diff options
| author | Matt Fleming <matt.fleming@intel.com> | 2014-01-10 18:48:30 +0000 |
|---|---|---|
| committer | Matt Fleming <matt.fleming@intel.com> | 2014-03-04 21:43:14 +0000 |
| commit | 4f9dbcfc40299ddaa780fe8c1cd74998c1be3af5 (patch) | |
| tree | f6d2f85b23fae5ee8d9da79f30c47351aa890d5b /arch/x86/platform/efi/efi_thunk_64.S | |
| parent | b8ff87a6158886771677e6dc8139bac6e3cba717 (diff) | |
x86/efi: Add mixed runtime services support
Setup the runtime services based on whether we're booting in EFI native
mode or not. For non-native mode we need to thunk from 64-bit into
32-bit mode before invoking the EFI runtime services.
Using the runtime services after SetVirtualAddressMap() is slightly more
complicated because we need to ensure that all the addresses we pass to
the firmware are below the 4GB boundary so that they can be addressed
with 32-bit pointers, see efi_setup_page_tables().
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Diffstat (limited to 'arch/x86/platform/efi/efi_thunk_64.S')
| -rw-r--r-- | arch/x86/platform/efi/efi_thunk_64.S | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/x86/platform/efi/efi_thunk_64.S b/arch/x86/platform/efi/efi_thunk_64.S new file mode 100644 index 000000000000..8806fa73e6e6 --- /dev/null +++ b/arch/x86/platform/efi/efi_thunk_64.S @@ -0,0 +1,65 @@ +/* + * Copyright (C) 2014 Intel Corporation; author Matt Fleming + */ + +#include <linux/linkage.h> +#include <asm/page_types.h> + + .text + .code64 +ENTRY(efi64_thunk) + push %rbp + push %rbx + + /* + * Switch to 1:1 mapped 32-bit stack pointer. + */ + movq %rsp, efi_saved_sp(%rip) + movq efi_scratch+25(%rip), %rsp + + /* + * Calculate the physical address of the kernel text. + */ + movq $__START_KERNEL_map, %rax + subq phys_base(%rip), %rax + + /* + * Push some physical addresses onto the stack. This is easier + * to do now in a code64 section while the assembler can address + * 64-bit values. Note that all the addresses on the stack are + * 32-bit. + */ + subq $16, %rsp + leaq efi_exit32(%rip), %rbx + subq %rax, %rbx + movl %ebx, 8(%rsp) + leaq efi_gdt64(%rip), %rbx + subq %rax, %rbx + movl %ebx, 2(%ebx) + movl %ebx, 4(%rsp) + leaq efi_gdt32(%rip), %rbx + subq %rax, %rbx + movl %ebx, 2(%ebx) + movl %ebx, (%rsp) + + leaq __efi64_thunk(%rip), %rbx + subq %rax, %rbx + call *%rbx + + movq efi_saved_sp(%rip), %rsp + pop %rbx + pop %rbp + retq +ENDPROC(efi64_thunk) + + .data +efi_gdt32: + .word efi_gdt32_end - efi_gdt32 + .long 0 /* Filled out above */ + .word 0 + .quad 0x0000000000000000 /* NULL descriptor */ + .quad 0x00cf9a000000ffff /* __KERNEL_CS */ + .quad 0x00cf93000000ffff /* __KERNEL_DS */ +efi_gdt32_end: + +efi_saved_sp: .quad 0 |