From: Peter Zijlstra <peterz@infradead.org>
To: Michal Simek <michal.simek@xilinx.com>
Cc: linux-kernel@vger.kernel.org, monstr@monstr.eu, git@xilinx.com,
arnd@arndb.de,
Stefan Asserhall load and store <stefan.asserhall@xilinx.com>,
Boqun Feng <boqun.feng@gmail.com>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH 7/7] microblaze: Do atomic operations by using exclusive ops
Date: Wed, 12 Feb 2020 16:55:00 +0100 [thread overview]
Message-ID: <20200212155500.GB14973@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <ba3047649af07dadecf1a52e7d815db8f068eb24.1581522136.git.michal.simek@xilinx.com>
On Wed, Feb 12, 2020 at 04:42:29PM +0100, Michal Simek wrote:
> From: Stefan Asserhall load and store <stefan.asserhall@xilinx.com>
>
> Implement SMP aware atomic operations.
>
> Signed-off-by: Stefan Asserhall <stefan.asserhall@xilinx.com>
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> ---
>
> arch/microblaze/include/asm/atomic.h | 265 +++++++++++++++++++++++++--
> 1 file changed, 253 insertions(+), 12 deletions(-)
>
> diff --git a/arch/microblaze/include/asm/atomic.h b/arch/microblaze/include/asm/atomic.h
> index 41e9aff23a62..522d704fad63 100644
> --- a/arch/microblaze/include/asm/atomic.h
> +++ b/arch/microblaze/include/asm/atomic.h
> @@ -1,28 +1,269 @@
> /* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2013-2020 Xilinx, Inc.
> + */
> +
> #ifndef _ASM_MICROBLAZE_ATOMIC_H
> #define _ASM_MICROBLAZE_ATOMIC_H
>
> +#include <linux/types.h>
> #include <asm/cmpxchg.h>
> -#include <asm-generic/atomic.h>
> -#include <asm-generic/atomic64.h>
> +
> +#define ATOMIC_INIT(i) { (i) }
> +
> +#define atomic_read(v) READ_ONCE((v)->counter)
> +
> +static inline void atomic_set(atomic_t *v, int i)
> +{
> + int result, tmp;
> +
> + __asm__ __volatile__ (
> + /* load conditional address in %2 to %0 */
> + "1: lwx %0, %2, r0;\n"
> + /* attempt store */
> + " swx %3, %2, r0;\n"
> + /* checking msr carry flag */
> + " addic %1, r0, 0;\n"
> + /* store failed (MSR[C] set)? try again */
> + " bnei %1, 1b;\n"
> + /* Outputs: result value */
> + : "=&r" (result), "=&r" (tmp)
> + /* Inputs: counter address */
> + : "r" (&v->counter), "r" (i)
> + : "cc", "memory"
> + );
> +}
> +#define atomic_set atomic_set
Uuuuhh.. *what* ?!?
Are you telling me your LL/SC implementation is so bugger that
atomic_set() being a WRITE_ONCE() does not in fact work?
next prev parent reply other threads:[~2020-02-12 15:55 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-12 15:42 [PATCH 0/7] microblaze: Define SMP safe operations Michal Simek
2020-02-12 15:42 ` [PATCH 1/7] microblaze: timer: Don't use cpu timer setting Michal Simek
2020-02-12 15:42 ` [PATCH 2/7] microblaze: Make cpuinfo structure SMP aware Michal Simek
2020-02-12 20:42 ` Arnd Bergmann
2020-02-12 15:42 ` [PATCH 3/7] microblaze: Define SMP safe bit operations Michal Simek
2020-02-12 15:53 ` Peter Zijlstra
2020-02-13 8:42 ` Michal Simek
2020-02-13 9:01 ` Stefan Asserhall
2020-02-13 9:11 ` Peter Zijlstra
2020-02-13 9:24 ` Stefan Asserhall
2020-02-12 15:42 ` [PATCH 4/7] microblaze: Add SMP implementation of xchg and cmpxchg Michal Simek
2020-02-12 15:42 ` [PATCH 5/7] microblaze: Remove disabling IRQ while pte_update() run Michal Simek
2020-02-12 15:42 ` [PATCH 6/7] microblaze: Implement architecture spinlock Michal Simek
2020-02-12 15:47 ` Peter Zijlstra
2020-02-13 7:51 ` Michal Simek
2020-02-13 8:00 ` Peter Zijlstra
2020-02-12 15:42 ` [PATCH 7/7] microblaze: Do atomic operations by using exclusive ops Michal Simek
2020-02-12 15:55 ` Peter Zijlstra [this message]
2020-02-13 8:06 ` Michal Simek
2020-02-13 8:58 ` Peter Zijlstra
2020-02-13 9:16 ` Peter Zijlstra
2020-02-13 10:04 ` Will Deacon
2020-02-13 10:14 ` Stefan Asserhall
2020-02-13 10:20 ` Will Deacon
2020-02-13 10:15 ` Peter Zijlstra
2020-02-13 11:34 ` Boqun Feng
2020-02-13 11:38 ` Boqun Feng
2020-02-13 13:51 ` Andrea Parri
2020-02-13 14:01 ` Andrea Parri
2020-02-12 16:08 ` [PATCH 0/7] microblaze: Define SMP safe operations Peter Zijlstra
2020-02-12 16:38 ` Peter Zijlstra
2020-02-13 7:49 ` Michal Simek
2020-02-13 8:11 ` Peter Zijlstra
2020-02-13 8:12 ` Michal Simek
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