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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v4 1/5] xen/ppc: Implement atomic.h
Implement atomic.h for PPC, based off of the original Xen 3.2
implementation. This implementation depends on some functions that are
not yet defined (notably __cmpxchg), so it can't yet be used.
Signed-off-by: Shawn Anastasio <sanastasio@xxxxxxxxxxxxxxxxxxxxx>
---
v4:
- Clarify dependency on __cmpxchg which doesn't get implemented until
future patch
- Drop !CONFIG_SMP case for PPC_ATOMIC_{ENTRY,EXIT}_BARRIER macro
definitions
- Add missing newlines to inline asm instructions preceeding
PPC_ATOMIC_EXIT_BARRIER. This was only discovered by the change
to drop the !CONFIG_SMP definitions of those macros.
- Fix line wrapping in atomic_compareandswap
- Fix formatting of arch_cmpxchg macro
v3:
- Drop full copyright text headers
- Drop unnecessary spaces after casts
- const-ize write_atomic_size
- Don't use GNU 0-length array extension in read_atomic
- Use "+m" asm constraint instead of separate "=m" and "m"
- Fix line-continuing backslash formatting in arch_cmpxchg
v2:
- Fix style of asm block constraints to include required spaces
- Fix macro local variable naming (use trailing underscore instead of
leading)
- Drop unnecessary parens in __atomic_add_unless
xen/arch/ppc/include/asm/atomic.h | 385 ++++++++++++++++++++++++++++++
xen/arch/ppc/include/asm/memory.h | 14 ++
2 files changed, 399 insertions(+)
create mode 100644 xen/arch/ppc/include/asm/atomic.h
create mode 100644 xen/arch/ppc/include/asm/memory.h
diff --git a/xen/arch/ppc/include/asm/atomic.h
b/xen/arch/ppc/include/asm/atomic.h
new file mode 100644
index 0000000000..64168aa3f1
--- /dev/null
+++ b/xen/arch/ppc/include/asm/atomic.h
@@ -0,0 +1,385 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * PowerPC64 atomic operations
+ *
+ * Copyright (C) 2001 Paul Mackerras <paulus@xxxxxxxxxx>, IBM
+ * Copyright (C) 2001 Anton Blanchard <anton@xxxxxxxxxx>, IBM
+ * Copyright Raptor Engineering LLC
+ */
+
+#ifndef _ASM_PPC64_ATOMIC_H_
+#define _ASM_PPC64_ATOMIC_H_
+
+#include <xen/atomic.h>
+
+#include <asm/memory.h>
+
+static inline int atomic_read(const atomic_t *v)
+{
+ return *(volatile int *)&v->counter;
+}
+
+static inline int _atomic_read(atomic_t v)
+{
+ return v.counter;
+}
+
+static inline void atomic_set(atomic_t *v, int i)
+{
+ v->counter = i;
+}
+
+static inline void _atomic_set(atomic_t *v, int i)
+{
+ v->counter = i;
+}
+
+void __bad_atomic_read(const volatile void *p, void *res);
+void __bad_atomic_size(void);
+
+#define build_atomic_read(name, insn, type)
\
+ static inline type name(const volatile type *addr)
\
+ {
\
+ type ret;
\
+ asm volatile ( insn "%U1%X1 %0,%1" : "=r" (ret) : "m<>" (*addr) );
\
+ return ret;
\
+ }
+
+#define build_atomic_write(name, insn, type)
\
+ static inline void name(volatile type *addr, type val)
\
+ {
\
+ asm volatile ( insn "%U0%X0 %1,%0" : "=m<>" (*addr) : "r" (val) );
\
+ }
+
+#define build_add_sized(name, ldinsn, stinsn, type)
\
+ static inline void name(volatile type *addr, type val)
\
+ {
\
+ type t;
\
+ asm volatile ( "1: " ldinsn " %0,0,%3\n"
\
+ "add%I2 %0,%0,%2\n"
\
+ stinsn " %0,0,%3 \n"
\
+ "bne- 1b\n"
\
+ : "=&r" (t), "+m" (*addr)
\
+ : "r" (val), "r" (addr)
\
+ : "cc" );
\
+ }
+
+build_atomic_read(read_u8_atomic, "lbz", uint8_t)
+build_atomic_read(read_u16_atomic, "lhz", uint16_t)
+build_atomic_read(read_u32_atomic, "lwz", uint32_t)
+build_atomic_read(read_u64_atomic, "ldz", uint64_t)
+
+build_atomic_write(write_u8_atomic, "stb", uint8_t)
+build_atomic_write(write_u16_atomic, "sth", uint16_t)
+build_atomic_write(write_u32_atomic, "stw", uint32_t)
+build_atomic_write(write_u64_atomic, "std", uint64_t)
+
+build_add_sized(add_u8_sized, "lbarx", "stbcx.",uint8_t)
+build_add_sized(add_u16_sized, "lharx", "sthcx.", uint16_t)
+build_add_sized(add_u32_sized, "lwarx", "stwcx.", uint32_t)
+
+#undef build_atomic_read
+#undef build_atomic_write
+#undef build_add_sized
+
+static always_inline void read_atomic_size(const volatile void *p, void *res,
+ unsigned int size)
+{
+ ASSERT(IS_ALIGNED((vaddr_t)p, size));
+ switch ( size )
+ {
+ case 1:
+ *(uint8_t *)res = read_u8_atomic(p);
+ break;
+ case 2:
+ *(uint16_t *)res = read_u16_atomic(p);
+ break;
+ case 4:
+ *(uint32_t *)res = read_u32_atomic(p);
+ break;
+ case 8:
+ *(uint64_t *)res = read_u64_atomic(p);
+ break;
+ default:
+ __bad_atomic_read(p, res);
+ break;
+ }
+}
+
+static always_inline void write_atomic_size(volatile void *p, const void *val,
+ unsigned int size)
+{
+ ASSERT(IS_ALIGNED((vaddr_t)p, size));
+ switch ( size )
+ {
+ case 1:
+ write_u8_atomic(p, *(const uint8_t *)val);
+ break;
+ case 2:
+ write_u16_atomic(p, *(const uint16_t *)val);
+ break;
+ case 4:
+ write_u32_atomic(p, *(const uint32_t *)val);
+ break;
+ case 8:
+ write_u64_atomic(p, *(const uint64_t *)val);
+ break;
+ default:
+ __bad_atomic_size();
+ break;
+ }
+}
+
+#define read_atomic(p)
\
+ ({
\
+ union {
\
+ typeof(*(p)) val;
\
+ char c[sizeof(*(p))];
\
+ } x_;
\
+ read_atomic_size(p, x_.c, sizeof(*(p)));
\
+ x_.val;
\
+ })
+
+#define write_atomic(p, x)
\
+ do
\
+ {
\
+ typeof(*(p)) x_ = (x);
\
+ write_atomic_size(p, &x_, sizeof(*(p)));
\
+ } while ( 0 )
+
+#define add_sized(p, x)
\
+ ({
\
+ typeof(*(p)) x_ = (x);
\
+ switch ( sizeof(*(p)) )
\
+ {
\
+ case 1:
\
+ add_u8_sized((uint8_t *)(p), x_);
\
+ break;
\
+ case 2:
\
+ add_u16_sized((uint16_t *)(p), x_);
\
+ break;
\
+ case 4:
\
+ add_u32_sized((uint32_t *)(p), x_);
\
+ break;
\
+ default:
\
+ __bad_atomic_size();
\
+ break;
\
+ }
\
+ })
+
+static inline void atomic_add(int a, atomic_t *v)
+{
+ int t;
+
+ asm volatile ( "1: lwarx %0,0,%3\n"
+ "add %0,%2,%0\n"
+ "stwcx. %0,0,%3\n"
+ "bne- 1b"
+ : "=&r" (t), "+m" (v->counter)
+ : "r" (a), "r" (&v->counter)
+ : "cc" );
+}
+
+static inline int atomic_add_return(int a, atomic_t *v)
+{
+ int t;
+
+ asm volatile ( PPC_ATOMIC_ENTRY_BARRIER
+ "1: lwarx %0,0,%2\n"
+ "add %0,%1,%0\n"
+ "stwcx. %0,0,%2\n"
+ "bne- 1b\n"
+ PPC_ATOMIC_EXIT_BARRIER
+ : "=&r" (t)
+ : "r" (a), "r" (&v->counter)
+ : "cc", "memory" );
+
+ return t;
+}
+
+static inline void atomic_sub(int a, atomic_t *v)
+{
+ int t;
+
+ asm volatile ( "1: lwarx %0,0,%3\n"
+ "subf %0,%2,%0\n"
+ "stwcx. %0,0,%3\n"
+ "bne- 1b"
+ : "=&r" (t), "+m" (v->counter)
+ : "r" (a), "r" (&v->counter)
+ : "cc" );
+}
+
+static inline int atomic_sub_return(int a, atomic_t *v)
+{
+ int t;
+
+ asm volatile ( PPC_ATOMIC_ENTRY_BARRIER
+ "1: lwarx %0,0,%2\n"
+ "subf %0,%1,%0\n"
+ "stwcx. %0,0,%2\n"
+ "bne- 1b\n"
+ PPC_ATOMIC_EXIT_BARRIER
+ : "=&r" (t)
+ : "r" (a), "r" (&v->counter)
+ : "cc", "memory" );
+
+ return t;
+}
+
+static inline void atomic_inc(atomic_t *v)
+{
+ int t;
+
+ asm volatile ( "1: lwarx %0,0,%2\n"
+ "addic %0,%0,1\n"
+ "stwcx. %0,0,%2\n"
+ "bne- 1b"
+ : "=&r" (t), "+m" (v->counter)
+ : "r" (&v->counter)
+ : "cc" );
+}
+
+static inline int atomic_inc_return(atomic_t *v)
+{
+ int t;
+
+ asm volatile ( PPC_ATOMIC_ENTRY_BARRIER
+ "1: lwarx %0,0,%1\n"
+ "addic %0,%0,1\n"
+ "stwcx. %0,0,%1\n"
+ "bne- 1b\n"
+ PPC_ATOMIC_EXIT_BARRIER
+ : "=&r" (t)
+ : "r" (&v->counter)
+ : "cc", "memory" );
+
+ return t;
+}
+
+static inline void atomic_dec(atomic_t *v)
+{
+ int t;
+
+ asm volatile ( "1: lwarx %0,0,%2\n"
+ "addic %0,%0,-1\n"
+ "stwcx. %0,0,%2\n"
+ "bne- 1b"
+ : "=&r" (t), "+m" (v->counter)
+ : "r" (&v->counter)
+ : "cc" );
+}
+
+static inline int atomic_dec_return(atomic_t *v)
+{
+ int t;
+
+ asm volatile ( PPC_ATOMIC_ENTRY_BARRIER
+ "1: lwarx %0,0,%1\n"
+ "addic %0,%0,-1\n"
+ "stwcx. %0,0,%1\n"
+ "bne- 1b\n"
+ PPC_ATOMIC_EXIT_BARRIER
+ : "=&r" (t)
+ : "r" (&v->counter)
+ : "cc", "memory" );
+
+ return t;
+}
+
+/*
+ * Atomically test *v and decrement if it is greater than 0.
+ * The function returns the old value of *v minus 1.
+ */
+static inline int atomic_dec_if_positive(atomic_t *v)
+{
+ int t;
+
+ asm volatile( PPC_ATOMIC_ENTRY_BARRIER
+ "1: lwarx %0,0,%1 # atomic_dec_if_positive\n"
+ "addic. %0,%0,-1\n"
+ "blt- 2f\n"
+ "stwcx. %0,0,%1\n"
+ "bne- 1b\n"
+ PPC_ATOMIC_EXIT_BARRIER
+ "2:"
+ : "=&r" (t)
+ : "r" (&v->counter)
+ : "cc", "memory" );
+
+ return t;
+}
+
+static inline atomic_t atomic_compareandswap(atomic_t old, atomic_t new,
+ atomic_t *v)
+{
+ atomic_t rc;
+ rc.counter = __cmpxchg(&v->counter, old.counter, new.counter,
+ sizeof(v->counter));
+ return rc;
+}
+
+#define arch_cmpxchg(ptr, o, n)
\
+ ({
\
+ __typeof__(*(ptr)) o_ = (o);
\
+ __typeof__(*(ptr)) n_ = (n);
\
+ (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)o_,
\
+ (unsigned long)n_, sizeof(*(ptr)));
\
+ })
+
+static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
+{
+ return arch_cmpxchg(&v->counter, old, new);
+}
+
+#define ATOMIC_OP(op, insn, suffix, sign) \
+ static inline void atomic_##op(int a, atomic_t *v)
\
+ {
\
+ int t;
\
+ asm volatile ( "1: lwarx %0,0,%3\n"
\
+ insn "%I2" suffix " %0,%0,%2\n"
\
+ "stwcx. %0,0,%3 \n"
\
+ "bne- 1b\n"
\
+ : "=&r" (t), "+m" (v->counter)
\
+ : "r" #sign (a), "r" (&v->counter)
\
+ : "cc" );
\
+ }
+
+ATOMIC_OP(and, "and", ".", K)
+
+static inline int atomic_sub_and_test(int i, atomic_t *v)
+{
+ return atomic_sub_return(i, v) == 0;
+}
+
+static inline int atomic_inc_and_test(atomic_t *v)
+{
+ return atomic_add_return(1, v) == 0;
+}
+
+static inline int atomic_dec_and_test(atomic_t *v)
+{
+ return atomic_sub_return(1, v) == 0;
+}
+
+static inline int atomic_add_negative(int i, atomic_t *v)
+{
+ return atomic_add_return(i, v) < 0;
+}
+
+static inline int __atomic_add_unless(atomic_t *v, int a, int u)
+{
+ int c, old;
+
+ c = atomic_read(v);
+ while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c)
+ c = old;
+ return c;
+}
+
+static inline int atomic_add_unless(atomic_t *v, int a, int u)
+{
+ return __atomic_add_unless(v, a, u);
+}
+
+#endif /* _ASM_PPC64_ATOMIC_H_ */
diff --git a/xen/arch/ppc/include/asm/memory.h
b/xen/arch/ppc/include/asm/memory.h
new file mode 100644
index 0000000000..57310eb690
--- /dev/null
+++ b/xen/arch/ppc/include/asm/memory.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) IBM Corp. 2005
+ *
+ * Authors: Jimi Xenidis <jimix@xxxxxxxxxxxxxx>
+ */
+
+#ifndef _ASM_MEMORY_H_
+#define _ASM_MEMORY_H_
+
+#define PPC_ATOMIC_ENTRY_BARRIER "sync\n"
+#define PPC_ATOMIC_EXIT_BARRIER "sync\n"
+
+#endif
--
2.30.2
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