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Message-ID: <20090415154244.GA26063@jurassic.park.msu.ru>
Date: Wed, 15 Apr 2009 19:42:44 +0400
From: Ivan Kokshaysky <ink@...assic.park.msu.ru>
To: Matt Turner <mattst88@...il.com>
Cc: Richard Henderson <rth@...ddle.net>,
Linux on Alpha processors <axp-list@...hat.com>,
linux-kernel@...r.kernel.org, Jay Estabrook <jay.estabrook@...com>,
Oliver Falk <oliver@...ux-kernel.at>
Subject: Re: alpha: half done futex implementation
On Tue, Apr 14, 2009 at 06:38:52PM -0400, Matt Turner wrote:
> CC kernel/futex.o
> kernel/futex.c: In function 'do_futex':
> /usr/src/linux-radeon/glisse-drm/arch/alpha/include/asm/futex.h:47:
> error: invalid 'asm': operand number out of range
> {standard input}: Assembler messages:
> {standard input}:3722: Error: bad expression
> {standard input}:3722: Error: syntax error
>
> I can't make much sense out of that.
>
> I changed the %4's to %3 as we don't have a %4.
Other operands are messed up too.
Here is compile-tested variant.
Ivan.
---
arch/alpha/include/asm/barrier.h | 2 +
arch/alpha/include/asm/futex.h | 118 ++++++++++++++++++++++++++++++++++++-
2 files changed, 116 insertions(+), 4 deletions(-)
diff --git a/arch/alpha/include/asm/barrier.h b/arch/alpha/include/asm/barrier.h
index ac78eba..ce8860a 100644
--- a/arch/alpha/include/asm/barrier.h
+++ b/arch/alpha/include/asm/barrier.h
@@ -16,11 +16,13 @@ __asm__ __volatile__("wmb": : :"memory")
__asm__ __volatile__("mb": : :"memory")
#ifdef CONFIG_SMP
+#define __ASM_SMP_MB "\tmb\n"
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#define smp_read_barrier_depends() read_barrier_depends()
#else
+#define __ASM_SMP_MB
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
diff --git a/arch/alpha/include/asm/futex.h b/arch/alpha/include/asm/futex.h
index 6a332a9..f18ea4e 100644
--- a/arch/alpha/include/asm/futex.h
+++ b/arch/alpha/include/asm/futex.h
@@ -1,6 +1,116 @@
-#ifndef _ASM_FUTEX_H
-#define _ASM_FUTEX_H
+#ifndef _ASM_ALPHA_FUTEX_H
+#define _ASM_ALPHA_FUTEX_H
-#include <asm-generic/futex.h>
+#ifdef __KERNEL__
-#endif
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/errno.h>
+#include <asm/barrier.h>
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
+ __asm__ __volatile__( \
+ __ASM_SMP_MB \
+ "1: ldl_l %0,0(%2)\n" \
+ insn \
+ "2: stl_c %1,0(%2)\n" \
+ " beq %1,4f\n" \
+ " mov $31,%1\n" \
+ "3: .subsection 2\n" \
+ "4: br 1b\n" \
+ " .previous\n" \
+ " .section __ex_table,\"a\"\n" \
+ " .long 1b-.\n" \
+ " lda $31,3b-1b(%1)\n" \
+ " .long 2b-.\n" \
+ " lda $31,3b-2b(%1)\n" \
+ " .previous\n" \
+ : "=&r" (oldval), "=&r"(ret) \
+ : "r" (uaddr), "r"(oparg) \
+ : "memory")
+
+static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
+{
+ int op = (encoded_op >> 28) & 7;
+ int cmp = (encoded_op >> 24) & 15;
+ int oparg = (encoded_op << 8) >> 20;
+ int cmparg = (encoded_op << 20) >> 20;
+ int oldval = 0, ret;
+ if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
+ oparg = 1 << oparg;
+
+ if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
+ return -EFAULT;
+
+ pagefault_disable();
+
+ switch (op) {
+ case FUTEX_OP_SET:
+ __futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
+ break;
+ case FUTEX_OP_ADD:
+ __futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
+ break;
+ case FUTEX_OP_OR:
+ __futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
+ break;
+ case FUTEX_OP_ANDN:
+ __futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
+ break;
+ case FUTEX_OP_XOR:
+ __futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);
+ break;
+ default:
+ ret = -ENOSYS;
+ }
+
+ pagefault_enable();
+
+ if (!ret) {
+ switch (cmp) {
+ case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
+ case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
+ case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
+ case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
+ case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
+ case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
+ default: ret = -ENOSYS;
+ }
+ }
+ return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
+{
+ int prev, cmp;
+
+ if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
+ return -EFAULT;
+
+ __asm__ __volatile__ (
+ __ASM_SMP_MB \
+ "1: ldl_l %0,0(%2)\n"
+ " cmpeq %0,%3,%1\n"
+ " beq %1,3f\n"
+ " mov %4,%1\n"
+ "2: stl_c %1,0(%2)\n"
+ " beq %1,4f\n"
+ "3: .subsection 2\n"
+ "4: br 1b\n"
+ " .previous"
+ " .section __ex_table,\"a\"\n"
+ " .long 1b-.\n"
+ " lda $31,3b-1b(%0)\n"
+ " .long 2b-.\n"
+ " lda $31,3b-2b(%0)\n"
+ " .previous\n"
+ : "=&r"(prev), "=&r"(cmp)
+ : "r"(uaddr), "r"((long)oldval), "r"(newval)
+ : "memory");
+
+ return prev;
+}
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_ALPHA_FUTEX_H */
--
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