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Message-ID: <20121211100646.GA24919@gmail.com>
Date: Tue, 11 Dec 2012 11:06:46 +0100
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/asm changes for v3.8
Linus,
Please pull the latest x86-asm-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-asm-for-linus
HEAD: 6c8d8b3c69cef1330e0c5cbc2a8b9268024927a0 x86_32: Return actual stack when requesting sp from regs
Two fixlets and a cleanup.
Thanks,
Ingo
------------------>
Ma Ling (1):
x86/asm: Clean up copy_page_*() comments and code
Salman Qazi (1):
x86: Don't clobber top of pt_regs in nested NMI
Steven Rostedt (1):
x86_32: Return actual stack when requesting sp from regs
arch/x86/include/asm/ptrace.h | 9 ++++
arch/x86/kernel/entry_64.S | 41 ++++++++++-----
arch/x86/lib/copy_page_64.S | 120 +++++++++++++++++++++---------------------
3 files changed, 95 insertions(+), 75 deletions(-)
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index dcfde52..2233713 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -246,6 +246,15 @@ static inline unsigned long regs_get_register(struct pt_regs *regs,
{
if (unlikely(offset > MAX_REG_OFFSET))
return 0;
+#ifdef CONFIG_X86_32
+ /*
+ * Traps from the kernel do not save sp and ss.
+ * Use the helper function to retrieve sp.
+ */
+ if (offset == offsetof(struct pt_regs, sp) &&
+ regs->cs == __KERNEL_CS)
+ return kernel_stack_pointer(regs);
+#endif
return *(unsigned long *)((unsigned long)regs + offset);
}
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index b51b2c7..811795d 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)
diff --git a/arch/x86/lib/copy_page_64.S b/arch/x86/lib/copy_page_64.S
index 6b34d04..176cca6 100644
--- a/arch/x86/lib/copy_page_64.S
+++ b/arch/x86/lib/copy_page_64.S
@@ -5,91 +5,89 @@
#include <asm/alternative-asm.h>
ALIGN
-copy_page_c:
+copy_page_rep:
CFI_STARTPROC
- movl $4096/8,%ecx
- rep movsq
+ movl $4096/8, %ecx
+ rep movsq
ret
CFI_ENDPROC
-ENDPROC(copy_page_c)
+ENDPROC(copy_page_rep)
-/* Don't use streaming store because it's better when the target
- ends up in cache. */
-
-/* Could vary the prefetch distance based on SMP/UP */
+/*
+ * Don't use streaming copy unless the CPU indicates X86_FEATURE_REP_GOOD.
+ * Could vary the prefetch distance based on SMP/UP.
+*/
ENTRY(copy_page)
CFI_STARTPROC
- subq $2*8,%rsp
+ subq $2*8, %rsp
CFI_ADJUST_CFA_OFFSET 2*8
- movq %rbx,(%rsp)
+ movq %rbx, (%rsp)
CFI_REL_OFFSET rbx, 0
- movq %r12,1*8(%rsp)
+ movq %r12, 1*8(%rsp)
CFI_REL_OFFSET r12, 1*8
- movl $(4096/64)-5,%ecx
+ movl $(4096/64)-5, %ecx
.p2align 4
.Loop64:
- dec %rcx
-
- movq (%rsi), %rax
- movq 8 (%rsi), %rbx
- movq 16 (%rsi), %rdx
- movq 24 (%rsi), %r8
- movq 32 (%rsi), %r9
- movq 40 (%rsi), %r10
- movq 48 (%rsi), %r11
- movq 56 (%rsi), %r12
+ dec %rcx
+ movq 0x8*0(%rsi), %rax
+ movq 0x8*1(%rsi), %rbx
+ movq 0x8*2(%rsi), %rdx
+ movq 0x8*3(%rsi), %r8
+ movq 0x8*4(%rsi), %r9
+ movq 0x8*5(%rsi), %r10
+ movq 0x8*6(%rsi), %r11
+ movq 0x8*7(%rsi), %r12
prefetcht0 5*64(%rsi)
- movq %rax, (%rdi)
- movq %rbx, 8 (%rdi)
- movq %rdx, 16 (%rdi)
- movq %r8, 24 (%rdi)
- movq %r9, 32 (%rdi)
- movq %r10, 40 (%rdi)
- movq %r11, 48 (%rdi)
- movq %r12, 56 (%rdi)
+ movq %rax, 0x8*0(%rdi)
+ movq %rbx, 0x8*1(%rdi)
+ movq %rdx, 0x8*2(%rdi)
+ movq %r8, 0x8*3(%rdi)
+ movq %r9, 0x8*4(%rdi)
+ movq %r10, 0x8*5(%rdi)
+ movq %r11, 0x8*6(%rdi)
+ movq %r12, 0x8*7(%rdi)
- leaq 64 (%rsi), %rsi
- leaq 64 (%rdi), %rdi
+ leaq 64 (%rsi), %rsi
+ leaq 64 (%rdi), %rdi
- jnz .Loop64
+ jnz .Loop64
- movl $5,%ecx
+ movl $5, %ecx
.p2align 4
.Loop2:
- decl %ecx
-
- movq (%rsi), %rax
- movq 8 (%rsi), %rbx
- movq 16 (%rsi), %rdx
- movq 24 (%rsi), %r8
- movq 32 (%rsi), %r9
- movq 40 (%rsi), %r10
- movq 48 (%rsi), %r11
- movq 56 (%rsi), %r12
-
- movq %rax, (%rdi)
- movq %rbx, 8 (%rdi)
- movq %rdx, 16 (%rdi)
- movq %r8, 24 (%rdi)
- movq %r9, 32 (%rdi)
- movq %r10, 40 (%rdi)
- movq %r11, 48 (%rdi)
- movq %r12, 56 (%rdi)
-
- leaq 64(%rdi),%rdi
- leaq 64(%rsi),%rsi
-
+ decl %ecx
+
+ movq 0x8*0(%rsi), %rax
+ movq 0x8*1(%rsi), %rbx
+ movq 0x8*2(%rsi), %rdx
+ movq 0x8*3(%rsi), %r8
+ movq 0x8*4(%rsi), %r9
+ movq 0x8*5(%rsi), %r10
+ movq 0x8*6(%rsi), %r11
+ movq 0x8*7(%rsi), %r12
+
+ movq %rax, 0x8*0(%rdi)
+ movq %rbx, 0x8*1(%rdi)
+ movq %rdx, 0x8*2(%rdi)
+ movq %r8, 0x8*3(%rdi)
+ movq %r9, 0x8*4(%rdi)
+ movq %r10, 0x8*5(%rdi)
+ movq %r11, 0x8*6(%rdi)
+ movq %r12, 0x8*7(%rdi)
+
+ leaq 64(%rdi), %rdi
+ leaq 64(%rsi), %rsi
jnz .Loop2
- movq (%rsp),%rbx
+ movq (%rsp), %rbx
CFI_RESTORE rbx
- movq 1*8(%rsp),%r12
+ movq 1*8(%rsp), %r12
CFI_RESTORE r12
- addq $2*8,%rsp
+ addq $2*8, %rsp
CFI_ADJUST_CFA_OFFSET -2*8
ret
.Lcopy_page_end:
@@ -103,7 +101,7 @@ ENDPROC(copy_page)
.section .altinstr_replacement,"ax"
1: .byte 0xeb /* jmp <disp8> */
- .byte (copy_page_c - copy_page) - (2f - 1b) /* offset */
+ .byte (copy_page_rep - copy_page) - (2f - 1b) /* offset */
2:
.previous
.section .altinstructions,"a"
--
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