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authorArd Biesheuvel <ardb@kernel.org>2020-03-08 09:08:52 +0100
committerIngo Molnar <mingo@kernel.org>2020-03-08 09:58:23 +0100
commit57648adb317c6f05d80a813130f8b88cecf1facf (patch)
tree7524247dc648934cc3e98774ab933fc10de21d8f /arch/x86/platform
parentdd09fad9d2caad2325a39b766ce9e79cfc690184 (diff)
efi/x86: Preserve %ebx correctly in efi_set_virtual_address_map()
Commit: 59f2a619a2db8611 ("efi: Add 'runtime' pointer to struct efi") modified the assembler routine called by efi_set_virtual_address_map(), to grab the 'runtime' EFI service pointer while running with paging disabled (which is tricky to do in C code) After the change, register %ebx is not restored correctly, resulting in all kinds of weird behavior, so fix that. Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200304133515.15035-1-ardb@kernel.org Link: https://lore.kernel.org/r/20200308080859.21568-22-ardb@kernel.org
Diffstat (limited to 'arch/x86/platform')
-rw-r--r--arch/x86/platform/efi/efi_stub_32.S2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/platform/efi/efi_stub_32.S b/arch/x86/platform/efi/efi_stub_32.S
index 09237236fb25..09ec84f6ef51 100644
--- a/arch/x86/platform/efi/efi_stub_32.S
+++ b/arch/x86/platform/efi/efi_stub_32.S
@@ -54,7 +54,7 @@ SYM_FUNC_START(efi_call_svam)
orl $0x80000000, %edx
movl %edx, %cr0
- pop %ebx
+ movl 16(%esp), %ebx
leave
ret
SYM_FUNC_END(efi_call_svam)