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Commit 829bf7af authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Merge tag 'efi-urgent' of... 

Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi

 into x86/urgent

Pull EFI fixes from Matt Fleming:

" - Leave a valid 64-bit IDT installed during runtime EFI mixed mode
    calls to avoid triple faults if an NMI/MCE is received.

  - Revert Ard's change to the libstub get_memory_map() that went into
    the v3.20 merge window because it causes boot regressions on Qemu and
    Xen. "

Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents e07e0d4c 43a9f696

arch/x86/boot/compressed/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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)

arch/x86/boot/compressed/efi_stub_64.S

+0 −25
Original line number Diff line number Diff line
@@ -3,28 +3,3 @@ 
#include <asm/processor-flags.h>



#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 */

arch/x86/boot/compressed/efi_thunk_64.S

0 → 100644
+196 −0
Original line number Diff line number Diff line 
/*

 * 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 <linux/linkage.h>

#include <asm/msr.h>

#include <asm/page_types.h>

#include <asm/processor-flags.h>

#include <asm/segment.h>



	.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:

arch/x86/platform/efi/efi_stub_64.S

+0 −161
Original line number Diff line number Diff line
@@ -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

arch/x86/platform/efi/efi_thunk_64.S

+104 −17
Original line number Diff line number Diff line 
/*

 * 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 <linux/linkage.h>

#include <asm/page_types.h>

#include <asm/segment.h>



	.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