diff options
| -rw-r--r-- | arch/x86/boot/compressed/efi_mixed.S | 77 |
1 files changed, 37 insertions, 40 deletions
diff --git a/arch/x86/boot/compressed/efi_mixed.S b/arch/x86/boot/compressed/efi_mixed.S index 984956931ed7..e04ed99bc449 100644 --- a/arch/x86/boot/compressed/efi_mixed.S +++ b/arch/x86/boot/compressed/efi_mixed.S @@ -22,43 +22,7 @@ #include <asm/processor-flags.h> #include <asm/segment.h> - .code64 .text -SYM_FUNC_START(__efi64_thunk) - push %rbp - push %rbx - - /* Copy args passed on stack */ - movq 0x18(%rsp), %rbp - movq 0x20(%rsp), %rbx - movq 0x28(%rsp), %rax - - /* - * Convert x86-64 ABI params to i386 ABI - */ - subq $64, %rsp - movl %esi, 0x0(%rsp) - movl %edx, 0x4(%rsp) - movl %ecx, 0x8(%rsp) - movl %r8d, 0xc(%rsp) - movl %r9d, 0x10(%rsp) - movl %ebp, 0x14(%rsp) - movl %ebx, 0x18(%rsp) - movl %eax, 0x1c(%rsp) - - leaq 1f(%rip), %rbp - movl %cs, %ebx - - ljmpl *efi32_call(%rip) - -1: addq $64, %rsp - movq %rdi, %rax - - pop %rbx - pop %rbp - RET -SYM_FUNC_END(__efi64_thunk) - .code32 #ifdef CONFIG_EFI_HANDOVER_PROTOCOL SYM_FUNC_START(efi32_stub_entry) @@ -81,11 +45,26 @@ SYM_FUNC_END(efi32_stub_entry) #endif /* - * EFI service pointer must be in %edi. + * Called using a far call from __efi64_thunk() below, using the x86_64 SysV + * ABI (except for R8/R9 which are inaccessible to 32-bit code - EAX/EBX are + * used instead). EBP+16 points to the arguments passed via the stack. * - * The stack should represent the 32-bit calling convention. + * The first argument (EDI) is a pointer to the boot service or protocol, to + * which the remaining arguments are passed, each truncated to 32 bits. */ SYM_FUNC_START_LOCAL(efi_enter32) + /* + * Convert x86-64 SysV ABI params to i386 ABI + */ + pushl 32(%ebp) /* Up to 3 args passed via the stack */ + pushl 24(%ebp) + pushl 16(%ebp) + pushl %ebx /* R9 */ + pushl %eax /* R8 */ + pushl %ecx + pushl %edx + pushl %esi + /* Disable paging */ movl %cr0, %eax btrl $X86_CR0_PG_BIT, %eax @@ -104,11 +83,29 @@ SYM_FUNC_START_LOCAL(efi_enter32) call efi32_enable_long_mode - pushl %ebx - pushl %ebp + addl $32, %esp + movl %edi, %eax lret SYM_FUNC_END(efi_enter32) + .code64 +SYM_FUNC_START(__efi64_thunk) + push %rbp + movl %esp, %ebp + push %rbx + + /* Move args #5 and #6 into 32-bit accessible registers */ + movl %r8d, %eax + movl %r9d, %ebx + + lcalll *efi32_call(%rip) + + pop %rbx + pop %rbp + RET +SYM_FUNC_END(__efi64_thunk) + + .code32 SYM_FUNC_START_LOCAL(efi32_enable_long_mode) movl %cr4, %eax btsl $(X86_CR4_PAE_BIT), %eax |