diff options
| author | Andy Lutomirski <luto@kernel.org> | 2015-07-31 03:32:41 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-08-04 08:16:54 (GMT) |
| commit | ab513927ab449af00cc70b0269e15ee80dd537f9 (patch) | |
| tree | 69d69b3fedd3d792c3d9634246f67fdeca7acc41 | |
| parent | e5779e8e12299f77c2421a707855d8d124171d85 (diff) | |
| download | linux-ab513927ab449af00cc70b0269e15ee80dd537f9.tar.xz | |
perf/x86/hw_breakpoints: Improve range breakpoint validation
Range breakpoints will do the wrong thing if the address isn't
aligned. While we're there, add comments about why it's safe for
instruction breakpoints.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/ae25d14d61f2f43b78e0a247e469f3072df7e201.1438312874.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/kernel/hw_breakpoint.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c index 78f3e90..6f345d3 100644 --- a/arch/x86/kernel/hw_breakpoint.c +++ b/arch/x86/kernel/hw_breakpoint.c @@ -291,8 +291,18 @@ static int arch_build_bp_info(struct perf_event *bp) break; #endif default: + /* AMD range breakpoint */ if (!is_power_of_2(bp->attr.bp_len)) return -EINVAL; + if (bp->attr.bp_addr & (bp->attr.bp_len - 1)) + return -EINVAL; + /* + * It's impossible to use a range breakpoint to fake out + * user vs kernel detection because bp_len - 1 can't + * have the high bit set. If we ever allow range instruction + * breakpoints, then we'll have to check for kprobe-blacklisted + * addresses anywhere in the range. + */ if (!cpu_has_bpext) return -EOPNOTSUPP; info->mask = bp->attr.bp_len - 1; |