[PATCH v3 3/4] riscv/barrier: Consolidate fence definitions

Eric Chan
2024-02-13T14:29:51Z

Disparate fence implementations are consolidated into fence.h.
And align with the existing form.

Signed-off-by: Eric Chan <ericchancf@google.com>
---
arch/riscv/include/asm/atomic.h | 8 ++------
arch/riscv/include/asm/barrier.h | 3 +--
arch/riscv/include/asm/cmpxchg.h | 1 -
arch/riscv/include/asm/fence.h | 10 +++++++---
arch/riscv/include/asm/io.h | 8 ++++----
arch/riscv/include/asm/mmio.h | 5 +++--
arch/riscv/include/asm/mmiowb.h | 2 +-
7 files changed, 18 insertions(+), 19 deletions(-)

diff --git a/arch/riscv/include/asm/atomic.h b/arch/riscv/include/asm/atomic.h
index 31e6e2e7cc18..1b2ae3259f1d 100644
--- a/arch/riscv/include/asm/atomic.h
+++ b/arch/riscv/include/asm/atomic.h
@@ -17,13 +17,9 @@
#endif

#include <asm/cmpxchg.h>
-#include <asm/barrier.h>

-#define __atomic_acquire_fence() \
- __asm__ __volatile__(RISCV_ACQUIRE_BARRIER "" ::: "memory")
-
-#define __atomic_release_fence() \
- __asm__ __volatile__(RISCV_RELEASE_BARRIER "" ::: "memory");
+#define __atomic_acquire_fence() RISCV_FENCE(r,rw)
+#define __atomic_release_fence() RISCV_FENCE(rw,r)

static __always_inline int arch_atomic_read(const atomic_t *v)
{
diff --git a/arch/riscv/include/asm/barrier.h b/arch/riscv/include/asm/barrier.h
index 4c49a8ff2c68..4f4743d7440d 100644
--- a/arch/riscv/include/asm/barrier.h
+++ b/arch/riscv/include/asm/barrier.h
@@ -11,13 +11,12 @@
#define _ASM_RISCV_BARRIER_H

#ifndef __ASSEMBLY__
+#include <asm/fence.h>

#define nop() __asm__ __volatile__ ("nop")
#define __nops(n) ".rept " #n "\nnop\n.endr\n"
#define nops(n) __asm__ __volatile__ (__nops(n))

-#define RISCV_FENCE(p, s) \
- __asm__ __volatile__ ("fence " #p "," #s : : : "memory")

/* These barriers need to enforce ordering on both devices or memory. */
#define __mb() RISCV_FENCE(iorw,iorw)
diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h
index a608e4d1a0a4..2fee65cc8443 100644
--- a/arch/riscv/include/asm/cmpxchg.h
+++ b/arch/riscv/include/asm/cmpxchg.h
@@ -8,7 +8,6 @@

#include <linux/bug.h>

-#include <asm/barrier.h>
#include <asm/fence.h>

#define __xchg_relaxed(ptr, new, size) \
diff --git a/arch/riscv/include/asm/fence.h b/arch/riscv/include/asm/fence.h
index 6c26c44dfcd6..ca094d72ec20 100644
--- a/arch/riscv/include/asm/fence.h
+++ b/arch/riscv/include/asm/fence.h
@@ -1,10 +1,14 @@
#ifndef _ASM_RISCV_FENCE_H
#define _ASM_RISCV_FENCE_H

+#define RISCV_FENCE_ASM(p, s) "\tfence " #p "," #s "\n"
+#define RISCV_FENCE(p, s) \
+ ({ __asm__ __volatile__ (RISCV_FENCE_ASM(p, s) : : : "memory"); })
+
#ifdef CONFIG_SMP
-#define RISCV_ACQUIRE_BARRIER "\tfence r , rw\n"
-#define RISCV_RELEASE_BARRIER "\tfence rw, w\n"
-#define RISCV_FULL_BARRIER "\tfence rw, rw\n"
+#define RISCV_ACQUIRE_BARRIER RISCV_FENCE_ASM(r,rw)
+#define RISCV_RELEASE_BARRIER RISCV_FENCE_ASM(rw,r)
+#define RISCV_FULL_BARRIER RISCV_FENCE_ASM(rw,rw)
#else
#define RISCV_ACQUIRE_BARRIER
#define RISCV_RELEASE_BARRIER
diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h
index 42497d487a17..afb5ead7552e 100644
--- a/arch/riscv/include/asm/io.h
+++ b/arch/riscv/include/asm/io.h
@@ -47,10 +47,10 @@
* sufficient to ensure this works sanely on controllers that support I/O
* writes.
*/
-#define __io_pbr() __asm__ __volatile__ ("fence io,i" : : : "memory");
-#define __io_par(v) __asm__ __volatile__ ("fence i,ior" : : : "memory");
-#define __io_pbw() __asm__ __volatile__ ("fence iow,o" : : : "memory");
-#define __io_paw() __asm__ __volatile__ ("fence o,io" : : : "memory");
+#define __io_pbr() RISCV_FENCE(io,i)
+#define __io_par(v) RISCV_FENCE(i,ior)
+#define __io_pbw() RISCV_FENCE(iow,o)
+#define __io_paw() RISCV_FENCE(o,io)

/*
* Accesses from a single hart to a single I/O address must be ordered. This
diff --git a/arch/riscv/include/asm/mmio.h b/arch/riscv/include/asm/mmio.h
index 4c58ee7f95ec..a708968d4a0f 100644
--- a/arch/riscv/include/asm/mmio.h
+++ b/arch/riscv/include/asm/mmio.h
@@ -12,6 +12,7 @@
#define _ASM_RISCV_MMIO_H

#include <linux/types.h>
+#include <asm/fence.h>
#include <asm/mmiowb.h>

/* Generic IO read/write. These perform native-endian accesses. */
@@ -131,8 +132,8 @@ static inline u64 __raw_readq(const volatile void __iomem *addr)
* doesn't define any ordering between the memory space and the I/O space.
*/
#define __io_br() do {} while (0)
-#define __io_ar(v) ({ __asm__ __volatile__ ("fence i,ir" : : : "memory"); })
-#define __io_bw() ({ __asm__ __volatile__ ("fence w,o" : : : "memory"); })
+#define __io_ar(v) RISCV_FENCE(i,ir)
+#define __io_bw() RISCV_FENCE(w,o)
#define __io_aw() mmiowb_set_pending()

#define readb(c) ({ u8 __v; __io_br(); __v = readb_cpu(c); __io_ar(__v); __v; })
diff --git a/arch/riscv/include/asm/mmiowb.h b/arch/riscv/include/asm/mmiowb.h
index 0b2333e71fdc..3bcae97d4803 100644
--- a/arch/riscv/include/asm/mmiowb.h
+++ b/arch/riscv/include/asm/mmiowb.h
@@ -7,7 +7,7 @@
* "o,w" is sufficient to ensure that all writes to the device have completed
* before the write to the spinlock is allowed to commit.
*/
-#define mmiowb() __asm__ __volatile__ ("fence o,w" : : : "memory");
+#define mmiowb() RISCV_FENCE(o,w)

#include <linux/smp.h>
#include <asm-generic/mmiowb.h>