x86/entry/32: Pass cr2 to do_async_page_fault() (b8f70953) · Commits · 戴 / test

Commit ("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: ("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

arch/x86/entry/entry_32.S

+9 −4

Original line number	Diff line number	Diff line
		@@ -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

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