x86/efi: Hoist page table switching code into efi_call_virt()
commit c9f2a9a65e4855b74d92cdad688f6ee4a1a323ff upstream.
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>
Cc: "Ghannam, Yazen" <Yazen.Ghannam@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Matt Fleming
Greg Kroah-Hartman
parent
87e2bd898d
commit
b73adb6085
3 changed files with 36 additions and 56 deletions
|
|
@ -3,6 +3,7 @@
|
|||
|
||||
#include <asm/fpu/api.h>
|
||||
#include <asm/pgtable.h>
|
||||
#include <asm/tlb.h>
|
||||
|
||||
/*
|
||||
* We map the EFI regions needed for runtime services non-contiguously,
|
||||
|
|
@ -64,6 +65,17 @@ extern u64 asmlinkage efi_call(void *fp, ...);
|
|||
|
||||
#define efi_call_phys(f, args...) efi_call((f), args)
|
||||
|
||||
/*
|
||||
* Scratch space used for switching the pagetable in the EFI stub
|
||||
*/
|
||||
struct efi_scratch {
|
||||
u64 r15;
|
||||
u64 prev_cr3;
|
||||
pgd_t *efi_pgt;
|
||||
bool use_pgd;
|
||||
u64 phys_stack;
|
||||
} __packed;
|
||||
|
||||
#define efi_call_virt(f, ...) \
|
||||
({ \
|
||||
efi_status_t __s; \
|
||||
|
|
@ -71,7 +83,20 @@ extern u64 asmlinkage efi_call(void *fp, ...);
|
|||
efi_sync_low_kernel_mappings(); \
|
||||
preempt_disable(); \
|
||||
__kernel_fpu_begin(); \
|
||||
\
|
||||
if (efi_scratch.use_pgd) { \
|
||||
efi_scratch.prev_cr3 = read_cr3(); \
|
||||
write_cr3((unsigned long)efi_scratch.efi_pgt); \
|
||||
__flush_tlb_all(); \
|
||||
} \
|
||||
\
|
||||
__s = efi_call((void *)efi.systab->runtime->f, __VA_ARGS__); \
|
||||
\
|
||||
if (efi_scratch.use_pgd) { \
|
||||
write_cr3(efi_scratch.prev_cr3); \
|
||||
__flush_tlb_all(); \
|
||||
} \
|
||||
\
|
||||
__kernel_fpu_end(); \
|
||||
preempt_enable(); \
|
||||
__s; \
|
||||
|
|
|
|||
|
|
@ -47,16 +47,7 @@
|
|||
*/
|
||||
static u64 efi_va = EFI_VA_START;
|
||||
|
||||
/*
|
||||
* Scratch space used for switching the pagetable in the EFI stub
|
||||
*/
|
||||
struct efi_scratch {
|
||||
u64 r15;
|
||||
u64 prev_cr3;
|
||||
pgd_t *efi_pgt;
|
||||
bool use_pgd;
|
||||
u64 phys_stack;
|
||||
} __packed;
|
||||
struct efi_scratch efi_scratch;
|
||||
|
||||
static void __init early_code_mapping_set_exec(int executable)
|
||||
{
|
||||
|
|
@ -83,8 +74,11 @@ pgd_t * __init efi_call_phys_prolog(void)
|
|||
int pgd;
|
||||
int n_pgds;
|
||||
|
||||
if (!efi_enabled(EFI_OLD_MEMMAP))
|
||||
return NULL;
|
||||
if (!efi_enabled(EFI_OLD_MEMMAP)) {
|
||||
save_pgd = (pgd_t *)read_cr3();
|
||||
write_cr3((unsigned long)efi_scratch.efi_pgt);
|
||||
goto out;
|
||||
}
|
||||
|
||||
early_code_mapping_set_exec(1);
|
||||
|
||||
|
|
@ -96,6 +90,7 @@ pgd_t * __init efi_call_phys_prolog(void)
|
|||
vaddress = (unsigned long)__va(pgd * PGDIR_SIZE);
|
||||
set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress));
|
||||
}
|
||||
out:
|
||||
__flush_tlb_all();
|
||||
|
||||
return save_pgd;
|
||||
|
|
@ -109,8 +104,11 @@ void __init efi_call_phys_epilog(pgd_t *save_pgd)
|
|||
int pgd_idx;
|
||||
int nr_pgds;
|
||||
|
||||
if (!save_pgd)
|
||||
if (!efi_enabled(EFI_OLD_MEMMAP)) {
|
||||
write_cr3((unsigned long)save_pgd);
|
||||
__flush_tlb_all();
|
||||
return;
|
||||
}
|
||||
|
||||
nr_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
|
||||
|
||||
|
|
|
|||
|
|
@ -38,41 +38,6 @@
|
|||
mov %rsi, %cr0; \
|
||||
mov (%rsp), %rsp
|
||||
|
||||
/* stolen from gcc */
|
||||
.macro FLUSH_TLB_ALL
|
||||
movq %r15, efi_scratch(%rip)
|
||||
movq %r14, efi_scratch+8(%rip)
|
||||
movq %cr4, %r15
|
||||
movq %r15, %r14
|
||||
andb $0x7f, %r14b
|
||||
movq %r14, %cr4
|
||||
movq %r15, %cr4
|
||||
movq efi_scratch+8(%rip), %r14
|
||||
movq efi_scratch(%rip), %r15
|
||||
.endm
|
||||
|
||||
.macro SWITCH_PGT
|
||||
cmpb $0, efi_scratch+24(%rip)
|
||||
je 1f
|
||||
movq %r15, efi_scratch(%rip) # r15
|
||||
# save previous CR3
|
||||
movq %cr3, %r15
|
||||
movq %r15, efi_scratch+8(%rip) # prev_cr3
|
||||
movq efi_scratch+16(%rip), %r15 # EFI pgt
|
||||
movq %r15, %cr3
|
||||
1:
|
||||
.endm
|
||||
|
||||
.macro RESTORE_PGT
|
||||
cmpb $0, efi_scratch+24(%rip)
|
||||
je 2f
|
||||
movq efi_scratch+8(%rip), %r15
|
||||
movq %r15, %cr3
|
||||
movq efi_scratch(%rip), %r15
|
||||
FLUSH_TLB_ALL
|
||||
2:
|
||||
.endm
|
||||
|
||||
ENTRY(efi_call)
|
||||
SAVE_XMM
|
||||
mov (%rsp), %rax
|
||||
|
|
@ -83,16 +48,8 @@ ENTRY(efi_call)
|
|||
mov %r8, %r9
|
||||
mov %rcx, %r8
|
||||
mov %rsi, %rcx
|
||||
SWITCH_PGT
|
||||
call *%rdi
|
||||
RESTORE_PGT
|
||||
addq $48, %rsp
|
||||
RESTORE_XMM
|
||||
ret
|
||||
ENDPROC(efi_call)
|
||||
|
||||
.data
|
||||
ENTRY(efi_scratch)
|
||||
.fill 3,8,0
|
||||
.byte 0
|
||||
.quad 0
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue