Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=3aa4b37d3e899cfe7a9cbdcda2b277df4c1f210d
Commit: 3aa4b37d3e899cfe7a9cbdcda2b277df4c1f210d
Parent: 551e4fb2465b87de9d4aa1669b27d624435443bb
Author: Roland McGrath <[EMAIL PROTECTED]>
AuthorDate: Wed Feb 6 22:39:43 2008 +0100
Committer: Ingo Molnar <[EMAIL PROTECTED]>
CommitDate: Wed Feb 6 22:39:43 2008 +0100
x86: make traps on entry code be debuggable in user space, 64-bit
Unify the x86-64 behavior for 32-bit processes that set
bogus %cs/%ss values (the only ones that can fault in iret)
match what the native i386 behavior is. (do not kill the task
via do_exit but generate a SIGSEGV signal)
[ [EMAIL PROTECTED]: build fix ]
Signed-off-by: Roland McGrath <[EMAIL PROTECTED]>
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
---
arch/x86/kernel/entry_64.S | 21 +++++++++++++++------
1 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index bea8474..e518928 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -593,13 +593,22 @@ ENTRY(native_iret)
.quad native_iret, bad_iret
.previous
.section .fixup,"ax"
- /* force a signal here? this matches i386 behaviour */
- /* running with kernel gs */
bad_iret:
- movq $11,%rdi /* SIGSEGV */
- TRACE_IRQS_ON
- ENABLE_INTERRUPTS(CLBR_ANY | ~(CLBR_RDI))
- jmp do_exit
+ /*
+ * The iret traps when the %cs or %ss being restored is bogus.
+ * We've lost the original trap vector and error code.
+ * #GPF is the most likely one to get for an invalid selector.
+ * So pretend we completed the iret and took the #GPF in user mode.
+ *
+ * We are now running with the kernel GS after exception recovery.
+ * But error_entry expects us to have user GS to match the user %cs,
+ * so swap back.
+ */
+ pushq $0
+
+ SWAPGS
+ jmp general_protection
+
.previous
/* edi: workmask, edx: work */
-
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