[Xen-devel] [tip:x86/asm] x86/head: Move the early NMI fixup into C

[tip-bot for Andy Lutomirski <tipbot@xxxxxxxxx>]

Commit-ID:  0d0efc07f3df677d7622bb760f8e2920b5e33f42
Gitweb:     http://git.kernel.org/tip/0d0efc07f3df677d7622bb760f8e2920b5e33f42
Author:     Andy Lutomirski <luto@xxxxxxxxxx>
AuthorDate: Sat, 2 Apr 2016 07:01:33 -0700
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 13 Apr 2016 11:37:44 +0200

x86/head: Move the early NMI fixup into C

C is nicer than asm.

Tested-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Acked-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: KVM list <kvm@xxxxxxxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: xen-devel <Xen-devel@xxxxxxxxxxxxx>
Link: 
http://lkml.kernel.org/r/dd068269f8d59fe44e9e43a50d0efd67da65c2b5.1459605520.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/kernel/head_32.S | 7 -------
 arch/x86/kernel/head_64.S | 6 ------
 arch/x86/mm/extable.c     | 5 +++++
 3 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 0904536..184291c 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -561,9 +561,6 @@ early_idt_handler_common:
         */
        cld
 
-       cmpl $2,(%esp)          # X86_TRAP_NMI
-       je .Lis_nmi             # Ignore NMI
-
        cmpl $2,%ss:early_recursion_flag
        je hlt_loop
        incl %ss:early_recursion_flag
@@ -642,10 +639,6 @@ early_idt_handler_common:
 hlt_loop:
        hlt
        jmp hlt_loop
-
-.Lis_nmi:
-       addl $8,%esp            /* drop vector number and error code */
-       iret
 ENDPROC(early_idt_handler_common)
 
 /* This is the default interrupt "handler" :-) */
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 9e8636d..2308437 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -351,9 +351,6 @@ early_idt_handler_common:
         */
        cld
 
-       cmpl $2,(%rsp)          # X86_TRAP_NMI
-       je .Lis_nmi             # Ignore NMI
-
        cmpl $2,early_recursion_flag(%rip)
        jz  1f
        incl early_recursion_flag(%rip)
@@ -422,9 +419,6 @@ early_idt_handler_common:
 20:    /* Exception table entry found or page table generated */
        decl early_recursion_flag(%rip)
        jmp restore_regs_and_iret
-.Lis_nmi:
-       addq $16,%rsp           # drop vector number and error code
-       INTERRUPT_RETURN
 ENDPROC(early_idt_handler_common)
 
        __INITDATA
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 1366e06..4be0419 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -1,5 +1,6 @@
 #include <linux/module.h>
 #include <asm/uaccess.h>
+#include <asm/traps.h>
 
 typedef bool (*ex_handler_t)(const struct exception_table_entry *,
                            struct pt_regs *, int);
@@ -89,6 +90,10 @@ int __init early_fixup_exception(struct pt_regs *regs, int 
trapnr)
        unsigned long new_ip;
        ex_handler_t handler;
 
+       /* Ignore early NMIs. */
+       if (trapnr == X86_TRAP_NMI)
+               return 1;
+
        e = search_exception_tables(regs->ip);
        if (!e)
                return 0;

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