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74d613e046
Given that memset/memcpy are intrinsics, the compiler might insert calls to these routines unexpectedly, including in code that executes after ExitBootServices(). In this case, the respective boot services are no longer accessible, and calling them will cause a crash. So fall back to a bytewise copy/store if this happens to occur, even though no such occurrences are known to exist in the kernel currently. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
74 lines
1.6 KiB
C
74 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/efi.h>
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#include <asm/efi.h>
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#include <asm/string.h>
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#include "efistub.h"
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#ifdef CONFIG_KASAN
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#undef memcpy
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#undef memmove
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#undef memset
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void *__memcpy(void *__dest, const void *__src, size_t __n) __alias(memcpy);
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void *__memmove(void *__dest, const void *__src, size_t count) __alias(memmove);
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void *__memset(void *s, int c, size_t count) __alias(memset);
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#endif
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static void *efistub_memmove(u8 *dst, const u8 *src, size_t len)
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{
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if (src > dst || dst >= (src + len))
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for (size_t i = 0; i < len; i++)
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dst[i] = src[i];
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else
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for (ssize_t i = len - 1; i >= 0; i--)
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dst[i] = src[i];
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return dst;
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}
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static void *efistub_memset(void *dst, int c, size_t len)
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{
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for (u8 *d = dst; len--; d++)
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*d = c;
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return dst;
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}
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void *memcpy(void *dst, const void *src, size_t len)
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{
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if (efi_table_attr(efi_system_table, boottime) == NULL)
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return efistub_memmove(dst, src, len);
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efi_bs_call(copy_mem, dst, src, len);
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return dst;
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}
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extern void *memmove(void *dst, const void *src, size_t len) __alias(memcpy);
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void *memset(void *dst, int c, size_t len)
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{
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if (efi_table_attr(efi_system_table, boottime) == NULL)
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return efistub_memset(dst, c, len);
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efi_bs_call(set_mem, dst, len, c & U8_MAX);
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return dst;
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}
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/**
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* memcmp - Compare two areas of memory
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* @cs: One area of memory
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* @ct: Another area of memory
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* @count: The size of the area.
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*/
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#undef memcmp
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int memcmp(const void *cs, const void *ct, size_t count)
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{
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const unsigned char *su1, *su2;
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int res = 0;
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for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
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if ((res = *su1 - *su2) != 0)
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break;
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return res;
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}
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