From 3d8ca014b31b43c78d3240b2574670f2ab38519c Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Thu, 21 Sep 2017 20:39:56 -0700 Subject: [PATCH 010/102] kaiser: fix regs to do_nmi() ifndef CONFIG_KAISER pjt has observed that nmi's second (nmi_from_kernel) call to do_nmi() adjusted the %rdi regs arg, rightly when CONFIG_KAISER, but wrongly when not CONFIG_KAISER. Although the minimal change is to add an #ifdef CONFIG_KAISER around the addq line, that looks cluttered, and I prefer how the first call to do_nmi() handled it: prepare args in %rdi and %rsi before getting into the CONFIG_KAISER block, since it does not touch them at all. And while we're here, place the "#ifdef CONFIG_KAISER" that follows each, to enclose the "Unconditionally restore CR3" comment: matching how the "Unconditionally use kernel CR3" comment above is enclosed. Signed-off-by: Hugh Dickins Signed-off-by: Greg Kroah-Hartman --- arch/x86/entry/entry_64.S | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index d84e3a7..57f7993 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1321,12 +1321,13 @@ ENTRY(nmi) movq %rax, %cr3 #endif call do_nmi + +#ifdef CONFIG_KAISER /* * Unconditionally restore CR3. I know we return to * kernel code that needs user CR3, but do we ever return * to "user mode" where we need the kernel CR3? */ -#ifdef CONFIG_KAISER popq %rax mov %rax, %cr3 #endif @@ -1550,6 +1551,8 @@ end_repeat_nmi: SWAPGS xorl %ebx, %ebx 1: + movq %rsp, %rdi + movq $-1, %rsi #ifdef CONFIG_KAISER /* Unconditionally use kernel CR3 for do_nmi() */ /* %rax is saved above, so OK to clobber here */ @@ -1562,16 +1565,14 @@ end_repeat_nmi: #endif /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ - movq %rsp, %rdi - addq $8, %rdi /* point %rdi at ptregs, fixed up for CR3 */ - movq $-1, %rsi call do_nmi + +#ifdef CONFIG_KAISER /* * Unconditionally restore CR3. We might be returning to * kernel code that needs user CR3, like just just before * a sysret. */ -#ifdef CONFIG_KAISER popq %rax mov %rax, %cr3 #endif -- 2.7.4