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)