linux-kernel - [PATCH] x86/oprofile: Fix cast of counter value

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Date:	Tue, 28 Jul 2009 17:43:05 +0200
From:	Robert Richter <robert.richter@....com>
To:	oprofile-list <oprofile-list@...ts.sourceforge.net>
CC:	LKML <linux-kernel@...r.kernel.org>,
	Robert Richter <robert.richter@....com>
Subject: [PATCH] x86/oprofile: Fix cast of counter value

When casting the counter value to a 64 bit value in 32 bit mode, sign
extension may lead to broken counter values. This patch fixes this by
casting to (u64) instead of (s64).

Signed-off-by: Robert Richter <robert.richter@....com>
---
 arch/x86/oprofile/op_model_amd.c |    4 ++--
 arch/x86/oprofile/op_model_p4.c  |    6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/oprofile/op_model_amd.c b/arch/x86/oprofile/op_model_amd.c
index e95268e..7ca8306 100644
--- a/arch/x86/oprofile/op_model_amd.c
+++ b/arch/x86/oprofile/op_model_amd.c
@@ -111,7 +111,7 @@ static void op_amd_setup_ctrs(struct op_x86_model_spec const *model,
 		if (counter_config[i].enabled && msrs->counters[i].addr) {
 			reset_value[i] = counter_config[i].count;
 			wrmsrl(msrs->counters[i].addr,
-			       -(s64)counter_config[i].count);
+			       -(u64)counter_config[i].count);
 			rdmsrl(msrs->controls[i].addr, val);
 			val &= model->reserved;
 			val |= op_x86_get_ctrl(model, &counter_config[i]);
@@ -237,7 +237,7 @@ static int op_amd_check_ctrs(struct pt_regs * const regs,
 		if (val & OP_CTR_OVERFLOW)
 			continue;
 		oprofile_add_sample(regs, i);
-		wrmsrl(msrs->counters[i].addr, -(s64)reset_value[i]);
+		wrmsrl(msrs->counters[i].addr, -(u64)reset_value[i]);
 	}
 
 	op_amd_handle_ibs(regs, msrs);
diff --git a/arch/x86/oprofile/op_model_p4.c b/arch/x86/oprofile/op_model_p4.c
index f01e53b..9db9e36 100644
--- a/arch/x86/oprofile/op_model_p4.c
+++ b/arch/x86/oprofile/op_model_p4.c
@@ -580,7 +580,7 @@ static void p4_setup_ctrs(struct op_x86_model_spec const *model,
 			reset_value[i] = counter_config[i].count;
 			pmc_setup_one_p4_counter(i);
 			wrmsrl(p4_counters[VIRT_CTR(stag, i)].counter_address,
-			       -(s64)counter_config[i].count);
+			       -(u64)counter_config[i].count);
 		} else {
 			reset_value[i] = 0;
 		}
@@ -625,11 +625,11 @@ static int p4_check_ctrs(struct pt_regs * const regs,
 		if (CCCR_OVF_P(low) || !(ctr & OP_CTR_OVERFLOW)) {
 			oprofile_add_sample(regs, i);
 			wrmsrl(p4_counters[real].counter_address,
-			       -(s64)reset_value[i]);
+			       -(u64)reset_value[i]);
 			CCCR_CLEAR_OVF(low);
 			wrmsr(p4_counters[real].cccr_address, low, high);
 			wrmsrl(p4_counters[real].counter_address,
-			       -(s64)reset_value[i]);
+			       -(u64)reset_value[i]);
 		}
 	}
 
-- 
1.6.3.3


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