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x86/entry/32: Pass cr2 to do_async_page_fault()

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Commit a0d14b8909 ("x86/mm, tracing: Fix CR2 corruption") added the
address parameter to do_async_page_fault(), but does not pass it from the
32-bit entry point.  To plumb it through, factor-out
common_exception_read_cr2 in the same fashion as common_exception, and uses
it from both page_fault and async_page_fault.

For a 32-bit KVM guest, this fixes:

  Run /sbin/init as init process
  Starting init: /sbin/init exists but couldn't execute it (error -14)

Fixes: a0d14b8909 ("x86/mm, tracing: Fix CR2 corruption")
Signed-off-by: Matt Mullins <mmullins@fb.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190724042058.24506-1-mmullins@fb.com
This commit is contained in:
Matt Mullins 2019-07-23 21:20:58 -07:00 committed by Thomas Gleixner
parent 385065734c
commit b8f70953c1
1 changed files with 9 additions and 4 deletions
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13
arch/x86/entry/entry_32.S
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@ -1443,8 +1443,12 @@ BUILD_INTERRUPT3(hv_stimer0_callback_vector, HYPERV_STIMER0_VECTOR,
ENTRY(page_fault)
ASM_CLAC
pushl $0; /* %gs's slot on the stack */
pushl $do_page_fault
jmp common_exception_read_cr2
END(page_fault)
common_exception_read_cr2:
/* the function address is in %gs's slot on the stack */
SAVE_ALL switch_stacks=1 skip_gs=1
ENCODE_FRAME_POINTER
@ -1452,6 +1456,7 @@ ENTRY(page_fault)
/* fixup %gs */
GS_TO_REG %ecx
movl PT_GS(%esp), %edi
REG_TO_PTGS %ecx
SET_KERNEL_GS %ecx
@ -1463,9 +1468,9 @@ ENTRY(page_fault)
TRACE_IRQS_OFF
movl %esp, %eax # pt_regs pointer
call do_page_fault
CALL_NOSPEC %edi
jmp ret_from_exception
END(page_fault)
END(common_exception_read_cr2)
common_exception:
/* the function address is in %gs's slot on the stack */
@ -1595,7 +1600,7 @@ END(general_protection)
ENTRY(async_page_fault)
ASM_CLAC
pushl $do_async_page_fault
jmp common_exception
jmp common_exception_read_cr2
END(async_page_fault)
#endif