From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>, Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <garsilva@embeddedor.com>
Subject: [PATCH] ACPI / CPPC: Use 64-bit arithmetic instead of 32-bit
Date: Tue, 6 Feb 2018 17:36:17 -0600 [thread overview]
Message-ID: <20180206233617.GA30829@embeddedgus> (raw)
Add suffix ULL to constant 500 in order to give the compiler complete
information about the proper arithmetic to use. Notice that this
constant is used in a context that expects an expression of type
u64 (64 bits, unsigned).
The expression NUM_RETRIES * cppc_ss->latency at line 578, which at
preprocessing time translates to 500 * cppc_ss->latency is currently
being evaluated using 32-bit arithmetic.
Addresses-Coverity-ID: 1382602
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
Notice that another option is to cast NUM_RETRIES to u64 at line 578,
but as there is only one instace in which this macro is being used I
think adding the ULL is just enough.
drivers/acpi/cppc_acpi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 06ea474..0afbb26 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -119,7 +119,7 @@ static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
* to PCC commands. Keeping it high enough to cover emulators where
* the processors run painfully slow.
*/
-#define NUM_RETRIES 500
+#define NUM_RETRIES 500ULL
struct cppc_attr {
struct attribute attr;
--
2.7.4
next reply other threads:[~2018-02-06 23:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-06 23:36 Gustavo A. R. Silva [this message]
2018-02-08 9:49 ` [PATCH] ACPI / CPPC: Use 64-bit arithmetic instead of 32-bit Rafael J. Wysocki
2018-02-08 16:40 ` Gustavo A. R. Silva
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