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authorChuck Ebbert <76306.1226@compuserve.com>2006-01-11 22:46:03 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-11 19:05:00 -0800
commit60923df35edab273d0bd8e829cdfdc5cfbb4fd2c (patch)
treed4869124d1344f711671a33628e5eebb16ecd68c /arch/x86_64/kernel
parent100c0e36852a771864c56c31b260b7810b554170 (diff)
[PATCH] x86_64: allow setting RF in EFLAGS
Setting RF (resume flag) allows a debugger to resume execution after a code breakpoint without tripping the breakpoint again. It is reset by the CPU after executing one instruction. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/x86_64/kernel')
-rw-r--r--arch/x86_64/kernel/ptrace.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c
index a87b6cebe80..86248bc9303 100644
--- a/arch/x86_64/kernel/ptrace.c
+++ b/arch/x86_64/kernel/ptrace.c
@@ -36,9 +36,12 @@
* in exit.c or in signal.c.
*/
-/* determines which flags the user has access to. */
-/* 1 = access 0 = no access */
-#define FLAG_MASK 0x44dd5UL
+/*
+ * Determines which flags the user has access to [1 = access, 0 = no access].
+ * Prohibits changing ID(21), VIP(20), VIF(19), VM(17), IOPL(12-13), IF(9).
+ * Also masks reserved bits (63-22, 15, 5, 3, 1).
+ */
+#define FLAG_MASK 0x54dd5UL
/* set's the trap flag. */
#define TRAP_FLAG 0x100UL