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| author | Dan Williams <dan.j.williams@intel.com> | 2020-01-13 18:22:44 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-01-20 08:14:29 +0100 |
| commit | f0ef6523475f18ccd213e22ee593dfd131a2c5ea (patch) | |
| tree | a0f2df98870bb25830765bc735ef282c83fefc0a /drivers/firmware | |
| parent | 1db91035d01aa8bfa2350c00ccb63d629b4041ad (diff) | |
| download | linux-f0ef6523475f18ccd213e22ee593dfd131a2c5ea.tar.bz2 | |
efi: Fix efi_memmap_alloc() leaks
With efi_fake_memmap() and efi_arch_mem_reserve() the efi table may be
updated and replaced multiple times. When that happens a previous
dynamically allocated efi memory map can be garbage collected. Use the
new EFI_MEMMAP_{SLAB,MEMBLOCK} flags to detect when a dynamically
allocated memory map is being replaced.
Debug statements in efi_memmap_free() reveal:
efi: __efi_memmap_free:37: phys: 0x23ffdd580 size: 2688 flags: 0x2
efi: __efi_memmap_free:37: phys: 0x9db00 size: 2640 flags: 0x2
efi: __efi_memmap_free:37: phys: 0x9e580 size: 2640 flags: 0x2
...a savings of 7968 bytes on a qemu boot with 2 entries specified to
efi_fake_mem=.
[ ardb: added a comment to clarify that efi_memmap_free() does nothing when
called from efi_clean_memmap(), i.e., with data->flags == 0x0 ]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200113172245.27925-13-ardb@kernel.org
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/efi/memmap.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c index 04dfa56b994b..501672166502 100644 --- a/drivers/firmware/efi/memmap.c +++ b/drivers/firmware/efi/memmap.c @@ -29,6 +29,28 @@ static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size) return PFN_PHYS(page_to_pfn(p)); } +static void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags) +{ + if (flags & EFI_MEMMAP_MEMBLOCK) { + if (slab_is_available()) + memblock_free_late(phys, size); + else + memblock_free(phys, size); + } else if (flags & EFI_MEMMAP_SLAB) { + struct page *p = pfn_to_page(PHYS_PFN(phys)); + unsigned int order = get_order(size); + + free_pages((unsigned long) page_address(p), order); + } +} + +static void __init efi_memmap_free(void) +{ + __efi_memmap_free(efi.memmap.phys_map, + efi.memmap.desc_size * efi.memmap.nr_map, + efi.memmap.flags); +} + /** * efi_memmap_alloc - Allocate memory for the EFI memory map * @num_entries: Number of entries in the allocated map. @@ -100,6 +122,9 @@ static int __init __efi_memmap_init(struct efi_memory_map_data *data) return -ENOMEM; } + /* NOP if data->flags & (EFI_MEMMAP_MEMBLOCK | EFI_MEMMAP_SLAB) == 0 */ + efi_memmap_free(); + map.phys_map = data->phys_map; map.nr_map = data->size / data->desc_size; map.map_end = map.map + data->size; |