diff options
| author | Arvind Sankar <nivedita@alum.mit.edu> | 2020-03-08 09:08:42 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-03-08 09:58:16 +0100 |
| commit | 3fab43318f0565ffb45925bea5903bc400ce2864 (patch) | |
| tree | f6ca8c4f1ec34b28ec4fd2635e9b6199cdf87c9b /arch/x86/boot/compressed/head_64.S | |
| parent | 71ff44ac6cfaa1d8d3dff6c73636f4fb97b2be10 (diff) | |
efi/x86: Make efi32_pe_entry() more readable
Set up a proper frame pointer in efi32_pe_entry() so that it's easier to
calculate offsets for arguments.
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/20200301230436.2246909-4-nivedita@alum.mit.edu
Link: https://lore.kernel.org/r/20200308080859.21568-12-ardb@kernel.org
Diffstat (limited to 'arch/x86/boot/compressed/head_64.S')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 57 |
1 files changed, 40 insertions, 17 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 920daf62dac2..fabbd4c2e9f2 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -658,42 +658,65 @@ SYM_DATA(efi_is64, .byte 1) .text .code32 SYM_FUNC_START(efi32_pe_entry) +/* + * efi_status_t efi32_pe_entry(efi_handle_t image_handle, + * efi_system_table_32_t *sys_table) + */ + pushl %ebp + movl %esp, %ebp + pushl %eax // dummy push to allocate loaded_image - pushl %ebx + pushl %ebx // save callee-save registers pushl %edi + call verify_cpu // check for long mode support - popl %edi - popl %ebx testl %eax, %eax movl $0x80000003, %eax // EFI_UNSUPPORTED - jnz 3f + jnz 2f call 1f -1: pop %ebp - subl $1b, %ebp +1: pop %ebx + subl $1b, %ebx /* Get the loaded image protocol pointer from the image handle */ - subl $12, %esp // space for the loaded image pointer - pushl %esp // pass its address - leal loaded_image_proto(%ebp), %eax + leal -4(%ebp), %eax + pushl %eax // &loaded_image + leal loaded_image_proto(%ebx), %eax pushl %eax // pass the GUID address - pushl 28(%esp) // pass the image handle + pushl 8(%ebp) // pass the image handle - movl 36(%esp), %eax // sys_table + /* + * Note the alignment of the stack frame. + * sys_table + * handle <-- 16-byte aligned on entry by ABI + * return address + * frame pointer + * loaded_image <-- local variable + * saved %ebx <-- 16-byte aligned here + * saved %edi + * &loaded_image + * &loaded_image_proto + * handle <-- 16-byte aligned for call to handle_protocol + */ + + movl 12(%ebp), %eax // sys_table movl ST32_boottime(%eax), %eax // sys_table->boottime call *BS32_handle_protocol(%eax) // sys_table->boottime->handle_protocol - cmp $0, %eax + addl $12, %esp // restore argument space + testl %eax, %eax jnz 2f - movl 32(%esp), %ecx // image_handle - movl 36(%esp), %edx // sys_table - movl 12(%esp), %esi // loaded_image + movl 8(%ebp), %ecx // image_handle + movl 12(%ebp), %edx // sys_table + movl -4(%ebp), %esi // loaded_image movl LI32_image_base(%esi), %esi // loaded_image->image_base + movl %ebx, %ebp // startup_32 for efi32_pe_stub_entry jmp efi32_pe_stub_entry -2: addl $24, %esp -3: popl %ebp +2: popl %edi // restore callee-save registers + popl %ebx + leave ret SYM_FUNC_END(efi32_pe_entry) |