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Merge pull request #23701 from medhefgo/boot-mem

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boot: Use memcpy/memset provided by firmware
This commit is contained in:
Yu Watanabe
2022-06-11 04:29:27 +09:00
committed by GitHub
parent 1dea9f1268 8494bd1ced
commit 3e808e0769
1 changed files with 25 additions and 5 deletions
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30
src/boot/efi/efi-string.c
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@@ -264,6 +264,16 @@ void *efi_memcpy(void * restrict dest, const void * restrict src, size_t n) {
if (!dest || !src || n == 0)
return dest;
#ifdef SD_BOOT
/* The firmware-provided memcpy is likely optimized, so use that. The function is guaranteed to be
* available by the UEFI spec. We still make it depend on the boot services pointer being set just in
* case the compiler emits a call before it is available. */
if (_likely_(BS)) {
BS->CopyMem(dest, (void *) src, n);
return dest;
}
#endif
uint8_t *d = dest;
const uint8_t *s = src;
@@ -281,6 +291,14 @@ void *efi_memset(void *p, int c, size_t n) {
if (!p || n == 0)
return p;
#ifdef SD_BOOT
/* See comment in efi_memcpy. Note that the signature has c and n swapped! */
if (_likely_(BS)) {
BS->SetMem(p, n, c);
return p;
}
#endif
uint8_t *q = p;
while (n > 0) {
*q = c;
@@ -295,9 +313,11 @@ void *efi_memset(void *p, int c, size_t n) {
# undef memcmp
# undef memcpy
# undef memset
/* Provide the actual implementation for the builtins. To prevent a linker error, we mark memcpy/memset as
* weak, because gnu-efi is currently providing them. */
__attribute__((alias("efi_memcmp"))) int memcmp(const void *p1, const void *p2, size_t n);
__attribute__((weak, alias("efi_memcpy"))) void *memcpy(void * restrict dest, const void * restrict src, size_t n);
__attribute__((weak, alias("efi_memset"))) void *memset(void *p, int c, size_t n);
/* Provide the actual implementation for the builtins by providing aliases. These need to be marked as used,
* as otherwise the compiler might remove them but still emit calls, which would break when linking.
* To prevent a different linker error, we mark memcpy/memset as weak, because gnu-efi is currently
* providing them. */
__attribute__((used, alias("efi_memcmp"))) int memcmp(const void *p1, const void *p2, size_t n);
__attribute__((used, weak, alias("efi_memcpy"))) void *memcpy(void * restrict dest, const void * restrict src, size_t n);
__attribute__((used, weak, alias("efi_memset"))) void *memset(void *p, int c, size_t n);
#endif