644 --- a/arch/arm64/mm/extable.c +++ b/arch/arm64/mm/extable.c @@ -16,7 +16,7 @@ get_ex_fixup(const struct exception_table_entry *ex) return ((unsigned long)&ex->fixup + ex->fixup); }-static bool ex_handler_uaccess_err_zero(const struct exception_table_entry *ex,+static bool ex_handler_fixup_err_zero(const struct exception_table_entry *ex, struct pt_regs *regs) { int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data); @@ -69,7 +69,7 @@ bool fixup_exception(struct pt_regs *regs) return ex_handler_bpf(ex, regs); case EX_TYPE_UACCESS_ERR_ZERO: case EX_TYPE_KACCESS_ERR_ZERO: - return ex_handler_uaccess_err_zero(ex, regs); + return ex_handler_fixup_err_zero(ex, regs); case EX_TYPE_LOAD_UNALIGNED_ZEROPAD: return ex_handler_load_unaligned_zeropad(ex, regs); } @@ -87,7 +87,8 @@ bool fixup_exception_mc(struct pt_regs *regs)switch (ex->type) {case EX_TYPE_UACCESS_ERR_ZERO: - return ex_handler_uaccess_err_zero(ex, regs); + case EX_TYPE_COPY_MC_PAGE_ERR_ZERO: + return ex_handler_fixup_err_zero(ex, regs); }return false;diff --git a/include/linux/highmem.h b/include/linux/highmem.h index c5ca1a1fc4f5..a42470ca42f2 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -332,6 +332,7 @@ static inline void copy_highpage(struct page *to, struct page *from) #endif#ifdef copy_mc_to_kernel+#ifndef __HAVE_ARCH_COPY_MC_USER_HIGHPAGE /* * If architecture supports machine check exception handling, define the * #MC versions of copy_user_highpage and copy_highpage. They copy a memory @@ -354,7 +355,9 @@ static inline int copy_mc_user_highpage(struct page *to, struct page *from,return ret ? -EFAULT : 0;} +#endif+#ifndef __HAVE_ARCH_COPY_MC_HIGHPAGEstatic inline int copy_mc_highpage(struct page *to, struct page *from) { unsigned long ret; @@ -370,20 +373,25 @@ static inline int copy_mc_highpage(struct page *to, struct page *from)return ret ? -EFAULT : 0;} +#endif #else +#ifndef __HAVE_ARCH_COPY_MC_USER_HIGHPAGE static inline int copy_mc_user_highpage(struct page *to, struct page *from, unsigned long vaddr, struct vm_area_struct *vma) { copy_user_highpage(to, from, vaddr, vma); return 0; } +#endif+#ifndef __HAVE_ARCH_COPY_MC_HIGHPAGEstatic inline int copy_mc_highpage(struct page *to, struct page *from) { copy_highpage(to, from); return 0; } #endif +#endifstatic inline void memcpy_page(struct page *dst_page, size_t dst_off,struct page *src_page, size_t src_off, -- 2.25.1.
