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Message-ID: <tip-ab513927ab449af00cc70b0269e15ee80dd537f9@git.kernel.org>
Date: Tue, 4 Aug 2015 01:54:35 -0700
From: tip-bot for Andy Lutomirski <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: tglx@...utronix.de, rostedt@...dmis.org, hpa@...or.com,
peterz@...radead.org, bp@...en8.de, brgerst@...il.com,
linux-kernel@...r.kernel.org, masami.hiramatsu.pt@...achi.com,
torvalds@...ux-foundation.org, luto@...nel.org, mingo@...nel.org
Subject: [tip:perf/core] perf/x86/hw_breakpoints:
Improve range breakpoint validation
Commit-ID: ab513927ab449af00cc70b0269e15ee80dd537f9
Gitweb: http://git.kernel.org/tip/ab513927ab449af00cc70b0269e15ee80dd537f9
Author: Andy Lutomirski <luto@...nel.org>
AuthorDate: Thu, 30 Jul 2015 20:32:41 -0700
Committer: Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 4 Aug 2015 10:16:54 +0200
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@...nel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/ae25d14d61f2f43b78e0a247e469f3072df7e201.1438312874.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
arch/x86/kernel/hw_breakpoint.c | 10 ++++++++++
1 file changed, 10 insertions(+)
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;
--
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