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) [ tglx@linutronix.de: build fix ] Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -593,13 +593,22 @@ ENTRY(native_iret)
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.quad native_iret, bad_iret
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.previous
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.section .fixup,"ax"
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/* force a signal here? this matches i386 behaviour */
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/* running with kernel gs */
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bad_iret:
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movq $11,%rdi /* SIGSEGV */
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TRACE_IRQS_ON
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ENABLE_INTERRUPTS(CLBR_ANY | ~(CLBR_RDI))
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jmp do_exit
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/*
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* The iret traps when the %cs or %ss being restored is bogus.
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* We've lost the original trap vector and error code.
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* #GPF is the most likely one to get for an invalid selector.
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* So pretend we completed the iret and took the #GPF in user mode.
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*
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* We are now running with the kernel GS after exception recovery.
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* But error_entry expects us to have user GS to match the user %cs,
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* so swap back.
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*/
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pushq $0
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SWAPGS
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jmp general_protection
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.previous
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/* edi: workmask, edx: work */
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