[RFC,v4,3/5] x86/fault: Attempt to fixup unhandled #PF on ENCLU before signaling
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Message ID 20181213213135.12913-4-sean.j.christopherson@intel.com
State New
Headers show
  • x86: Add vDSO exception fixup for SGX
Related show

Commit Message

Sean Christopherson Dec. 13, 2018, 9:31 p.m. UTC
Call fixup_sgx_enclu_exception() in the SIGSEGV and SIGBUS paths of
the page fault handler immediately prior to signaling.  If the fault
is fixed, return cleanly and do not generate a signal.

In the SIGSEGV flow, make sure the error code passed to userspace has
been sanitized.

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
 arch/x86/mm/fault.c | 7 +++++++
 1 file changed, 7 insertions(+)

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diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index fefeb745d21d..c6f5f77ffabd 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -28,6 +28,7 @@ 
 #include <asm/mmu_context.h>		/* vma_pkey()			*/
 #include <asm/efi.h>			/* efi_recover_from_page_fault()*/
 #include <asm/desc.h>			/* store_idt(), ...		*/
+#include <asm/vdso.h>			/* fixup_vdso_exception()	*/
 #include <asm/trace/exceptions.h>
@@ -928,6 +929,9 @@  __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 		sanitize_error_code(address, &error_code);
+		if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
+			return;
 		if (likely(show_unhandled_signals))
 			show_signal_msg(regs, error_code, address, tsk);
@@ -1047,6 +1051,9 @@  do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 	sanitize_error_code(address, &error_code);
+	if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
+		return;
 	set_signal_archinfo(address, error_code);