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| author | Andy Lutomirski <luto@amacapital.net> | 2014-11-22 18:00:31 -0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-12-14 16:23:59 +0000 |
| commit | a6ac298db86a1add225ca7e655176bb5249f9a9d (patch) | |
| tree | 0528f854fed0a1ee8926946738376031a7ce872d /arch/x86/kernel/entry_64.S | |
| parent | 4c414592a79b82ddca76945c7afb4843684aa9a8 (diff) | |
| download | kernel_samsung_smdk4412-a6ac298db86a1add225ca7e655176bb5249f9a9d.zip kernel_samsung_smdk4412-a6ac298db86a1add225ca7e655176bb5249f9a9d.tar.gz kernel_samsung_smdk4412-a6ac298db86a1add225ca7e655176bb5249f9a9d.tar.bz2 | |
x86_64, traps: Fix the espfix64 #DF fixup and rewrite it in C
commit af726f21ed8af2cdaa4e93098dc211521218ae65 upstream.
There's nothing special enough about the espfix64 double fault fixup to
justify writing it in assembly. Move it to C.
This also fixes a bug: if the double fault came from an IST stack, the
old asm code would return to a partially uninitialized stack frame.
Fixes: 3891a04aafd668686239349ea58f3314ea2af86b
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
- Keep using the paranoiderrorentry macro to generate the asm code
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/x86/kernel/entry_64.S')
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 34 |
1 files changed, 2 insertions, 32 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 50650dc..7201785 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -873,6 +873,7 @@ ENTRY(native_iret) jnz native_irq_return_ldt #endif +.global native_irq_return_iret native_irq_return_iret: iretq @@ -972,37 +973,6 @@ ENTRY(retint_kernel) CFI_ENDPROC END(common_interrupt) - /* - * If IRET takes a fault on the espfix stack, then we - * end up promoting it to a doublefault. In that case, - * modify the stack to make it look like we just entered - * the #GP handler from user space, similar to bad_iret. - */ -#ifdef CONFIG_X86_ESPFIX64 - ALIGN -__do_double_fault: - XCPT_FRAME 1 RDI+8 - movq RSP(%rdi),%rax /* Trap on the espfix stack? */ - sarq $PGDIR_SHIFT,%rax - cmpl $ESPFIX_PGD_ENTRY,%eax - jne do_double_fault /* No, just deliver the fault */ - cmpl $__KERNEL_CS,CS(%rdi) - jne do_double_fault - movq RIP(%rdi),%rax - cmpq $native_irq_return_iret,%rax - jne do_double_fault /* This shouldn't happen... */ - movq PER_CPU_VAR(kernel_stack),%rax - subq $(6*8-KERNEL_STACK_OFFSET),%rax /* Reset to original stack */ - movq %rax,RSP(%rdi) - movq $0,(%rax) /* Missing (lost) #GP error code */ - movq $general_protection,RIP(%rdi) - retq - CFI_ENDPROC -END(__do_double_fault) -#else -# define __do_double_fault do_double_fault -#endif - /* * End of kprobes section */ @@ -1169,7 +1139,7 @@ zeroentry overflow do_overflow zeroentry bounds do_bounds zeroentry invalid_op do_invalid_op zeroentry device_not_available do_device_not_available -paranoiderrorentry double_fault __do_double_fault +paranoiderrorentry double_fault do_double_fault zeroentry coprocessor_segment_overrun do_coprocessor_segment_overrun errorentry invalid_TSS do_invalid_TSS errorentry segment_not_present do_segment_not_present |