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| author | Guenter Roeck <linux@roeck-us.net> | 2018-09-11 21:18:12 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-09-12 22:53:34 +0300 |
| commit | cf40361ede6cf9dc09349e4c049dc0d166ca2d8b (patch) | |
| tree | 8832845b28d3efc4278209a47e72ce60708c8175 /arch | |
| parent | 999696752db1099aba595aac4f8d881f8c7cf4e6 (diff) | |
| download | linux-cf40361ede6cf9dc09349e4c049dc0d166ca2d8b.tar.xz | |
x86/efi: Load fixmap GDT in efi_call_phys_epilog() before setting %cr3
Commit eeb89e2bb1ac ("x86/efi: Load fixmap GDT in efi_call_phys_epilog()")
moved loading the fixmap in efi_call_phys_epilog() after load_cr3() since
it was assumed to be more logical.
Turns out this is incorrect: In efi_call_phys_prolog(), the gdt with its
physical address is loaded first, and when the %cr3 is reloaded in _epilog
from initial_page_table to swapper_pg_dir again the gdt is no longer
mapped. This results in a triple fault if an interrupt occurs after
load_cr3() and before load_fixmap_gdt(0). Calling load_fixmap_gdt(0) first
restores the execution order prior to commit eeb89e2bb1ac and fixes the
problem.
Fixes: eeb89e2bb1ac ("x86/efi: Load fixmap GDT in efi_call_phys_epilog()")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-efi@vger.kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Joerg Roedel <jroedel@suse.de>
Link: https://lkml.kernel.org/r/1536689892-21538-1-git-send-email-linux@roeck-us.net
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/platform/efi/efi_32.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c index 05ca14222463..9959657127f4 100644 --- a/arch/x86/platform/efi/efi_32.c +++ b/arch/x86/platform/efi/efi_32.c @@ -85,10 +85,9 @@ pgd_t * __init efi_call_phys_prolog(void) void __init efi_call_phys_epilog(pgd_t *save_pgd) { + load_fixmap_gdt(0); load_cr3(save_pgd); __flush_tlb_all(); - - load_fixmap_gdt(0); } void __init efi_runtime_update_mappings(void) |