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x86/efi: Use efi_switch_mm() rather than manually twiddling with %cr3

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Use helper function efi_switch_mm() to switch to/from efi_mm when
invoking any UEFI runtime services.

Likewise, we need to switch back to previous mm (mm context stolen
by efi_mm) after the above calls return successfully. We can use
efi_switch_mm() helper function only with x86_64 kernel and
"efi=old_map" disabled because, x86_32 and efi=old_map do not use
efi_pgd, rather they use swapper_pg_dir.

Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
[ardb: add #include of sched/task.h for task_lock/_unlock]
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Lee, Chun-Yi <jlee@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-efi@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Sai Praneeth
2018-03-12 09:43:55 +00:00
committed by Ingo Molnar
parent 3ede3417f8
commit 03781e4089
3 changed files with 33 additions and 35 deletions
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25
arch/x86/include/asm/efi.h
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@@ -70,14 +70,13 @@ extern asmlinkage u64 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 - Scratch space used while switching to/from efi_mm
* @phys_stack: stack used during EFI Mixed Mode
* @prev_mm: store/restore stolen mm_struct while switching to/from efi_mm
*/
struct efi_scratch {
u64 r15;
u64 prev_cr3;
pgd_t *efi_pgt;
bool use_pgd;
u64 phys_stack;
u64 phys_stack;
struct mm_struct *prev_mm;
} __packed;
#define arch_efi_call_virt_setup() \
@@ -87,11 +86,8 @@ struct efi_scratch {
__kernel_fpu_begin(); \
firmware_restrict_branch_speculation_start(); \
\
if (efi_scratch.use_pgd) { \
efi_scratch.prev_cr3 = __read_cr3(); \
write_cr3((unsigned long)efi_scratch.efi_pgt); \
__flush_tlb_all(); \
} \
if (!efi_enabled(EFI_OLD_MEMMAP)) \
efi_switch_mm(&efi_mm); \
})
#define arch_efi_call_virt(p, f, args...) \
@@ -99,10 +95,8 @@ struct efi_scratch {
#define arch_efi_call_virt_teardown() \
({ \
if (efi_scratch.use_pgd) { \
write_cr3(efi_scratch.prev_cr3); \
__flush_tlb_all(); \
} \
if (!efi_enabled(EFI_OLD_MEMMAP)) \
efi_switch_mm(efi_scratch.prev_mm); \
\
firmware_restrict_branch_speculation_end(); \
__kernel_fpu_end(); \
@@ -145,6 +139,7 @@ extern void __init efi_dump_pagetable(void);
extern void __init efi_apply_memmap_quirks(void);
extern int __init efi_reuse_config(u64 tables, int nr_tables);
extern void efi_delete_dummy_variable(void);
extern void efi_switch_mm(struct mm_struct *mm);
struct efi_setup_data {
u64 fw_vendor;