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Message-ID: <34a1c2bd-53f2-4f4f-9f5a-272f677eb9a3@amd.com> Date: Wed, 9 Apr 2025 17:24:26 +0530 From: "Aithal, Srikanth" <sraithal@....com> To: Ard Biesheuvel <ardb@...nel.org> Cc: linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>, David Woodhouse <dwmw@...zon.co.uk>, "H. Peter Anvin" <hpa@...or.com>, Kees Cook <keescook@...omium.org>, x86@...nel.org Subject: Re: [tip: x86/boot] x86/boot: Move the EFI mixed mode startup code back under arch/x86, into startup/ On 4/7/2025 3:11 PM, Aithal, Srikanth wrote: > On 4/7/2025 2:00 PM, Ard Biesheuvel wrote: >> On Mon, 7 Apr 2025 at 10:38, Aithal, Srikanth <sraithal@....com> wrote: >>> >>> Hello, >>> >>> This commit breaks the build of next-20250407. The kernel config is >>> attached here. >>> >>> Build error: >>> >>> arch/x86/boot/startup/efi-mixed.o: warning: objtool: >>> efi32_stub_entry+0x0: unannotated intra-function call >>> make[3]: *** [scripts/Makefile.build:335: >>> arch/x86/boot/startup/efi-mixed.o] Error 255 >>> make[3]: *** Deleting file 'arch/x86/boot/startup/efi-mixed.o' >>> make[3]: *** Waiting for unfinished jobs.... >>> make[2]: *** [scripts/Makefile.build:461: arch/x86/boot/startup] Error 2 >>> make[2]: *** Waiting for unfinished jobs.... >>> make[1]: *** [/home/VT_BUILD/linux/Makefile:2006: .] Error 2 >>> make: *** [Makefile:248: __sub-make] Error 2 >>> >>> >> >> Apologies for the breakage. >> >> Does it help to add the following to arch/x86/boot/startup/Makefile: >> >> OBJECT_FILES_NON_STANDARD := y >> >> ? If the above is the solution, could you please let me know how soon it might be included in the linux-next build? > > yes, this fixes the issue. > > Reported-by: Srikanth Aithal <sraithal@....com> > Tested-by: Srikanth Aithal <sraithal@....com> > >> >>> >>> Thanks, >>> Srikanth Aithal <sraithal@....com> >>> >>> >>> On 4/7/2025 12:03 AM, tip-bot2 for Ard Biesheuvel wrote: >>>> The following commit has been merged into the x86/boot branch of tip: >>>> >>>> Commit-ID: 4f2d1bbc2c92a32fd612e6c3b51832d5c1c3678e >>>> Gitweb: https://git.kernel.org/ >>>> tip/4f2d1bbc2c92a32fd612e6c3b51832d5c1c3678e >>>> Author: Ard Biesheuvel <ardb@...nel.org> >>>> AuthorDate: Tue, 01 Apr 2025 15:34:20 +02:00 >>>> Committer: Ingo Molnar <mingo@...nel.org> >>>> CommitterDate: Sun, 06 Apr 2025 20:15:14 +02:00 >>>> >>>> x86/boot: Move the EFI mixed mode startup code back under arch/x86, >>>> into startup/ >>>> >>>> Linus expressed a strong preference for arch-specific asm code (i.e., >>>> virtually all of it) to reside under arch/ rather than anywhere else. >>>> >>>> So move the EFI mixed mode startup code back, and put it under >>>> arch/x86/boot/startup/ where all shared x86 startup code is going to >>>> live. >>>> >>>> Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org> >>>> Signed-off-by: Ard Biesheuvel <ardb@...nel.org> >>>> Signed-off-by: Ingo Molnar <mingo@...nel.org> >>>> Cc: David Woodhouse <dwmw@...zon.co.uk> >>>> Cc: H. Peter Anvin <hpa@...or.com> >>>> Cc: Kees Cook <keescook@...omium.org> >>>> Link: https://lore.kernel.org/r/20250401133416.1436741-11- >>>> ardb+git@...gle.com >>>> --- >>>> arch/x86/boot/startup/Makefile | 3 +- >>>> arch/x86/boot/startup/efi-mixed.S | 253 ++++++++++++++++++ >>>> ++++- >>>> drivers/firmware/efi/libstub/Makefile | 1 +- >>>> drivers/firmware/efi/libstub/x86-mixed.S | 253 >>>> +---------------------- >>>> 4 files changed, 256 insertions(+), 254 deletions(-) >>>> create mode 100644 arch/x86/boot/startup/efi-mixed.S >>>> delete mode 100644 drivers/firmware/efi/libstub/x86-mixed.S >>>> >>>> diff --git a/arch/x86/boot/startup/Makefile b/arch/x86/boot/startup/ >>>> Makefile >>>> index 03519ef..73946a3 100644 >>>> --- a/arch/x86/boot/startup/Makefile >>>> +++ b/arch/x86/boot/startup/Makefile >>>> @@ -1,3 +1,6 @@ >>>> # SPDX-License-Identifier: GPL-2.0 >>>> >>>> +KBUILD_AFLAGS += -D__DISABLE_EXPORTS >>>> + >>>> lib-$(CONFIG_X86_64) += la57toggle.o >>>> +lib-$(CONFIG_EFI_MIXED) += efi-mixed.o >>>> diff --git a/arch/x86/boot/startup/efi-mixed.S b/arch/x86/boot/ >>>> startup/efi-mixed.S >>>> new file mode 100644 >>>> index 0000000..e04ed99 >>>> --- /dev/null >>>> +++ b/arch/x86/boot/startup/efi-mixed.S >>>> @@ -0,0 +1,253 @@ >>>> +/* SPDX-License-Identifier: GPL-2.0 */ >>>> +/* >>>> + * 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 and IDT before we make EFI >>>> service >>>> + * calls. >>>> + * >>>> + * On the plus side, we don't have to worry about mangling 64-bit >>>> + * addresses into 32-bits because we're executing with an identity >>>> + * mapped pagetable and haven't transitioned to 64-bit virtual >>>> addresses >>>> + * yet. >>>> + */ >>>> + >>>> +#include <linux/linkage.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> >>>> + >>>> + .text >>>> + .code32 >>>> +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL >>>> +SYM_FUNC_START(efi32_stub_entry) >>>> + call 1f >>>> +1: popl %ecx >>>> + >>>> + /* Clear BSS */ >>>> + xorl %eax, %eax >>>> + leal (_bss - 1b)(%ecx), %edi >>>> + leal (_ebss - 1b)(%ecx), %ecx >>>> + subl %edi, %ecx >>>> + shrl $2, %ecx >>>> + cld >>>> + rep stosl >>>> + >>>> + add $0x4, %esp /* Discard return address */ >>>> + movl 8(%esp), %ebx /* struct boot_params pointer */ >>>> + jmp efi32_startup >>>> +SYM_FUNC_END(efi32_stub_entry) >>>> +#endif >>>> + >>>> +/* >>>> + * Called using a far call from __efi64_thunk() below, using the >>>> x86_64 SysV >>>> + * ABI (except for R8/R9 which are inaccessible to 32-bit code - >>>> EAX/EBX are >>>> + * used instead). EBP+16 points to the arguments passed via the >>>> stack. >>>> + * >>>> + * The first argument (EDI) is a pointer to the boot service or >>>> protocol, to >>>> + * which the remaining arguments are passed, each truncated to 32 >>>> bits. >>>> + */ >>>> +SYM_FUNC_START_LOCAL(efi_enter32) >>>> + /* >>>> + * Convert x86-64 SysV ABI params to i386 ABI >>>> + */ >>>> + pushl 32(%ebp) /* Up to 3 args passed via the stack */ >>>> + pushl 24(%ebp) >>>> + pushl 16(%ebp) >>>> + pushl %ebx /* R9 */ >>>> + pushl %eax /* R8 */ >>>> + pushl %ecx >>>> + pushl %edx >>>> + pushl %esi >>>> + >>>> + /* 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 >>>> + >>>> + call efi32_enable_long_mode >>>> + >>>> + addl $32, %esp >>>> + movl %edi, %eax >>>> + lret >>>> +SYM_FUNC_END(efi_enter32) >>>> + >>>> + .code64 >>>> +SYM_FUNC_START(__efi64_thunk) >>>> + push %rbp >>>> + movl %esp, %ebp >>>> + push %rbx >>>> + >>>> + /* Move args #5 and #6 into 32-bit accessible registers */ >>>> + movl %r8d, %eax >>>> + movl %r9d, %ebx >>>> + >>>> + lcalll *efi32_call(%rip) >>>> + >>>> + pop %rbx >>>> + pop %rbp >>>> + RET >>>> +SYM_FUNC_END(__efi64_thunk) >>>> + >>>> + .code32 >>>> +SYM_FUNC_START_LOCAL(efi32_enable_long_mode) >>>> + movl %cr4, %eax >>>> + btsl $(X86_CR4_PAE_BIT), %eax >>>> + movl %eax, %cr4 >>>> + >>>> + movl $MSR_EFER, %ecx >>>> + rdmsr >>>> + btsl $_EFER_LME, %eax >>>> + wrmsr >>>> + >>>> + /* Disable interrupts - the firmware's IDT does not work in >>>> long mode */ >>>> + cli >>>> + >>>> + /* Enable paging */ >>>> + movl %cr0, %eax >>>> + btsl $X86_CR0_PG_BIT, %eax >>>> + movl %eax, %cr0 >>>> + ret >>>> +SYM_FUNC_END(efi32_enable_long_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: 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_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 >>>> + movl %eax, %cr0 >>>> + >>>> + /* Set up 1:1 mapping */ >>>> + leal (pte - 1b)(%edi), %eax >>>> + movl $_PAGE_PRESENT | _PAGE_RW | _PAGE_PSE, %ecx >>>> + leal (_PAGE_PRESENT | _PAGE_RW)(%eax), %edx >>>> +2: movl %ecx, (%eax) >>>> + addl $8, %eax >>>> + addl $PMD_SIZE, %ecx >>>> + jnc 2b >>>> + >>>> + movl $PAGE_SIZE, %ecx >>>> + .irpc l, 0123 >>>> + movl %edx, \l * 8(%eax) >>>> + addl %ecx, %edx >>>> + .endr >>>> + addl %ecx, %eax >>>> + movl %edx, (%eax) >>>> + movl %eax, %cr3 >>>> + >>>> + 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, >>>> + * efi_system_table_32_t *sys_table) >>>> + */ >>>> +SYM_FUNC_START(efi32_pe_entry) >>>> + pushl %ebx // save callee-save >>>> registers >>>> + >>>> + /* Check whether the CPU supports long mode */ >>>> + movl $0x80000001, %eax // assume extended >>>> info support >>>> + cpuid >>>> + btl $29, %edx // check long mode bit >>>> + jnc 1f >>>> + leal 8(%esp), %esp // preserve stack >>>> alignment >>>> + xor %ebx, %ebx // no struct >>>> boot_params pointer >>>> + jmp efi32_startup // only ESP and EBX >>>> remain live >>>> +1: movl $0x80000003, %eax // EFI_UNSUPPORTED >>>> + popl %ebx >>>> + RET >>>> +SYM_FUNC_END(efi32_pe_entry) >>>> + >>>> +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL >>>> + .org efi32_stub_entry + 0x200 >>>> + .code64 >>>> +SYM_FUNC_START_NOALIGN(efi64_stub_entry) >>>> + jmp efi_handover_entry >>>> +SYM_FUNC_END(efi64_stub_entry) >>>> +#endif >>>> + >>>> + .data >>>> + .balign 8 >>>> +SYM_DATA_START_LOCAL(efi32_call) >>>> + .long efi_enter32 - . >>>> + .word 0x0 >>>> +SYM_DATA_END(efi32_call) >>>> +SYM_DATA(efi_is64, .byte 1) >>>> + >>>> + .bss >>>> + .balign PAGE_SIZE >>>> +SYM_DATA_LOCAL(pte, .fill 6 * PAGE_SIZE, 1, 0) >>>> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/ >>>> firmware/efi/libstub/Makefile >>>> index d23a1b9..2f17339 100644 >>>> --- a/drivers/firmware/efi/libstub/Makefile >>>> +++ b/drivers/firmware/efi/libstub/Makefile >>>> @@ -85,7 +85,6 @@ lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o >>>> string.o intrinsics.o systable.o \ >>>> lib-$(CONFIG_ARM) += arm32-stub.o >>>> lib-$(CONFIG_ARM64) += kaslr.o arm64.o arm64-stub.o smbios.o >>>> lib-$(CONFIG_X86) += x86-stub.o smbios.o >>>> -lib-$(CONFIG_EFI_MIXED) += x86-mixed.o >>>> lib-$(CONFIG_X86_64) += x86-5lvl.o >>>> lib-$(CONFIG_RISCV) += kaslr.o riscv.o riscv-stub.o >>>> lib-$(CONFIG_LOONGARCH) += loongarch.o loongarch-stub.o >>>> diff --git a/drivers/firmware/efi/libstub/x86-mixed.S b/drivers/ >>>> firmware/efi/libstub/x86-mixed.S >>>> deleted file mode 100644 >>>> index e04ed99..0000000 >>>> --- a/drivers/firmware/efi/libstub/x86-mixed.S >>>> +++ /dev/null >>>> @@ -1,253 +0,0 @@ >>>> -/* SPDX-License-Identifier: GPL-2.0 */ >>>> -/* >>>> - * 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 and IDT before we make EFI >>>> service >>>> - * calls. >>>> - * >>>> - * On the plus side, we don't have to worry about mangling 64-bit >>>> - * addresses into 32-bits because we're executing with an identity >>>> - * mapped pagetable and haven't transitioned to 64-bit virtual >>>> addresses >>>> - * yet. >>>> - */ >>>> - >>>> -#include <linux/linkage.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> >>>> - >>>> - .text >>>> - .code32 >>>> -#ifdef CONFIG_EFI_HANDOVER_PROTOCOL >>>> -SYM_FUNC_START(efi32_stub_entry) >>>> - call 1f >>>> -1: popl %ecx >>>> - >>>> - /* Clear BSS */ >>>> - xorl %eax, %eax >>>> - leal (_bss - 1b)(%ecx), %edi >>>> - leal (_ebss - 1b)(%ecx), %ecx >>>> - subl %edi, %ecx >>>> - shrl $2, %ecx >>>> - cld >>>> - rep stosl >>>> - >>>> - add $0x4, %esp /* Discard return address */ >>>> - movl 8(%esp), %ebx /* struct boot_params pointer */ >>>> - jmp efi32_startup >>>> -SYM_FUNC_END(efi32_stub_entry) >>>> -#endif >>>> - >>>> -/* >>>> - * Called using a far call from __efi64_thunk() below, using the >>>> x86_64 SysV >>>> - * ABI (except for R8/R9 which are inaccessible to 32-bit code - >>>> EAX/EBX are >>>> - * used instead). EBP+16 points to the arguments passed via the >>>> stack. >>>> - * >>>> - * The first argument (EDI) is a pointer to the boot service or >>>> protocol, to >>>> - * which the remaining arguments are passed, each truncated to 32 >>>> bits. >>>> - */ >>>> -SYM_FUNC_START_LOCAL(efi_enter32) >>>> - /* >>>> - * Convert x86-64 SysV ABI params to i386 ABI >>>> - */ >>>> - pushl 32(%ebp) /* Up to 3 args passed via the stack */ >>>> - pushl 24(%ebp) >>>> - pushl 16(%ebp) >>>> - pushl %ebx /* R9 */ >>>> - pushl %eax /* R8 */ >>>> - pushl %ecx >>>> - pushl %edx >>>> - pushl %esi >>>> - >>>> - /* 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 >>>> - >>>> - call efi32_enable_long_mode >>>> - >>>> - addl $32, %esp >>>> - movl %edi, %eax >>>> - lret >>>> -SYM_FUNC_END(efi_enter32) >>>> - >>>> - .code64 >>>> -SYM_FUNC_START(__efi64_thunk) >>>> - push %rbp >>>> - movl %esp, %ebp >>>> - push %rbx >>>> - >>>> - /* Move args #5 and #6 into 32-bit accessible registers */ >>>> - movl %r8d, %eax >>>> - movl %r9d, %ebx >>>> - >>>> - lcalll *efi32_call(%rip) >>>> - >>>> - pop %rbx >>>> - pop %rbp >>>> - RET >>>> -SYM_FUNC_END(__efi64_thunk) >>>> - >>>> - .code32 >>>> -SYM_FUNC_START_LOCAL(efi32_enable_long_mode) >>>> - movl %cr4, %eax >>>> - btsl $(X86_CR4_PAE_BIT), %eax >>>> - movl %eax, %cr4 >>>> - >>>> - movl $MSR_EFER, %ecx >>>> - rdmsr >>>> - btsl $_EFER_LME, %eax >>>> - wrmsr >>>> - >>>> - /* Disable interrupts - the firmware's IDT does not work in >>>> long mode */ >>>> - cli >>>> - >>>> - /* Enable paging */ >>>> - movl %cr0, %eax >>>> - btsl $X86_CR0_PG_BIT, %eax >>>> - movl %eax, %cr0 >>>> - ret >>>> -SYM_FUNC_END(efi32_enable_long_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: 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_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 >>>> - movl %eax, %cr0 >>>> - >>>> - /* Set up 1:1 mapping */ >>>> - leal (pte - 1b)(%edi), %eax >>>> - movl $_PAGE_PRESENT | _PAGE_RW | _PAGE_PSE, %ecx >>>> - leal (_PAGE_PRESENT | _PAGE_RW)(%eax), %edx >>>> -2: movl %ecx, (%eax) >>>> - addl $8, %eax >>>> - addl $PMD_SIZE, %ecx >>>> - jnc 2b >>>> - >>>> - movl $PAGE_SIZE, %ecx >>>> - .irpc l, 0123 >>>> - movl %edx, \l * 8(%eax) >>>> - addl %ecx, %edx >>>> - .endr >>>> - addl %ecx, %eax >>>> - movl %edx, (%eax) >>>> - movl %eax, %cr3 >>>> - >>>> - 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, >>>> - * efi_system_table_32_t *sys_table) >>>> - */ >>>> -SYM_FUNC_START(efi32_pe_entry) >>>> - pushl %ebx // save callee-save >>>> registers >>>> - >>>> - /* Check whether the CPU supports long mode */ >>>> - movl $0x80000001, %eax // assume extended >>>> info support >>>> - cpuid >>>> - btl $29, %edx // check long mode bit >>>> - jnc 1f >>>> - leal 8(%esp), %esp // preserve stack >>>> alignment >>>> - 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 >>>> -SYM_FUNC_END(efi32_pe_entry) >>>> - >>>> -#ifdef CONFIG_EFI_HANDOVER_PROTOCOL >>>> - .org efi32_stub_entry + 0x200 >>>> - .code64 >>>> -SYM_FUNC_START_NOALIGN(efi64_stub_entry) >>>> - jmp efi_handover_entry >>>> -SYM_FUNC_END(efi64_stub_entry) >>>> -#endif >>>> - >>>> - .data >>>> - .balign 8 >>>> -SYM_DATA_START_LOCAL(efi32_call) >>>> - .long efi_enter32 - . >>>> - .word 0x0 >>>> -SYM_DATA_END(efi32_call) >>>> -SYM_DATA(efi_is64, .byte 1) >>>> - >>>> - .bss >>>> - .balign PAGE_SIZE >>>> -SYM_DATA_LOCAL(pte, .fill 6 * PAGE_SIZE, 1, 0) >
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