On 10/21/2013 03:47 PM, Rafael J. Wysocki wrote:
On Monday, October 21, 2013 08:56:22 AM Dirk Brandewie wrote:
On 10/19/2013 08:31 PM, Geyslan G. Bem wrote:
The expression 'pstate << 8' is evaluated using 32-bit arithmetic while
'val' expects an expression of type u64.
Signed-off-by: Geyslan G. Bem <geyslan@xxxxxxxxx>
Acked-by: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
Actually, isn't (pstate << 8) guaranteed not to overflow?
Yes, I was assuming this was caught by a static checking tool. I
didn't see a downside to giving the compilier complete information.
---
drivers/cpufreq/intel_pstate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index badf620..43446b5 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -395,7 +395,7 @@ static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
trace_cpu_frequency(pstate * 100000, cpu->cpu);
cpu->pstate.current_pstate = pstate;
- val = pstate << 8;
+ val = (u64)pstate << 8;
if (limits.no_turbo)
val |= (u64)1 << 32;
--
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