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authorkib <kib@FreeBSD.org>2010-06-23 20:44:07 +0000
committerkib <kib@FreeBSD.org>2010-06-23 20:44:07 +0000
commit8dcd1daee8fe0803727673a014545c545bf684e4 (patch)
tree6f2a6ce8d3aa678205f3ae8e8fe722441473ab3e /sys/amd64/ia32
parent1cd81ae69301b363e554de070b5f1f28f5b93d17 (diff)
downloadFreeBSD-src-8dcd1daee8fe0803727673a014545c545bf684e4.zip
FreeBSD-src-8dcd1daee8fe0803727673a014545c545bf684e4.tar.gz
Clear DF bit in eflags/rflags on the kernel entry. The i386 and amd64
ABI specifies the DF should be zero, and newer compilers do not clear DF before using DF-sensitive instructions. The DF clearing for signal handlers was done some time ago. MFC after: 1 week
Diffstat (limited to 'sys/amd64/ia32')
-rw-r--r--sys/amd64/ia32/ia32_exception.S1
1 files changed, 1 insertions, 0 deletions
diff --git a/sys/amd64/ia32/ia32_exception.S b/sys/amd64/ia32/ia32_exception.S
index 341f00e..6ca7afc 100644
--- a/sys/amd64/ia32/ia32_exception.S
+++ b/sys/amd64/ia32/ia32_exception.S
@@ -67,6 +67,7 @@ IDTVEC(int0x80_syscall)
movq %r14,TF_R14(%rsp)
movq %r15,TF_R15(%rsp)
movl $TF_HASSEGS,TF_FLAGS(%rsp)
+ cld
FAKE_MCOUNT(TF_RIP(%rsp))
movq %rsp, %rdi
call ia32_syscall
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