diff options
author | Lenny Szubowicz <lszubowi@redhat.com> | 2020-05-07 14:33:32 -0400 |
---|---|---|
committer | Ard Biesheuvel <ardb@kernel.org> | 2020-05-14 11:11:18 +0200 |
commit | fd62619598069c974739476d1851a00d665041d7 (patch) | |
tree | 1e09c7a397112e1db2c671edc077b3997d6df96b /drivers/firmware/efi/libstub/efistub.h | |
parent | efi/earlycon: Fix early printk for wider fonts (diff) | |
download | linux-dev-fd62619598069c974739476d1851a00d665041d7.tar.xz linux-dev-fd62619598069c974739476d1851a00d665041d7.zip |
efi/libstub/x86: Avoid EFI map buffer alloc in allocate_e820()
In allocate_e820(), call the EFI get_memory_map() service directly
instead of indirectly via efi_get_memory_map(). This avoids allocation
of a buffer and return of the full EFI memory map, which is not needed
here and would otherwise need to be freed.
Routine allocate_e820() only needs to know how many EFI memory
descriptors there are in the map to allocate an adequately sized
e820ext buffer, if it's needed. Note that since efi_get_memory_map()
returns a memory map buffer sized with extra headroom, allocate_e820()
now needs to explicitly factor that into the e820ext size calculation.
Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Diffstat (limited to 'drivers/firmware/efi/libstub/efistub.h')
-rw-r--r-- | drivers/firmware/efi/libstub/efistub.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 67d26949fd26..62943992f02f 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -92,6 +92,19 @@ extern __pure efi_system_table_t *efi_system_table(void); #define EFI_LOCATE_BY_REGISTER_NOTIFY 1 #define EFI_LOCATE_BY_PROTOCOL 2 +/* + * An efi_boot_memmap is used by efi_get_memory_map() to return the + * EFI memory map in a dynamically allocated buffer. + * + * The buffer allocated for the EFI memory map includes extra room for + * a minimum of EFI_MMAP_NR_SLACK_SLOTS additional EFI memory descriptors. + * This facilitates the reuse of the EFI memory map buffer when a second + * call to ExitBootServices() is needed because of intervening changes to + * the EFI memory map. Other related structures, e.g. x86 e820ext, need + * to factor in this headroom requirement as well. + */ +#define EFI_MMAP_NR_SLACK_SLOTS 8 + struct efi_boot_memmap { efi_memory_desc_t **map; unsigned long *map_size; |