From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH] asm-generic: fix variable 'p4d' set but not used Date: Tue, 6 Aug 2019 13:51:48 -0700 Message-ID: <20190806135148.867b32afce5a64e4ed651ccd@linux-foundation.org> References: <1564774882-22926-1-git-send-email-cai@lca.pw> <20190806143904.GE11627@ziepe.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190806143904.GE11627@ziepe.ca> Sender: linux-kernel-owner@vger.kernel.org To: Jason Gunthorpe Cc: Qian Cai , arnd@arndb.de, kirill.shutemov@linux.intel.com, mhocko@suse.com, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-arch.vger.kernel.org On Tue, 6 Aug 2019 11:39:04 -0300 Jason Gunthorpe wrote: > On Fri, Aug 02, 2019 at 03:41:22PM -0400, Qian Cai wrote: > > GCC throws a warning on an arm64 system since the commit 9849a5697d3d > > ("arch, mm: convert all architectures to use 5level-fixup.h"), > > > > mm/kasan/init.c: In function 'kasan_free_p4d': > > mm/kasan/init.c:344:9: warning: variable 'p4d' set but not used > > [-Wunused-but-set-variable] > > p4d_t *p4d; > > ^~~ > > > > because p4d_none() in "5level-fixup.h" is compiled away while it is a > > static inline function in "pgtable-nopud.h". However, if converted > > p4d_none() to a static inline there, powerpc would be unhappy as it > > reads those in assembler language in > > "arch/powerpc/include/asm/book3s/64/pgtable.h", > > > > ./include/asm-generic/5level-fixup.h: Assembler messages: > > ./include/asm-generic/5level-fixup.h:20: Error: unrecognized opcode: > > `static' > > ./include/asm-generic/5level-fixup.h:21: Error: junk at end of line, > > first unrecognized character is `{' > > ./include/asm-generic/5level-fixup.h:22: Error: unrecognized opcode: > > `return' > > ./include/asm-generic/5level-fixup.h:23: Error: junk at end of line, > > first unrecognized character is `}' > > ./include/asm-generic/5level-fixup.h:25: Error: unrecognized opcode: > > `static' > > ./include/asm-generic/5level-fixup.h:26: Error: junk at end of line, > > first unrecognized character is `{' > > ./include/asm-generic/5level-fixup.h:27: Error: unrecognized opcode: > > `return' > > ./include/asm-generic/5level-fixup.h:28: Error: junk at end of line, > > first unrecognized character is `}' > > ./include/asm-generic/5level-fixup.h:30: Error: unrecognized opcode: > > `static' > > ./include/asm-generic/5level-fixup.h:31: Error: junk at end of line, > > first unrecognized character is `{' > > ./include/asm-generic/5level-fixup.h:32: Error: unrecognized opcode: > > `return' > > ./include/asm-generic/5level-fixup.h:33: Error: junk at end of line, > > first unrecognized character is `}' > > make[2]: *** [scripts/Makefile.build:375: > > arch/powerpc/kvm/book3s_hv_rmhandlers.o] Error 1 > > > > Fix it by reference the variable in the macro instead. > > > > Signed-off-by: Qian Cai > > include/asm-generic/5level-fixup.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h > > index bb6cb347018c..2c3e14c924b6 100644 > > +++ b/include/asm-generic/5level-fixup.h > > @@ -19,7 +19,7 @@ > > > > #define p4d_alloc(mm, pgd, address) (pgd) > > #define p4d_offset(pgd, start) (pgd) > > -#define p4d_none(p4d) 0 > > +#define p4d_none(p4d) ((void)p4d, 0) > > Yuk, how about a static inline instead? Yes. With the appropriate `#ifndef __ASSEMBLY__' to avoid powerpc build errors? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:43144 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726009AbfHFUvv (ORCPT ); Tue, 6 Aug 2019 16:51:51 -0400 Date: Tue, 6 Aug 2019 13:51:48 -0700 From: Andrew Morton Subject: Re: [PATCH] asm-generic: fix variable 'p4d' set but not used Message-ID: <20190806135148.867b32afce5a64e4ed651ccd@linux-foundation.org> In-Reply-To: <20190806143904.GE11627@ziepe.ca> References: <1564774882-22926-1-git-send-email-cai@lca.pw> <20190806143904.GE11627@ziepe.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Jason Gunthorpe Cc: Qian Cai , arnd@arndb.de, kirill.shutemov@linux.intel.com, mhocko@suse.com, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <20190806205148.nbZ8uQD1sBi5264xVVCxhbBbIxaGh7qmDpsWfMJj5n0@z> On Tue, 6 Aug 2019 11:39:04 -0300 Jason Gunthorpe wrote: > On Fri, Aug 02, 2019 at 03:41:22PM -0400, Qian Cai wrote: > > GCC throws a warning on an arm64 system since the commit 9849a5697d3d > > ("arch, mm: convert all architectures to use 5level-fixup.h"), > > > > mm/kasan/init.c: In function 'kasan_free_p4d': > > mm/kasan/init.c:344:9: warning: variable 'p4d' set but not used > > [-Wunused-but-set-variable] > > p4d_t *p4d; > > ^~~ > > > > because p4d_none() in "5level-fixup.h" is compiled away while it is a > > static inline function in "pgtable-nopud.h". However, if converted > > p4d_none() to a static inline there, powerpc would be unhappy as it > > reads those in assembler language in > > "arch/powerpc/include/asm/book3s/64/pgtable.h", > > > > ./include/asm-generic/5level-fixup.h: Assembler messages: > > ./include/asm-generic/5level-fixup.h:20: Error: unrecognized opcode: > > `static' > > ./include/asm-generic/5level-fixup.h:21: Error: junk at end of line, > > first unrecognized character is `{' > > ./include/asm-generic/5level-fixup.h:22: Error: unrecognized opcode: > > `return' > > ./include/asm-generic/5level-fixup.h:23: Error: junk at end of line, > > first unrecognized character is `}' > > ./include/asm-generic/5level-fixup.h:25: Error: unrecognized opcode: > > `static' > > ./include/asm-generic/5level-fixup.h:26: Error: junk at end of line, > > first unrecognized character is `{' > > ./include/asm-generic/5level-fixup.h:27: Error: unrecognized opcode: > > `return' > > ./include/asm-generic/5level-fixup.h:28: Error: junk at end of line, > > first unrecognized character is `}' > > ./include/asm-generic/5level-fixup.h:30: Error: unrecognized opcode: > > `static' > > ./include/asm-generic/5level-fixup.h:31: Error: junk at end of line, > > first unrecognized character is `{' > > ./include/asm-generic/5level-fixup.h:32: Error: unrecognized opcode: > > `return' > > ./include/asm-generic/5level-fixup.h:33: Error: junk at end of line, > > first unrecognized character is `}' > > make[2]: *** [scripts/Makefile.build:375: > > arch/powerpc/kvm/book3s_hv_rmhandlers.o] Error 1 > > > > Fix it by reference the variable in the macro instead. > > > > Signed-off-by: Qian Cai > > include/asm-generic/5level-fixup.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h > > index bb6cb347018c..2c3e14c924b6 100644 > > +++ b/include/asm-generic/5level-fixup.h > > @@ -19,7 +19,7 @@ > > > > #define p4d_alloc(mm, pgd, address) (pgd) > > #define p4d_offset(pgd, start) (pgd) > > -#define p4d_none(p4d) 0 > > +#define p4d_none(p4d) ((void)p4d, 0) > > Yuk, how about a static inline instead? Yes. With the appropriate `#ifndef __ASSEMBLY__' to avoid powerpc build errors?