Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9e085cef authored by Jiri Slaby's avatar Jiri Slaby Committed by Ingo Molnar
Browse files

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:

  99f857db ("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: default avatarJiri Slaby <jslaby@suse.cz>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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: default avatarIngo Molnar <mingo@kernel.org>
parent f4dee0bb

arch/x86/boot/compressed/head_64.S

+53 −59
Original line number Diff line number Diff line
@@ -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 */