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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	Jan Beulich <JBeulich@suse.com>, Keir Fraser <keir@xen.org>
Subject: x86_64: Fix double fault stack setup
Date: Thu, 24 May 2012 15:59:14 +0100	[thread overview]
Message-ID: <4FBE4CC2.2090606@citrix.com> (raw)

[-- Attachment #1: Type: text/plain, Size: 1392 bytes --]

x86_64: Fix double fault stack setup.

Dont forget to push error_code and entry_vector onto the stack for a double
fault.  If it is missed, the register information printed looks like

(XEN) CPU:    0
(XEN) RIP:    0246:[<000000000000e008>] ???
(XEN) RFLAGS: ffff82c480287eb8
(XEN) rax: 0000000000000282   rbx: ffff82c480242dd0   rcx: 0000000000000282
(XEN) rdx: 0000000000000000   rsi: 0000000000000282   rdi: 0000000000000031
(XEN) rbp: 0000000000000031   rsp: 0000000000000000   r8:  ffff83007ee52488
(XEN) r9:  ffff83007ee61088   r10: 0000000000000007   r11: ffff82c480116460
(XEN) r12: 0000000000000000   r13: ffff82c4802c37e0   r14: 00026501a9ced0b8
(XEN) r15: ffff82c4802c37c0    cs: 0000000000000246    ss: 0000000000000000

which incorrectly displays cs, rip, rflags and rsp; the useful pieces of
information when trying to identify the cause of a double fault.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff -r 69c3ae25bb1d xen/arch/x86/x86_64/entry.S
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -595,6 +595,8 @@ ENTRY(spurious_interrupt_bug)
         jmp   handle_exception
 
 ENTRY(double_fault)
+        pushq $0
+        movl $TRAP_double_fault,4(%rsp)
         SAVE_ALL
         movq  %rsp,%rdi
         call  do_double_fault

-- 
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com


[-- Attachment #2: x86_64-double-fault-stack.patch --]
[-- Type: text/x-patch, Size: 1356 bytes --]

# HG changeset patch
# Parent 69c3ae25bb1ddcb0ea44b7566d36d34e9d6a70aa
x86_64: Fix double fault stack setup.

Dont forget to push error_code and entry_vector onto the stack for a double
fault.  If it is missed, the register information printed looks like

(XEN) CPU:    0
(XEN) RIP:    0246:[<000000000000e008>] ???
(XEN) RFLAGS: ffff82c480287eb8
(XEN) rax: 0000000000000282   rbx: ffff82c480242dd0   rcx: 0000000000000282
(XEN) rdx: 0000000000000000   rsi: 0000000000000282   rdi: 0000000000000031
(XEN) rbp: 0000000000000031   rsp: 0000000000000000   r8:  ffff83007ee52488
(XEN) r9:  ffff83007ee61088   r10: 0000000000000007   r11: ffff82c480116460
(XEN) r12: 0000000000000000   r13: ffff82c4802c37e0   r14: 00026501a9ced0b8
(XEN) r15: ffff82c4802c37c0    cs: 0000000000000246    ss: 0000000000000000

which incorrectly displays cs, rip, rflags and rsp; the useful pieces of
information when trying to identify the cause of a double fault.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff -r 69c3ae25bb1d xen/arch/x86/x86_64/entry.S
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -595,6 +595,8 @@ ENTRY(spurious_interrupt_bug)
         jmp   handle_exception
 
 ENTRY(double_fault)
+        pushq $0
+        movl $TRAP_double_fault,4(%rsp)
         SAVE_ALL
         movq  %rsp,%rdi
         call  do_double_fault

[-- Attachment #3: Type: text/plain, Size: 126 bytes --]

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             reply	other threads:[~2012-05-24 14:59 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-24 14:59 Andrew Cooper [this message]
2012-05-24 15:14 ` x86_64: Fix double fault stack setup Jan Beulich
2012-05-24 15:28   ` Andrew Cooper
2012-05-24 15:46     ` Jan Beulich
2012-05-24 16:12       ` Andrew Cooper
2012-05-25 10:35         ` Jan Beulich
2012-05-25 11:04           ` Keir Fraser
2012-05-24 18:04     ` Keir Fraser
2012-05-24 18:15       ` Andrew Cooper

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