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| author | Andy Lutomirski <luto@kernel.org> | 2021-02-09 18:33:46 -0800 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-02-10 18:39:23 +0100 |
| commit | c46f52231e79af025e2c89e889d69ec20a4c024f (patch) | |
| tree | edd2bdcce0593d181156fa6fb744e1ddc3fe5610 /arch/x86/platform | |
| parent | ca247283781d754216395a41c5e8be8ec79a5f1c (diff) | |
| download | linux-c46f52231e79af025e2c89e889d69ec20a4c024f.tar.bz2 | |
x86/{fault,efi}: Fix and rename efi_recover_from_page_fault()
efi_recover_from_page_fault() doesn't recover -- it does a special EFI
mini-oops. Rename it to make it clear that it crashes.
While renaming it, I noticed a blatant bug: a page fault oops in a
different thread happening concurrently with an EFI runtime service call
would be misinterpreted as an EFI page fault. Fix that.
This isn't quite exact. The situation could be improved by using a
special CS for calls into EFI.
[ bp: Massage commit message and simplify in interrupt check. ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/f43b1e80830dc78ed60ed8b0826f4f189254570c.1612924255.git.luto@kernel.org
Diffstat (limited to 'arch/x86/platform')
| -rw-r--r-- | arch/x86/platform/efi/quirks.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index 5a40fe411ebd..67d93a243c35 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -687,15 +687,25 @@ int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff, * @return: Returns, if the page fault is not handled. This function * will never return if the page fault is handled successfully. */ -void efi_recover_from_page_fault(unsigned long phys_addr) +void efi_crash_gracefully_on_page_fault(unsigned long phys_addr) { if (!IS_ENABLED(CONFIG_X86_64)) return; /* + * If we get an interrupt/NMI while processing an EFI runtime service + * then this is a regular OOPS, not an EFI failure. + */ + if (in_interrupt()) + return; + + /* * Make sure that an efi runtime service caused the page fault. + * READ_ONCE() because we might be OOPSing in a different thread, + * and we don't want to trip KTSAN while trying to OOPS. */ - if (efi_rts_work.efi_rts_id == EFI_NONE) + if (READ_ONCE(efi_rts_work.efi_rts_id) == EFI_NONE || + current_work() != &efi_rts_work.work) return; /* @@ -747,6 +757,4 @@ void efi_recover_from_page_fault(unsigned long phys_addr) set_current_state(TASK_IDLE); schedule(); } - - return; } |