[PATCH 10/18] arm/arm64: add simple cpumask API

Andrew Jones
2015-02-01T18:35:07Z

On smp, cpumasks become quite useful. Add a simple implementation,
along with implementations of bitops it needs.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
config/config-arm-common.mak | 1 +
lib/arm/asm/bitops.h | 53 +++++++++++++++++++
lib/arm/asm/cpumask.h | 118 +++++++++++++++++++++++++++++++++++++++++++
lib/arm/bitops.c | 81 +++++++++++++++++++++++++++++
lib/arm64/asm/bitops.h | 51 +++++++++++++++++++
lib/arm64/asm/cpumask.h | 1 +
6 files changed, 305 insertions(+)
create mode 100644 lib/arm/asm/bitops.h
create mode 100644 lib/arm/asm/cpumask.h
create mode 100644 lib/arm/bitops.c
create mode 100644 lib/arm64/asm/bitops.h
create mode 100644 lib/arm64/asm/cpumask.h

diff --git a/config/config-arm-common.mak b/config/config-arm-common.mak
index b01e9ab836b2d..94eac8967e234 100644
--- a/config/config-arm-common.mak
+++ b/config/config-arm-common.mak
@@ -34,6 +34,7 @@ cflatobjs += lib/chr-testdev.o
cflatobjs += lib/arm/io.o
cflatobjs += lib/arm/setup.o
cflatobjs += lib/arm/mmu.o
+cflatobjs += lib/arm/bitops.o

libeabi = lib/arm/libeabi.a
eabiobjs = lib/arm/eabi_compat.o
diff --git a/lib/arm/asm/bitops.h b/lib/arm/asm/bitops.h
new file mode 100644
index 0000000000000..8049634be0485
--- /dev/null
+++ b/lib/arm/asm/bitops.h
@@ -0,0 +1,53 @@
+#ifndef _ASMARM_BITOPS_H_
+#define _ASMARM_BITOPS_H_
+/*
+ * Adapated from
+ * include/linux/bitops.h
+ * arch/arm/lib/bitops.h
+ *
+ * Copyright (C) 2015, Red Hat Inc, Andrew Jones <drjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+
+#define BITS_PER_LONG 32
+#define BIT(nr) (1UL << (nr))
+#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
+#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
+
+#define ATOMIC_BITOP(insn, mask, word) \
+({ \
+ unsigned long tmp1, tmp2; \
+ asm volatile( \
+ "1: ldrex %0, [%2]\n" \
+ insn" %0, %0, %3\n" \
+ " strex %1, %0, [%2]\n" \
+ " cmp %1, #0\n" \
+ " bne 1b\n" \
+ : "=&r" (tmp1), "=&r" (tmp2) \
+ : "r" (word), "r" (mask) \
+ : "cc"); \
+})
+
+#define ATOMIC_TESTOP(insn, mask, word, old) \
+({ \
+ unsigned long tmp1, tmp2; \
+ asm volatile( \
+ "1: ldrex %0, [%3]\n" \
+ " and %1, %0, %4\n" \
+ insn" %0, %0, %4\n" \
+ " strex %2, %0, [%3]\n" \
+ " cmp %2, #0\n" \
+ " bne 1b\n" \
+ : "=&r" (tmp1), "=&r" (old), "=&r" (tmp2) \
+ : "r" (word), "r" (mask) \
+ : "cc"); \
+})
+
+extern void set_bit(int nr, volatile unsigned long *addr);
+extern void clear_bit(int nr, volatile unsigned long *addr);
+extern int test_bit(int nr, const volatile unsigned long *addr);
+extern int test_and_set_bit(int nr, volatile unsigned long *addr);
+extern int test_and_clear_bit(int nr, volatile unsigned long *addr);
+
+#endif /* _ASMARM_BITOPS_H_ */
diff --git a/lib/arm/asm/cpumask.h b/lib/arm/asm/cpumask.h
new file mode 100644
index 0000000000000..85b8e4b51a403
--- /dev/null
+++ b/lib/arm/asm/cpumask.h
@@ -0,0 +1,118 @@
+#ifndef _ASMARM_CPUMASK_H_
+#define _ASMARM_CPUMASK_H_
+/*
+ * Simple cpumask implementation
+ *
+ * Copyright (C) 2015, Red Hat Inc, Andrew Jones <drjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+#include <asm/setup.h>
+#include <asm/bitops.h>
+
+#define CPUMASK_NR_LONGS ((NR_CPUS + BITS_PER_LONG - 1) / BITS_PER_LONG)
+
+typedef struct cpumask {
+ unsigned long bits[CPUMASK_NR_LONGS];
+} cpumask_t;
+
+#define cpumask_bits(maskp) ((maskp)->bits)
+
+static inline void cpumask_set_cpu(int cpu, cpumask_t *mask)
+{
+ set_bit(cpu, cpumask_bits(mask));
+}
+
+static inline void cpumask_clear_cpu(int cpu, cpumask_t *mask)
+{
+ clear_bit(cpu, cpumask_bits(mask));
+}
+
+static inline int cpumask_test_cpu(int cpu, const cpumask_t *mask)
+{
+ return test_bit(cpu, cpumask_bits(mask));
+}
+
+static inline int cpumask_test_and_set_cpu(int cpu, cpumask_t *mask)
+{
+ return test_and_set_bit(cpu, cpumask_bits(mask));
+}
+
+static inline int cpumask_test_and_clear_cpu(int cpu, cpumask_t *mask)
+{
+ return test_and_clear_bit(cpu, cpumask_bits(mask));
+}
+
+static inline void cpumask_setall(cpumask_t *mask)
+{
+ int i;
+ for (i = 0; i < nr_cpus; i += BITS_PER_LONG)
+ cpumask_bits(mask)[BIT_WORD(i)] = ~0UL;
+ i -= BITS_PER_LONG;
+ if ((nr_cpus - i) < BITS_PER_LONG)
+ cpumask_bits(mask)[BIT_WORD(i)] = BIT_MASK(nr_cpus - i) - 1;
+}
+
+static inline void cpumask_clear(cpumask_t *mask)
+{
+ int i;
+ for (i = 0; i < nr_cpus; i += BITS_PER_LONG)
+ cpumask_bits(mask)[BIT_WORD(i)] = 0UL;
+}
+
+static inline bool cpumask_empty(const cpumask_t *mask)
+{
+ int i;
+ for (i = 0; i < nr_cpus; i += BITS_PER_LONG) {
+ if (i < NR_CPUS) { /* silence crazy compiler warning */
+ if (cpumask_bits(mask)[BIT_WORD(i)] != 0UL)
+ return false;
+ }
+ }
+ return true;
+}
+
+static inline bool cpumask_full(const cpumask_t *mask)
+{
+ int i;
+ for (i = 0; i < nr_cpus; i += BITS_PER_LONG) {
+ if (cpumask_bits(mask)[BIT_WORD(i)] != ~0UL) {
+ if ((nr_cpus - i) >= BITS_PER_LONG)
+ return false;
+ if (cpumask_bits(mask)[BIT_WORD(i)]
+ != BIT_MASK(nr_cpus - i) - 1)
+ return false;
+ }
+ }
+ return true;
+}
+
+static inline int cpumask_weight(const cpumask_t *mask)
+{
+ int w = 0, i;
+
+ for (i = 0; i < nr_cpus; ++i)
+ if (cpumask_test_cpu(i, mask))
+ ++w;
+ return w;
+}
+
+static inline void cpumask_copy(cpumask_t *dst, const cpumask_t *src)
+{
+ memcpy(cpumask_bits(dst), cpumask_bits(src),
+ CPUMASK_NR_LONGS * sizeof(long));
+}
+
+static inline int cpumask_next(int cpu, const cpumask_t *mask)
+{
+ while (cpu < nr_cpus && !cpumask_test_cpu(++cpu, mask))
+ ;
+ return cpu;
+}
+
+#define for_each_cpu(cpu, mask) \
+ for ((cpu) = cpumask_next(-1, mask); \
+ (cpu) < nr_cpus; \
+ (cpu) = cpumask_next(cpu, mask))
+
+#endif /* _ASMARM_CPUMASK_H_ */
diff --git a/lib/arm/bitops.c b/lib/arm/bitops.c
new file mode 100644
index 0000000000000..9ad112162a29f
--- /dev/null
+++ b/lib/arm/bitops.c
@@ -0,0 +1,81 @@
+/*
+ * Adapated from
+ * include/asm-generic/bitops/atomic.h
+ *
+ * Copyright (C) 2015, Red Hat Inc, Andrew Jones <drjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+#include <asm/bitops.h>
+#include <asm/barrier.h>
+#include <asm/mmu.h>
+
+void set_bit(int nr, volatile unsigned long *addr)
+{
+ volatile unsigned long *word = addr + BIT_WORD(nr);
+ unsigned long mask = BIT_MASK(nr);
+
+ if (mmu_enabled())
+ ATOMIC_BITOP("orr", mask, word);
+ else
+ *word |= mask;
+ smp_mb();
+}
+
+void clear_bit(int nr, volatile unsigned long *addr)
+{
+ volatile unsigned long *word = addr + BIT_WORD(nr);
+ unsigned long mask = BIT_MASK(nr);
+
+ if (mmu_enabled())
+ ATOMIC_BITOP("bic", mask, word);
+ else
+ *word &= ~mask;
+ smp_mb();
+}
+
+int test_bit(int nr, const volatile unsigned long *addr)
+{
+ const volatile unsigned long *word = addr + BIT_WORD(nr);
+ unsigned long mask = BIT_MASK(nr);
+
+ return (*word & mask) != 0;
+}
+
+int test_and_set_bit(int nr, volatile unsigned long *addr)
+{
+ volatile unsigned long *word = addr + BIT_WORD(nr);
+ unsigned long mask = BIT_MASK(nr);
+ unsigned long old;
+
+ smp_mb();
+
+ if (mmu_enabled()) {
+ ATOMIC_TESTOP("orr", mask, word, old);
+ } else {
+ old = *word;
+ *word = old | mask;
+ }
+ smp_mb();
+
+ return (old & mask) != 0;
+}
+
+int test_and_clear_bit(int nr, volatile unsigned long *addr)
+{
+ volatile unsigned long *word = addr + BIT_WORD(nr);
+ unsigned long mask = BIT_MASK(nr);
+ unsigned long old;
+
+ smp_mb();
+
+ if (mmu_enabled()) {
+ ATOMIC_TESTOP("bic", mask, word, old);
+ } else {
+ old = *word;
+ *word = old & ~mask;
+ }
+ smp_mb();
+
+ return (old & mask) != 0;
+}
diff --git a/lib/arm64/asm/bitops.h b/lib/arm64/asm/bitops.h
new file mode 100644
index 0000000000000..3371c60bdc4f2
--- /dev/null
+++ b/lib/arm64/asm/bitops.h
@@ -0,0 +1,51 @@
+#ifndef _ASMARM64_BITOPS_H_
+#define _ASMARM64_BITOPS_H_
+/*
+ * Adapated from
+ * include/linux/bitops.h
+ * arch/arm64/lib/bitops.S
+ *
+ * Copyright (C) 2015, Red Hat Inc, Andrew Jones <drjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+
+#define BITS_PER_LONG 64
+#define BIT(nr) (1UL << (nr))
+#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
+#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
+
+#define ATOMIC_BITOP(insn, mask, word) \
+({ \
+ unsigned long tmp1, tmp2; \
+ asm volatile( \
+ "1: ldxr %0, [%2]\n" \
+ insn" %0, %0, %3\n" \
+ " stxr %w1, %0, [%2]\n" \
+ " cbnz %w1, 1b\n" \
+ : "=&r" (tmp1), "=&r" (tmp2) \
+ : "r" (word), "r" (mask) \
+ : "cc"); \
+})
+
+#define ATOMIC_TESTOP(insn, mask, word, old) \
+({ \
+ unsigned long tmp1, tmp2; \
+ asm volatile( \
+ "1: ldxr %0, [%3]\n" \
+ " and %1, %0, %4\n" \
+ insn" %0, %0, %4\n" \
+ " stlxr %w2, %0, [%3]\n" \
+ " cbnz %w2, 1b\n" \
+ : "=&r" (tmp1), "=&r" (old), "=&r" (tmp2) \
+ : "r" (word), "r" (mask) \
+ : "cc"); \
+})
+
+extern void set_bit(int nr, volatile unsigned long *addr);
+extern void clear_bit(int nr, volatile unsigned long *addr);
+extern int test_bit(int nr, const volatile unsigned long *addr);
+extern int test_and_set_bit(int nr, volatile unsigned long *addr);
+extern int test_and_clear_bit(int nr, volatile unsigned long *addr);
+
+#endif /* _ASMARM64_BITOPS_H_ */
diff --git a/lib/arm64/asm/cpumask.h b/lib/arm64/asm/cpumask.h
new file mode 100644
index 0000000000000..d1421e7abe310
--- /dev/null
+++ b/lib/arm64/asm/cpumask.h
@@ -0,0 +1 @@
+#include "../../arm/asm/cpumask.h"
--
1.9.3