| From foo@baz Wed Jan 3 18:58:12 CET 2018 |
| From: Hugh Dickins <hughd@google.com> |
| Date: Thu, 21 Sep 2017 20:39:56 -0700 |
| Subject: kaiser: fix regs to do_nmi() ifndef CONFIG_KAISER |
| |
| From: Hugh Dickins <hughd@google.com> |
| |
| |
| 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 <hughd@google.com> |
| Acked-by: Jiri Kosina <jkosina@suse.cz> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/x86/entry/entry_64.S | 11 ++++++----- |
| 1 file changed, 6 insertions(+), 5 deletions(-) |
| |
| --- a/arch/x86/entry/entry_64.S |
| +++ b/arch/x86/entry/entry_64.S |
| @@ -1297,12 +1297,13 @@ 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 |
| @@ -1526,6 +1527,8 @@ 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 */ |
| @@ -1538,16 +1541,14 @@ 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 |
