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References: <20220617144031.2549432-1-alexandr.lobakin@intel.com> <20220617144031.2549432-6-alexandr.lobakin@intel.com>
In-Reply-To: <20220617144031.2549432-6-alexandr.lobakin@intel.com>
From:   Marco Elver <elver@google.com>
Date:   Mon, 20 Jun 2022 11:50:44 +0200
Message-ID: <CANpmjNMfBceSv+RXQuqS+=n2wLULSn5dMYz-9qGt=Yes4xobUg@mail.gmail.com>
Subject: Re: [PATCH v3 5/7] bitops: wrap non-atomic bitops with a transparent macro
To:     Alexander Lobakin <alexandr.lobakin@intel.com>
Cc:     Arnd Bergmann <arnd@arndb.de>, Yury Norov <yury.norov@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Matt Turner <mattst88@gmail.com>,
        Brian Cain <bcain@quicinc.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>,
        "David S. Miller" <davem@davemloft.net>,
        Kees Cook <keescook@chromium.org>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Borislav Petkov <bp@suse.de>, Tony Luck <tony.luck@intel.com>,
        Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-alpha@vger.kernel.org, linux-hexagon@vger.kernel.org,
        linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
        linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
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On Fri, 17 Jun 2022 at 19:19, Alexander Lobakin
<alexandr.lobakin@intel.com> wrote:
>
> In preparation for altering the non-atomic bitops with a macro, wrap
> them in a transparent definition. This requires prepending one more
> '_' to their names in order to be able to do that seamlessly. It is
> a simple change, given that all the non-prefixed definitions are now
> in asm-generic.
> sparc32 already has several triple-underscored functions, so I had
> to rename them ('___' -> 'sp32_').
>
> Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>

Reviewed-by: Marco Elver <elver@google.com>

> ---
>  arch/sparc/include/asm/bitops_32.h            | 18 ++++++------
>  arch/sparc/lib/atomic32.c                     | 12 ++++----
>  .../bitops/instrumented-non-atomic.h          | 28 +++++++++----------
>  .../bitops/non-instrumented-non-atomic.h      | 14 +++++-----
>  include/linux/bitops.h                        | 18 +++++++++++-
>  tools/include/asm-generic/bitops/non-atomic.h | 24 ++++++++--------
>  tools/include/linux/bitops.h                  | 16 +++++++++++
>  7 files changed, 81 insertions(+), 49 deletions(-)
>
> diff --git a/arch/sparc/include/asm/bitops_32.h b/arch/sparc/include/asm/bitops_32.h
> index 889afa9f990f..3448c191b484 100644
> --- a/arch/sparc/include/asm/bitops_32.h
> +++ b/arch/sparc/include/asm/bitops_32.h
> @@ -19,9 +19,9 @@
>  #error only <linux/bitops.h> can be included directly
>  #endif
>
> -unsigned long ___set_bit(unsigned long *addr, unsigned long mask);
> -unsigned long ___clear_bit(unsigned long *addr, unsigned long mask);
> -unsigned long ___change_bit(unsigned long *addr, unsigned long mask);
> +unsigned long sp32___set_bit(unsigned long *addr, unsigned long mask);
> +unsigned long sp32___clear_bit(unsigned long *addr, unsigned long mask);
> +unsigned long sp32___change_bit(unsigned long *addr, unsigned long mask);
>
>  /*
>   * Set bit 'nr' in 32-bit quantity at address 'addr' where bit '0'
> @@ -36,7 +36,7 @@ static inline int test_and_set_bit(unsigned long nr, volatile unsigned long *add
>         ADDR = ((unsigned long *) addr) + (nr >> 5);
>         mask = 1 << (nr & 31);
>
> -       return ___set_bit(ADDR, mask) != 0;
> +       return sp32___set_bit(ADDR, mask) != 0;
>  }
>
>  static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
> @@ -46,7 +46,7 @@ static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
>         ADDR = ((unsigned long *) addr) + (nr >> 5);
>         mask = 1 << (nr & 31);
>
> -       (void) ___set_bit(ADDR, mask);
> +       (void) sp32___set_bit(ADDR, mask);
>  }
>
>  static inline int test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
> @@ -56,7 +56,7 @@ static inline int test_and_clear_bit(unsigned long nr, volatile unsigned long *a
>         ADDR = ((unsigned long *) addr) + (nr >> 5);
>         mask = 1 << (nr & 31);
>
> -       return ___clear_bit(ADDR, mask) != 0;
> +       return sp32___clear_bit(ADDR, mask) != 0;
>  }
>
>  static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
> @@ -66,7 +66,7 @@ static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
>         ADDR = ((unsigned long *) addr) + (nr >> 5);
>         mask = 1 << (nr & 31);
>
> -       (void) ___clear_bit(ADDR, mask);
> +       (void) sp32___clear_bit(ADDR, mask);
>  }
>
>  static inline int test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
> @@ -76,7 +76,7 @@ static inline int test_and_change_bit(unsigned long nr, volatile unsigned long *
>         ADDR = ((unsigned long *) addr) + (nr >> 5);
>         mask = 1 << (nr & 31);
>
> -       return ___change_bit(ADDR, mask) != 0;
> +       return sp32___change_bit(ADDR, mask) != 0;
>  }
>
>  static inline void change_bit(unsigned long nr, volatile unsigned long *addr)
> @@ -86,7 +86,7 @@ static inline void change_bit(unsigned long nr, volatile unsigned long *addr)
>         ADDR = ((unsigned long *) addr) + (nr >> 5);
>         mask = 1 << (nr & 31);
>
> -       (void) ___change_bit(ADDR, mask);
> +       (void) sp32___change_bit(ADDR, mask);
>  }
>
>  #include <asm-generic/bitops/non-atomic.h>
> diff --git a/arch/sparc/lib/atomic32.c b/arch/sparc/lib/atomic32.c
> index 8b81d0f00c97..cf80d1ae352b 100644
> --- a/arch/sparc/lib/atomic32.c
> +++ b/arch/sparc/lib/atomic32.c
> @@ -120,7 +120,7 @@ void arch_atomic_set(atomic_t *v, int i)
>  }
>  EXPORT_SYMBOL(arch_atomic_set);
>
> -unsigned long ___set_bit(unsigned long *addr, unsigned long mask)
> +unsigned long sp32___set_bit(unsigned long *addr, unsigned long mask)
>  {
>         unsigned long old, flags;
>
> @@ -131,9 +131,9 @@ unsigned long ___set_bit(unsigned long *addr, unsigned long mask)
>
>         return old & mask;
>  }
> -EXPORT_SYMBOL(___set_bit);
> +EXPORT_SYMBOL(sp32___set_bit);
>
> -unsigned long ___clear_bit(unsigned long *addr, unsigned long mask)
> +unsigned long sp32___clear_bit(unsigned long *addr, unsigned long mask)
>  {
>         unsigned long old, flags;
>
> @@ -144,9 +144,9 @@ unsigned long ___clear_bit(unsigned long *addr, unsigned long mask)
>
>         return old & mask;
>  }
> -EXPORT_SYMBOL(___clear_bit);
> +EXPORT_SYMBOL(sp32___clear_bit);
>
> -unsigned long ___change_bit(unsigned long *addr, unsigned long mask)
> +unsigned long sp32___change_bit(unsigned long *addr, unsigned long mask)
>  {
>         unsigned long old, flags;
>
> @@ -157,7 +157,7 @@ unsigned long ___change_bit(unsigned long *addr, unsigned long mask)
>
>         return old & mask;
>  }
> -EXPORT_SYMBOL(___change_bit);
> +EXPORT_SYMBOL(sp32___change_bit);
>
>  unsigned long __cmpxchg_u32(volatile u32 *ptr, u32 old, u32 new)
>  {
> diff --git a/include/asm-generic/bitops/instrumented-non-atomic.h b/include/asm-generic/bitops/instrumented-non-atomic.h
> index b019f77ef21c..988a3bbfba34 100644
> --- a/include/asm-generic/bitops/instrumented-non-atomic.h
> +++ b/include/asm-generic/bitops/instrumented-non-atomic.h
> @@ -14,7 +14,7 @@
>  #include <linux/instrumented.h>
>
>  /**
> - * __set_bit - Set a bit in memory
> + * ___set_bit - Set a bit in memory
>   * @nr: the bit to set
>   * @addr: the address to start counting from
>   *
> @@ -23,14 +23,14 @@
>   * succeeds.
>   */
>  static __always_inline void
> -__set_bit(unsigned long nr, volatile unsigned long *addr)
> +___set_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         instrument_write(addr + BIT_WORD(nr), sizeof(long));
>         arch___set_bit(nr, addr);
>  }
>
>  /**
> - * __clear_bit - Clears a bit in memory
> + * ___clear_bit - Clears a bit in memory
>   * @nr: the bit to clear
>   * @addr: the address to start counting from
>   *
> @@ -39,14 +39,14 @@ __set_bit(unsigned long nr, volatile unsigned long *addr)
>   * succeeds.
>   */
>  static __always_inline void
> -__clear_bit(unsigned long nr, volatile unsigned long *addr)
> +___clear_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         instrument_write(addr + BIT_WORD(nr), sizeof(long));
>         arch___clear_bit(nr, addr);
>  }
>
>  /**
> - * __change_bit - Toggle a bit in memory
> + * ___change_bit - Toggle a bit in memory
>   * @nr: the bit to change
>   * @addr: the address to start counting from
>   *
> @@ -55,7 +55,7 @@ __clear_bit(unsigned long nr, volatile unsigned long *addr)
>   * succeeds.
>   */
>  static __always_inline void
> -__change_bit(unsigned long nr, volatile unsigned long *addr)
> +___change_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         instrument_write(addr + BIT_WORD(nr), sizeof(long));
>         arch___change_bit(nr, addr);
> @@ -86,7 +86,7 @@ static __always_inline void __instrument_read_write_bitop(long nr, volatile unsi
>  }
>
>  /**
> - * __test_and_set_bit - Set a bit and return its old value
> + * ___test_and_set_bit - Set a bit and return its old value
>   * @nr: Bit to set
>   * @addr: Address to count from
>   *
> @@ -94,14 +94,14 @@ static __always_inline void __instrument_read_write_bitop(long nr, volatile unsi
>   * can appear to succeed but actually fail.
>   */
>  static __always_inline bool
> -__test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
> +___test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         __instrument_read_write_bitop(nr, addr);
>         return arch___test_and_set_bit(nr, addr);
>  }
>
>  /**
> - * __test_and_clear_bit - Clear a bit and return its old value
> + * ___test_and_clear_bit - Clear a bit and return its old value
>   * @nr: Bit to clear
>   * @addr: Address to count from
>   *
> @@ -109,14 +109,14 @@ __test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
>   * can appear to succeed but actually fail.
>   */
>  static __always_inline bool
> -__test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
> +___test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         __instrument_read_write_bitop(nr, addr);
>         return arch___test_and_clear_bit(nr, addr);
>  }
>
>  /**
> - * __test_and_change_bit - Change a bit and return its old value
> + * ___test_and_change_bit - Change a bit and return its old value
>   * @nr: Bit to change
>   * @addr: Address to count from
>   *
> @@ -124,19 +124,19 @@ __test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
>   * can appear to succeed but actually fail.
>   */
>  static __always_inline bool
> -__test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
> +___test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         __instrument_read_write_bitop(nr, addr);
>         return arch___test_and_change_bit(nr, addr);
>  }
>
>  /**
> - * test_bit - Determine whether a bit is set
> + * _test_bit - Determine whether a bit is set
>   * @nr: bit number to test
>   * @addr: Address to start counting from
>   */
>  static __always_inline bool
> -test_bit(unsigned long nr, const volatile unsigned long *addr)
> +_test_bit(unsigned long nr, const volatile unsigned long *addr)
>  {
>         instrument_atomic_read(addr + BIT_WORD(nr), sizeof(long));
>         return arch_test_bit(nr, addr);
> diff --git a/include/asm-generic/bitops/non-instrumented-non-atomic.h b/include/asm-generic/bitops/non-instrumented-non-atomic.h
> index e0fd7bf72a56..bdb9b1ffaee9 100644
> --- a/include/asm-generic/bitops/non-instrumented-non-atomic.h
> +++ b/include/asm-generic/bitops/non-instrumented-non-atomic.h
> @@ -3,14 +3,14 @@
>  #ifndef __ASM_GENERIC_BITOPS_NON_INSTRUMENTED_NON_ATOMIC_H
>  #define __ASM_GENERIC_BITOPS_NON_INSTRUMENTED_NON_ATOMIC_H
>
> -#define __set_bit              arch___set_bit
> -#define __clear_bit            arch___clear_bit
> -#define __change_bit           arch___change_bit
> +#define ___set_bit             arch___set_bit
> +#define ___clear_bit           arch___clear_bit
> +#define ___change_bit          arch___change_bit
>
> -#define __test_and_set_bit     arch___test_and_set_bit
> -#define __test_and_clear_bit   arch___test_and_clear_bit
> -#define __test_and_change_bit  arch___test_and_change_bit
> +#define ___test_and_set_bit    arch___test_and_set_bit
> +#define ___test_and_clear_bit  arch___test_and_clear_bit
> +#define ___test_and_change_bit arch___test_and_change_bit
>
> -#define test_bit               arch_test_bit
> +#define _test_bit              arch_test_bit
>
>  #endif /* __ASM_GENERIC_BITOPS_NON_INSTRUMENTED_NON_ATOMIC_H */
> diff --git a/include/linux/bitops.h b/include/linux/bitops.h
> index d393297287d5..3c3afbae1533 100644
> --- a/include/linux/bitops.h
> +++ b/include/linux/bitops.h
> @@ -26,8 +26,24 @@ extern unsigned int __sw_hweight16(unsigned int w);
>  extern unsigned int __sw_hweight32(unsigned int w);
>  extern unsigned long __sw_hweight64(__u64 w);
>
> +/*
> + * Defined here because those may be needed by architecture-specific static
> + * inlines.
> + */
> +
>  #include <asm-generic/bitops/generic-non-atomic.h>
>
> +#define bitop(op, nr, addr)                                            \
> +       op(nr, addr)
> +
> +#define __set_bit(nr, addr)            bitop(___set_bit, nr, addr)
> +#define __clear_bit(nr, addr)          bitop(___clear_bit, nr, addr)
> +#define __change_bit(nr, addr)         bitop(___change_bit, nr, addr)
> +#define __test_and_set_bit(nr, addr)   bitop(___test_and_set_bit, nr, addr)
> +#define __test_and_clear_bit(nr, addr) bitop(___test_and_clear_bit, nr, addr)
> +#define __test_and_change_bit(nr, addr)        bitop(___test_and_change_bit, nr, addr)
> +#define test_bit(nr, addr)             bitop(_test_bit, nr, addr)
> +
>  /*
>   * Include this here because some architectures need generic_ffs/fls in
>   * scope
> @@ -38,7 +54,7 @@ extern unsigned long __sw_hweight64(__u64 w);
>  #define __check_bitop_pr(name)                                         \
>         static_assert(__same_type(arch_##name, generic_##name) &&       \
>                       __same_type(const_##name, generic_##name) &&      \
> -                     __same_type(name, generic_##name))
> +                     __same_type(_##name, generic_##name))
>
>  __check_bitop_pr(__set_bit);
>  __check_bitop_pr(__clear_bit);
> diff --git a/tools/include/asm-generic/bitops/non-atomic.h b/tools/include/asm-generic/bitops/non-atomic.h
> index e5e78e42e57b..0c472a833408 100644
> --- a/tools/include/asm-generic/bitops/non-atomic.h
> +++ b/tools/include/asm-generic/bitops/non-atomic.h
> @@ -5,7 +5,7 @@
>  #include <linux/bits.h>
>
>  /**
> - * __set_bit - Set a bit in memory
> + * ___set_bit - Set a bit in memory
>   * @nr: the bit to set
>   * @addr: the address to start counting from
>   *
> @@ -14,7 +14,7 @@
>   * may be that only one operation succeeds.
>   */
>  static __always_inline void
> -__set_bit(unsigned long nr, volatile unsigned long *addr)
> +___set_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         unsigned long mask = BIT_MASK(nr);
>         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@ -23,7 +23,7 @@ __set_bit(unsigned long nr, volatile unsigned long *addr)
>  }
>
>  static __always_inline void
> -__clear_bit(unsigned long nr, volatile unsigned long *addr)
> +___clear_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         unsigned long mask = BIT_MASK(nr);
>         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@ -32,7 +32,7 @@ __clear_bit(unsigned long nr, volatile unsigned long *addr)
>  }
>
>  /**
> - * __change_bit - Toggle a bit in memory
> + * ___change_bit - Toggle a bit in memory
>   * @nr: the bit to change
>   * @addr: the address to start counting from
>   *
> @@ -41,7 +41,7 @@ __clear_bit(unsigned long nr, volatile unsigned long *addr)
>   * may be that only one operation succeeds.
>   */
>  static __always_inline void
> -__change_bit(unsigned long nr, volatile unsigned long *addr)
> +___change_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         unsigned long mask = BIT_MASK(nr);
>         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@ -50,7 +50,7 @@ __change_bit(unsigned long nr, volatile unsigned long *addr)
>  }
>
>  /**
> - * __test_and_set_bit - Set a bit and return its old value
> + * ___test_and_set_bit - Set a bit and return its old value
>   * @nr: Bit to set
>   * @addr: Address to count from
>   *
> @@ -59,7 +59,7 @@ __change_bit(unsigned long nr, volatile unsigned long *addr)
>   * but actually fail.  You must protect multiple accesses with a lock.
>   */
>  static __always_inline bool
> -__test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
> +___test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         unsigned long mask = BIT_MASK(nr);
>         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@ -70,7 +70,7 @@ __test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
>  }
>
>  /**
> - * __test_and_clear_bit - Clear a bit and return its old value
> + * ___test_and_clear_bit - Clear a bit and return its old value
>   * @nr: Bit to clear
>   * @addr: Address to count from
>   *
> @@ -79,7 +79,7 @@ __test_and_set_bit(unsigned long nr, volatile unsigned long *addr)
>   * but actually fail.  You must protect multiple accesses with a lock.
>   */
>  static __always_inline bool
> -__test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
> +___test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         unsigned long mask = BIT_MASK(nr);
>         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@ -91,7 +91,7 @@ __test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
>
>  /* WARNING: non atomic and it can be reordered! */
>  static __always_inline bool
> -__test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
> +___test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
>  {
>         unsigned long mask = BIT_MASK(nr);
>         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
> @@ -102,12 +102,12 @@ __test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
>  }
>
>  /**
> - * test_bit - Determine whether a bit is set
> + * _test_bit - Determine whether a bit is set
>   * @nr: bit number to test
>   * @addr: Address to start counting from
>   */
>  static __always_inline bool
> -test_bit(unsigned long nr, const volatile unsigned long *addr)
> +_test_bit(unsigned long nr, const volatile unsigned long *addr)
>  {
>         return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
>  }
> diff --git a/tools/include/linux/bitops.h b/tools/include/linux/bitops.h
> index 5fca38fe1ba8..f18683b95ea6 100644
> --- a/tools/include/linux/bitops.h
> +++ b/tools/include/linux/bitops.h
> @@ -25,6 +25,22 @@ extern unsigned int __sw_hweight16(unsigned int w);
>  extern unsigned int __sw_hweight32(unsigned int w);
>  extern unsigned long __sw_hweight64(__u64 w);
>
> +/*
> + * Defined here because those may be needed by architecture-specific static
> + * inlines.
> + */
> +
> +#define bitop(op, nr, addr)                                            \
> +       op(nr, addr)
> +
> +#define __set_bit(nr, addr)            bitop(___set_bit, nr, addr)
> +#define __clear_bit(nr, addr)          bitop(___clear_bit, nr, addr)
> +#define __change_bit(nr, addr)         bitop(___change_bit, nr, addr)
> +#define __test_and_set_bit(nr, addr)   bitop(___test_and_set_bit, nr, addr)
> +#define __test_and_clear_bit(nr, addr) bitop(___test_and_clear_bit, nr, addr)
> +#define __test_and_change_bit(nr, addr)        bitop(___test_and_change_bit, nr, addr)
> +#define test_bit(nr, addr)             bitop(_test_bit, nr, addr)
> +
>  /*
>   * Include this here because some architectures need generic_ffs/fls in
>   * scope
> --
> 2.36.1
>