diff options
Diffstat (limited to 'gnu-efi/gnu-efi-3.0/lib/x86_64/efi_stub.S')
| -rw-r--r-- | gnu-efi/gnu-efi-3.0/lib/x86_64/efi_stub.S | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/gnu-efi/gnu-efi-3.0/lib/x86_64/efi_stub.S b/gnu-efi/gnu-efi-3.0/lib/x86_64/efi_stub.S new file mode 100644 index 0000000..b431255 --- /dev/null +++ b/gnu-efi/gnu-efi-3.0/lib/x86_64/efi_stub.S @@ -0,0 +1,189 @@ +/* + * Function calling ABI conversion from Linux to EFI for x86_64 + * + * Copyright (C) 2007 Intel Corp + * Bibo Mao <bibo.mao@intel.com> + * Huang Ying <ying.huang@intel.com> + * Copyright (C) 2012 Felipe Contreras <felipe.contreras@gmail.com> + */ + +#if !defined(HAVE_USE_MS_ABI) +/* + * EFI calling conventions are documented at: + * http://msdn.microsoft.com/en-us/library/ms235286%28v=vs.80%29.aspx + * ELF calling conventions are documented at: + * http://www.x86-64.org/documentation/abi.pdf + * + * Basically here are the conversion rules: + * a) our function pointer is in %rdi + * b) rsi through r8 (elf) aka rcx through r9 (ms) require stack space + * on the MS side even though it's not getting used at all. + * c) 8(%rsp) is always aligned to 16 in ELF, so %rsp is shifted 8 bytes extra + * d) arguments are as follows: (elf -> ms) + * 1) rdi -> rcx (32 saved) + * 2) rsi -> rdx (32 saved) + * 3) rdx -> r8 (32 saved) + * 4) rcx -> r9 (32 saved) + * 5) r8 -> 32(%rsp) (32 saved) + * 6) r9 -> 40(%rsp) (48 saved) + * 7) 8(%rsp) -> 48(%rsp) (48 saved) + * 8) 16(%rsp) -> 56(%rsp) (64 saved) + * 9) 24(%rsp) -> 64(%rsp) (64 saved) + * 10) 32(%rsp) -> 72(%rsp) (80 saved) + * e) because the first argument we recieve in a thunker is actually the + * function to be called, arguments are offset as such: + * 0) rdi -> caller + * 1) rsi -> rcx (32 saved) + * 2) rdx -> rdx (32 saved) + * 3) rcx -> r8 (32 saved) + * 4) r8 -> r9 (32 saved) + * 5) r9 -> 32(%rsp) (32 saved) + * 6) 8(%rsp) -> 40(%rsp) (48 saved) + * 7) 16(%rsp) -> 48(%rsp) (48 saved) + * 8) 24(%rsp) -> 56(%rsp) (64 saved) + * 9) 32(%rsp) -> 64(%rsp) (64 saved) + * 10) 40(%rsp) -> 72(%rsp) (80 saved) + * f) arguments need to be moved in opposite order to avoid clobbering + */ + +#define ENTRY(name) \ + .globl name; \ + name: + +ENTRY(efi_call0) + subq $40, %rsp + call *%rdi + addq $40, %rsp + ret + +ENTRY(efi_call1) + subq $40, %rsp + mov %rsi, %rcx + call *%rdi + addq $40, %rsp + ret + +ENTRY(efi_call2) + subq $40, %rsp + /* mov %rdx, %rdx */ + mov %rsi, %rcx + call *%rdi + addq $40, %rsp + ret + +ENTRY(efi_call3) + subq $40, %rsp + mov %rcx, %r8 + /* mov %rdx, %rdx */ + mov %rsi, %rcx + call *%rdi + addq $40, %rsp + ret + +ENTRY(efi_call4) + subq $40, %rsp + mov %r8, %r9 + mov %rcx, %r8 + /* mov %rdx, %rdx */ + mov %rsi, %rcx + call *%rdi + addq $40, %rsp + ret + +ENTRY(efi_call5) + subq $40, %rsp + mov %r9, 32(%rsp) + mov %r8, %r9 + mov %rcx, %r8 + /* mov %rdx, %rdx */ + mov %rsi, %rcx + call *%rdi + addq $40, %rsp + ret + +ENTRY(efi_call6) + subq $56, %rsp + mov 56+8(%rsp), %rax + mov %rax, 40(%rsp) + mov %r9, 32(%rsp) + mov %r8, %r9 + mov %rcx, %r8 + /* mov %rdx, %rdx */ + mov %rsi, %rcx + call *%rdi + addq $56, %rsp + ret + +ENTRY(efi_call7) + subq $56, %rsp + mov 56+16(%rsp), %rax + mov %rax, 48(%rsp) + mov 56+8(%rsp), %rax + mov %rax, 40(%rsp) + mov %r9, 32(%rsp) + mov %r8, %r9 + mov %rcx, %r8 + /* mov %rdx, %rdx */ + mov %rsi, %rcx + call *%rdi + addq $56, %rsp + ret + +ENTRY(efi_call8) + subq $72, %rsp + mov 72+24(%rsp), %rax + mov %rax, 56(%rsp) + mov 72+16(%rsp), %rax + mov %rax, 48(%rsp) + mov 72+8(%rsp), %rax + mov %rax, 40(%rsp) + mov %r9, 32(%rsp) + mov %r8, %r9 + mov %rcx, %r8 + /* mov %rdx, %rdx */ + mov %rsi, %rcx + call *%rdi + addq $72, %rsp + ret + +ENTRY(efi_call9) + subq $72, %rsp + mov 72+32(%rsp), %rax + mov %rax, 64(%rsp) + mov 72+24(%rsp), %rax + mov %rax, 56(%rsp) + mov 72+16(%rsp), %rax + mov %rax, 48(%rsp) + mov 72+8(%rsp), %rax + mov %rax, 40(%rsp) + mov %r9, 32(%rsp) + mov %r8, %r9 + mov %rcx, %r8 + /* mov %rdx, %rdx */ + mov %rsi, %rcx + call *%rdi + addq $72, %rsp + ret + +ENTRY(efi_call10) + subq $88, %rsp + mov 88+40(%rsp), %rax + mov %rax, 72(%rsp) + mov 88+32(%rsp), %rax + mov %rax, 64(%rsp) + mov 88+24(%rsp), %rax + mov %rax, 56(%rsp) + mov 88+16(%rsp), %rax + mov %rax, 48(%rsp) + mov 88+8(%rsp), %rax + mov %rax, 40(%rsp) + mov %r9, 32(%rsp) + mov %r8, %r9 + mov %rcx, %r8 + /* mov %rdx, %rdx */ + mov %rsi, %rcx + call *%rdi + addq $88, %rsp + ret + +#endif |