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authorLinus Torvalds <torvalds@linux-foundation.org>2016-01-18 16:44:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-18 16:44:24 -0800
commita200dcb34693084e56496960d855afdeaaf9578f (patch)
treebf65e4350460b7f98247278469f7600d1808c3fc /arch/sh
parentd05d82f7110b08fd36178a641b69a1f206e1142b (diff)
parent43e361f23c49dbddf74f56ddf6cdd85c5dbff6da (diff)
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull virtio barrier rework+fixes from Michael Tsirkin: "This adds a new kind of barrier, and reworks virtio and xen to use it. Plus some fixes here and there" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (44 commits) checkpatch: add virt barriers checkpatch: check for __smp outside barrier.h checkpatch.pl: add missing memory barriers virtio: make find_vqs() checkpatch.pl-friendly virtio_balloon: fix race between migration and ballooning virtio_balloon: fix race by fill and leak s390: more efficient smp barriers s390: use generic memory barriers xen/events: use virt_xxx barriers xen/io: use virt_xxx barriers xenbus: use virt_xxx barriers virtio_ring: use virt_store_mb sh: move xchg_cmpxchg to a header by itself sh: support 1 and 2 byte xchg virtio_ring: update weak barriers to use virt_xxx Revert "virtio_ring: Update weak barriers to use dma_wmb/rmb" asm-generic: implement virt_xxx memory barriers x86: define __smp_xxx xtensa: define __smp_xxx tile: define __smp_xxx ...
Diffstat (limited to 'arch/sh')
-rw-r--r--arch/sh/include/asm/barrier.h3
-rw-r--r--arch/sh/include/asm/cmpxchg-grb.h22
-rw-r--r--arch/sh/include/asm/cmpxchg-irq.h11
-rw-r--r--arch/sh/include/asm/cmpxchg-llsc.h25
-rw-r--r--arch/sh/include/asm/cmpxchg-xchg.h51
-rw-r--r--arch/sh/include/asm/cmpxchg.h3
6 files changed, 92 insertions, 23 deletions
diff --git a/arch/sh/include/asm/barrier.h b/arch/sh/include/asm/barrier.h
index bf91037db4e0..f887c6465a82 100644
--- a/arch/sh/include/asm/barrier.h
+++ b/arch/sh/include/asm/barrier.h
@@ -32,7 +32,8 @@
#define ctrl_barrier() __asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop")
#endif
-#define smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0)
+#define __smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0)
+#define smp_store_mb(var, value) __smp_store_mb(var, value)
#include <asm-generic/barrier.h>
diff --git a/arch/sh/include/asm/cmpxchg-grb.h b/arch/sh/include/asm/cmpxchg-grb.h
index f848dec9e483..2ed557b31bd9 100644
--- a/arch/sh/include/asm/cmpxchg-grb.h
+++ b/arch/sh/include/asm/cmpxchg-grb.h
@@ -23,6 +23,28 @@ static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
return retval;
}
+static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val)
+{
+ unsigned long retval;
+
+ __asm__ __volatile__ (
+ " .align 2 \n\t"
+ " mova 1f, r0 \n\t" /* r0 = end point */
+ " mov r15, r1 \n\t" /* r1 = saved sp */
+ " mov #-6, r15 \n\t" /* LOGIN */
+ " mov.w @%1, %0 \n\t" /* load old value */
+ " extu.w %0, %0 \n\t" /* extend as unsigned */
+ " mov.w %2, @%1 \n\t" /* store new value */
+ "1: mov r1, r15 \n\t" /* LOGOUT */
+ : "=&r" (retval),
+ "+r" (m),
+ "+r" (val) /* inhibit r15 overloading */
+ :
+ : "memory" , "r0", "r1");
+
+ return retval;
+}
+
static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
{
unsigned long retval;
diff --git a/arch/sh/include/asm/cmpxchg-irq.h b/arch/sh/include/asm/cmpxchg-irq.h
index bd11f630414a..f88877257171 100644
--- a/arch/sh/include/asm/cmpxchg-irq.h
+++ b/arch/sh/include/asm/cmpxchg-irq.h
@@ -14,6 +14,17 @@ static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
return retval;
}
+static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val)
+{
+ unsigned long flags, retval;
+
+ local_irq_save(flags);
+ retval = *m;
+ *m = val;
+ local_irq_restore(flags);
+ return retval;
+}
+
static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
{
unsigned long flags, retval;
diff --git a/arch/sh/include/asm/cmpxchg-llsc.h b/arch/sh/include/asm/cmpxchg-llsc.h
index 47136661a203..fcfd32271bff 100644
--- a/arch/sh/include/asm/cmpxchg-llsc.h
+++ b/arch/sh/include/asm/cmpxchg-llsc.h
@@ -22,29 +22,8 @@ static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val)
return retval;
}
-static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
-{
- unsigned long retval;
- unsigned long tmp;
-
- __asm__ __volatile__ (
- "1: \n\t"
- "movli.l @%2, %0 ! xchg_u8 \n\t"
- "mov %0, %1 \n\t"
- "mov %3, %0 \n\t"
- "movco.l %0, @%2 \n\t"
- "bf 1b \n\t"
- "synco \n\t"
- : "=&z"(tmp), "=&r" (retval)
- : "r" (m), "r" (val & 0xff)
- : "t", "memory"
- );
-
- return retval;
-}
-
static inline unsigned long
-__cmpxchg_u32(volatile int *m, unsigned long old, unsigned long new)
+__cmpxchg_u32(volatile u32 *m, unsigned long old, unsigned long new)
{
unsigned long retval;
unsigned long tmp;
@@ -68,4 +47,6 @@ __cmpxchg_u32(volatile int *m, unsigned long old, unsigned long new)
return retval;
}
+#include <asm/cmpxchg-xchg.h>
+
#endif /* __ASM_SH_CMPXCHG_LLSC_H */
diff --git a/arch/sh/include/asm/cmpxchg-xchg.h b/arch/sh/include/asm/cmpxchg-xchg.h
new file mode 100644
index 000000000000..7219719c23a3
--- /dev/null
+++ b/arch/sh/include/asm/cmpxchg-xchg.h
@@ -0,0 +1,51 @@
+#ifndef __ASM_SH_CMPXCHG_XCHG_H
+#define __ASM_SH_CMPXCHG_XCHG_H
+
+/*
+ * Copyright (C) 2016 Red Hat, Inc.
+ * Author: Michael S. Tsirkin <mst@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See the
+ * file "COPYING" in the main directory of this archive for more details.
+ */
+#include <linux/bitops.h>
+#include <asm/byteorder.h>
+
+/*
+ * Portable implementations of 1 and 2 byte xchg using a 4 byte cmpxchg.
+ * Note: this header isn't self-contained: before including it, __cmpxchg_u32
+ * must be defined first.
+ */
+static inline u32 __xchg_cmpxchg(volatile void *ptr, u32 x, int size)
+{
+ int off = (unsigned long)ptr % sizeof(u32);
+ volatile u32 *p = ptr - off;
+#ifdef __BIG_ENDIAN
+ int bitoff = (sizeof(u32) - 1 - off) * BITS_PER_BYTE;
+#else
+ int bitoff = off * BITS_PER_BYTE;
+#endif
+ u32 bitmask = ((0x1 << size * BITS_PER_BYTE) - 1) << bitoff;
+ u32 oldv, newv;
+ u32 ret;
+
+ do {
+ oldv = READ_ONCE(*p);
+ ret = (oldv & bitmask) >> bitoff;
+ newv = (oldv & ~bitmask) | (x << bitoff);
+ } while (__cmpxchg_u32(p, oldv, newv) != oldv);
+
+ return ret;
+}
+
+static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val)
+{
+ return __xchg_cmpxchg(m, val, sizeof *m);
+}
+
+static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val)
+{
+ return __xchg_cmpxchg(m, val, sizeof *m);
+}
+
+#endif /* __ASM_SH_CMPXCHG_XCHG_H */
diff --git a/arch/sh/include/asm/cmpxchg.h b/arch/sh/include/asm/cmpxchg.h
index 85c97b188d71..5225916c1057 100644
--- a/arch/sh/include/asm/cmpxchg.h
+++ b/arch/sh/include/asm/cmpxchg.h
@@ -27,6 +27,9 @@ extern void __xchg_called_with_bad_pointer(void);
case 4: \
__xchg__res = xchg_u32(__xchg_ptr, x); \
break; \
+ case 2: \
+ __xchg__res = xchg_u16(__xchg_ptr, x); \
+ break; \
case 1: \
__xchg__res = xchg_u8(__xchg_ptr, x); \
break; \