From: tip-bot for Arnd Bergmann <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, arnd@arndb.de, tglx@linutronix.de,
hpa@zytor.com, mingo@kernel.org
Subject: [tip:x86/urgent] x86/pgtable/32: Fix LOWMEM_PAGES constant
Date: Wed, 10 Jul 2019 08:25:02 -0700 [thread overview]
Message-ID: <tip-26515699863d68058e290e18e83f444925920be5@git.kernel.org> (raw)
In-Reply-To: <20190710130522.1802800-1-arnd@arndb.de>
Commit-ID: 26515699863d68058e290e18e83f444925920be5
Gitweb: https://git.kernel.org/tip/26515699863d68058e290e18e83f444925920be5
Author: Arnd Bergmann <arnd@arndb.de>
AuthorDate: Wed, 10 Jul 2019 15:04:55 +0200
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 10 Jul 2019 17:19:58 +0200
x86/pgtable/32: Fix LOWMEM_PAGES constant
clang points out that the computation of LOWMEM_PAGES causes a signed
integer overflow on 32-bit x86:
arch/x86/kernel/head32.c:83:20: error: signed shift result (0x100000000) requires 34 bits to represent, but 'int' only has 32 bits [-Werror,-Wshift-overflow]
(PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT);
^~~~~~~~~~~~
arch/x86/include/asm/pgtable_32.h:109:27: note: expanded from macro 'LOWMEM_PAGES'
#define LOWMEM_PAGES ((((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT))
~^ ~~
arch/x86/include/asm/pgtable_32.h:98:34: note: expanded from macro 'PAGE_TABLE_SIZE'
#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
Use the _ULL() macro to make it a 64-bit constant.
Fixes: 1e620f9b23e5 ("x86/boot/32: Convert the 32-bit pgtable setup code from assembly to C")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190710130522.1802800-1-arnd@arndb.de
---
arch/x86/include/asm/pgtable_32.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h
index 4fe9e7fc74d3..c78da8eda8f2 100644
--- a/arch/x86/include/asm/pgtable_32.h
+++ b/arch/x86/include/asm/pgtable_32.h
@@ -106,6 +106,6 @@ do { \
* with only a host target support using a 32-bit type for internal
* representation.
*/
-#define LOWMEM_PAGES ((((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT))
+#define LOWMEM_PAGES ((((_ULL(2)<<31) - __PAGE_OFFSET) >> PAGE_SHIFT))
#endif /* _ASM_X86_PGTABLE_32_H */
prev parent reply other threads:[~2019-07-10 15:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-10 13:04 [PATCH] x86: fix LOWMEM_PAGES constant Arnd Bergmann
2019-07-10 15:25 ` tip-bot for Arnd Bergmann [this message]
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