From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: + x86-bitops-fix-build-regression.patch added to -mm tree Date: Fri, 15 May 2020 13:53:42 -0700 Message-ID: <20200515205342.17UvbQbmL%akpm@linux-foundation.org> References: <20200513175005.1f4839360c18c0238df292d1@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:45572 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726541AbgEOUxo (ORCPT ); Fri, 15 May 2020 16:53:44 -0400 In-Reply-To: <20200513175005.1f4839360c18c0238df292d1@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: andriy.shevchenko@intel.com, aryabinin@virtuozzo.com, bot@kernelci.org, bp@alien8.de, brgerst@gmail.com, dja@axtens.net, elver@google.com, hpa@zytor.com, ilie.halip@gmail.com, jesse.brandeburg@intel.com, luc.vanoostenryck@gmail.com, mingo@redhat.com, mm-commits@vger.kernel.org, natechancellor@gmail.com, ndesaulniers@google.com, paulmck@kernel.org, peterz@infradead.org, sedat.dilek@gmail.com, tglx@linutronix.de, yamada.masahiro@socionext.com The patch titled Subject: x86: bitops: fix build regression has been added to the -mm tree. Its filename is x86-bitops-fix-build-regression.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/x86-bitops-fix-build-regression.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/x86-bitops-fix-build-regression.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Nick Desaulniers Subject: x86: bitops: fix build regression This is easily reproducible via CC=clang+CONFIG_STAGING=y+CONFIG_VT6656=m. It turns out that if your config tickles __builtin_constant_p via differences in choices to inline or not, these statements produce invalid assembly: $ cat foo.c long a(long b, long c) { asm("orb %1, %0" : "+q"(c): "r"(b)); return c; } $ gcc foo.c foo.c: Assembler messages: foo.c:2: Error: `%rax' not allowed with `orb' Use the `%b` "x86 Operand Modifier" to instead force register allocation to select a lower-8-bit GPR operand. The "q" constraint only has meaning on -m32 otherwise is treated as "r". Not all GPRs have low-8-bit aliases for -m32. Link: http://lkml.kernel.org/r/20200508183230.229464-1-ndesaulniers@google.com Link: https://github.com/ClangBuiltLinux/linux/issues/961 Link: https://lore.kernel.org/lkml/20200504193524.GA221287@google.com/ Link: https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#x86Operandmodifiers Fixes: 1651e700664b4 ("x86: Fix bitops.h warning with a moved cast") Signed-off-by: Nick Desaulniers Tested-by: Sedat Dilek Reported-by: kernelci.org bot Suggested-by: Andy Shevchenko Suggested-by: Brian Gerst Suggested-by: H. Peter Anvin Suggested-by: Ilie Halip Reviewed-by: Nathan Chancellor Reviewed-By: Brian Gerst Tested-by: Nathan Chancellor [build, clang-11] Reviewed-by: Jesse Brandeburg Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Marco Elver Cc: "Paul E. McKenney" Cc: Andrey Ryabinin Cc: Luc Van Oostenryck Cc: Masahiro Yamada Cc: Daniel Axtens Cc: "Peter Zijlstra (Intel)" Signed-off-by: Andrew Morton --- arch/x86/include/asm/bitops.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/arch/x86/include/asm/bitops.h~x86-bitops-fix-build-regression +++ a/arch/x86/include/asm/bitops.h @@ -52,9 +52,9 @@ static __always_inline void arch_set_bit(long nr, volatile unsigned long *addr) { if (__builtin_constant_p(nr)) { - asm volatile(LOCK_PREFIX "orb %1,%0" + asm volatile(LOCK_PREFIX "orb %b1,%0" : CONST_MASK_ADDR(nr, addr) - : "iq" (CONST_MASK(nr) & 0xff) + : "iq" (CONST_MASK(nr)) : "memory"); } else { asm volatile(LOCK_PREFIX __ASM_SIZE(bts) " %1,%0" @@ -72,9 +72,9 @@ static __always_inline void arch_clear_bit(long nr, volatile unsigned long *addr) { if (__builtin_constant_p(nr)) { - asm volatile(LOCK_PREFIX "andb %1,%0" + asm volatile(LOCK_PREFIX "andb %b1,%0" : CONST_MASK_ADDR(nr, addr) - : "iq" (CONST_MASK(nr) ^ 0xff)); + : "iq" (~CONST_MASK(nr))); } else { asm volatile(LOCK_PREFIX __ASM_SIZE(btr) " %1,%0" : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); @@ -123,9 +123,9 @@ static __always_inline void arch_change_bit(long nr, volatile unsigned long *addr) { if (__builtin_constant_p(nr)) { - asm volatile(LOCK_PREFIX "xorb %1,%0" + asm volatile(LOCK_PREFIX "xorb %b1,%0" : CONST_MASK_ADDR(nr, addr) - : "iq" ((u8)CONST_MASK(nr))); + : "iq" (CONST_MASK(nr))); } else { asm volatile(LOCK_PREFIX __ASM_SIZE(btc) " %1,%0" : : RLONG_ADDR(addr), "Ir" (nr) : "memory"); _ Patches currently in -mm which might be from ndesaulniers@google.com are elfnote-mark-all-note-sections-shf_alloc.patch x86-bitops-fix-build-regression.patch