diff options
Diffstat (limited to 'arch/x86/platform/efi/efi_thunk_64.S')
| -rw-r--r-- | arch/x86/platform/efi/efi_thunk_64.S | 145 |
1 files changed, 45 insertions, 100 deletions
diff --git a/arch/x86/platform/efi/efi_thunk_64.S b/arch/x86/platform/efi/efi_thunk_64.S index 46c58b08739c..c4b1144f99f6 100644 --- a/arch/x86/platform/efi/efi_thunk_64.S +++ b/arch/x86/platform/efi/efi_thunk_64.S @@ -8,7 +8,7 @@ * The below thunking functions are only used after ExitBootServices() * has been called. This simplifies things considerably as compared with * the early EFI thunking because we can leave all the kernel state - * intact (GDT, IDT, etc) and simply invoke the the 32-bit EFI runtime + * intact (GDT, IDT, etc) and simply invoke the 32-bit EFI runtime * services from __KERNEL32_CS. This means we can continue to service * interrupts across an EFI mixed mode call. * @@ -20,134 +20,79 @@ */ #include <linux/linkage.h> +#include <linux/objtool.h> #include <asm/page_types.h> #include <asm/segment.h> .text .code64 -ENTRY(efi64_thunk) +SYM_FUNC_START(__efi64_thunk) +STACK_FRAME_NON_STANDARD __efi64_thunk push %rbp push %rbx /* * Switch to 1:1 mapped 32-bit stack pointer. */ - movq %rsp, efi_saved_sp(%rip) - movq efi_scratch(%rip), %rsp + movq %rsp, %rax + movq efi_mixed_mode_stack_pa(%rip), %rsp + push %rax /* - * Calculate the physical address of the kernel text. + * Copy args passed via the stack */ - movq $__START_KERNEL_map, %rax - subq phys_base(%rip), %rax + subq $0x24, %rsp + movq 0x18(%rax), %rbp + movq 0x20(%rax), %rbx + movq 0x28(%rax), %rax + movl %ebp, 0x18(%rsp) + movl %ebx, 0x1c(%rsp) + movl %eax, 0x20(%rsp) /* - * 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. + * Calculate the physical address of the kernel text. */ - subq $16, %rsp - leaq efi_exit32(%rip), %rbx - subq %rax, %rbx - movl %ebx, 8(%rsp) + movq $__START_KERNEL_map, %rax + subq phys_base(%rip), %rax - leaq __efi64_thunk(%rip), %rbx + leaq 1f(%rip), %rbp + leaq 2f(%rip), %rbx + subq %rax, %rbp subq %rax, %rbx - call *%rbx - - movq efi_saved_sp(%rip), %rsp - pop %rbx - pop %rbp - retq -ENDPROC(efi64_thunk) - -/* - * We run this function from the 1:1 mapping. - * - * This function must be invoked with a 1:1 mapped stack. - */ -ENTRY(__efi64_thunk) - movl %ds, %eax - push %rax - movl %es, %eax - push %rax - movl %ss, %eax - push %rax - subq $32, %rsp - movl %esi, 0x0(%rsp) - movl %edx, 0x4(%rsp) - movl %ecx, 0x8(%rsp) - movq %r8, %rsi - movl %esi, 0xc(%rsp) - movq %r9, %rsi - movl %esi, 0x10(%rsp) - - leaq 1f(%rip), %rbx - movq %rbx, func_rt_ptr(%rip) + movl %ebx, 0x0(%rsp) /* return address */ + movl %esi, 0x4(%rsp) + movl %edx, 0x8(%rsp) + movl %ecx, 0xc(%rsp) + movl %r8d, 0x10(%rsp) + movl %r9d, 0x14(%rsp) /* Switch to 32-bit descriptor */ pushq $__KERNEL32_CS - leaq efi_enter32(%rip), %rax - pushq %rax + pushq %rdi /* EFI runtime service address */ lretq -1: addq $32, %rsp + // This return instruction is not needed for correctness, as it will + // never be reached. It only exists to make objtool happy, which will + // otherwise complain about unreachable instructions in the callers. + RET +SYM_FUNC_END(__efi64_thunk) + .section ".rodata", "a", @progbits + .balign 16 +SYM_DATA_START(__efi64_thunk_ret_tramp) +1: movq 0x20(%rsp), %rsp pop %rbx - movl %ebx, %ss - pop %rbx - movl %ebx, %es - pop %rbx - movl %ebx, %ds - - /* - * Convert 32-bit status code into 64-bit. - */ - test %rax, %rax - jz 1f - movl %eax, %ecx - andl $0x0fffffff, %ecx - andl $0xf0000000, %eax - shl $32, %rax - or %rcx, %rax -1: - ret -ENDPROC(__efi64_thunk) - -ENTRY(efi_exit32) - movq func_rt_ptr(%rip), %rax - push %rax - mov %rdi, %rax + pop %rbp ret -ENDPROC(efi_exit32) + int3 .code32 -/* - * EFI service pointer must be in %edi. - * - * The stack should represent the 32-bit calling convention. - */ -ENTRY(efi_enter32) - movl $__KERNEL_DS, %eax - movl %eax, %ds - movl %eax, %es - movl %eax, %ss - - call *%edi - - /* We must preserve return value */ - movl %eax, %edi - - movl 72(%esp), %eax - pushl $__KERNEL_CS - pushl %eax - +2: pushl $__KERNEL_CS + pushl %ebp lret -ENDPROC(efi_enter32) +SYM_DATA_END(__efi64_thunk_ret_tramp) - .data - .balign 8 -func_rt_ptr: .quad 0 -efi_saved_sp: .quad 0 + .bss + .balign 8 +SYM_DATA(efi_mixed_mode_stack_pa, .quad 0) |