From: guoren@kernel.org
To: guoren@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org,
Guo Ren <guoren@linux.alibaba.com>,
Arnd Bergmann <arnd@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH 06/29] csky: Fixup futex SMP implementation
Date: Thu, 21 Jan 2021 14:53:26 +0800 [thread overview]
Message-ID: <20210121065349.3188251-6-guoren@kernel.org> (raw)
In-Reply-To: <20210121065349.3188251-1-guoren@kernel.org>
From: Guo Ren <guoren@linux.alibaba.com>
Arnd said:
I would guess that for csky, this is a mistake, as the architecture
is fairly new and should be able to implement it.
Guo reply:
The c610, c807, c810 don't support SMP, so futex_cmpxchg_enabled = 1
with asm-generic's implementation.
For c860, there is no HAVE_FUTEX_CMPXCHG and cmpxchg_inatomic/inuser
implementation, so futex_cmpxchg_enabled = 0.
Thx for point it out, we'll implement cmpxchg_inatomic/inuser for
C860 and still use asm-generic for non-smp CPUs.
LTP test:
futex_wait01 1 TPASS : futex_wait(): errno=ETIMEDOUT(110): Connection timed out
futex_wait01 2 TPASS : futex_wait(): errno=EAGAIN/EWOULDBLOCK(11): Resource temporarily unavailable
futex_wait01 3 TPASS : futex_wait(): errno=ETIMEDOUT(110): Connection timed out
futex_wait01 4 TPASS : futex_wait(): errno=EAGAIN/EWOULDBLOCK(11): Resource temporarily unavailable
futex_wait02 1 TPASS : futex_wait() woken up
futex_wait03 1 TPASS : futex_wait() woken up
futex_wait04 1 TPASS : futex_wait() returned -1: errno=EAGAIN/EWOULDBLOCK(11): Resource temporarily unavailable
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/lkml/CAK8P3a3+WaQNyJ6Za2qfu6=0mBgU1hApnRXrdp1b1=P7wwyRUg@mail.gmail.com/
---
arch/csky/Kconfig | 1 +
arch/csky/include/asm/futex.h | 121 ++++++++++++++++++++++++++++++++++
2 files changed, 122 insertions(+)
create mode 100644 arch/csky/include/asm/futex.h
diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 21b2ab099c8b..c74a8e2e8549 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -48,6 +48,7 @@ config CSKY
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_ERROR_INJECTION
+ select HAVE_FUTEX_CMPXCHG if FUTEX && SMP
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZO
diff --git a/arch/csky/include/asm/futex.h b/arch/csky/include/asm/futex.h
new file mode 100644
index 000000000000..6cfd312723fa
--- /dev/null
+++ b/arch/csky/include/asm/futex.h
@@ -0,0 +1,121 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_CSKY_FUTEX_H
+#define __ASM_CSKY_FUTEX_H
+
+#ifndef CONFIG_SMP
+#include <asm-generic/futex.h>
+#else
+#include <linux/atomic.h>
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <linux/errno.h>
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
+{ \
+ u32 tmp; \
+ \
+ __atomic_pre_full_fence(); \
+ \
+ __asm__ __volatile__ ( \
+ "1: ldex.w %[ov], %[u] \n" \
+ " "insn" \n" \
+ "2: stex.w %[t], %[u] \n" \
+ " bez %[t], 1b \n" \
+ " br 4f \n" \
+ "3: mov %[r], %[e] \n" \
+ "4: \n" \
+ " .section __ex_table,\"a\" \n" \
+ " .balign 4 \n" \
+ " .long 1b, 3b \n" \
+ " .long 2b, 3b \n" \
+ " .previous \n" \
+ : [r] "+r" (ret), [ov] "=&r" (oldval), \
+ [u] "+m" (*uaddr), [t] "=&r" (tmp) \
+ : [op] "Jr" (oparg), [e] "jr" (-EFAULT) \
+ : "memory"); \
+ \
+ __atomic_post_full_fence(); \
+}
+
+static inline int
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
+{
+ int oldval = 0, ret = 0;
+
+ if (!access_ok(uaddr, sizeof(u32)))
+ return -EFAULT;
+
+ switch (op) {
+ case FUTEX_OP_SET:
+ __futex_atomic_op("mov %[t], %[ov]",
+ ret, oldval, uaddr, oparg);
+ break;
+ case FUTEX_OP_ADD:
+ __futex_atomic_op("add %[t], %[ov], %[op]",
+ ret, oldval, uaddr, oparg);
+ break;
+ case FUTEX_OP_OR:
+ __futex_atomic_op("or %[t], %[ov], %[op]",
+ ret, oldval, uaddr, oparg);
+ break;
+ case FUTEX_OP_ANDN:
+ __futex_atomic_op("and %[t], %[ov], %[op]",
+ ret, oldval, uaddr, ~oparg);
+ break;
+ case FUTEX_OP_XOR:
+ __futex_atomic_op("xor %[t], %[ov], %[op]",
+ ret, oldval, uaddr, oparg);
+ break;
+ default:
+ ret = -ENOSYS;
+ }
+
+ if (!ret)
+ *oval = oldval;
+
+ return ret;
+}
+
+
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+ u32 oldval, u32 newval)
+{
+ int ret = 0;
+ u32 val, tmp;
+
+ if (!access_ok(uaddr, sizeof(u32)))
+ return -EFAULT;
+
+ __atomic_pre_full_fence();
+
+ __asm__ __volatile__ (
+ "1: ldex.w %[v], %[u] \n"
+ " cmpne %[v], %[ov] \n"
+ " bt 4f \n"
+ " mov %[t], %[nv] \n"
+ "2: stex.w %[t], %[u] \n"
+ " bez %[t], 1b \n"
+ " br 4f \n"
+ "3: mov %[r], %[e] \n"
+ "4: \n"
+ " .section __ex_table,\"a\" \n"
+ " .balign 4 \n"
+ " .long 1b, 3b \n"
+ " .long 2b, 3b \n"
+ " .previous \n"
+ : [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr),
+ [t] "=&r" (tmp)
+ : [ov] "Jr" (oldval), [nv] "Jr" (newval), [e] "Jr" (-EFAULT)
+ : "memory");
+
+ __atomic_post_full_fence();
+
+ *uval = val;
+ return ret;
+}
+
+#endif /* CONFIG_SMP */
+#endif /* __ASM_CSKY_FUTEX_H */
--
2.17.1
next prev parent reply other threads:[~2021-01-21 7:50 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 6:53 [PATCH 01/29] csky: Add memory layout 2.5G(user):1.5G(kernel) guoren
2021-01-21 6:53 ` [PATCH 02/29] csky: Fixup perf probe failed guoren
2021-01-21 6:53 ` [PATCH 03/29] csky: Fixup show_regs doesn't contain regs->usp guoren
2021-01-21 6:53 ` [PATCH 04/29] csky: Remove custom asm/atomic.h implementation guoren
2021-01-21 6:53 ` [PATCH 05/29] csky: Fixup barrier design guoren
2021-01-21 6:53 ` guoren [this message]
2021-01-21 6:53 ` [PATCH 07/29] csky: Fixup asm/cmpxchg.h with correct ordering barrier guoren
2021-01-21 6:53 ` [PATCH 08/29] csky: Cleanup asm/spinlock.h guoren
2021-01-21 6:53 ` [PATCH 09/29] csky: Fixup PTE global for 2.5:1.5 virtual memory guoren
2021-01-21 6:53 ` [PATCH 10/29] csky: Remove prologue of page fault handler in entry.S guoren
2021-01-21 6:53 ` [PATCH 11/29] csky: Add kmemleak support guoren
2021-01-21 6:53 ` [PATCH 12/29] csky: Fix TLB maintenance synchronization problem guoren
2021-01-21 6:53 ` [PATCH 13/29] csky: Add show_tlb for CPU_CK860 debug guoren
2021-01-21 6:53 ` [PATCH 14/29] csky: Fixup FAULT_FLAG_XXX param for handle_mm_fault guoren
2021-01-21 6:53 ` [PATCH 15/29] csky: Fixup update_mmu_cache called with user io mapping guoren
2021-01-21 6:53 ` [PATCH 16/29] csky: Add faulthandler_disabled() check guoren
2021-01-21 6:53 ` [PATCH 17/29] csky: Fixup do_page_fault parent irq status guoren
2021-01-21 6:53 ` [PATCH 18/29] csky: Sync riscv mm/fault.c for easy maintenance guoren
2021-01-21 6:53 ` [PATCH 19/29] csky: mm: abort uaccess retries upon fatal signal guoren
2021-01-21 11:42 ` Mark Rutland
2021-01-21 6:53 ` [PATCH 20/29] csky: Reconstruct VDSO framework guoren
2021-01-21 6:53 ` [PATCH 21/29] csky: Fix a size determination in gpr_get() guoren
2021-01-21 6:53 ` [PATCH 22/29] csky: remove unused including <linux/version.h> guoren
2021-01-21 6:53 ` [PATCH 23/29] csky: Fixup _PAGE_ACCESSED for default pgprot guoren
2021-01-21 6:53 ` [PATCH 24/29] csky: Coding convention del unnecessary definition guoren
2021-01-21 6:53 ` [PATCH 25/29] csky: Fixup swapon guoren
2021-01-21 6:53 ` [PATCH 26/29] csky: kprobe: fix code in simulate without 'long' guoren
2021-01-21 6:53 ` [PATCH 27/29] csky: Add VDSO with GENERIC_GETTIMEOFDAY, GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO guoren
2021-01-21 6:53 ` [PATCH 28/29] csky: Using set_max_mapnr api guoren
2021-01-21 6:53 ` [PATCH 29/29] csky: Fixup pfn_valid error with wrong max_mapnr guoren
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210121065349.3188251-6-guoren@kernel.org \
--to=guoren@kernel.org \
--cc=arnd@kernel.org \
--cc=guoren@linux.alibaba.com \
--cc=linux-csky@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=paulmck@kernel.org \
--cc=peterz@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).