From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 69E967F for ; Tue, 2 Aug 2022 17:59:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76B6BC433B5; Tue, 2 Aug 2022 17:59:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659463183; bh=xpWA7Jpv8r6INPM8eC9dRH0bjB0EBSQdgOjBy0N4/rw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V15liBSsJpZKesOb/8eDlMArbGuucPgpmrtWaDszI2rKEzxMbDCo0O95EcymiP/Gp hgvNMmLbm1E/ShJPRVRXIXi9EaBllYBTW3GEAjm718erwAGJskfqJORShJdSvPuNbQ iwAUvD2pCUmKfk3TcIc0HVHOG2CT8xYrYzkhhrOlRbyepLiKpGC5bezksL0I3N+KzC Jv4qtfYKy9y1e9icY9Kkg9JLXewDMZ4CEcfa1K++dF9fJD6y37IAJgFl4+f0I149YC edPUIBhg/MRDSCtYNChFU0UpEPNcFAl7jQ87XMhYIPr1NXSx95oRx15uf1S6GtFrhp 5GKo0/IDk4IgQ== From: Nathan Chancellor To: Thomas Bogendoerfer Cc: Nick Desaulniers , Tom Rix , "Maciej W. Rozycki" , torvalds@linux-foundation.org, linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Nathan Chancellor , Sudip Mukherjee Subject: [PATCH] MIPS: tlbex: Explicitly compare _PAGE_NO_EXEC against 0 Date: Tue, 2 Aug 2022 10:59:36 -0700 Message-Id: <20220802175936.2278362-1-nathan@kernel.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When CONFIG_XPA is enabled, Clang warns: arch/mips/mm/tlbex.c:629:24: error: converting the result of '<<' to a boolean; did you mean '(1 << _PAGE_NO_EXEC_SHIFT) != 0'? [-Werror,-Wint-in-bool-context] if (cpu_has_rixi && !!_PAGE_NO_EXEC) { ^ arch/mips/include/asm/pgtable-bits.h:174:28: note: expanded from macro '_PAGE_NO_EXEC' # define _PAGE_NO_EXEC (1 << _PAGE_NO_EXEC_SHIFT) ^ arch/mips/mm/tlbex.c:2568:24: error: converting the result of '<<' to a boolean; did you mean '(1 << _PAGE_NO_EXEC_SHIFT) != 0'? [-Werror,-Wint-in-bool-context] if (!cpu_has_rixi || !_PAGE_NO_EXEC) { ^ arch/mips/include/asm/pgtable-bits.h:174:28: note: expanded from macro '_PAGE_NO_EXEC' # define _PAGE_NO_EXEC (1 << _PAGE_NO_EXEC_SHIFT) ^ 2 errors generated. _PAGE_NO_EXEC can be '0' or '1 << _PAGE_NO_EXEC_SHIFT' depending on the build and runtime configuration, which is what the negation operators are trying to convey. To silence the warning, explicitly compare against 0 so the result of the '<<' operator is not implicitly converted to a boolean. According to its documentation, GCC enables -Wint-in-bool-context with -Wall but this warning is not visible when building the same configuration with GCC. It appears GCC only warns when compiling C++, not C, although the documentation makes no note of this: https://godbolt.org/z/x39q3brxf Reported-by: Sudip Mukherjee (Codethink) Signed-off-by: Nathan Chancellor --- arch/mips/mm/tlbex.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c index 8dbbd99fc7e8..be4d4670d649 100644 --- a/arch/mips/mm/tlbex.c +++ b/arch/mips/mm/tlbex.c @@ -626,7 +626,7 @@ static __maybe_unused void build_convert_pte_to_entrylo(u32 **p, return; } - if (cpu_has_rixi && !!_PAGE_NO_EXEC) { + if (cpu_has_rixi && _PAGE_NO_EXEC != 0) { if (fill_includes_sw_bits) { UASM_i_ROTR(p, reg, reg, ilog2(_PAGE_GLOBAL)); } else { @@ -2565,7 +2565,7 @@ static void check_pabits(void) unsigned long entry; unsigned pabits, fillbits; - if (!cpu_has_rixi || !_PAGE_NO_EXEC) { + if (!cpu_has_rixi || _PAGE_NO_EXEC == 0) { /* * We'll only be making use of the fact that we can rotate bits * into the fill if the CPU supports RIXI, so don't bother base-commit: 7d0d3fa7339ed5a06d6608b7cde9f079eba62bb1 -- 2.37.1