From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>,
xen-devel <xen-devel@lists.xenproject.org>
Cc: Keir Fraser <keir@xen.org>
Subject: Re: [PATCH] x86: simplify a few macros / inline functions
Date: Fri, 8 May 2015 09:25:23 +0100 [thread overview]
Message-ID: <554C72F3.8060501@citrix.com> (raw)
In-Reply-To: <554C76FE0200007800077F45@mail.emea.novell.com>
On 08/05/15 07:42, Jan Beulich wrote:
> Drop pointless casts and write_atomic()'s bogus and unused "return
> value".
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>, given
confirmation of one query...
>
> --- a/xen/include/asm-x86/atomic.h
> +++ b/xen/include/asm-x86/atomic.h
> @@ -17,12 +17,11 @@ static inline void name(volatile type *a
> build_read_atomic(read_u8_atomic, "b", uint8_t, "=q", )
> build_read_atomic(read_u16_atomic, "w", uint16_t, "=r", )
> build_read_atomic(read_u32_atomic, "l", uint32_t, "=r", )
> +build_read_atomic(read_u64_atomic, "q", uint64_t, "=r", )
>
> build_write_atomic(write_u8_atomic, "b", uint8_t, "q", )
> build_write_atomic(write_u16_atomic, "w", uint16_t, "r", )
> build_write_atomic(write_u32_atomic, "l", uint32_t, "r", )
> -
> -build_read_atomic(read_u64_atomic, "q", uint64_t, "=r", )
> build_write_atomic(write_u64_atomic, "q", uint64_t, "r", )
>
> #undef build_read_atomic
> @@ -30,29 +29,28 @@ build_write_atomic(write_u64_atomic, "q"
>
> void __bad_atomic_size(void);
>
> -#define read_atomic(p) ({ \
> - unsigned long x_; \
> - switch ( sizeof(*(p)) ) { \
> - case 1: x_ = read_u8_atomic((uint8_t *)(p)); break; \
> - case 2: x_ = read_u16_atomic((uint16_t *)(p)); break; \
> - case 4: x_ = read_u32_atomic((uint32_t *)(p)); break; \
> - case 8: x_ = read_u64_atomic((uint64_t *)(p)); break; \
> - default: x_ = 0; __bad_atomic_size(); break; \
> - } \
> - (typeof(*(p)))x_; \
> +#define read_atomic(p) ({ \
> + unsigned long x_; \
> + switch ( sizeof(*(p)) ) { \
> + case 1: x_ = read_u8_atomic((uint8_t *)(p)); break; \
> + case 2: x_ = read_u16_atomic((uint16_t *)(p)); break; \
> + case 4: x_ = read_u32_atomic((uint32_t *)(p)); break; \
> + case 8: x_ = read_u64_atomic((uint64_t *)(p)); break; \
> + default: x_ = 0; __bad_atomic_size(); break; \
> + } \
> + (typeof(*(p)))x_; \
> })
I cant spot a change in read_atomic(), other than the alignment of the
\'s. I just want to double check that I haven't missed something.
~Andrew
>
> -#define write_atomic(p, x) ({ \
> - typeof(*(p)) __x = (x); \
> - unsigned long x_ = (unsigned long)__x; \
> - switch ( sizeof(*(p)) ) { \
> - case 1: write_u8_atomic((uint8_t *)(p), (uint8_t)x_); break; \
> - case 2: write_u16_atomic((uint16_t *)(p), (uint16_t)x_); break; \
> - case 4: write_u32_atomic((uint32_t *)(p), (uint32_t)x_); break; \
> - case 8: write_u64_atomic((uint64_t *)(p), (uint64_t)x_); break; \
> - default: __bad_atomic_size(); break; \
> - } \
> - __x; \
> +#define write_atomic(p, x) ({ \
> + typeof(*(p)) __x = (x); \
> + unsigned long x_ = (unsigned long)__x; \
> + switch ( sizeof(*(p)) ) { \
> + case 1: write_u8_atomic((uint8_t *)(p), x_); break; \
> + case 2: write_u16_atomic((uint16_t *)(p), x_); break; \
> + case 4: write_u32_atomic((uint32_t *)(p), x_); break; \
> + case 8: write_u64_atomic((uint64_t *)(p), x_); break; \
> + default: __bad_atomic_size(); break; \
> + } \
> })
>
> /*
> --- a/xen/include/asm-x86/system.h
> +++ b/xen/include/asm-x86/system.h
> @@ -41,25 +41,25 @@ static always_inline unsigned long __xch
> case 1:
> asm volatile ( "xchgb %b0,%1"
> : "=q" (x)
> - : "m" (*__xg((volatile void *)ptr)), "0" (x)
> + : "m" (*__xg(ptr)), "0" (x)
> : "memory" );
> break;
> case 2:
> asm volatile ( "xchgw %w0,%1"
> : "=r" (x)
> - : "m" (*__xg((volatile void *)ptr)), "0" (x)
> + : "m" (*__xg(ptr)), "0" (x)
> : "memory" );
> break;
> case 4:
> asm volatile ( "xchgl %k0,%1"
> : "=r" (x)
> - : "m" (*__xg((volatile void *)ptr)), "0" (x)
> + : "m" (*__xg(ptr)), "0" (x)
> : "memory" );
> break;
> case 8:
> asm volatile ( "xchgq %0,%1"
> : "=r" (x)
> - : "m" (*__xg((volatile void *)ptr)), "0" (x)
> + : "m" (*__xg(ptr)), "0" (x)
> : "memory" );
> break;
> }
> @@ -81,28 +81,28 @@ static always_inline unsigned long __cmp
> case 1:
> asm volatile ( "lock; cmpxchgb %b1,%2"
> : "=a" (prev)
> - : "q" (new), "m" (*__xg((volatile void *)ptr)),
> + : "q" (new), "m" (*__xg(ptr)),
> "0" (old)
> : "memory" );
> return prev;
> case 2:
> asm volatile ( "lock; cmpxchgw %w1,%2"
> : "=a" (prev)
> - : "r" (new), "m" (*__xg((volatile void *)ptr)),
> + : "r" (new), "m" (*__xg(ptr)),
> "0" (old)
> : "memory" );
> return prev;
> case 4:
> asm volatile ( "lock; cmpxchgl %k1,%2"
> : "=a" (prev)
> - : "r" (new), "m" (*__xg((volatile void *)ptr)),
> + : "r" (new), "m" (*__xg(ptr)),
> "0" (old)
> : "memory" );
> return prev;
> case 8:
> asm volatile ( "lock; cmpxchgq %1,%2"
> : "=a" (prev)
> - : "r" (new), "m" (*__xg((volatile void *)ptr)),
> + : "r" (new), "m" (*__xg(ptr)),
> "0" (old)
> : "memory" );
> return prev;
>
>
next prev parent reply other threads:[~2015-05-08 8:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-08 6:42 [PATCH] x86: simplify a few macros / inline functions Jan Beulich
2015-05-08 8:25 ` Andrew Cooper [this message]
2015-05-08 8:29 ` Jan Beulich
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