4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
This reverts commit b73adb60852034d84092d123b323196ca42529cd which is
commit c9f2a9a65e4855b74d92cdad688f6ee4a1a323ff upstream.
Turns there was too many other issues with this patch to make it viable
for the stable tree.
Reported-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@xxxxxxxxx>
Cc: Stephen Smalley <sds@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxx>
Cc: linux-efi@xxxxxxxxxxxxxxx
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "Ghannam, Yazen" <Yazen.Ghannam@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/efi.h | 25 --------------------
arch/x86/platform/efi/efi_64.c | 24 ++++++++++----------
arch/x86/platform/efi/efi_stub_64.S | 43 ++++++++++++++++++++++++++++++++++++
3 files changed, 56 insertions(+), 36 deletions(-)
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -3,7 +3,6 @@
#include <asm/fpu/api.h>
#include <asm/pgtable.h>
-#include <asm/tlb.h>
/*
* We map the EFI regions needed for runtime services non-contiguously,
@@ -65,17 +64,6 @@ 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; \
@@ -83,20 +71,7 @@ struct efi_scratch {
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; \
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -47,7 +47,16 @@
*/
static u64 efi_va = EFI_VA_START;
-struct efi_scratch efi_scratch;
+/*
+ * 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;
static void __init early_code_mapping_set_exec(int executable)
{
@@ -74,11 +83,8 @@ pgd_t * __init efi_call_phys_prolog(void
int pgd;
int n_pgds;
- if (!efi_enabled(EFI_OLD_MEMMAP)) {
- save_pgd = (pgd_t *)read_cr3();
- write_cr3((unsigned long)efi_scratch.efi_pgt);
- goto out;
- }
+ if (!efi_enabled(EFI_OLD_MEMMAP))
+ return NULL;
early_code_mapping_set_exec(1);
@@ -90,7 +96,6 @@ 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;
@@ -104,11 +109,8 @@ void __init efi_call_phys_epilog(pgd_t *
int pgd_idx;
int nr_pgds;
- if (!efi_enabled(EFI_OLD_MEMMAP)) {
- write_cr3((unsigned long)save_pgd);
- __flush_tlb_all();
+ if (!save_pgd)
return;
- }
nr_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
--- a/arch/x86/platform/efi/efi_stub_64.S
+++ b/arch/x86/platform/efi/efi_stub_64.S
@@ -38,6 +38,41 @@
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
@@ -48,8 +83,16 @@ 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
--
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