diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2020-01-13 18:22:45 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-01-20 08:14:29 +0100 |
| commit | 484a418d075488c6999528247cc711d12c373447 (patch) | |
| tree | 37ad16cdd5b0cbc13ce22ea6a14ff4b05ecda2ab /include/linux/efi.h | |
| parent | f0ef6523475f18ccd213e22ee593dfd131a2c5ea (diff) | |
efi: Fix handling of multiple efi_fake_mem= entries
Dave noticed that when specifying multiple efi_fake_mem= entries only
the last entry was successfully being reflected in the efi memory map.
This is due to the fact that the efi_memmap_insert() is being called
multiple times, but on successive invocations the insertion should be
applied to the last new memmap rather than the original map at
efi_fake_memmap() entry.
Rework efi_fake_memmap() to install the new memory map after each
efi_fake_mem= entry is parsed.
This also fixes an issue in efi_fake_memmap() that caused it to litter
emtpy entries into the end of the efi memory map. An empty entry causes
efi_memmap_insert() to attempt more memmap splits / copies than
efi_memmap_split_count() accounted for when sizing the new map. When
that happens efi_memmap_insert() may overrun its allocation, and if you
are lucky will spill over to an unmapped page leading to crash
signature like the following rather than silent corruption:
BUG: unable to handle page fault for address: ffffffffff281000
[..]
RIP: 0010:efi_memmap_insert+0x11d/0x191
[..]
Call Trace:
? bgrt_init+0xbe/0xbe
? efi_arch_mem_reserve+0x1cb/0x228
? acpi_parse_bgrt+0xa/0xd
? acpi_table_parse+0x86/0xb8
? acpi_boot_init+0x494/0x4e3
? acpi_parse_x2apic+0x87/0x87
? setup_acpi_sci+0xa2/0xa2
? setup_arch+0x8db/0x9e1
? start_kernel+0x6a/0x547
? secondary_startup_64+0xb6/0xc0
Commit af1648984828 "x86/efi: Update e820 with reserved EFI boot
services data to fix kexec breakage" introduced more occurrences where
efi_memmap_insert() is invoked after an efi_fake_mem= configuration has
been parsed. Previously the side effects of vestigial empty entries were
benign, but with commit af1648984828 that follow-on efi_memmap_insert()
invocation triggers efi_memmap_insert() overruns.
Reported-by: Dave Young <dyoung@redhat.com>
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/20191231014630.GA24942@dhcp-128-65.nay.redhat.com
Link: https://lore.kernel.org/r/20200113172245.27925-14-ardb@kernel.org
Diffstat (limited to 'include/linux/efi.h')
| -rw-r--r-- | include/linux/efi.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/efi.h b/include/linux/efi.h index adbe421835c1..7efd7072cca5 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -976,6 +976,8 @@ extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr); extern int __init efi_memmap_alloc(unsigned int num_entries, struct efi_memory_map_data *data); +extern void __efi_memmap_free(u64 phys, unsigned long size, + unsigned long flags); extern int __init efi_memmap_init_early(struct efi_memory_map_data *data); extern int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size); extern void __init efi_memmap_unmap(void); |