diff options
| author | Arvind Sankar <nivedita@alum.mit.edu> | 2020-03-08 09:08:44 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-04-17 10:50:03 +0200 |
| commit | fc427b7a0266266f94badc325b0134997ed261b7 (patch) | |
| tree | 7828c9cfef3e319042b82dd6f8f03a2ee9ec5b47 | |
| parent | f6bb3ea812f03f373266fee117d4e4640febf5ef (diff) | |
x86/boot: Use unsigned comparison for addresses
[ Upstream commit 81a34892c2c7c809f9c4e22c5ac936ae673fb9a2 ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/x86/boot/compressed/head_32.S | 2 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 4 |
2 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S index 5e30eaaf8576..70ffce98c568 100644 --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -106,7 +106,7 @@ ENTRY(startup_32) notl %eax andl %eax, %ebx cmpl $LOAD_PHYSICAL_ADDR, %ebx - jge 1f + jae 1f #endif movl $LOAD_PHYSICAL_ADDR, %ebx 1: diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index e9a7f7cadb12..07d2002da642 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -106,7 +106,7 @@ ENTRY(startup_32) notl %eax andl %eax, %ebx cmpl $LOAD_PHYSICAL_ADDR, %ebx - jge 1f + jae 1f #endif movl $LOAD_PHYSICAL_ADDR, %ebx 1: @@ -297,7 +297,7 @@ ENTRY(startup_64) notq %rax andq %rax, %rbp cmpq $LOAD_PHYSICAL_ADDR, %rbp - jge 1f + jae 1f #endif movq $LOAD_PHYSICAL_ADDR, %rbp 1: |