diff options
| author | K.Prasad <prasad@linux.vnet.ibm.com> | 2010-01-28 16:44:01 +0530 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2010-01-29 02:26:10 +0100 |
| commit | 40f9249a73f6c251adea492b1c3d19d39e2a9bda (patch) | |
| tree | c60a605bdd1ca6981de926234dffd93a3f9b970f | |
| parent | 1e12a4a7a3a78bc9c3aaf3486dde3b8ab1cdf465 (diff) | |
x86/debug: Clear reserved bits of DR6 in do_debug()
Clear the reserved bits from the stored copy of debug status
register (DR6).
This will help easy bitwise operations such as quick testing
of a debug event origin.
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20100128111401.GB13935@in.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| -rw-r--r-- | arch/x86/include/asm/debugreg.h | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 3 |
2 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h index 8240f76b531..b81002f2361 100644 --- a/arch/x86/include/asm/debugreg.h +++ b/arch/x86/include/asm/debugreg.h @@ -14,6 +14,9 @@ which debugging register was responsible for the trap. The other bits are either reserved or not of interest to us. */ +/* Define reserved bits in DR6 which are always set to 1 */ +#define DR6_RESERVED (0xFFFF0FF0) + #define DR_TRAP0 (0x1) /* db0 */ #define DR_TRAP1 (0x2) /* db1 */ #define DR_TRAP2 (0x4) /* db2 */ diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 33399176512..1168e445418 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -534,6 +534,9 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) get_debugreg(dr6, 6); + /* Filter out all the reserved bits which are preset to 1 */ + dr6 &= ~DR6_RESERVED; + /* Catch kmemcheck conditions first of all! */ if ((dr6 & DR_STEP) && kmemcheck_trap(regs)) return; |