linux/arch/x86/platform/efi/efi_stub_64.S
Matt Fleming c9f2a9a65e x86/efi: Hoist page table switching code into efi_call_virt()
This change is a prerequisite for pending patches that switch to
a dedicated EFI page table, instead of using 'trampoline_pgd'
which shares PGD entries with 'swapper_pg_dir'. The pending
patches make it impossible to dereference the runtime service
function pointer without first switching %cr3.

It's true that we now have duplicated switching code in
efi_call_virt() and efi_call_phys_{prolog,epilog}() but we are
sacrificing code duplication for a little more clarity and the
ease of writing the page table switching code in C instead of
asm.

Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1448658575-17029-5-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-11-29 09:15:42 +01:00

56 lines
1.1 KiB
ArmAsm

/*
* Function calling ABI conversion from Linux to EFI for x86_64
*
* Copyright (C) 2007 Intel Corp
* Bibo Mao <bibo.mao@intel.com>
* Huang Ying <ying.huang@intel.com>
*/
#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/msr.h>
#include <asm/processor-flags.h>
#include <asm/page_types.h>
#define SAVE_XMM \
mov %rsp, %rax; \
subq $0x70, %rsp; \
and $~0xf, %rsp; \
mov %rax, (%rsp); \
mov %cr0, %rax; \
clts; \
mov %rax, 0x8(%rsp); \
movaps %xmm0, 0x60(%rsp); \
movaps %xmm1, 0x50(%rsp); \
movaps %xmm2, 0x40(%rsp); \
movaps %xmm3, 0x30(%rsp); \
movaps %xmm4, 0x20(%rsp); \
movaps %xmm5, 0x10(%rsp)
#define RESTORE_XMM \
movaps 0x60(%rsp), %xmm0; \
movaps 0x50(%rsp), %xmm1; \
movaps 0x40(%rsp), %xmm2; \
movaps 0x30(%rsp), %xmm3; \
movaps 0x20(%rsp), %xmm4; \
movaps 0x10(%rsp), %xmm5; \
mov 0x8(%rsp), %rsi; \
mov %rsi, %cr0; \
mov (%rsp), %rsp
ENTRY(efi_call)
SAVE_XMM
mov (%rsp), %rax
mov 8(%rax), %rax
subq $48, %rsp
mov %r9, 32(%rsp)
mov %rax, 40(%rsp)
mov %r8, %r9
mov %rcx, %r8
mov %rsi, %rcx
call *%rdi
addq $48, %rsp
RESTORE_XMM
ret
ENDPROC(efi_call)