From: Thomas Gleixner Date: Thu, 21 May 2020 20:05:30 +0000 (+0200) Subject: x86/entry: Change exit path of xen_failsafe_callback X-Git-Tag: v5.8-rc1~21^2~50 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e88d974136dbb5d6962eeb63075900603e737a1e;p=thirdparty%2Flinux.git x86/entry: Change exit path of xen_failsafe_callback xen_failsafe_callback() is invoked from XEN for two cases: 1. Fault while reloading DS, ES, FS or GS 2. Fault while executing IRET #1 retries the IRET after XEN has fixed up the segments. #2 injects a #GP which kills the task For #1 there is no reason to go through the full exception return path because the tasks TIF state is still the same. So just going straight to the IRET path is good enough. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Acked-by: Andy Lutomirski Link: https://lore.kernel.org/r/20200521202118.423224507@linutronix.de --- diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 6c6ae3a8c1fc0..6fcdee9feba0e 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1355,7 +1355,7 @@ SYM_FUNC_START(xen_failsafe_callback) 5: pushl $-1 /* orig_ax = -1 => not a system call */ SAVE_ALL ENCODE_FRAME_POINTER - jmp ret_from_exception + jmp handle_exception_return .section .fixup, "ax" 6: xorl %eax, %eax diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 2e476f488acef..a526fb57b65d5 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1175,7 +1175,7 @@ SYM_CODE_START(xen_failsafe_callback) pushq $-1 /* orig_ax = -1 => not a system call */ PUSH_AND_CLEAR_REGS ENCODE_FRAME_POINTER - jmp error_exit + jmp error_return SYM_CODE_END(xen_failsafe_callback) #endif /* CONFIG_XEN_PV */