Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 asm changes from Ingo Molnar:
 "Two fixlets and a cleanup."

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86_32: Return actual stack when requesting sp from regs
  x86: Don't clobber top of pt_regs in nested NMI
  x86/asm: Clean up copy_page_*() comments and code

1 files changed, 27 insertions, 14 deletions

diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 2a3806b95831..31b46128a63d 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1699,9 +1699,10 @@ nested_nmi:
 
 1:
         /* Set up the interrupted NMIs stack to jump to repeat_nmi */
-        leaq -6*8(%rsp), %rdx
+        leaq -1*8(%rsp), %rdx
         movq %rdx, %rsp
-        CFI_ADJUST_CFA_OFFSET 6*8
+        CFI_ADJUST_CFA_OFFSET 1*8
+        leaq -10*8(%rsp), %rdx
         pushq_cfi $__KERNEL_DS
         pushq_cfi %rdx
         pushfq_cfi
@@ -1709,8 +1710,8 @@ nested_nmi:
         pushq_cfi $repeat_nmi
 
         /* Put stack back */
-        addq $(11*8), %rsp
-        CFI_ADJUST_CFA_OFFSET -11*8
+        addq $(6*8), %rsp
+        CFI_ADJUST_CFA_OFFSET -6*8
 
 nested_nmi_out:
         popq_cfi %rdx
@@ -1736,18 +1737,18 @@ first_nmi:
          * +-------------------------+
          * | NMI executing variable  |
          * +-------------------------+
-         * | Saved SS                |
-         * | Saved Return RSP        |
-         * | Saved RFLAGS            |
-         * | Saved CS                |
-         * | Saved RIP               |
-         * +-------------------------+
          * | copied SS               |
          * | copied Return RSP       |
          * | copied RFLAGS           |
          * | copied CS               |
          * | copied RIP              |
          * +-------------------------+
+         * | Saved SS                |
+         * | Saved Return RSP        |
+         * | Saved RFLAGS            |
+         * | Saved CS                |
+         * | Saved RIP               |
+         * +-------------------------+
          * | pt_regs                 |
          * +-------------------------+
          *
@@ -1763,9 +1764,14 @@ first_nmi:
         /* Set the NMI executing variable on the stack. */
         pushq_cfi $1
 
+        /*
+         * Leave room for the "copied" frame
+         */
+        subq $(5*8), %rsp
+
         /* Copy the stack frame to the Saved frame */
         .rept 5
-        pushq_cfi 6*8(%rsp)
+        pushq_cfi 11*8(%rsp)
         .endr
         CFI_DEF_CFA_OFFSET SS+8-RIP
 
@@ -1786,12 +1792,15 @@ repeat_nmi:
          * is benign for the non-repeat case, where 1 was pushed just above
          * to this very stack slot).
          */
-        movq $1, 5*8(%rsp)
+        movq $1, 10*8(%rsp)
 
         /* Make another copy, this one may be modified by nested NMIs */
+        addq $(10*8), %rsp
+        CFI_ADJUST_CFA_OFFSET -10*8
         .rept 5
-        pushq_cfi 4*8(%rsp)
+        pushq_cfi -6*8(%rsp)
         .endr
+        subq $(5*8), %rsp
         CFI_DEF_CFA_OFFSET SS+8-RIP
 end_repeat_nmi:
 
@@ -1842,8 +1851,12 @@ nmi_swapgs:
         SWAPGS_UNSAFE_STACK
 nmi_restore:
         RESTORE_ALL 8
+
+        /* Pop the extra iret frame */
+        addq $(5*8), %rsp
+
         /* Clear the NMI executing stack variable */
-        movq $0, 10*8(%rsp)
+        movq $0, 5*8(%rsp)
         jmp irq_return
         CFI_ENDPROC
 END(nmi)