diff options
| -rw-r--r-- | arch/x86/boot/compressed/efi_mixed.S | 227 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 7 |
2 files changed, 65 insertions, 169 deletions
diff --git a/arch/x86/boot/compressed/efi_mixed.S b/arch/x86/boot/compressed/efi_mixed.S index dca916c3e6f0..984956931ed7 100644 --- a/arch/x86/boot/compressed/efi_mixed.S +++ b/arch/x86/boot/compressed/efi_mixed.S @@ -15,70 +15,23 @@ */ #include <linux/linkage.h> -#include <asm/asm-offsets.h> +#include <asm/desc_defs.h> #include <asm/msr.h> #include <asm/page_types.h> #include <asm/pgtable_types.h> #include <asm/processor-flags.h> #include <asm/segment.h> -#include <asm/setup.h> .code64 .text -/* - * When booting in 64-bit mode on 32-bit EFI firmware, startup_64_mixed_mode() - * is the first thing that runs after switching to long mode. Depending on - * whether the EFI handover protocol or the compat entry point was used to - * enter the kernel, it will either branch to the common 64-bit EFI stub - * entrypoint efi_stub_entry() directly, or via the 64-bit EFI PE/COFF - * entrypoint efi_pe_entry(). In the former case, the bootloader must provide a - * struct bootparams pointer as the third argument, so the presence of such a - * pointer is used to disambiguate. - * - * +--------------+ - * +------------------+ +------------+ +------>| efi_pe_entry | - * | efi32_pe_entry |---->| | | +-----------+--+ - * +------------------+ | | +------+----------------+ | - * | startup_32 |---->| startup_64_mixed_mode | | - * +------------------+ | | +------+----------------+ | - * | efi32_stub_entry |---->| | | | - * +------------------+ +------------+ | | - * V | - * +------------+ +----------------+ | - * | startup_64 |<----| efi_stub_entry |<--------+ - * +------------+ +----------------+ - */ -SYM_FUNC_START(startup_64_mixed_mode) - lea efi32_boot_args(%rip), %rdx - mov 0(%rdx), %edi - mov 4(%rdx), %esi - - leaq (pte + 5 * PAGE_SIZE)(%rip), %rax - movq %rax, %cr3 // reload after startup_32 - - /* Switch to the firmware's stack */ - movl efi32_boot_sp(%rip), %esp - andl $~7, %esp - - mov 8(%rdx), %edx // saved bootparams pointer - call efi_stub_entry -SYM_FUNC_END(startup_64_mixed_mode) - SYM_FUNC_START(__efi64_thunk) push %rbp push %rbx - movl %ds, %eax - push %rax - movl %es, %eax - push %rax - movl %ss, %eax - push %rax - /* Copy args passed on stack */ - movq 0x30(%rsp), %rbp - movq 0x38(%rsp), %rbx - movq 0x40(%rsp), %rax + movq 0x18(%rsp), %rbp + movq 0x20(%rsp), %rbx + movq 0x28(%rsp), %rax /* * Convert x86-64 ABI params to i386 ABI @@ -93,45 +46,15 @@ SYM_FUNC_START(__efi64_thunk) movl %ebx, 0x18(%rsp) movl %eax, 0x1c(%rsp) - leaq 0x20(%rsp), %rbx - sgdt (%rbx) - sidt 16(%rbx) - leaq 1f(%rip), %rbp + movl %cs, %ebx - /* - * Switch to IDT and GDT with 32-bit segments. These are the firmware - * GDT and IDT that were installed when the kernel started executing. - * The pointers were saved by the efi32_entry() routine below. - * - * Pass the saved DS selector to the 32-bit code, and use far return to - * restore the saved CS selector. - */ - lidt efi32_boot_idt(%rip) - lgdt efi32_boot_gdt(%rip) - - movzwl efi32_boot_ds(%rip), %edx - movzwq efi32_boot_cs(%rip), %rax - pushq %rax - leaq efi_enter32(%rip), %rax - pushq %rax - lretq + ljmpl *efi32_call(%rip) 1: addq $64, %rsp movq %rdi, %rax pop %rbx - movl %ebx, %ss - pop %rbx - movl %ebx, %es - pop %rbx - movl %ebx, %ds - /* Clear out 32-bit selector from FS and GS */ - xorl %ebx, %ebx - movl %ebx, %fs - movl %ebx, %gs - - pop %rbx pop %rbp RET SYM_FUNC_END(__efi64_thunk) @@ -141,7 +64,6 @@ SYM_FUNC_END(__efi64_thunk) SYM_FUNC_START(efi32_stub_entry) call 1f 1: popl %ecx - leal (efi32_boot_args - 1b)(%ecx), %ebx /* Clear BSS */ xorl %eax, %eax @@ -153,11 +75,8 @@ SYM_FUNC_START(efi32_stub_entry) rep stosl add $0x4, %esp /* Discard return address */ - popl %ecx - popl %edx - popl %esi - movl %esi, 8(%ebx) - jmp efi32_entry + movl 8(%esp), %ebx /* struct boot_params pointer */ + jmp efi32_startup SYM_FUNC_END(efi32_stub_entry) #endif @@ -167,13 +86,6 @@ SYM_FUNC_END(efi32_stub_entry) * The stack should represent the 32-bit calling convention. */ SYM_FUNC_START_LOCAL(efi_enter32) - /* Load firmware selector into data and stack segment registers */ - movl %edx, %ds - movl %edx, %es - movl %edx, %fs - movl %edx, %gs - movl %edx, %ss - /* Disable paging */ movl %cr0, %eax btrl $X86_CR0_PG_BIT, %eax @@ -190,21 +102,9 @@ SYM_FUNC_START_LOCAL(efi_enter32) /* We must preserve return value */ movl %eax, %edi - /* - * Some firmware will return with interrupts enabled. Be sure to - * disable them before we switch GDTs and IDTs. - */ - cli - - lidtl 16(%ebx) - lgdtl (%ebx) - - xorl %eax, %eax - lldt %ax - call efi32_enable_long_mode - pushl $__KERNEL_CS + pushl %ebx pushl %ebp lret SYM_FUNC_END(efi_enter32) @@ -230,50 +130,56 @@ SYM_FUNC_START_LOCAL(efi32_enable_long_mode) SYM_FUNC_END(efi32_enable_long_mode) /* - * This is the common EFI stub entry point for mixed mode. + * This is the common EFI stub entry point for mixed mode. It sets up the GDT + * and page tables needed for 64-bit execution, after which it calls the + * common 64-bit EFI entrypoint efi_stub_entry(). * - * Arguments: %ecx image handle - * %edx EFI system table pointer + * Arguments: 0(%esp) image handle + * 4(%esp) EFI system table pointer + * %ebx struct boot_params pointer (or NULL) * * Since this is the point of no return for ordinary execution, no registers * are considered live except for the function parameters. [Note that the EFI * stub may still exit and return to the firmware using the Exit() EFI boot * service.] */ -SYM_FUNC_START_LOCAL(efi32_entry) - call 1f -1: pop %ebx - - /* Save firmware GDTR and code/data selectors */ - sgdtl (efi32_boot_gdt - 1b)(%ebx) - movw %cs, (efi32_boot_cs - 1b)(%ebx) - movw %ds, (efi32_boot_ds - 1b)(%ebx) - - /* Store firmware IDT descriptor */ - sidtl (efi32_boot_idt - 1b)(%ebx) - - /* Store firmware stack pointer */ - movl %esp, (efi32_boot_sp - 1b)(%ebx) - - /* Store boot arguments */ - leal (efi32_boot_args - 1b)(%ebx), %ebx - movl %ecx, 0(%ebx) - movl %edx, 4(%ebx) - movb $0x0, 12(%ebx) // efi_is64 - - /* - * Allocate some memory for a temporary struct boot_params, which only - * needs the minimal pieces that startup_32() relies on. - */ - subl $PARAM_SIZE, %esp - movl %esp, %esi - movl $PAGE_SIZE, BP_kernel_alignment(%esi) - movl $_end - 1b, BP_init_size(%esi) - subl $startup_32 - 1b, BP_init_size(%esi) +SYM_FUNC_START_LOCAL(efi32_startup) + movl %esp, %ebp + + subl $8, %esp + sgdtl (%esp) /* Save GDT descriptor to the stack */ + movl 2(%esp), %esi /* Existing GDT pointer */ + movzwl (%esp), %ecx /* Existing GDT limit */ + inc %ecx /* Existing GDT size */ + andl $~7, %ecx /* Ensure size is multiple of 8 */ + + subl %ecx, %esp /* Allocate new GDT */ + andl $~15, %esp /* Realign the stack */ + movl %esp, %edi /* New GDT address */ + leal 7(%ecx), %eax /* New GDT limit */ + pushw %cx /* Push 64-bit CS (for LJMP below) */ + pushl %edi /* Push new GDT address */ + pushw %ax /* Push new GDT limit */ + + /* Copy GDT to the stack and add a 64-bit code segment at the end */ + movl $GDT_ENTRY(DESC_CODE64, 0, 0xfffff) & 0xffffffff, (%edi,%ecx) + movl $GDT_ENTRY(DESC_CODE64, 0, 0xfffff) >> 32, 4(%edi,%ecx) + shrl $2, %ecx + cld + rep movsl /* Copy the firmware GDT */ + lgdtl (%esp) /* Switch to the new GDT */ call 1f 1: pop %edi + /* Record mixed mode entry */ + movb $0x0, (efi_is64 - 1b)(%edi) + + /* Set up indirect far call to re-enter 32-bit mode */ + leal (efi32_call - 1b)(%edi), %eax + addl %eax, (%eax) + movw %cs, 4(%eax) + /* Disable paging */ movl %cr0, %eax btrl $X86_CR0_PG_BIT, %eax @@ -297,8 +203,17 @@ SYM_FUNC_START_LOCAL(efi32_entry) movl %edx, (%eax) movl %eax, %cr3 - jmp startup_32 -SYM_FUNC_END(efi32_entry) + call efi32_enable_long_mode + + /* Set up far jump to 64-bit mode (CS is already on the stack) */ + leal (efi_stub_entry - 1b)(%edi), %eax + movl %eax, 2(%esp) + + movl 0(%ebp), %edi + movl 4(%ebp), %esi + movl %ebx, %edx + ljmpl *2(%esp) +SYM_FUNC_END(efi32_startup) /* * efi_status_t efi32_pe_entry(efi_handle_t image_handle, @@ -313,10 +228,8 @@ SYM_FUNC_START(efi32_pe_entry) btl $29, %edx // check long mode bit jnc 1f leal 8(%esp), %esp // preserve stack alignment - movl (%esp), %ecx // image_handle - movl 4(%esp), %edx // sys_table - jmp efi32_entry // pass %ecx, %edx - // no other registers remain live + xor %ebx, %ebx // no struct boot_params pointer + jmp efi32_startup // only ESP and EBX remain live 1: movl $0x80000003, %eax // EFI_UNSUPPORTED popl %ebx RET @@ -332,20 +245,10 @@ SYM_FUNC_END(efi64_stub_entry) .data .balign 8 -SYM_DATA_START_LOCAL(efi32_boot_gdt) - .word 0 - .quad 0 -SYM_DATA_END(efi32_boot_gdt) - -SYM_DATA_START_LOCAL(efi32_boot_idt) - .word 0 - .quad 0 -SYM_DATA_END(efi32_boot_idt) - -SYM_DATA_LOCAL(efi32_boot_cs, .word 0) -SYM_DATA_LOCAL(efi32_boot_ds, .word 0) -SYM_DATA_LOCAL(efi32_boot_sp, .long 0) -SYM_DATA_LOCAL(efi32_boot_args, .long 0, 0, 0) +SYM_DATA_START_LOCAL(efi32_call) + .long efi_enter32 - . + .word 0x0 +SYM_DATA_END(efi32_call) SYM_DATA(efi_is64, .byte 1) .bss diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 1dcb794c5479..5db6495a3bb9 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -263,13 +263,6 @@ SYM_FUNC_START(startup_32) * used to perform that far jump. */ leal rva(startup_64)(%ebp), %eax -#ifdef CONFIG_EFI_MIXED - cmpb $1, rva(efi_is64)(%ebp) - je 1f - leal rva(startup_64_mixed_mode)(%ebp), %eax -1: -#endif - pushl $__KERNEL_CS pushl %eax |