diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/Kconfig.debug | 3 | ||||
| -rw-r--r-- | arch/x86/include/asm/mcsafe_test.h | 75 | ||||
| -rw-r--r-- | arch/x86/include/asm/string_64.h | 10 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess_64.h | 14 | ||||
| -rw-r--r-- | arch/x86/lib/memcpy_64.S | 112 | ||||
| -rw-r--r-- | arch/x86/lib/usercopy_64.c | 21 |
7 files changed, 174 insertions, 62 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c07f492b871a..6ca22706cd64 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -60,6 +60,7 @@ config X86 select ARCH_HAS_PMEM_API if X86_64 select ARCH_HAS_REFCOUNT select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 + select ARCH_HAS_UACCESS_MCSAFE if X86_64 select ARCH_HAS_SET_MEMORY select ARCH_HAS_SG_CHAIN select ARCH_HAS_STRICT_KERNEL_RWX diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 192e4d2f9efc..c6dd1d980081 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -72,6 +72,9 @@ 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 + def_bool n + config X86_PTDUMP_CORE def_bool n diff --git a/arch/x86/include/asm/mcsafe_test.h b/arch/x86/include/asm/mcsafe_test.h new file mode 100644 index 000000000000..eb59804b6201 --- /dev/null +++ b/arch/x86/include/asm/mcsafe_test.h @@ -0,0 +1,75 @@ +/* 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 533f74c300c2..d33f92b9fa22 100644 --- a/arch/x86/include/asm/string_64.h +++ b/arch/x86/include/asm/string_64.h @@ -116,7 +116,8 @@ int strcmp(const char *cs, const char *ct); #endif #define __HAVE_ARCH_MEMCPY_MCSAFE 1 -__must_check int memcpy_mcsafe_unrolled(void *dst, const void *src, size_t cnt); +__must_check unsigned long __memcpy_mcsafe(void *dst, const void *src, + size_t cnt); DECLARE_STATIC_KEY_FALSE(mcsafe_key); /** @@ -131,14 +132,15 @@ DECLARE_STATIC_KEY_FALSE(mcsafe_key); * actually do machine check recovery. Everyone else can just * use memcpy(). * - * Return 0 for success, -EFAULT for fail + * Return 0 for success, or number of bytes not copied if there was an + * exception. */ -static __always_inline __must_check int +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_unrolled(dst, src, cnt); + return __memcpy_mcsafe(dst, src, cnt); else #endif memcpy(dst, src, cnt); diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h index 62546b3a398e..62acb613114b 100644 --- a/arch/x86/include/asm/uaccess_64.h +++ b/arch/x86/include/asm/uaccess_64.h @@ -47,6 +47,17 @@ 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(); + 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) { int ret = 0; @@ -194,4 +205,7 @@ __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size) unsigned long copy_user_handle_tail(char *to, char *from, unsigned len); +unsigned long +mcsafe_handle_tail(char *to, char *from, unsigned len); + #endif /* _ASM_X86_UACCESS_64_H */ diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S index 9a53a06e5a3e..298ef1479240 100644 --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -3,6 +3,7 @@ #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> @@ -183,12 +184,15 @@ ENTRY(memcpy_orig) ENDPROC(memcpy_orig) #ifndef CONFIG_UML + +MCSAFE_TEST_CTL + /* - * memcpy_mcsafe_unrolled - memory copy with machine check exception handling + * __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. */ -ENTRY(memcpy_mcsafe_unrolled) +ENTRY(__memcpy_mcsafe) cmpl $8, %edx /* Less than 8 bytes? Go to byte copy loop */ jb .L_no_whole_words @@ -204,58 +208,33 @@ ENTRY(memcpy_mcsafe_unrolled) subl $8, %ecx negl %ecx subl %ecx, %edx -.L_copy_leading_bytes: +.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_copy_leading_bytes + jnz .L_read_leading_bytes .L_8byte_aligned: - /* Figure out how many whole cache lines (64-bytes) to copy */ - movl %edx, %ecx - andl $63, %edx - shrl $6, %ecx - jz .L_no_whole_cache_lines - - /* Loop copying whole cache lines */ -.L_cache_w0: movq (%rsi), %r8 -.L_cache_w1: movq 1*8(%rsi), %r9 -.L_cache_w2: movq 2*8(%rsi), %r10 -.L_cache_w3: movq 3*8(%rsi), %r11 - movq %r8, (%rdi) - movq %r9, 1*8(%rdi) - movq %r10, 2*8(%rdi) - movq %r11, 3*8(%rdi) -.L_cache_w4: movq 4*8(%rsi), %r8 -.L_cache_w5: movq 5*8(%rsi), %r9 -.L_cache_w6: movq 6*8(%rsi), %r10 -.L_cache_w7: movq 7*8(%rsi), %r11 - movq %r8, 4*8(%rdi) - movq %r9, 5*8(%rdi) - movq %r10, 6*8(%rdi) - movq %r11, 7*8(%rdi) - leaq 64(%rsi), %rsi - leaq 64(%rdi), %rdi - decl %ecx - jnz .L_cache_w0 - - /* Are there any trailing 8-byte words? */ -.L_no_whole_cache_lines: movl %edx, %ecx andl $7, %edx shrl $3, %ecx jz .L_no_whole_words - /* Copy trailing words */ -.L_copy_trailing_words: +.L_read_words: movq (%rsi), %r8 - mov %r8, (%rdi) - leaq 8(%rsi), %rsi - leaq 8(%rdi), %rdi + 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_copy_trailing_words + jnz .L_read_words /* Any trailing bytes? */ .L_no_whole_words: @@ -264,38 +243,55 @@ ENTRY(memcpy_mcsafe_unrolled) /* Copy trailing bytes */ movl %edx, %ecx -.L_copy_trailing_bytes: +.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_copy_trailing_bytes + jnz .L_read_trailing_bytes /* Copy successful. Return zero */ .L_done_memcpy_trap: xorq %rax, %rax ret -ENDPROC(memcpy_mcsafe_unrolled) -EXPORT_SYMBOL_GPL(memcpy_mcsafe_unrolled) +ENDPROC(__memcpy_mcsafe) +EXPORT_SYMBOL_GPL(__memcpy_mcsafe) .section .fixup, "ax" - /* Return -EFAULT for any failure */ -.L_memcpy_mcsafe_fail: - mov $-EFAULT, %rax + /* + * 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 ret + /* + * 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_copy_leading_bytes, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_cache_w0, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_cache_w1, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_cache_w2, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_cache_w3, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_cache_w4, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_cache_w5, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_cache_w6, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_cache_w7, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_copy_trailing_words, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_copy_trailing_bytes, .L_memcpy_mcsafe_fail) + _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 75d3776123cc..7ebc9901dd05 100644 --- a/arch/x86/lib/usercopy_64.c +++ b/arch/x86/lib/usercopy_64.c @@ -75,6 +75,27 @@ copy_user_handle_tail(char *to, char *from, unsigned len) return len; } +/* + * 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 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 |