[PATCH v4 14/19] ARC: [plat-eznps] Use dedicated atomic/bitops/cmpxchg
From: Noam Camus
Date: Tue Dec 15 2015 - 20:31:15 EST
From: Noam Camus <noamc@xxxxxxxxxx>
We need our own implementaions since we lack LLSC support.
Our extended ISA provided with optimized solution for all 32bit
operations we see in these three headers.
Signed-off-by: Noam Camus <noamc@xxxxxxxxxx>
---
arch/arc/include/asm/atomic.h | 79 +++++++++++++++++++++++++++++++++++-
arch/arc/include/asm/bitops.h | 54 +++++++++++++++++++++++++
arch/arc/include/asm/cmpxchg.h | 87 +++++++++++++++++++++++++++++++++-------
3 files changed, 202 insertions(+), 18 deletions(-)
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h
index 7730d30..a626996 100644
--- a/arch/arc/include/asm/atomic.h
+++ b/arch/arc/include/asm/atomic.h
@@ -17,6 +17,7 @@
#include <asm/barrier.h>
#include <asm/smp.h>
+#ifndef CONFIG_ARC_PLAT_EZNPS
#define atomic_read(v) READ_ONCE((v)->counter)
#ifdef CONFIG_ARC_HAS_LLSC
@@ -180,12 +181,84 @@ ATOMIC_OP(andnot, &= ~, bic)
ATOMIC_OP(or, |=, or)
ATOMIC_OP(xor, ^=, xor)
-#undef ATOMIC_OPS
-#undef ATOMIC_OP_RETURN
-#undef ATOMIC_OP
#undef SCOND_FAIL_RETRY_VAR_DEF
#undef SCOND_FAIL_RETRY_ASM
#undef SCOND_FAIL_RETRY_VARS
+#else /* CONFIG_ARC_PLAT_EZNPS */
+static inline int atomic_read(const atomic_t *v)
+{
+ int temp;
+
+ __asm__ __volatile__(
+ " ld.di %0, [%1]"
+ : "=r"(temp)
+ : "r"(&v->counter)
+ : "memory");
+ return temp;
+}
+
+static inline void atomic_set(atomic_t *v, int i)
+{
+ __asm__ __volatile__(
+ " st.di %0,[%1]"
+ :
+ : "r"(i), "r"(&v->counter)
+ : "memory");
+}
+
+#define ATOMIC_OP(op, c_op, asm_op) \
+static inline void atomic_##op(int i, atomic_t *v) \
+{ \
+ __asm__ __volatile__( \
+ " mov r2, %0\n" \
+ " mov r3, %1\n" \
+ " .word %2\n" \
+ : \
+ : "r"(i), "r"(&v->counter), "i"(asm_op) \
+ : "r2", "r3", "memory"); \
+} \
+
+#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
+static inline int atomic_##op##_return(int i, atomic_t *v) \
+{ \
+ unsigned int temp = i; \
+ \
+ /* Explicit full memory barrier needed before/after */ \
+ smp_mb(); \
+ \
+ __asm__ __volatile__( \
+ " mov r2, %0\n" \
+ " mov r3, %1\n" \
+ " .word %2\n" \
+ " mov %0, r2" \
+ : "+r"(temp) \
+ : "r"(&v->counter), "i"(asm_op) \
+ : "r2", "r3", "memory"); \
+ \
+ smp_mb(); \
+ \
+ temp c_op i; \
+ \
+ return temp; \
+}
+
+#define ATOMIC_OPS(op, c_op, asm_op) \
+ ATOMIC_OP(op, c_op, asm_op) \
+ ATOMIC_OP_RETURN(op, c_op, asm_op)
+
+ATOMIC_OPS(add, +=, CTOP_INST_AADD_DI_R2_R2_R3)
+#define atomic_sub(i, v) atomic_add(-(i), (v))
+#define atomic_sub_return(i, v) atomic_add_return(-(i), (v))
+
+ATOMIC_OP(and, &=, CTOP_INST_AAND_DI_R2_R2_R3)
+#define atomic_andnot(mask, v) atomic_and(~(mask), (v))
+ATOMIC_OP(or, |=, CTOP_INST_AOR_DI_R2_R2_R3)
+ATOMIC_OP(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3)
+#endif /* CONFIG_ARC_PLAT_EZNPS */
+
+#undef ATOMIC_OPS
+#undef ATOMIC_OP_RETURN
+#undef ATOMIC_OP
/**
* __atomic_add_unless - add unless the number is a given value
diff --git a/arch/arc/include/asm/bitops.h b/arch/arc/include/asm/bitops.h
index 57c1f33..5a29185 100644
--- a/arch/arc/include/asm/bitops.h
+++ b/arch/arc/include/asm/bitops.h
@@ -22,6 +22,7 @@
#include <asm/smp.h>
#endif
+#ifndef CONFIG_ARC_PLAT_EZNPS
#if defined(CONFIG_ARC_HAS_LLSC)
/*
@@ -155,6 +156,53 @@ static inline int test_and_##op##_bit(unsigned long nr, volatile unsigned long *
}
#endif /* CONFIG_ARC_HAS_LLSC */
+#else /* CONFIG_ARC_PLAT_EZNPS */
+#define BIT_OP(op, c_op, asm_op) \
+static inline void op##_bit(unsigned long nr, volatile unsigned long *m)\
+{ \
+ m += nr >> 5; \
+ \
+ nr = (1UL << (nr & 0x1f)); \
+ if (asm_op == CTOP_INST_AAND_DI_R2_R2_R3) \
+ nr = ~nr; \
+ \
+ __asm__ __volatile__( \
+ " mov r2, %0\n" \
+ " mov r3, %1\n" \
+ " .word %2\n" \
+ : \
+ : "r"(nr), "r"(m), "i"(asm_op) \
+ : "r2", "r3", "memory"); \
+}
+
+#define TEST_N_BIT_OP(op, c_op, asm_op) \
+static inline int test_and_##op##_bit(unsigned long nr, volatile unsigned long *m)\
+{ \
+ unsigned long old; \
+ \
+ m += nr >> 5; \
+ \
+ nr = old = (1UL << (nr & 0x1f)); \
+ if (asm_op == CTOP_INST_AAND_DI_R2_R2_R3) \
+ old = ~old; \
+ \
+ /* Explicit full memory barrier needed before/after */ \
+ smp_mb(); \
+ \
+ __asm__ __volatile__( \
+ " mov r2, %0\n" \
+ " mov r3, %1\n" \
+ " .word %2\n" \
+ " mov %0, r2" \
+ : "+r"(old) \
+ : "r"(m), "i"(asm_op) \
+ : "r2", "r3", "memory"); \
+ \
+ smp_mb(); \
+ \
+ return (old & nr) != 0; \
+}
+#endif /* CONFIG_ARC_PLAT_EZNPS */
/***************************************
* Non atomic variants
@@ -196,9 +244,15 @@ static inline int __test_and_##op##_bit(unsigned long nr, volatile unsigned long
/* __test_and_set_bit(), __test_and_clear_bit(), __test_and_change_bit() */\
__TEST_N_BIT_OP(op, c_op, asm_op)
+#ifndef CONFIG_ARC_PLAT_EZNPS
BIT_OPS(set, |, bset)
BIT_OPS(clear, & ~, bclr)
BIT_OPS(change, ^, bxor)
+#else
+BIT_OPS(set, |, CTOP_INST_AOR_DI_R2_R2_R3)
+BIT_OPS(clear, & ~, CTOP_INST_AAND_DI_R2_R2_R3)
+BIT_OPS(change, ^, CTOP_INST_AXOR_DI_R2_R2_R3)
+#endif
/*
* This routine doesn't need to be atomic.
diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h
index af7a2db..6d320d3 100644
--- a/arch/arc/include/asm/cmpxchg.h
+++ b/arch/arc/include/asm/cmpxchg.h
@@ -14,6 +14,7 @@
#include <asm/barrier.h>
#include <asm/smp.h>
+#ifndef CONFIG_ARC_PLAT_EZNPS
#ifdef CONFIG_ARC_HAS_LLSC
static inline unsigned long
@@ -66,21 +67,6 @@ __cmpxchg(volatile void *ptr, unsigned long expected, unsigned long new)
#endif /* CONFIG_ARC_HAS_LLSC */
-#define cmpxchg(ptr, o, n) ((typeof(*(ptr)))__cmpxchg((ptr), \
- (unsigned long)(o), (unsigned long)(n)))
-
-/*
- * Since not supported natively, ARC cmpxchg() uses atomic_ops_lock (UP/SMP)
- * just to gaurantee semantics.
- * atomic_cmpxchg() needs to use the same locks as it's other atomic siblings
- * which also happens to be atomic_ops_lock.
- *
- * Thus despite semantically being different, implementation of atomic_cmpxchg()
- * is same as cmpxchg().
- */
-#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
-
-
/*
* xchg (reg with memory) based on "Native atomic" EX insn
*/
@@ -143,6 +129,63 @@ static inline unsigned long __xchg(unsigned long val, volatile void *ptr,
#endif
+#else /* CONFIG_ARC_PLAT_EZNPS */
+static inline unsigned long
+__cmpxchg(volatile void *ptr, unsigned long expected, unsigned long new)
+{
+ /*
+ * Explicit full memory barrier needed before/after
+ */
+ smp_mb();
+
+ write_aux_reg(CTOP_AUX_GPA1, expected);
+
+ __asm__ __volatile__(
+ " mov r2, %0\n"
+ " mov r3, %1\n"
+ " .word %2\n"
+ " mov %0, r2"
+ : "+r"(new)
+ : "r"(ptr), "i"(CTOP_INST_EXC_DI_R2_R2_R3)
+ : "r2", "r3", "memory");
+
+ smp_mb();
+
+ return new;
+}
+
+static inline unsigned long __xchg(unsigned long val, volatile void *ptr,
+ int size)
+{
+ extern unsigned long __xchg_bad_pointer(void);
+
+ switch (size) {
+ case 4:
+ /*
+ * Explicit full memory barrier needed before/after
+ */
+ smp_mb();
+
+ __asm__ __volatile__(
+ " mov r2, %0\n"
+ " mov r3, %1\n"
+ " .word %2\n"
+ " mov %0, r2\n"
+ : "+r"(val)
+ : "r"(ptr), "i"(CTOP_INST_XEX_DI_R2_R2_R3)
+ : "r2", "r3", "memory");
+
+ smp_mb();
+
+ return val;
+ }
+ return __xchg_bad_pointer();
+}
+
+#define xchg(ptr, with) ((typeof(*(ptr)))__xchg((unsigned long)(with), (ptr), \
+ sizeof(*(ptr))))
+#endif /* CONFIG_ARC_PLAT_EZNPS */
+
/*
* "atomic" variant of xchg()
* REQ: It needs to follow the same serialization rules as other atomic_xxx()
@@ -158,4 +201,18 @@ static inline unsigned long __xchg(unsigned long val, volatile void *ptr,
*/
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
+#define cmpxchg(ptr, o, n) ((typeof(*(ptr)))__cmpxchg((ptr), \
+ (unsigned long)(o), (unsigned long)(n)))
+
+/*
+ * Since not supported natively, ARC cmpxchg() uses atomic_ops_lock (UP/SMP)
+ * just to gaurantee semantics.
+ * atomic_cmpxchg() needs to use the same locks as it's other atomic siblings
+ * which also happens to be atomic_ops_lock.
+ *
+ * Thus despite semantically being different, implementation of atomic_cmpxchg()
+ * is same as cmpxchg().
+ */
+#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
+
#endif
--
1.7.1
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