diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/Kconfig | 2 | ||||
| -rw-r--r-- | arch/x86/Kconfig.debug | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/copy_mc_test.h | 75 | ||||
| -rw-r--r-- | arch/x86/include/asm/mce.h | 9 | ||||
| -rw-r--r-- | arch/x86/include/asm/mcsafe_test.h | 75 | ||||
| -rw-r--r-- | arch/x86/include/asm/string_64.h | 32 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 9 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess_64.h | 20 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/mce/core.c | 8 | ||||
| -rw-r--r-- | arch/x86/kernel/quirks.c | 10 | ||||
| -rw-r--r-- | arch/x86/lib/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/lib/copy_mc.c | 82 | ||||
| -rw-r--r-- | arch/x86/lib/copy_mc_64.S | 127 | ||||
| -rw-r--r-- | arch/x86/lib/memcpy_64.S | 115 | ||||
| -rw-r--r-- | arch/x86/lib/usercopy_64.c | 21 |
15 files changed, 310 insertions, 278 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 7101ac64bb20..e876b3a087f9 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -75,7 +75,7 @@ config X86 select ARCH_HAS_PTE_DEVMAP if X86_64 select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 - select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE + select ARCH_HAS_COPY_MC if X86_64 select ARCH_HAS_SET_MEMORY select ARCH_HAS_SET_DIRECT_MAP select ARCH_HAS_STRICT_KERNEL_RWX diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index ee1d3c5834c6..27b5e2bc6a01 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -62,7 +62,7 @@ config EARLY_PRINTK_USB_XDBC You should normally say N here, unless you want to debug early crashes or need a very simple printk logging facility. -config MCSAFE_TEST +config COPY_MC_TEST def_bool n config EFI_PGT_DUMP diff --git a/arch/x86/include/asm/copy_mc_test.h b/arch/x86/include/asm/copy_mc_test.h new file mode 100644 index 000000000000..e4991ba96726 --- /dev/null +++ b/arch/x86/include/asm/copy_mc_test.h @@ -0,0 +1,75 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _COPY_MC_TEST_H_ +#define _COPY_MC_TEST_H_ + +#ifndef __ASSEMBLY__ +#ifdef CONFIG_COPY_MC_TEST +extern unsigned long copy_mc_test_src; +extern unsigned long copy_mc_test_dst; + +static inline void copy_mc_inject_src(void *addr) +{ + if (addr) + copy_mc_test_src = (unsigned long) addr; + else + copy_mc_test_src = ~0UL; +} + +static inline void copy_mc_inject_dst(void *addr) +{ + if (addr) + copy_mc_test_dst = (unsigned long) addr; + else + copy_mc_test_dst = ~0UL; +} +#else /* CONFIG_COPY_MC_TEST */ +static inline void copy_mc_inject_src(void *addr) +{ +} + +static inline void copy_mc_inject_dst(void *addr) +{ +} +#endif /* CONFIG_COPY_MC_TEST */ + +#else /* __ASSEMBLY__ */ +#include <asm/export.h> + +#ifdef CONFIG_COPY_MC_TEST +.macro COPY_MC_TEST_CTL + .pushsection .data + .align 8 + .globl copy_mc_test_src + copy_mc_test_src: + .quad 0 + EXPORT_SYMBOL_GPL(copy_mc_test_src) + .globl copy_mc_test_dst + copy_mc_test_dst: + .quad 0 + EXPORT_SYMBOL_GPL(copy_mc_test_dst) + .popsection +.endm + +.macro COPY_MC_TEST_SRC reg count target + leaq \count(\reg), %r9 + cmp copy_mc_test_src, %r9 + ja \target +.endm + +.macro COPY_MC_TEST_DST reg count target + leaq \count(\reg), %r9 + cmp copy_mc_test_dst, %r9 + ja \target +.endm +#else +.macro COPY_MC_TEST_CTL +.endm + +.macro COPY_MC_TEST_SRC reg count target +.endm + +.macro COPY_MC_TEST_DST reg count target +.endm +#endif /* CONFIG_COPY_MC_TEST */ +#endif /* __ASSEMBLY__ */ +#endif /* _COPY_MC_TEST_H_ */ diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h index cf503824529c..9b9112e4379a 100644 --- a/arch/x86/include/asm/mce.h +++ b/arch/x86/include/asm/mce.h @@ -174,6 +174,15 @@ extern void mce_unregister_decode_chain(struct notifier_block *nb); extern int mce_p5_enabled; +#ifdef CONFIG_ARCH_HAS_COPY_MC +extern void enable_copy_mc_fragile(void); +unsigned long __must_check copy_mc_fragile(void *dst, const void *src, unsigned cnt); +#else +static inline void enable_copy_mc_fragile(void) +{ +} +#endif + #ifdef CONFIG_X86_MCE int mcheck_init(void); void mcheck_cpu_init(struct cpuinfo_x86 *c); diff --git a/arch/x86/include/asm/mcsafe_test.h b/arch/x86/include/asm/mcsafe_test.h deleted file mode 100644 index eb59804b6201..000000000000 --- a/arch/x86/include/asm/mcsafe_test.h +++ /dev/null @@ -1,75 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _MCSAFE_TEST_H_ -#define _MCSAFE_TEST_H_ - -#ifndef __ASSEMBLY__ -#ifdef CONFIG_MCSAFE_TEST -extern unsigned long mcsafe_test_src; -extern unsigned long mcsafe_test_dst; - -static inline void mcsafe_inject_src(void *addr) -{ - if (addr) - mcsafe_test_src = (unsigned long) addr; - else - mcsafe_test_src = ~0UL; -} - -static inline void mcsafe_inject_dst(void *addr) -{ - if (addr) - mcsafe_test_dst = (unsigned long) addr; - else - mcsafe_test_dst = ~0UL; -} -#else /* CONFIG_MCSAFE_TEST */ -static inline void mcsafe_inject_src(void *addr) -{ -} - -static inline void mcsafe_inject_dst(void *addr) -{ -} -#endif /* CONFIG_MCSAFE_TEST */ - -#else /* __ASSEMBLY__ */ -#include <asm/export.h> - -#ifdef CONFIG_MCSAFE_TEST -.macro MCSAFE_TEST_CTL - .pushsection .data - .align 8 - .globl mcsafe_test_src - mcsafe_test_src: - .quad 0 - EXPORT_SYMBOL_GPL(mcsafe_test_src) - .globl mcsafe_test_dst - mcsafe_test_dst: - .quad 0 - EXPORT_SYMBOL_GPL(mcsafe_test_dst) - .popsection -.endm - -.macro MCSAFE_TEST_SRC reg count target - leaq \count(\reg), %r9 - cmp mcsafe_test_src, %r9 - ja \target -.endm - -.macro MCSAFE_TEST_DST reg count target - leaq \count(\reg), %r9 - cmp mcsafe_test_dst, %r9 - ja \target -.endm -#else -.macro MCSAFE_TEST_CTL -.endm - -.macro MCSAFE_TEST_SRC reg count target -.endm - -.macro MCSAFE_TEST_DST reg count target -.endm -#endif /* CONFIG_MCSAFE_TEST */ -#endif /* __ASSEMBLY__ */ -#endif /* _MCSAFE_TEST_H_ */ diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h index 75314c3dbe47..6e450827f677 100644 --- a/arch/x86/include/asm/string_64.h +++ b/arch/x86/include/asm/string_64.h @@ -82,38 +82,6 @@ int strcmp(const char *cs, const char *ct); #endif -#define __HAVE_ARCH_MEMCPY_MCSAFE 1 -__must_check unsigned long __memcpy_mcsafe(void *dst, const void *src, - size_t cnt); -DECLARE_STATIC_KEY_FALSE(mcsafe_key); - -/** - * memcpy_mcsafe - copy memory with indication if a machine check happened - * - * @dst: destination address - * @src: source address - * @cnt: number of bytes to copy - * - * Low level memory copy function that catches machine checks - * We only call into the "safe" function on systems that can - * actually do machine check recovery. Everyone else can just - * use memcpy(). - * - * Return 0 for success, or number of bytes not copied if there was an - * exception. - */ -static __always_inline __must_check unsigned long -memcpy_mcsafe(void *dst, const void *src, size_t cnt) -{ -#ifdef CONFIG_X86_MCE - if (static_branch_unlikely(&mcsafe_key)) - return __memcpy_mcsafe(dst, src, cnt); - else -#endif - memcpy(dst, src, cnt); - return 0; -} - #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE #define __HAVE_ARCH_MEMCPY_FLUSHCACHE 1 void __memcpy_flushcache(void *dst, const void *src, size_t cnt); diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index ecefaffd15d4..eff7fb847149 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -455,6 +455,15 @@ extern __must_check long strnlen_user(const char __user *str, long n); unsigned long __must_check clear_user(void __user *mem, unsigned long len); unsigned long __must_check __clear_user(void __user *mem, unsigned long len); +#ifdef CONFIG_ARCH_HAS_COPY_MC +unsigned long __must_check +copy_mc_to_kernel(void *to, const void *from, unsigned len); +#define copy_mc_to_kernel copy_mc_to_kernel + +unsigned long __must_check +copy_mc_to_user(void *to, const void *from, unsigned len); +#endif + /* * movsl can be slow when source and dest are not both 8-byte aligned */ diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h index bc10e3dc64fe..e7265a552f4f 100644 --- a/arch/x86/include/asm/uaccess_64.h +++ b/arch/x86/include/asm/uaccess_64.h @@ -47,22 +47,6 @@ copy_user_generic(void *to, const void *from, unsigned len) } static __always_inline __must_check unsigned long -copy_to_user_mcsafe(void *to, const void *from, unsigned len) -{ - unsigned long ret; - - __uaccess_begin(); - /* - * Note, __memcpy_mcsafe() is explicitly used since it can - * handle exceptions / faults. memcpy_mcsafe() may fall back to - * memcpy() which lacks this handling. - */ - ret = __memcpy_mcsafe(to, from, len); - __uaccess_end(); - return ret; -} - -static __always_inline __must_check unsigned long raw_copy_from_user(void *dst, const void __user *src, unsigned long size) { return copy_user_generic(dst, (__force void *)src, size); @@ -102,8 +86,4 @@ __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size) kasan_check_write(dst, size); return __copy_user_flushcache(dst, src, size); } - -unsigned long -mcsafe_handle_tail(char *to, char *from, unsigned len); - #endif /* _ASM_X86_UACCESS_64_H */ diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 84eef4fa9599..de29c4a267c0 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -40,7 +40,6 @@ #include <linux/debugfs.h> #include <linux/irq_work.h> #include <linux/export.h> -#include <linux/jump_label.h> #include <linux/set_memory.h> #include <linux/sync_core.h> #include <linux/task_work.h> @@ -2127,7 +2126,7 @@ void mce_disable_bank(int bank) and older. * mce=nobootlog Don't log MCEs from before booting. * mce=bios_cmci_threshold Don't program the CMCI threshold - * mce=recovery force enable memcpy_mcsafe() + * mce=recovery force enable copy_mc_fragile() */ static int __init mcheck_enable(char *str) { @@ -2735,13 +2734,10 @@ static void __init mcheck_debugfs_init(void) static void __init mcheck_debugfs_init(void) { } #endif -DEFINE_STATIC_KEY_FALSE(mcsafe_key); -EXPORT_SYMBOL_GPL(mcsafe_key); - static int __init mcheck_late_init(void) { if (mca_cfg.recovery) - static_branch_inc(&mcsafe_key); + enable_copy_mc_fragile(); mcheck_debugfs_init(); diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c index 1b10717c9321..6d0df6a58873 100644 --- a/arch/x86/kernel/quirks.c +++ b/arch/x86/kernel/quirks.c @@ -8,6 +8,7 @@ #include <asm/hpet.h> #include <asm/setup.h> +#include <asm/mce.h> #if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_SMP) && defined(CONFIG_PCI) @@ -624,10 +625,6 @@ static void amd_disable_seq_and_redirect_scrub(struct pci_dev *dev) DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3, amd_disable_seq_and_redirect_scrub); -#if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE) -#include <linux/jump_label.h> -#include <asm/string_64.h> - /* Ivy Bridge, Haswell, Broadwell */ static void quirk_intel_brickland_xeon_ras_cap(struct pci_dev *pdev) { @@ -636,7 +633,7 @@ static void quirk_intel_brickland_xeon_ras_cap(struct pci_dev *pdev) pci_read_config_dword(pdev, 0x84, &capid0); if (capid0 & 0x10) - static_branch_inc(&mcsafe_key); + enable_copy_mc_fragile(); } /* Skylake */ @@ -653,7 +650,7 @@ static void quirk_intel_purley_xeon_ras_cap(struct pci_dev *pdev) * enabled, so memory machine check recovery is also enabled. */ if ((capid0 & 0xc0) == 0xc0 || (capid5 & 0x1e0)) - static_branch_inc(&mcsafe_key); + enable_copy_mc_fragile(); } DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x0ec3, quirk_intel_brickland_xeon_ras_cap); @@ -661,7 +658,6 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2fc0, quirk_intel_brickland_xeon_ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fc0, quirk_intel_brickland_xeon_ras_cap); DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2083, quirk_intel_purley_xeon_ras_cap); #endif -#endif bool x86_apple_machine; EXPORT_SYMBOL(x86_apple_machine); diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index aa067859a70b..bad4dee4f0e4 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -44,6 +44,7 @@ obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o lib-y := delay.o misc.o cmdline.o cpu.o lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o lib-y += memcpy_$(BITS).o +lib-$(CONFIG_ARCH_HAS_COPY_MC) += copy_mc.o copy_mc_64.o lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o diff --git a/arch/x86/lib/copy_mc.c b/arch/x86/lib/copy_mc.c new file mode 100644 index 000000000000..2633635530b7 --- /dev/null +++ b/arch/x86/lib/copy_mc.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright(c) 2016-2020 Intel Corporation. All rights reserved. */ + +#include <linux/jump_label.h> +#include <linux/uaccess.h> +#include <linux/export.h> +#include <linux/string.h> +#include <linux/types.h> + +#include <asm/mce.h> + +#ifdef CONFIG_X86_MCE +/* + * See COPY_MC_TEST for self-test of the copy_mc_fragile() + * implementation. + */ +static DEFINE_STATIC_KEY_FALSE(copy_mc_fragile_key); + +void enable_copy_mc_fragile(void) +{ + static_branch_inc(©_mc_fragile_key); +} +#define copy_mc_fragile_enabled (static_branch_unlikely(©_mc_fragile_key)) + +/* + * Similar to copy_user_handle_tail, probe for the write fault point, or + * source exception point. + */ +__visible notrace unsigned long +copy_mc_fragile_handle_tail(char *to, char *from, unsigned len) +{ + for (; len; --len, to++, from++) + if (copy_mc_fragile(to, from, 1)) + break; + return len; +} +#else +/* + * No point in doing careful copying, or consulting a static key when + * there is no #MC handler in the CONFIG_X86_MCE=n case. + */ +void enable_copy_mc_fragile(void) +{ +} +#define copy_mc_fragile_enabled (0) +#endif + +/** + * copy_mc_to_kernel - memory copy that handles source exceptions + * + * @dst: destination address + * @src: source address + * @len: number of bytes to copy + * + * Call into the 'fragile' version on systems that have trouble + * actually do machine check recovery. Everyone else can just + * use memcpy(). + * + * Return 0 for success, or number of bytes not copied if there was an + * exception. + */ +unsigned long __must_check copy_mc_to_kernel(void *dst, const void *src, unsigned len) +{ + if (copy_mc_fragile_enabled) + return copy_mc_fragile(dst, src, len); + memcpy(dst, src, len); + return 0; +} +EXPORT_SYMBOL_GPL(copy_mc_to_kernel); + +unsigned long __must_check copy_mc_to_user(void *dst, const void *src, unsigned len) +{ + unsigned long ret; + + if (!copy_mc_fragile_enabled) + return copy_user_generic(dst, src, len); + + __uaccess_begin(); + ret = copy_mc_fragile(dst, src, len); + __uaccess_end(); + return ret; +} diff --git a/arch/x86/lib/copy_mc_64.S b/arch/x86/lib/copy_mc_64.S new file mode 100644 index 000000000000..c3b613c4544a --- /dev/null +++ b/arch/x86/lib/copy_mc_64.S @@ -0,0 +1,127 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* Copyright(c) 2016-2020 Intel Corporation. All rights reserved. */ + +#include <linux/linkage.h> +#include <asm/copy_mc_test.h> +#include <asm/export.h> +#include <asm/asm.h> + +#ifndef CONFIG_UML + +#ifdef CONFIG_X86_MCE +COPY_MC_TEST_CTL + +/* + * copy_mc_fragile - copy memory with indication if an exception / fault happened + * + * The 'fragile' version is opted into by platform quirks and takes + * pains to avoid unrecoverable corner cases like 'fast-string' + * instruction sequences, and consuming poison across a cacheline + * boundary. The non-fragile version is equivalent to memcpy() + * regardless of CPU machine-check-recovery capability. + */ +SYM_FUNC_START(copy_mc_fragile) + cmpl $8, %edx + /* Less than 8 bytes? Go to byte copy loop */ + jb .L_no_whole_words + + /* Check for bad alignment of source */ + testl $7, %esi + /* Already aligned */ + jz .L_8byte_aligned + + /* Copy one byte at a time until source is 8-byte aligned */ + movl %esi, %ecx + andl $7, %ecx + subl $8, %ecx + negl %ecx + subl %ecx, %edx +.L_read_leading_bytes: + movb (%rsi), %al + COPY_MC_TEST_SRC %rsi 1 .E_leading_bytes + COPY_MC_TEST_DST %rdi 1 .E_leading_bytes +.L_write_leading_bytes: + movb %al, (%rdi) + incq %rsi + incq %rdi + decl %ecx + jnz .L_read_leading_bytes + +.L_8byte_aligned: + movl %edx, %ecx + andl $7, %edx + shrl $3, %ecx + jz .L_no_whole_words + +.L_read_words: + movq (%rsi), %r8 + COPY_MC_TEST_SRC %rsi 8 .E_read_words + COPY_MC_TEST_DST %rdi 8 .E_write_words +.L_write_words: + movq %r8, (%rdi) + addq $8, %rsi + addq $8, %rdi + decl %ecx + jnz .L_read_words + + /* Any trailing bytes? */ +.L_no_whole_words: + andl %edx, %edx + jz .L_done_memcpy_trap + + /* Copy trailing bytes */ + movl %edx, %ecx +.L_read_trailing_bytes: + movb (%rsi), %al + COPY_MC_TEST_SRC %rsi 1 .E_trailing_bytes + COPY_MC_TEST_DST %rdi 1 .E_trailing_bytes +.L_write_trailing_bytes: + movb %al, (%rdi) + incq %rsi + incq %rdi + decl %ecx + jnz .L_read_trailing_bytes + + /* Copy successful. Return zero */ +.L_done_memcpy_trap: + xorl %eax, %eax +.L_done: + ret +SYM_FUNC_END(copy_mc_fragile) +EXPORT_SYMBOL_GPL(copy_mc_fragile) + + .section .fixup, "ax" + /* + * Return number of bytes not copied for any failure. Note that + * there is no "tail" handling since the source buffer is 8-byte + * aligned and poison is cacheline aligned. + */ +.E_read_words: + shll $3, %ecx +.E_leading_bytes: + addl %edx, %ecx +.E_trailing_bytes: + mov %ecx, %eax + jmp .L_done + + /* + * For write fault handling, given the destination is unaligned, + * we handle faults on multi-byte writes with a byte-by-byte + * copy up to the write-protected page. + */ +.E_write_words: + shll $3, %ecx + addl %edx, %ecx + movl %ecx, %edx + jmp copy_mc_fragile_handle_tail + + .previous + + _ASM_EXTABLE_FAULT(.L_read_leading_bytes, .E_leading_bytes) + _ASM_EXTABLE_FAULT(.L_read_words, .E_read_words) + _ASM_EXTABLE_FAULT(.L_read_trailing_bytes, .E_trailing_bytes) + _ASM_EXTABLE(.L_write_leading_bytes, .E_leading_bytes) + _ASM_EXTABLE(.L_write_words, .E_write_words) + _ASM_EXTABLE(.L_write_trailing_bytes, .E_trailing_bytes) +#endif /* CONFIG_X86_MCE */ +#endif /* !CONFIG_UML */ diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S index bbcc05bcefad..037faac46b0c 100644 --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -4,7 +4,6 @@ #include <linux/linkage.h> #include <asm/errno.h> #include <asm/cpufeatures.h> -#include <asm/mcsafe_test.h> #include <asm/alternative-asm.h> #include <asm/export.h> @@ -187,117 +186,3 @@ SYM_FUNC_START_LOCAL(memcpy_orig) SYM_FUNC_END(memcpy_orig) .popsection - -#ifndef CONFIG_UML - -MCSAFE_TEST_CTL - -/* - * __memcpy_mcsafe - memory copy with machine check exception handling - * Note that we only catch machine checks when reading the source addresses. - * Writes to target are posted and don't generate machine checks. - */ -SYM_FUNC_START(__memcpy_mcsafe) - cmpl $8, %edx - /* Less than 8 bytes? Go to byte copy loop */ - jb .L_no_whole_words - - /* Check for bad alignment of source */ - testl $7, %esi - /* Already aligned */ - jz .L_8byte_aligned - - /* Copy one byte at a time until source is 8-byte aligned */ - movl %esi, %ecx - andl $7, %ecx - subl $8, %ecx - negl %ecx - subl %ecx, %edx -.L_read_leading_bytes: - movb (%rsi), %al - MCSAFE_TEST_SRC %rsi 1 .E_leading_bytes - MCSAFE_TEST_DST %rdi 1 .E_leading_bytes -.L_write_leading_bytes: - movb %al, (%rdi) - incq %rsi - incq %rdi - decl %ecx - jnz .L_read_leading_bytes - -.L_8byte_aligned: - movl %edx, %ecx - andl $7, %edx - shrl $3, %ecx - jz .L_no_whole_words - -.L_read_words: - movq (%rsi), %r8 - MCSAFE_TEST_SRC %rsi 8 .E_read_words - MCSAFE_TEST_DST %rdi 8 .E_write_words -.L_write_words: - movq %r8, (%rdi) - addq $8, %rsi - addq $8, %rdi - decl %ecx - jnz .L_read_words - - /* Any trailing bytes? */ -.L_no_whole_words: - andl %edx, %edx - jz .L_done_memcpy_trap - - /* Copy trailing bytes */ - movl %edx, %ecx -.L_read_trailing_bytes: - movb (%rsi), %al - MCSAFE_TEST_SRC %rsi 1 .E_trailing_bytes - MCSAFE_TEST_DST %rdi 1 .E_trailing_bytes -.L_write_trailing_bytes: - movb %al, (%rdi) - incq %rsi - incq %rdi - decl %ecx - jnz .L_read_trailing_bytes - - /* Copy successful. Return zero */ -.L_done_memcpy_trap: - xorl %eax, %eax -.L_done: - ret -SYM_FUNC_END(__memcpy_mcsafe) -EXPORT_SYMBOL_GPL(__memcpy_mcsafe) - - .section .fixup, "ax" - /* - * Return number of bytes not copied for any failure. Note that - * there is no "tail" handling since the source buffer is 8-byte - * aligned and poison is cacheline aligned. - */ -.E_read_words: - shll $3, %ecx -.E_leading_bytes: - addl %edx, %ecx -.E_trailing_bytes: - mov %ecx, %eax - jmp .L_done - - /* - * For write fault handling, given the destination is unaligned, - * we handle faults on multi-byte writes with a byte-by-byte - * copy up to the write-protected page. - */ -.E_write_words: - shll $3, %ecx - addl %edx, %ecx - movl %ecx, %edx - jmp mcsafe_handle_tail - - .previous - - _ASM_EXTABLE_FAULT(.L_read_leading_bytes, .E_leading_bytes) - _ASM_EXTABLE_FAULT(.L_read_words, .E_read_words) - _ASM_EXTABLE_FAULT(.L_read_trailing_bytes, .E_trailing_bytes) - _ASM_EXTABLE(.L_write_leading_bytes, .E_leading_bytes) - _ASM_EXTABLE(.L_write_words, .E_write_words) - _ASM_EXTABLE(.L_write_trailing_bytes, .E_trailing_bytes) -#endif diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c index 1847e993ac63..508c81e97ab1 100644 --- a/arch/x86/lib/usercopy_64.c +++ b/arch/x86/lib/usercopy_64.c @@ -56,27 +56,6 @@ unsigned long clear_user(void __user *to, unsigned long n) } EXPORT_SYMBOL(clear_user); -/* - * Similar to copy_user_handle_tail, probe for the write fault point, - * but reuse __memcpy_mcsafe in case a new read error is encountered. - * clac() is handled in _copy_to_iter_mcsafe(). - */ -__visible notrace unsigned long -mcsafe_handle_tail(char *to, char *from, unsigned len) -{ - for (; len; --len, to++, from++) { - /* - * Call the assembly routine back directly since - * memcpy_mcsafe() may silently fallback to memcpy. - */ - unsigned long rem = __memcpy_mcsafe(to, from, 1); - - if (rem) - break; - } - return len; -} - #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE /** * clean_cache_range - write back a cache range with CLWB |