linux-kernel - [PATCH] crypto: ccree - avoid out-of-range warnings from clang

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Date:   Mon, 27 Sep 2021 14:18:03 +0200
From:   Arnd Bergmann <arnd@...nel.org>
To:     Gilad Ben-Yossef <gilad@...yossef.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     Arnd Bergmann <arnd@...db.de>, YueHaibing <yuehaibing@...wei.com>,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev
Subject: [PATCH] crypto: ccree - avoid out-of-range warnings from clang

From: Arnd Bergmann <arnd@...db.de>

clang points out inconsistencies in the FIELD_PREP() invocation in
this driver that result from the 'mask' being a 32-bit value:

drivers/crypto/ccree/cc_driver.c:117:18: error: result of comparison of constant 18446744073709551615 with expression of type 'u32' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
        cache_params |= FIELD_PREP(mask, val);
                        ^~~~~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:94:3: note: expanded from macro 'FIELD_PREP'
                __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");    \
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/bitfield.h:52:28: note: expanded from macro '__BF_FIELD_CHECK'
                BUILD_BUG_ON_MSG((_mask) > (typeof(_reg))~0ull,         \
                ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This does not happen in other places that just pass a constant here.

Work around the warnings by widening the type of the temporary variable.

Fixes: 05c2a705917b ("crypto: ccree - rework cache parameters handling")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/crypto/ccree/cc_driver.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/ccree/cc_driver.c b/drivers/crypto/ccree/cc_driver.c
index e599ac6dc162..790fa9058a36 100644
--- a/drivers/crypto/ccree/cc_driver.c
+++ b/drivers/crypto/ccree/cc_driver.c
@@ -103,7 +103,8 @@ MODULE_DEVICE_TABLE(of, arm_ccree_dev_of_match);
 static void init_cc_cache_params(struct cc_drvdata *drvdata)
 {
 	struct device *dev = drvdata_to_dev(drvdata);
-	u32 cache_params, ace_const, val, mask;
+	u32 cache_params, ace_const, val;
+	u64 mask;
 
 	/* compute CC_AXIM_CACHE_PARAMS */
 	cache_params = cc_ioread(drvdata, CC_REG(AXIM_CACHE_PARAMS));
-- 
2.29.2