diff options
| author | Arvind Sankar <nivedita@alum.mit.edu> | 2020-05-23 18:15:13 -0400 |
|---|---|---|
| committer | Ard Biesheuvel <ardb@kernel.org> | 2020-05-24 00:25:15 +0200 |
| commit | 9241dfe7f2772fc73c82eb950afb1c795d2c012c (patch) | |
| tree | 6c04350f6b935f54893741a27642dd4eaec9f68e | |
| parent | 6e99d3213b10ee18428d6d20715ad6c0e89ead4d (diff) | |
efi/x86: Drop the special GDT for the EFI thunk
Instead of using efi_gdt64 to switch back to 64-bit mode and then
switching to the real boot-time GDT, just switch to the boot-time GDT
directly. The two GDT's are identical other than efi_gdt64 not including
the 32-bit code segment.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200523221513.1642948-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
| -rw-r--r-- | arch/x86/boot/compressed/efi_thunk_64.S | 19 |
1 files changed, 3 insertions, 16 deletions
diff --git a/arch/x86/boot/compressed/efi_thunk_64.S b/arch/x86/boot/compressed/efi_thunk_64.S index 2b2049259619..c4bb0f9363f5 100644 --- a/arch/x86/boot/compressed/efi_thunk_64.S +++ b/arch/x86/boot/compressed/efi_thunk_64.S @@ -28,8 +28,6 @@ SYM_FUNC_START(__efi64_thunk) push %rbx leaq 1f(%rip), %rbp - leaq efi_gdt64(%rip), %rbx - movl %ebx, 2(%rbx) /* Fixup the gdt base address */ movl %ds, %eax push %rax @@ -48,7 +46,8 @@ SYM_FUNC_START(__efi64_thunk) movl %r8d, 0xc(%rsp) movl %r9d, 0x10(%rsp) - sgdt 0x14(%rsp) + leaq 0x14(%rsp), %rbx + sgdt (%rbx) /* * Switch to gdt with 32-bit segments. This is the firmware GDT @@ -68,8 +67,7 @@ SYM_FUNC_START(__efi64_thunk) pushq %rax lretq -1: lgdt 0x14(%rsp) - addq $32, %rsp +1: addq $32, %rsp movq %rdi, %rax pop %rbx @@ -175,14 +173,3 @@ SYM_DATA_END(efi32_boot_cs) SYM_DATA_START(efi32_boot_ds) .word 0 SYM_DATA_END(efi32_boot_ds) - -SYM_DATA_START(efi_gdt64) - .word efi_gdt64_end - efi_gdt64 - .long 0 /* Filled out by user */ - .word 0 - .quad 0x0000000000000000 /* NULL descriptor */ - .quad 0x00af9a000000ffff /* __KERNEL_CS */ - .quad 0x00cf92000000ffff /* __KERNEL_DS */ - .quad 0x0080890000000000 /* TS descriptor */ - .quad 0x0000000000000000 /* TS continued */ -SYM_DATA_END_LABEL(efi_gdt64, SYM_L_LOCAL, efi_gdt64_end) |