diff options
| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2019-06-09 20:17:44 +0200 |
|---|---|---|
| committer | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2019-06-11 16:07:19 +0200 |
| commit | 18df7577adae6c6c778bf774b3aebcacbc1fb439 (patch) | |
| tree | cce8336e8bbd24c5ab1212df1b829e35c37bc769 /drivers/firmware | |
| parent | d1fdb6d8f6a4109a4263176c84b899076a5f8008 (diff) | |
efi/memreserve: deal with memreserve entries in unmapped memory
Ensure that the EFI memreserve entries can be accessed, even if they
are located in memory that the kernel (e.g., a crashkernel) omits from
the linear map.
Fixes: 80424b02d42b ("efi: Reduce the amount of memblock reservations ...")
Cc: <stable@vger.kernel.org> # 5.0+
Reported-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
Reviewed-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
Tested-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/efi/efi.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 16b2137d117c..4b7cf7bc0ded 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -1009,14 +1009,16 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) /* first try to find a slot in an existing linked list entry */ for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) { - rsv = __va(prsv); + rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB); index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size); if (index < rsv->size) { rsv->entry[index].base = addr; rsv->entry[index].size = size; + memunmap(rsv); return 0; } + memunmap(rsv); } /* no slot found - allocate a new linked list entry */ @@ -1024,7 +1026,13 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) if (!rsv) return -ENOMEM; - rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE); + /* + * The memremap() call above assumes that a linux_efi_memreserve entry + * never crosses a page boundary, so let's ensure that this remains true + * even when kexec'ing a 4k pages kernel from a >4k pages kernel, by + * using SZ_4K explicitly in the size calculation below. + */ + rsv->size = EFI_MEMRESERVE_COUNT(SZ_4K); atomic_set(&rsv->count, 1); rsv->entry[0].base = addr; rsv->entry[0].size = size; |