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boot: introduce xmalloc_aligned_pages

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To be used for block I/O which may require specific buffer alignment.
This commit is contained in:
Artur Kowalski
2026-01-29 18:42:24 +01:00
parent 248bc94fbf
commit fd7c6d1ac1
2 changed files with 52 additions and 0 deletions
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45
src/boot/util.c
View File

@@ -517,6 +517,51 @@ void *xmalloc(size_t size) {
return p;
}
Pages xmalloc_aligned_pages(
EFI_ALLOCATE_TYPE type,
EFI_MEMORY_TYPE memory_type,
size_t n_pages,
size_t alignment,
EFI_PHYSICAL_ADDRESS addr) {
EFI_PHYSICAL_ADDRESS aligned = addr;
/* Allow to pass block_io->Media->IoAlign to this function directly.
* alignment <= 1 means no alignment is required, in that case just
* allocate pages directly.
*/
if (alignment <= 1)
alignment = EFI_PAGE_SIZE;
assert(ISPOWEROF2(alignment));
if (alignment <= EFI_PAGE_SIZE) {
assert_se(BS->AllocatePages(type, memory_type, n_pages, &aligned) == EFI_SUCCESS);
return (Pages) {
.addr = aligned,
.n_pages = n_pages,
};
}
size_t total_pages = n_pages + EFI_SIZE_TO_PAGES(alignment);
assert_se(BS->AllocatePages(type, memory_type, total_pages, &addr) == EFI_SUCCESS);
aligned = ALIGN_TO(addr, alignment);
size_t unaligned_pages = EFI_SIZE_TO_PAGES(aligned - addr);
if (unaligned_pages > 0)
assert_se(BS->FreePages(addr, unaligned_pages) == EFI_SUCCESS);
addr = aligned + n_pages * EFI_PAGE_SIZE;
unaligned_pages = total_pages - n_pages - unaligned_pages;
if (unaligned_pages > 0)
assert_se(BS->FreePages(addr, unaligned_pages) == EFI_SUCCESS);
return (Pages) {
.addr = aligned,
.n_pages = n_pages,
};
}
bool free_and_xstrdup16(char16_t **p, const char16_t *s) {
char16_t *t;

7
src/boot/util.h
View File

@@ -96,6 +96,13 @@ static inline Pages xmalloc_pages(
};
}
Pages xmalloc_aligned_pages(
EFI_ALLOCATE_TYPE type,
EFI_MEMORY_TYPE memory_type,
size_t n_pages,
size_t alignment,
EFI_PHYSICAL_ADDRESS addr);
static inline Pages xmalloc_initrd_pages(size_t n_pages) {
/* The original native x86 boot protocol of the Linux kernel was not 64bit safe, hence we try to
* allocate memory for the initrds below the 4G boundary on x86, since we don't know early enough