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authorSeiichi Ikarashi <s.ikarashi@jp.fujitsu.com>2011-12-06 17:58:14 +0900
committerIngo Molnar <mingo@elte.hu>2011-12-06 10:02:38 +0100
commit1cf8343f55525c09c88da0a494a96e1b034f84e2 (patch)
tree5cb45ead7d10d3021fd2a9424c47d25eefa4201f /drivers/lguest
parentcc3a1bf52a9d2808c7cd6e8f413b02b650b6b84b (diff)
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x86: Fix rflags in FAKE_STACK_FRAME
The x86_64 kernel pushes the fake kernel stack in arch/x86/kernel/entry_64.S:FAKE_STACK_FRAME, and rflags register in it does not conform to the specification. Although Intel's manual[1] says bit 1 of it shall be set to 1, this bit is cleared to 0 on pushing the fake stack. [1] Intel(R) 64 and IA-32 Architectures Software Developer's Manual Vol.1 3-21 Figure 3-8. EFLAGS Register If it is not on purpose, it is better to be fixed, because it can lead some tools misunderstanding the stack frame. For example, "crash" utility[2] actually detects it and warns you like below: RIP: ffffffff8005dfa2 RSP: ffff8104ce0c7f58 RFLAGS: 00000200 [...] bt: WARNING: possibly bogus exception frame Signed-off-by: Seiichi Ikarashi <s.ikarashi@jp.fujitsu.com> Tested-by: Masayoshi MIZUMA <m.mizuma@jp.fujitsu.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'drivers/lguest')
-rw-r--r--drivers/lguest/x86/core.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index 65af42f2d593..39809035320a 100644
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -697,7 +697,7 @@ void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start)
* interrupts are enabled. We always leave interrupts enabled while
* running the Guest.
*/
- regs->eflags = X86_EFLAGS_IF | 0x2;
+ regs->eflags = X86_EFLAGS_IF | X86_EFLAGS_BIT1;
/*
* The "Extended Instruction Pointer" register says where the Guest is