diff options
| author | Arvind Sankar <nivedita@alum.mit.edu> | 2020-03-08 09:08:44 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-03-08 09:58:17 +0100 |
| commit | 81a34892c2c7c809f9c4e22c5ac936ae673fb9a2 (patch) | |
| tree | 1a8e222219763f69142fdaf020922f875ceff19d /arch/x86/boot/compressed/head_64.S | |
| parent | 8acf63efa1712fa5495425a4224378bb3e1231e0 (diff) | |
x86/boot: Use unsigned comparison for addresses
The load address is compared with LOAD_PHYSICAL_ADDR using a signed
comparison currently (using jge instruction).
When loading a 64-bit kernel using the new efi32_pe_entry() point added by:
97aa276579b2 ("efi/x86: Add true mixed mode entry point into .compat section")
using Qemu with -m 3072, the firmware actually loads us above 2Gb,
resulting in a very early crash.
Use the JAE instruction to perform a unsigned comparison instead, as physical
addresses should be considered unsigned.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200301230436.2246909-6-nivedita@alum.mit.edu
Link: https://lore.kernel.org/r/20200308080859.21568-14-ardb@kernel.org
Diffstat (limited to 'arch/x86/boot/compressed/head_64.S')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 6a4ff919008c..5d8338a693ce 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -105,7 +105,7 @@ SYM_FUNC_START(startup_32) notl %eax andl %eax, %ebx cmpl $LOAD_PHYSICAL_ADDR, %ebx - jge 1f + jae 1f #endif movl $LOAD_PHYSICAL_ADDR, %ebx 1: @@ -305,7 +305,7 @@ SYM_CODE_START(startup_64) notq %rax andq %rax, %rbp cmpq $LOAD_PHYSICAL_ADDR, %rbp - jge 1f + jae 1f #endif movq $LOAD_PHYSICAL_ADDR, %rbp 1: |