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Date: Fri, 29 Mar 2024 11:52:16 -0700
From: "Paul E. McKenney" <paulmck@kernel.org>
To: kernel test robot <lkp@intel.com>
Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
	linux-kernel@vger.kernel.org
Subject: Re: [paulmck-rcu:dev.2024.03.27b 66/69]
 include/linux/atomic/atomic-arch-fallback.h:2026:9: error: call to
 undeclared function 'cmpxchg_emu_u8'; ISO C99 and later do not support
 implicit function declarations
Message-ID: <45452057-6655-4bab-a27d-38f2dff018e8@paulmck-laptop>
Reply-To: paulmck@kernel.org
References: <202403292322.bwguovKc-lkp@intel.com>
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In-Reply-To: <202403292322.bwguovKc-lkp@intel.com>

On Fri, Mar 29, 2024 at 11:08:05PM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev.2024.03.27b
> head:   786fab3085d764055a78edb54023420920344333
> commit: 032d9f7e1213171131a3f45c5c532ea5d11b4b9a [66/69] riscv: Emulate one-byte and two-byte cmpxchg
> config: riscv-defconfig (https://download.01.org/0day-ci/archive/20240329/202403292322.bwguovKc-lkp@intel.com/config)
> compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 79ba323bdd0843275019e16b6e9b35133677c514)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240329/202403292322.bwguovKc-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202403292322.bwguovKc-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from arch/riscv/kernel/asm-offsets.c:10:
>    In file included from include/linux/mm.h:7:
>    In file included from include/linux/gfp.h:7:
>    In file included from include/linux/mmzone.h:8:
>    In file included from include/linux/spinlock.h:63:
>    In file included from include/linux/lockdep.h:14:
>    In file included from include/linux/smp.h:13:
>    In file included from include/linux/cpumask.h:14:
>    In file included from include/linux/atomic.h:80:
> >> include/linux/atomic/atomic-arch-fallback.h:2026:9: error: call to undeclared function 'cmpxchg_emu_u8'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>     2026 |         return raw_cmpxchg(&v->counter, old, new);
>          |                ^
>    include/linux/atomic/atomic-arch-fallback.h:55:21: note: expanded from macro 'raw_cmpxchg'
>       55 | #define raw_cmpxchg arch_cmpxchg
>          |                     ^
>    arch/riscv/include/asm/cmpxchg.h:367:23: note: expanded from macro 'arch_cmpxchg'
>      367 |         (__typeof__(*(ptr))) __cmpxchg((ptr),                           \
>          |                              ^
>    arch/riscv/include/asm/cmpxchg.h:328:11: note: expanded from macro '__cmpxchg'
>      328 |                 __ret = cmpxchg_emu_u8((volatile u8 *)__ptr, __old, __new); \
>          |                         ^

Again, good catch!  And again, does the diff at the end of this email
fix things for you?

							Thanx, Paul

>    In file included from arch/riscv/kernel/asm-offsets.c:10:
>    In file included from include/linux/mm.h:7:
>    In file included from include/linux/gfp.h:7:
>    In file included from include/linux/mmzone.h:8:
>    In file included from include/linux/spinlock.h:63:
>    In file included from include/linux/lockdep.h:14:
>    In file included from include/linux/smp.h:13:
>    In file included from include/linux/cpumask.h:14:
>    In file included from include/linux/atomic.h:80:
> >> include/linux/atomic/atomic-arch-fallback.h:2026:9: error: call to undeclared function 'cmpxchg_emu_u16'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>    include/linux/atomic/atomic-arch-fallback.h:55:21: note: expanded from macro 'raw_cmpxchg'
>       55 | #define raw_cmpxchg arch_cmpxchg
>          |                     ^
>    arch/riscv/include/asm/cmpxchg.h:367:23: note: expanded from macro 'arch_cmpxchg'
>      367 |         (__typeof__(*(ptr))) __cmpxchg((ptr),                           \
>          |                              ^
>    arch/riscv/include/asm/cmpxchg.h:332:11: note: expanded from macro '__cmpxchg'
>      332 |                 __ret = cmpxchg_emu_u16((volatile u16 *)__ptr, __old, __new); \
>          |                         ^
>    In file included from arch/riscv/kernel/asm-offsets.c:10:
>    In file included from include/linux/mm.h:7:
>    In file included from include/linux/gfp.h:7:
>    In file included from include/linux/mmzone.h:8:
>    In file included from include/linux/spinlock.h:63:
>    In file included from include/linux/lockdep.h:14:
>    In file included from include/linux/smp.h:13:
>    In file included from include/linux/cpumask.h:14:
>    In file included from include/linux/atomic.h:80:
>    include/linux/atomic/atomic-arch-fallback.h:2055:9: error: call to undeclared function 'cmpxchg_emu_u8'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>     2055 |         return raw_cmpxchg_acquire(&v->counter, old, new);
>          |                ^
>    include/linux/atomic/atomic-arch-fallback.h:65:29: note: expanded from macro 'raw_cmpxchg_acquire'
>       65 | #define raw_cmpxchg_acquire arch_cmpxchg_acquire
>          |                             ^
>    arch/riscv/include/asm/cmpxchg.h:263:23: note: expanded from macro 'arch_cmpxchg_acquire'
>      263 |         (__typeof__(*(ptr))) __cmpxchg_acquire((ptr),                   \
>          |                              ^
>    arch/riscv/include/asm/cmpxchg.h:224:11: note: expanded from macro '__cmpxchg_acquire'
>      224 |                 __ret = cmpxchg_emu_u8((volatile u8 *)__ptr, __old, __new); \
>          |                         ^
>    In file included from arch/riscv/kernel/asm-offsets.c:10:
>    In file included from include/linux/mm.h:7:
>    In file included from include/linux/gfp.h:7:
>    In file included from include/linux/mmzone.h:8:
>    In file included from include/linux/spinlock.h:63:
>    In file included from include/linux/lockdep.h:14:
>    In file included from include/linux/smp.h:13:
>    In file included from include/linux/cpumask.h:14:
>    In file included from include/linux/atomic.h:80:
>    include/linux/atomic/atomic-arch-fallback.h:2055:9: error: call to undeclared function 'cmpxchg_emu_u16'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>    include/linux/atomic/atomic-arch-fallback.h:65:29: note: expanded from macro 'raw_cmpxchg_acquire'
>       65 | #define raw_cmpxchg_acquire arch_cmpxchg_acquire
>          |                             ^
>    arch/riscv/include/asm/cmpxchg.h:263:23: note: expanded from macro 'arch_cmpxchg_acquire'
>      263 |         (__typeof__(*(ptr))) __cmpxchg_acquire((ptr),                   \
>          |                              ^
>    arch/riscv/include/asm/cmpxchg.h:228:11: note: expanded from macro '__cmpxchg_acquire'
>      228 |                 __ret = cmpxchg_emu_u16((volatile u16 *)__ptr, __old, __new); \
>          |                         ^
>    In file included from arch/riscv/kernel/asm-offsets.c:10:
>    In file included from include/linux/mm.h:7:
>    In file included from include/linux/gfp.h:7:
>    In file included from include/linux/mmzone.h:8:
>    In file included from include/linux/spinlock.h:63:
>    In file included from include/linux/lockdep.h:14:
>    In file included from include/linux/smp.h:13:
>    In file included from include/linux/cpumask.h:14:
>    In file included from include/linux/atomic.h:80:
>    include/linux/atomic/atomic-arch-fallback.h:2083:9: error: call to undeclared function 'cmpxchg_emu_u8'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>     2083 |         return raw_cmpxchg_release(&v->counter, old, new);
>          |                ^
>    include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
>       77 | #define raw_cmpxchg_release arch_cmpxchg_release
>          |                             ^
>    arch/riscv/include/asm/cmpxchg.h:315:23: note: expanded from macro 'arch_cmpxchg_release'
>      315 |         (__typeof__(*(ptr))) __cmpxchg_release((ptr),                   \
>          |                              ^
>    arch/riscv/include/asm/cmpxchg.h:276:11: note: expanded from macro '__cmpxchg_release'
>      276 |                 __ret = cmpxchg_emu_u8((volatile u8 *)__ptr, __old, __new); \
>          |                         ^
>    In file included from arch/riscv/kernel/asm-offsets.c:10:
>    In file included from include/linux/mm.h:7:
>    In file included from include/linux/gfp.h:7:
>    In file included from include/linux/mmzone.h:8:
>    In file included from include/linux/spinlock.h:63:
>    In file included from include/linux/lockdep.h:14:
>    In file included from include/linux/smp.h:13:
>    In file included from include/linux/cpumask.h:14:
>    In file included from include/linux/atomic.h:80:
>    include/linux/atomic/atomic-arch-fallback.h:2083:9: error: call to undeclared function 'cmpxchg_emu_u16'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>    include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
>       77 | #define raw_cmpxchg_release arch_cmpxchg_release
>          |                             ^
>    arch/riscv/include/asm/cmpxchg.h:315:23: note: expanded from macro 'arch_cmpxchg_release'
>      315 |         (__typeof__(*(ptr))) __cmpxchg_release((ptr),                   \
>          |                              ^
>    arch/riscv/include/asm/cmpxchg.h:280:11: note: expanded from macro '__cmpxchg_release'
>      280 |                 __ret = cmpxchg_emu_u16((volatile u16 *)__ptr, __old, __new); \
>          |                         ^
>    In file included from arch/riscv/kernel/asm-offsets.c:10:
>    In file included from include/linux/mm.h:7:
>    In file included from include/linux/gfp.h:7:
>    In file included from include/linux/mmzone.h:8:
>    In file included from include/linux/spinlock.h:63:
>    In file included from include/linux/lockdep.h:14:
>    In file included from include/linux/smp.h:13:
>    In file included from include/linux/cpumask.h:14:
>    In file included from include/linux/atomic.h:80:
>    include/linux/atomic/atomic-arch-fallback.h:2108:9: error: call to undeclared function 'cmpxchg_emu_u8'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>     2108 |         return raw_cmpxchg_relaxed(&v->counter, old, new);
> 
> 
> vim +/cmpxchg_emu_u8 +2026 include/linux/atomic/atomic-arch-fallback.h
> 
> 37f8173dd84936 include/linux/atomic-arch-fallback.h        Peter Zijlstra 2020-01-24  2000  
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2001  /**
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2002   * raw_atomic_cmpxchg() - atomic compare and exchange with full ordering
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2003   * @v: pointer to atomic_t
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2004   * @old: int value to compare with
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2005   * @new: int value to assign
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2006   *
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2007   * If (@v == @old), atomically updates @v to @new with full ordering.
> 6dfee110c6cc7a include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2024-02-09  2008   * Otherwise, @v is not modified and relaxed ordering is provided.
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2009   *
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2010   * Safe to use in noinstr code; prefer atomic_cmpxchg() elsewhere.
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2011   *
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2012   * Return: The original value of @v.
> ad8110706f3811 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2013   */
> 37f8173dd84936 include/linux/atomic-arch-fallback.h        Peter Zijlstra 2020-01-24  2014  static __always_inline int
> 9257959a6e5b4f include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2015  raw_atomic_cmpxchg(atomic_t *v, int old, int new)
> 37f8173dd84936 include/linux/atomic-arch-fallback.h        Peter Zijlstra 2020-01-24  2016  {
> 1d78814d41701c include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2017  #if defined(arch_atomic_cmpxchg)
> 1d78814d41701c include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2018  	return arch_atomic_cmpxchg(v, old, new);
> 1d78814d41701c include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2019  #elif defined(arch_atomic_cmpxchg_relaxed)
> 37f8173dd84936 include/linux/atomic-arch-fallback.h        Peter Zijlstra 2020-01-24  2020  	int ret;
> 37f8173dd84936 include/linux/atomic-arch-fallback.h        Peter Zijlstra 2020-01-24  2021  	__atomic_pre_full_fence();
> 9257959a6e5b4f include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2022  	ret = arch_atomic_cmpxchg_relaxed(v, old, new);
> 37f8173dd84936 include/linux/atomic-arch-fallback.h        Peter Zijlstra 2020-01-24  2023  	__atomic_post_full_fence();
> 37f8173dd84936 include/linux/atomic-arch-fallback.h        Peter Zijlstra 2020-01-24  2024  	return ret;
> 9257959a6e5b4f include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2025  #else
> 9257959a6e5b4f include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05 @2026  	return raw_cmpxchg(&v->counter, old, new);
> d12157efc8e083 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2027  #endif
> 1d78814d41701c include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2028  }
> d12157efc8e083 include/linux/atomic/atomic-arch-fallback.h Mark Rutland   2023-06-05  2029  
> 
> :::::: The code at line 2026 was first introduced by commit
> :::::: 9257959a6e5b4fca6fc8e985790bff62c2046f20 locking/atomic: scripts: restructure fallback ifdeffery
> 
> :::::: TO: Mark Rutland <mark.rutland@arm.com>
> :::::: CC: Peter Zijlstra <peterz@infradead.org>
> 
> -- 
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki

commit da6c6c7a30e5a5015a2995b2119053ca3d12b7a2
Author: Paul E. McKenney <paulmck@kernel.org>
Date:   Fri Mar 29 11:50:32 2024 -0700

    squash! riscv: Emulate one-byte and two-byte cmpxchg
    
    [ paulmck: Apply kernel test robot feedback. ]
    
    Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h
index b4cbea69ad2c8..a5b377481785c 100644
--- a/arch/riscv/include/asm/cmpxchg.h
+++ b/arch/riscv/include/asm/cmpxchg.h
@@ -9,6 +9,7 @@
 #include <linux/bug.h>
 
 #include <asm/fence.h>
+#include <linux/cmpxchg-emu.h>
 
 #define __xchg_relaxed(ptr, new, size)					\
 ({									\