From 9e085cefc61155e45b87a277440f96682e7921f1 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Thu, 24 Aug 2017 09:33:27 +0200 Subject: [PATCH] x86/boot/64: Extract efi_pe_entry() from startup_64() Similarly to the 32-bit code, efi_pe_entry body() is somehow squashed into startup_64(). In the old days, we forced startup_64() to start at offset 0x200 and efi_pe_entry() to start at 0x210. But this requirement was removed long time ago, in: 99f857db8857 ("x86, build: Dynamically find entry points in compressed startup code") The way it is now makes the code less readable and illogical. Given we can now safely extract the inlined efi_pe_entry() body from startup_64() into a separate function, we do so. We also annotate the function appropriatelly by ENTRY+ENDPROC. ABI offsets are preserved: 0000000000000000 T startup_32 0000000000000200 T startup_64 0000000000000390 T efi64_stub_entry On the top-level, it looked like: .org 0x200 ENTRY(startup_64) #ifdef CONFIG_EFI_STUB ; start of inlined jmp preferred_addr GLOBAL(efi_pe_entry) ... ; a lot of assembly (efi_pe_entry) leaq preferred_addr(%rax), %rax jmp *%rax preferred_addr: #endif ; end of inlined ... ; a lot of assembly (startup_64) ENDPROC(startup_64) And it is now converted into: .org 0x200 ENTRY(startup_64) ... ; a lot of assembly (startup_64) ENDPROC(startup_64) #ifdef CONFIG_EFI_STUB ENTRY(efi_pe_entry) ... ; a lot of assembly (efi_pe_entry) leaq startup_64(%rax), %rax jmp *%rax ENDPROC(efi_pe_entry) #endif Signed-off-by: Jiri Slaby Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: David Woodhouse Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: ard.biesheuvel@linaro.org Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20170824073327.4129-2-jslaby@suse.cz Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/head_64.S | 112 ++++++++++++++--------------- 1 file changed, 53 insertions(+), 59 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index fbf4c32d0b62..b4a5d284391c 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -243,65 +243,6 @@ ENTRY(startup_64) * that maps our entire kernel(text+data+bss+brk), zero page * and command line. */ -#ifdef CONFIG_EFI_STUB - /* - * The entry point for the PE/COFF executable is efi_pe_entry, so - * only legacy boot loaders will execute this jmp. - */ - jmp preferred_addr - -ENTRY(efi_pe_entry) - movq %rcx, efi64_config(%rip) /* Handle */ - movq %rdx, efi64_config+8(%rip) /* EFI System table pointer */ - - leaq efi64_config(%rip), %rax - movq %rax, efi_config(%rip) - - call 1f -1: popq %rbp - subq $1b, %rbp - - /* - * Relocate efi_config->call(). - */ - addq %rbp, efi64_config+40(%rip) - - movq %rax, %rdi - call make_boot_params - cmpq $0,%rax - je fail - mov %rax, %rsi - leaq startup_32(%rip), %rax - movl %eax, BP_code32_start(%rsi) - jmp 2f /* Skip the relocation */ - -handover_entry: - call 1f -1: popq %rbp - subq $1b, %rbp - - /* - * Relocate efi_config->call(). - */ - movq efi_config(%rip), %rax - addq %rbp, 40(%rax) -2: - movq efi_config(%rip), %rdi - call efi_main - movq %rax,%rsi - cmpq $0,%rax - jne 2f -fail: - /* EFI init failed, so hang. */ - hlt - jmp fail -2: - movl BP_code32_start(%esi), %eax - leaq preferred_addr(%rax), %rax - jmp *%rax - -preferred_addr: -#endif /* Setup data segments. */ xorl %eax, %eax @@ -413,6 +354,59 @@ lvl5: jmp *%rax #ifdef CONFIG_EFI_STUB + +/* The entry point for the PE/COFF executable is efi_pe_entry. */ +ENTRY(efi_pe_entry) + movq %rcx, efi64_config(%rip) /* Handle */ + movq %rdx, efi64_config+8(%rip) /* EFI System table pointer */ + + leaq efi64_config(%rip), %rax + movq %rax, efi_config(%rip) + + call 1f +1: popq %rbp + subq $1b, %rbp + + /* + * Relocate efi_config->call(). + */ + addq %rbp, efi64_config+40(%rip) + + movq %rax, %rdi + call make_boot_params + cmpq $0,%rax + je fail + mov %rax, %rsi + leaq startup_32(%rip), %rax + movl %eax, BP_code32_start(%rsi) + jmp 2f /* Skip the relocation */ + +handover_entry: + call 1f +1: popq %rbp + subq $1b, %rbp + + /* + * Relocate efi_config->call(). + */ + movq efi_config(%rip), %rax + addq %rbp, 40(%rax) +2: + movq efi_config(%rip), %rdi + call efi_main + movq %rax,%rsi + cmpq $0,%rax + jne 2f +fail: + /* EFI init failed, so hang. */ + hlt + jmp fail +2: + movl BP_code32_start(%esi), %eax + leaq startup_64(%rax), %rax + jmp *%rax +ENDPROC(efi_pe_entry) + .org 0x390 ENTRY(efi64_stub_entry) movq %rdi, efi64_config(%rip) /* Handle */ -- 2.20.1