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authorSai Praneeth <sai.praneeth.prakhya@intel.com>2018-03-12 10:43:55 +0100
committerIngo Molnar <mingo@kernel.org>2018-03-12 11:05:05 +0100
commit03781e40890c18bdea40092355b61431d0073c1d (patch)
tree4a7c7b0f467cfb1cd6d4d94384350d3f66ee32d4 /arch/x86/include/asm/efi.h
parentx86/efi: Replace efi_pgd with efi_mm.pgd (diff)
downloadlinux-03781e40890c18bdea40092355b61431d0073c1d.tar.xz
linux-03781e40890c18bdea40092355b61431d0073c1d.zip
x86/efi: Use efi_switch_mm() rather than manually twiddling with %cr3
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>
Diffstat (limited to 'arch/x86/include/asm/efi.h')
-rw-r--r--arch/x86/include/asm/efi.h25
1 files changed, 10 insertions, 15 deletions
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index c62443fa7d0a..cec5fae23eb3 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -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;