6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ard Biesheuvel ardb+git@google.com
From: Ard Biesheuvel ardb@kernel.org
[ Commit 12792064587623065250069d1df980e2c9ac3e67 upstream ]
The native 32-bit or 64-bit EFI handover protocol entrypoint offset relative to the respective startup_32/64 address is described in boot_params as handover_offset, so that the special Linux/x86 aware EFI loader can find it there.
When mixed mode is enabled, this single field has to describe this offset for both the 32-bit and 64-bit entrypoints, so their respective relative offsets have to be identical. Given that startup_32 and startup_64 are 0x200 bytes apart, and the EFI handover entrypoint resides at a fixed offset, the 32-bit and 64-bit versions of those entrypoints must be exactly 0x200 bytes apart as well.
Currently, hard-coded fixed offsets are used to ensure this, but it is sufficient to emit the 64-bit entrypoint 0x200 bytes after the 32-bit one, wherever it happens to reside. This allows this code (which is now EFI mixed mode specific) to be moved into efi_mixed.S and out of the startup code in head_64.S.
Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Link: https://lore.kernel.org/r/20230807162720.545787-6-ardb@kernel.org Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/boot/compressed/efi_mixed.S | 20 +++++++++++++++++++- arch/x86/boot/compressed/head_64.S | 18 ------------------ 2 files changed, 19 insertions(+), 19 deletions(-)
--- a/arch/x86/boot/compressed/efi_mixed.S +++ b/arch/x86/boot/compressed/efi_mixed.S @@ -146,6 +146,16 @@ SYM_FUNC_START(__efi64_thunk) SYM_FUNC_END(__efi64_thunk)
.code32 +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL +SYM_FUNC_START(efi32_stub_entry) + add $0x4, %esp /* Discard return address */ + popl %ecx + popl %edx + popl %esi + jmp efi32_entry +SYM_FUNC_END(efi32_stub_entry) +#endif + /* * EFI service pointer must be in %edi. * @@ -226,7 +236,7 @@ SYM_FUNC_END(efi_enter32) * stub may still exit and return to the firmware using the Exit() EFI boot * service.] */ -SYM_FUNC_START(efi32_entry) +SYM_FUNC_START_LOCAL(efi32_entry) call 1f 1: pop %ebx
@@ -326,6 +336,14 @@ SYM_FUNC_START(efi32_pe_entry) RET SYM_FUNC_END(efi32_pe_entry)
+#ifdef CONFIG_EFI_HANDOVER_PROTOCOL + .org efi32_stub_entry + 0x200 + .code64 +SYM_FUNC_START_NOALIGN(efi64_stub_entry) + jmp efi_stub_entry +SYM_FUNC_END(efi64_stub_entry) +#endif + .section ".rodata" /* EFI loaded image protocol GUID */ .balign 4 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -286,17 +286,6 @@ SYM_FUNC_START(startup_32) lret SYM_FUNC_END(startup_32)
-#if IS_ENABLED(CONFIG_EFI_MIXED) && IS_ENABLED(CONFIG_EFI_HANDOVER_PROTOCOL) - .org 0x190 -SYM_FUNC_START(efi32_stub_entry) - add $0x4, %esp /* Discard return address */ - popl %ecx - popl %edx - popl %esi - jmp efi32_entry -SYM_FUNC_END(efi32_stub_entry) -#endif - .code64 .org 0x200 SYM_CODE_START(startup_64) @@ -474,13 +463,6 @@ SYM_CODE_START(startup_64) jmp *%rax SYM_CODE_END(startup_64)
-#if IS_ENABLED(CONFIG_EFI_MIXED) && IS_ENABLED(CONFIG_EFI_HANDOVER_PROTOCOL) - .org 0x390 -SYM_FUNC_START(efi64_stub_entry) - jmp efi_stub_entry -SYM_FUNC_END(efi64_stub_entry) -#endif - .text SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated)