linux-kernel - [PATCH 2/4] perf/x86_64: get_regs_user: Do report user

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Date:	Fri, 10 Apr 2015 15:06:57 +0200
From:	Denys Vlasenko <dvlasenk@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	Denys Vlasenko <dvlasenk@...hat.com>, Jiri Olsa <jolsa@...hat.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>, x86@...nel.org
Subject: [PATCH 2/4] perf/x86_64: get_regs_user: Do report user_regs->cx while we are in syscall

Yes, it is true that cx contains return address.
It's not clear why we trash it.
Stop doing that.

Signed-off-by: Denys Vlasenko <dvlasenk@...hat.com>
CC: Jiri Olsa <jolsa@...hat.com>
CC: Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC: Paul Mackerras <paulus@...ba.org>
CC: Ingo Molnar <mingo@...hat.com>
CC: Arnaldo Carvalho de Melo <acme@...nel.org>
CC: x86@...nel.org
CC: linux-kernel@...r.kernel.org
---
 arch/x86/kernel/perf_regs.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
index 7ab198a..a8d4e48 100644
--- a/arch/x86/kernel/perf_regs.c
+++ b/arch/x86/kernel/perf_regs.c
@@ -177,8 +177,6 @@ void perf_get_regs_user(struct perf_regs *regs_user,
 		 * than just blindly copying user_regs.
 		 */
 		regs_user->abi = PERF_SAMPLE_REGS_ABI_64;
-		/* usually contains return address (same as ->ip) */
-		regs_user_copy->cx = -1;
 	} else {
 		/* We're probably in an interrupt or exception. */
 		regs_user->abi = user_64bit_mode(user_regs) ?
-- 
1.8.1.4

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