diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index ad754b4411f7..8bd44e8ee6e2 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -49,6 +49,7 @@ $(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone vmlinux-objs-$(CONFIG_EFI_STUB) += $(obj)/eboot.o $(obj)/efi_stub_$(BITS).o \ $(objtree)/drivers/firmware/efi/libstub/lib.a +vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o $(obj)/vmlinux: $(vmlinux-objs-y) FORCE $(call if_changed,ld) diff --git a/arch/x86/boot/compressed/efi_stub_64.S b/arch/x86/boot/compressed/efi_stub_64.S index 7ff3632806b1..99494dff2113 100644 --- a/arch/x86/boot/compressed/efi_stub_64.S +++ b/arch/x86/boot/compressed/efi_stub_64.S @@ -3,28 +3,3 @@ #include #include "../../platform/efi/efi_stub_64.S" - -#ifdef CONFIG_EFI_MIXED - .code64 - .text -ENTRY(efi64_thunk) - push %rbp - push %rbx - - subq $16, %rsp - leaq efi_exit32(%rip), %rax - movl %eax, 8(%rsp) - leaq efi_gdt64(%rip), %rax - movl %eax, 4(%rsp) - movl %eax, 2(%rax) /* Fixup the gdt base address */ - leaq efi32_boot_gdt(%rip), %rax - movl %eax, (%rsp) - - call __efi64_thunk - - addq $16, %rsp - pop %rbx - pop %rbp - ret -ENDPROC(efi64_thunk) -#endif /* CONFIG_EFI_MIXED */ diff --git a/arch/x86/boot/compressed/efi_thunk_64.S b/arch/x86/boot/compressed/efi_thunk_64.S new file mode 100644 index 000000000000..630384a4c14a --- /dev/null +++ b/arch/x86/boot/compressed/efi_thunk_64.S @@ -0,0 +1,196 @@ +/* + * Copyright (C) 2014, 2015 Intel Corporation; author Matt Fleming + * + * Early support for invoking 32-bit EFI services from a 64-bit kernel. + * + * Because this thunking occurs before ExitBootServices() we have to + * restore the firmware's 32-bit GDT before we make EFI serivce calls, + * since the firmware's 32-bit IDT is still currently installed and it + * needs to be able to service interrupts. + * + * On the plus side, we don't have to worry about mangling 64-bit + * addresses into 32-bits because we're executing with an identify + * mapped pagetable and haven't transitioned to 64-bit virtual addresses + * yet. + */ + +#include +#include +#include +#include +#include + + .code64 + .text +ENTRY(efi64_thunk) + push %rbp + push %rbx + + subq $8, %rsp + leaq efi_exit32(%rip), %rax + movl %eax, 4(%rsp) + leaq efi_gdt64(%rip), %rax + movl %eax, (%rsp) + movl %eax, 2(%rax) /* Fixup the gdt base address */ + + movl %ds, %eax + push %rax + movl %es, %eax + push %rax + movl %ss, %eax + push %rax + + /* + * Convert x86-64 ABI params to i386 ABI + */ + 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) + + sgdt save_gdt(%rip) + + leaq 1f(%rip), %rbx + movq %rbx, func_rt_ptr(%rip) + + /* + * Switch to gdt with 32-bit segments. This is the firmware GDT + * that was installed when the kernel started executing. This + * pointer was saved at the EFI stub entry point in head_64.S. + */ + leaq efi32_boot_gdt(%rip), %rax + lgdt (%rax) + + pushq $__KERNEL_CS + leaq efi_enter32(%rip), %rax + pushq %rax + lretq + +1: addq $32, %rsp + + lgdt save_gdt(%rip) + + 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: + addq $8, %rsp + pop %rbx + pop %rbp + ret +ENDPROC(efi64_thunk) + +ENTRY(efi_exit32) + movq func_rt_ptr(%rip), %rax + push %rax + mov %rdi, %rax + ret +ENDPROC(efi_exit32) + + .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 + + /* Reload pgtables */ + movl %cr3, %eax + movl %eax, %cr3 + + /* Disable paging */ + movl %cr0, %eax + btrl $X86_CR0_PG_BIT, %eax + movl %eax, %cr0 + + /* Disable long mode via EFER */ + movl $MSR_EFER, %ecx + rdmsr + btrl $_EFER_LME, %eax + wrmsr + + call *%edi + + /* We must preserve return value */ + movl %eax, %edi + + /* + * Some firmware will return with interrupts enabled. Be sure to + * disable them before we switch GDTs. + */ + cli + + movl 56(%esp), %eax + movl %eax, 2(%eax) + lgdtl (%eax) + + movl %cr4, %eax + btsl $(X86_CR4_PAE_BIT), %eax + movl %eax, %cr4 + + movl %cr3, %eax + movl %eax, %cr3 + + movl $MSR_EFER, %ecx + rdmsr + btsl $_EFER_LME, %eax + wrmsr + + xorl %eax, %eax + lldt %ax + + movl 60(%esp), %eax + pushl $__KERNEL_CS + pushl %eax + + /* Enable paging */ + movl %cr0, %eax + btsl $X86_CR0_PG_BIT, %eax + movl %eax, %cr0 + lret +ENDPROC(efi_enter32) + + .data + .balign 8 + .global efi32_boot_gdt +efi32_boot_gdt: .word 0 + .quad 0 + +save_gdt: .word 0 + .quad 0 +func_rt_ptr: .quad 0 + + .global efi_gdt64 +efi_gdt64: + .word efi_gdt64_end - efi_gdt64 + .long 0 /* Filled out by user */ + .word 0 + .quad 0x0000000000000000 /* NULL descriptor */ + .quad 0x00af9a000000ffff /* __KERNEL_CS */ + .quad 0x00cf92000000ffff /* __KERNEL_DS */ + .quad 0x0080890000000000 /* TS descriptor */ + .quad 0x0000000000000000 /* TS continued */ +efi_gdt64_end: diff --git a/arch/x86/platform/efi/efi_stub_64.S b/arch/x86/platform/efi/efi_stub_64.S index 5fcda7272550..86d0f9e08dd9 100644 --- a/arch/x86/platform/efi/efi_stub_64.S +++ b/arch/x86/platform/efi/efi_stub_64.S @@ -91,167 +91,6 @@ ENTRY(efi_call) ret ENDPROC(efi_call) -#ifdef CONFIG_EFI_MIXED - -/* - * 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) - - sgdt save_gdt(%rip) - - leaq 1f(%rip), %rbx - movq %rbx, func_rt_ptr(%rip) - - /* Switch to gdt with 32-bit segments */ - movl 64(%rsp), %eax - lgdt (%rax) - - leaq efi_enter32(%rip), %rax - pushq $__KERNEL_CS - pushq %rax - lretq - -1: addq $32, %rsp - - lgdt save_gdt(%rip) - - 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 - ret -ENDPROC(efi_exit32) - - .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 - - /* Reload pgtables */ - movl %cr3, %eax - movl %eax, %cr3 - - /* Disable paging */ - movl %cr0, %eax - btrl $X86_CR0_PG_BIT, %eax - movl %eax, %cr0 - - /* Disable long mode via EFER */ - movl $MSR_EFER, %ecx - rdmsr - btrl $_EFER_LME, %eax - wrmsr - - call *%edi - - /* We must preserve return value */ - movl %eax, %edi - - /* - * Some firmware will return with interrupts enabled. Be sure to - * disable them before we switch GDTs. - */ - cli - - movl 68(%esp), %eax - movl %eax, 2(%eax) - lgdtl (%eax) - - movl %cr4, %eax - btsl $(X86_CR4_PAE_BIT), %eax - movl %eax, %cr4 - - movl %cr3, %eax - movl %eax, %cr3 - - movl $MSR_EFER, %ecx - rdmsr - btsl $_EFER_LME, %eax - wrmsr - - xorl %eax, %eax - lldt %ax - - movl 72(%esp), %eax - pushl $__KERNEL_CS - pushl %eax - - /* Enable paging */ - movl %cr0, %eax - btsl $X86_CR0_PG_BIT, %eax - movl %eax, %cr0 - lret -ENDPROC(efi_enter32) - - .data - .balign 8 - .global efi32_boot_gdt -efi32_boot_gdt: .word 0 - .quad 0 - -save_gdt: .word 0 - .quad 0 -func_rt_ptr: .quad 0 - - .global efi_gdt64 -efi_gdt64: - .word efi_gdt64_end - efi_gdt64 - .long 0 /* Filled out by user */ - .word 0 - .quad 0x0000000000000000 /* NULL descriptor */ - .quad 0x00af9a000000ffff /* __KERNEL_CS */ - .quad 0x00cf92000000ffff /* __KERNEL_DS */ - .quad 0x0080890000000000 /* TS descriptor */ - .quad 0x0000000000000000 /* TS continued */ -efi_gdt64_end: -#endif /* CONFIG_EFI_MIXED */ - .data ENTRY(efi_scratch) .fill 3,8,0 diff --git a/arch/x86/platform/efi/efi_thunk_64.S b/arch/x86/platform/efi/efi_thunk_64.S index 8806fa73e6e6..ff85d28c50f2 100644 --- a/arch/x86/platform/efi/efi_thunk_64.S +++ b/arch/x86/platform/efi/efi_thunk_64.S @@ -1,9 +1,26 @@ /* * Copyright (C) 2014 Intel Corporation; author Matt Fleming + * + * Support for invoking 32-bit EFI runtime services from a 64-bit + * kernel. + * + * 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 + * services from __KERNEL32_CS. This means we can continue to service + * interrupts across an EFI mixed mode call. + * + * We do however, need to handle the fact that we're running in a full + * 64-bit virtual address space. Things like the stack and instruction + * addresses need to be accessible by the 32-bit firmware, so we rely on + * using the identity mappings in the EFI page table to access the stack + * and kernel text (see efi_setup_page_tables()). */ #include #include +#include .text .code64 @@ -33,14 +50,6 @@ ENTRY(efi64_thunk) 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 @@ -52,14 +61,92 @@ ENTRY(efi64_thunk) 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: +/* + * 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) + + /* Switch to 32-bit descriptor */ + pushq $__KERNEL32_CS + leaq efi_enter32(%rip), %rax + pushq %rax + lretq + +1: addq $32, %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 + ret +ENDPROC(efi_exit32) + + .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 + + lret +ENDPROC(efi_enter32) + + .data + .balign 8 +func_rt_ptr: .quad 0 efi_saved_sp: .quad 0 diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index d073e3946383..9bd9fbb5bea8 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -66,29 +66,25 @@ efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg, unsigned long key; u32 desc_version; - *map_size = 0; - *desc_size = 0; - key = 0; - status = efi_call_early(get_memory_map, map_size, NULL, - &key, desc_size, &desc_version); - if (status != EFI_BUFFER_TOO_SMALL) - return EFI_LOAD_ERROR; - + *map_size = sizeof(*m) * 32; +again: /* * Add an additional efi_memory_desc_t because we're doing an * allocation which may be in a new descriptor region. */ - *map_size += *desc_size; + *map_size += sizeof(*m); status = efi_call_early(allocate_pool, EFI_LOADER_DATA, *map_size, (void **)&m); if (status != EFI_SUCCESS) goto fail; + *desc_size = 0; + key = 0; status = efi_call_early(get_memory_map, map_size, m, &key, desc_size, &desc_version); if (status == EFI_BUFFER_TOO_SMALL) { efi_call_early(free_pool, m); - return EFI_LOAD_ERROR; + goto again; } if (status != EFI_SUCCESS)