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-rw-r--r--arch/arc/include/asm/Kbuild1
-rw-r--r--arch/arc/include/asm/arcregs.h7
-rw-r--r--arch/arc/include/asm/atomic.h78
-rw-r--r--arch/arc/include/asm/bitops.h35
-rw-r--r--arch/arc/include/asm/futex.h48
-rw-r--r--arch/arc/include/asm/mm-arch-hooks.h15
-rw-r--r--arch/arc/include/asm/ptrace.h52
-rw-r--r--arch/arc/include/asm/spinlock.h538
-rw-r--r--arch/arc/include/asm/spinlock_types.h2
9 files changed, 661 insertions, 115 deletions
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 1a80cc9..7611b10 100644
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -22,6 +22,7 @@ generic-y += kvm_para.h
generic-y += local.h
generic-y += local64.h
generic-y += mcs_spinlock.h
+generic-y += mm-arch-hooks.h
generic-y += mman.h
generic-y += msgbuf.h
generic-y += param.h
diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
index 070f588..c8f57b8 100644
--- a/arch/arc/include/asm/arcregs.h
+++ b/arch/arc/include/asm/arcregs.h
@@ -89,11 +89,10 @@
#define ECR_C_BIT_DTLB_LD_MISS 8
#define ECR_C_BIT_DTLB_ST_MISS 9
-
/* Auxiliary registers */
#define AUX_IDENTITY 4
#define AUX_INTR_VEC_BASE 0x25
-
+#define AUX_NON_VOL 0x5e
/*
* Floating Pt Registers
@@ -240,9 +239,9 @@ struct bcr_extn_xymem {
struct bcr_perip {
#ifdef CONFIG_CPU_BIG_ENDIAN
- unsigned int start:8, pad2:8, sz:8, pad:8;
+ unsigned int start:8, pad2:8, sz:8, ver:8;
#else
- unsigned int pad:8, sz:8, pad2:8, start:8;
+ unsigned int ver:8, sz:8, pad2:8, start:8;
#endif
};
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h
index 03484cb..87d18ae 100644
--- a/arch/arc/include/asm/atomic.h
+++ b/arch/arc/include/asm/atomic.h
@@ -23,33 +23,60 @@
#define atomic_set(v, i) (((v)->counter) = (i))
-#ifdef CONFIG_ISA_ARCV2
-#define PREFETCHW " prefetchw [%1] \n"
-#else
-#define PREFETCHW
+#ifdef CONFIG_ARC_STAR_9000923308
+
+#define SCOND_FAIL_RETRY_VAR_DEF \
+ unsigned int delay = 1, tmp; \
+
+#define SCOND_FAIL_RETRY_ASM \
+ " bz 4f \n" \
+ " ; --- scond fail delay --- \n" \
+ " mov %[tmp], %[delay] \n" /* tmp = delay */ \
+ "2: brne.d %[tmp], 0, 2b \n" /* while (tmp != 0) */ \
+ " sub %[tmp], %[tmp], 1 \n" /* tmp-- */ \
+ " rol %[delay], %[delay] \n" /* delay *= 2 */ \
+ " b 1b \n" /* start over */ \
+ "4: ; --- success --- \n" \
+
+#define SCOND_FAIL_RETRY_VARS \
+ ,[delay] "+&r" (delay),[tmp] "=&r" (tmp) \
+
+#else /* !CONFIG_ARC_STAR_9000923308 */
+
+#define SCOND_FAIL_RETRY_VAR_DEF
+
+#define SCOND_FAIL_RETRY_ASM \
+ " bnz 1b \n" \
+
+#define SCOND_FAIL_RETRY_VARS
+
#endif
#define ATOMIC_OP(op, c_op, asm_op) \
static inline void atomic_##op(int i, atomic_t *v) \
{ \
- unsigned int temp; \
+ unsigned int val; \
+ SCOND_FAIL_RETRY_VAR_DEF \
\
__asm__ __volatile__( \
- "1: \n" \
- PREFETCHW \
- " llock %0, [%1] \n" \
- " " #asm_op " %0, %0, %2 \n" \
- " scond %0, [%1] \n" \
- " bnz 1b \n" \
- : "=&r"(temp) /* Early clobber, to prevent reg reuse */ \
- : "r"(&v->counter), "ir"(i) \
+ "1: llock %[val], [%[ctr]] \n" \
+ " " #asm_op " %[val], %[val], %[i] \n" \
+ " scond %[val], [%[ctr]] \n" \
+ " \n" \
+ SCOND_FAIL_RETRY_ASM \
+ \
+ : [val] "=&r" (val) /* Early clobber to prevent reg reuse */ \
+ SCOND_FAIL_RETRY_VARS \
+ : [ctr] "r" (&v->counter), /* Not "m": llock only supports reg direct addr mode */ \
+ [i] "ir" (i) \
: "cc"); \
} \
#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
static inline int atomic_##op##_return(int i, atomic_t *v) \
{ \
- unsigned int temp; \
+ unsigned int val; \
+ SCOND_FAIL_RETRY_VAR_DEF \
\
/* \
* Explicit full memory barrier needed before/after as \
@@ -58,19 +85,21 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \
smp_mb(); \
\
__asm__ __volatile__( \
- "1: \n" \
- PREFETCHW \
- " llock %0, [%1] \n" \
- " " #asm_op " %0, %0, %2 \n" \
- " scond %0, [%1] \n" \
- " bnz 1b \n" \
- : "=&r"(temp) \
- : "r"(&v->counter), "ir"(i) \
+ "1: llock %[val], [%[ctr]] \n" \
+ " " #asm_op " %[val], %[val], %[i] \n" \
+ " scond %[val], [%[ctr]] \n" \
+ " \n" \
+ SCOND_FAIL_RETRY_ASM \
+ \
+ : [val] "=&r" (val) \
+ SCOND_FAIL_RETRY_VARS \
+ : [ctr] "r" (&v->counter), \
+ [i] "ir" (i) \
: "cc"); \
\
smp_mb(); \
\
- return temp; \
+ return val; \
}
#else /* !CONFIG_ARC_HAS_LLSC */
@@ -150,6 +179,9 @@ ATOMIC_OP(and, &=, and)
#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
/**
* __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 99fe118..57c1f33 100644
--- a/arch/arc/include/asm/bitops.h
+++ b/arch/arc/include/asm/bitops.h
@@ -50,8 +50,7 @@ static inline void op##_bit(unsigned long nr, volatile unsigned long *m)\
* done for const @nr, but no code is generated due to gcc \
* const prop. \
*/ \
- if (__builtin_constant_p(nr)) \
- nr &= 0x1f; \
+ nr &= 0x1f; \
\
__asm__ __volatile__( \
"1: llock %0, [%1] \n" \
@@ -82,8 +81,7 @@ static inline int test_and_##op##_bit(unsigned long nr, volatile unsigned long *
\
m += nr >> 5; \
\
- if (__builtin_constant_p(nr)) \
- nr &= 0x1f; \
+ nr &= 0x1f; \
\
/* \
* Explicit full memory barrier needed before/after as \
@@ -129,16 +127,13 @@ static inline void op##_bit(unsigned long nr, volatile unsigned long *m)\
unsigned long temp, flags; \
m += nr >> 5; \
\
- if (__builtin_constant_p(nr)) \
- nr &= 0x1f; \
- \
/* \
* spin lock/unlock provide the needed smp_mb() before/after \
*/ \
bitops_lock(flags); \
\
temp = *m; \
- *m = temp c_op (1UL << nr); \
+ *m = temp c_op (1UL << (nr & 0x1f)); \
\
bitops_unlock(flags); \
}
@@ -149,17 +144,14 @@ static inline int test_and_##op##_bit(unsigned long nr, volatile unsigned long *
unsigned long old, flags; \
m += nr >> 5; \
\
- if (__builtin_constant_p(nr)) \
- nr &= 0x1f; \
- \
bitops_lock(flags); \
\
old = *m; \
- *m = old c_op (1 << nr); \
+ *m = old c_op (1UL << (nr & 0x1f)); \
\
bitops_unlock(flags); \
\
- return (old & (1 << nr)) != 0; \
+ return (old & (1UL << (nr & 0x1f))) != 0; \
}
#endif /* CONFIG_ARC_HAS_LLSC */
@@ -174,11 +166,8 @@ static inline void __##op##_bit(unsigned long nr, volatile unsigned long *m) \
unsigned long temp; \
m += nr >> 5; \
\
- if (__builtin_constant_p(nr)) \
- nr &= 0x1f; \
- \
temp = *m; \
- *m = temp c_op (1UL << nr); \
+ *m = temp c_op (1UL << (nr & 0x1f)); \
}
#define __TEST_N_BIT_OP(op, c_op, asm_op) \
@@ -187,13 +176,10 @@ static inline int __test_and_##op##_bit(unsigned long nr, volatile unsigned long
unsigned long old; \
m += nr >> 5; \
\
- if (__builtin_constant_p(nr)) \
- nr &= 0x1f; \
- \
old = *m; \
- *m = old c_op (1 << nr); \
+ *m = old c_op (1UL << (nr & 0x1f)); \
\
- return (old & (1 << nr)) != 0; \
+ return (old & (1UL << (nr & 0x1f))) != 0; \
}
#define BIT_OPS(op, c_op, asm_op) \
@@ -224,10 +210,7 @@ test_bit(unsigned int nr, const volatile unsigned long *addr)
addr += nr >> 5;
- if (__builtin_constant_p(nr))
- nr &= 0x1f;
-
- mask = 1 << nr;
+ mask = 1UL << (nr & 0x1f);
return ((mask & *addr) != 0);
}
diff --git a/arch/arc/include/asm/futex.h b/arch/arc/include/asm/futex.h
index 05b5aaf..70cfe16 100644
--- a/arch/arc/include/asm/futex.h
+++ b/arch/arc/include/asm/futex.h
@@ -16,12 +16,40 @@
#include <linux/uaccess.h>
#include <asm/errno.h>
+#ifdef CONFIG_ARC_HAS_LLSC
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
+ \
+ __asm__ __volatile__( \
+ "1: llock %1, [%2] \n" \
+ insn "\n" \
+ "2: scond %0, [%2] \n" \
+ " bnz 1b \n" \
+ " mov %0, 0 \n" \
+ "3: \n" \
+ " .section .fixup,\"ax\" \n" \
+ " .align 4 \n" \
+ "4: mov %0, %4 \n" \
+ " b 3b \n" \
+ " .previous \n" \
+ " .section __ex_table,\"a\" \n" \
+ " .align 4 \n" \
+ " .word 1b, 4b \n" \
+ " .word 2b, 4b \n" \
+ " .previous \n" \
+ \
+ : "=&r" (ret), "=&r" (oldval) \
+ : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \
+ : "cc", "memory")
+
+#else /* !CONFIG_ARC_HAS_LLSC */
+
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\
\
__asm__ __volatile__( \
- "1: ld %1, [%2] \n" \
+ "1: ld %1, [%2] \n" \
insn "\n" \
- "2: st %0, [%2] \n" \
+ "2: st %0, [%2] \n" \
" mov %0, 0 \n" \
"3: \n" \
" .section .fixup,\"ax\" \n" \
@@ -39,6 +67,8 @@
: "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \
: "cc", "memory")
+#endif
+
static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
{
int op = (encoded_op >> 28) & 7;
@@ -123,11 +153,17 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
pagefault_disable();
- /* TBD : can use llock/scond */
__asm__ __volatile__(
- "1: ld %0, [%3] \n"
- " brne %0, %1, 3f \n"
- "2: st %2, [%3] \n"
+#ifdef CONFIG_ARC_HAS_LLSC
+ "1: llock %0, [%3] \n"
+ " brne %0, %1, 3f \n"
+ "2: scond %2, [%3] \n"
+ " bnz 1b \n"
+#else
+ "1: ld %0, [%3] \n"
+ " brne %0, %1, 3f \n"
+ "2: st %2, [%3] \n"
+#endif
"3: \n"
" .section .fixup,\"ax\" \n"
"4: mov %0, %4 \n"
diff --git a/arch/arc/include/asm/mm-arch-hooks.h b/arch/arc/include/asm/mm-arch-hooks.h
deleted file mode 100644
index c37541c..0000000
--- a/arch/arc/include/asm/mm-arch-hooks.h
+++ /dev/null
@@ -1,15 +0,0 @@
-/*
- * Architecture specific mm hooks
- *
- * Copyright (C) 2015, IBM Corporation
- * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#ifndef _ASM_ARC_MM_ARCH_HOOKS_H
-#define _ASM_ARC_MM_ARCH_HOOKS_H
-
-#endif /* _ASM_ARC_MM_ARCH_HOOKS_H */
diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h
index 9175597..69095da 100644
--- a/arch/arc/include/asm/ptrace.h
+++ b/arch/arc/include/asm/ptrace.h
@@ -20,20 +20,20 @@
struct pt_regs {
/* Real registers */
- long bta; /* bta_l1, bta_l2, erbta */
+ unsigned long bta; /* bta_l1, bta_l2, erbta */
- long lp_start, lp_end, lp_count;
+ unsigned long lp_start, lp_end, lp_count;
- long status32; /* status32_l1, status32_l2, erstatus */
- long ret; /* ilink1, ilink2 or eret */
- long blink;
- long fp;
- long r26; /* gp */
+ unsigned long status32; /* status32_l1, status32_l2, erstatus */
+ unsigned long ret; /* ilink1, ilink2 or eret */
+ unsigned long blink;
+ unsigned long fp;
+ unsigned long r26; /* gp */
- long r12, r11, r10, r9, r8, r7, r6, r5, r4, r3, r2, r1, r0;
+ unsigned long r12, r11, r10, r9, r8, r7, r6, r5, r4, r3, r2, r1, r0;
- long sp; /* user/kernel sp depending on where we came from */
- long orig_r0;
+ unsigned long sp; /* User/Kernel depending on where we came from */
+ unsigned long orig_r0;
/*
* To distinguish bet excp, syscall, irq
@@ -55,13 +55,13 @@ struct pt_regs {
unsigned long event;
};
- long user_r25;
+ unsigned long user_r25;
};
#else
struct pt_regs {
- long orig_r0;
+ unsigned long orig_r0;
union {
struct {
@@ -76,26 +76,26 @@ struct pt_regs {
unsigned long event;
};
- long bta; /* bta_l1, bta_l2, erbta */
+ unsigned long bta; /* bta_l1, bta_l2, erbta */
- long user_r25;
+ unsigned long user_r25;
- long r26; /* gp */
- long fp;
- long sp; /* user/kernel sp depending on where we came from */
+ unsigned long r26; /* gp */
+ unsigned long fp;
+ unsigned long sp; /* user/kernel sp depending on where we came from */
- long r12;
+ unsigned long r12;
/*------- Below list auto saved by h/w -----------*/
- long r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11;
+ unsigned long r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11;
- long blink;
- long lp_end, lp_start, lp_count;
+ unsigned long blink;
+ unsigned long lp_end, lp_start, lp_count;
- long ei, ldi, jli;
+ unsigned long ei, ldi, jli;
- long ret;
- long status32;
+ unsigned long ret;
+ unsigned long status32;
};
#endif
@@ -103,7 +103,7 @@ struct pt_regs {
/* Callee saved registers - need to be saved only when you are scheduled out */
struct callee_regs {
- long r25, r24, r23, r22, r21, r20, r19, r18, r17, r16, r15, r14, r13;
+ unsigned long r25, r24, r23, r22, r21, r20, r19, r18, r17, r16, r15, r14, r13;
};
#define instruction_pointer(regs) ((regs)->ret)
@@ -142,7 +142,7 @@ struct callee_regs {
static inline long regs_return_value(struct pt_regs *regs)
{
- return regs->r0;
+ return (long)regs->r0;
}
#endif /* !__ASSEMBLY__ */
diff --git a/arch/arc/include/asm/spinlock.h b/arch/arc/include/asm/spinlock.h
index e1651df..db8c59d 100644
--- a/arch/arc/include/asm/spinlock.h
+++ b/arch/arc/include/asm/spinlock.h
@@ -18,9 +18,518 @@
#define arch_spin_unlock_wait(x) \
do { while (arch_spin_is_locked(x)) cpu_relax(); } while (0)
+#ifdef CONFIG_ARC_HAS_LLSC
+
+/*
+ * A normal LLOCK/SCOND based system, w/o need for livelock workaround
+ */
+#ifndef CONFIG_ARC_STAR_9000923308
+
static inline void arch_spin_lock(arch_spinlock_t *lock)
{
- unsigned int tmp = __ARCH_SPIN_LOCK_LOCKED__;
+ unsigned int val;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "1: llock %[val], [%[slock]] \n"
+ " breq %[val], %[LOCKED], 1b \n" /* spin while LOCKED */
+ " scond %[LOCKED], [%[slock]] \n" /* acquire */
+ " bnz 1b \n"
+ " \n"
+ : [val] "=&r" (val)
+ : [slock] "r" (&(lock->slock)),
+ [LOCKED] "r" (__ARCH_SPIN_LOCK_LOCKED__)
+ : "memory", "cc");
+
+ smp_mb();
+}
+
+/* 1 - lock taken successfully */
+static inline int arch_spin_trylock(arch_spinlock_t *lock)
+{
+ unsigned int val, got_it = 0;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "1: llock %[val], [%[slock]] \n"
+ " breq %[val], %[LOCKED], 4f \n" /* already LOCKED, just bail */
+ " scond %[LOCKED], [%[slock]] \n" /* acquire */
+ " bnz 1b \n"
+ " mov %[got_it], 1 \n"
+ "4: \n"
+ " \n"
+ : [val] "=&r" (val),
+ [got_it] "+&r" (got_it)
+ : [slock] "r" (&(lock->slock)),
+ [LOCKED] "r" (__ARCH_SPIN_LOCK_LOCKED__)
+ : "memory", "cc");
+
+ smp_mb();
+
+ return got_it;
+}
+
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+ smp_mb();
+
+ lock->slock = __ARCH_SPIN_LOCK_UNLOCKED__;
+
+ smp_mb();
+}
+
+/*
+ * Read-write spinlocks, allowing multiple readers but only one writer.
+ * Unfair locking as Writers could be starved indefinitely by Reader(s)
+ */
+
+static inline void arch_read_lock(arch_rwlock_t *rw)
+{
+ unsigned int val;
+
+ smp_mb();
+
+ /*
+ * zero means writer holds the lock exclusively, deny Reader.
+ * Otherwise grant lock to first/subseq reader
+ *
+ * if (rw->counter > 0) {
+ * rw->counter--;
+ * ret = 1;
+ * }
+ */
+
+ __asm__ __volatile__(
+ "1: llock %[val], [%[rwlock]] \n"
+ " brls %[val], %[WR_LOCKED], 1b\n" /* <= 0: spin while write locked */
+ " sub %[val], %[val], 1 \n" /* reader lock */
+ " scond %[val], [%[rwlock]] \n"
+ " bnz 1b \n"
+ " \n"
+ : [val] "=&r" (val)
+ : [rwlock] "r" (&(rw->counter)),
+ [WR_LOCKED] "ir" (0)
+ : "memory", "cc");
+
+ smp_mb();
+}
+
+/* 1 - lock taken successfully */
+static inline int arch_read_trylock(arch_rwlock_t *rw)
+{
+ unsigned int val, got_it = 0;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "1: llock %[val], [%[rwlock]] \n"
+ " brls %[val], %[WR_LOCKED], 4f\n" /* <= 0: already write locked, bail */
+ " sub %[val], %[val], 1 \n" /* counter-- */
+ " scond %[val], [%[rwlock]] \n"
+ " bnz 1b \n" /* retry if collided with someone */
+ " mov %[got_it], 1 \n"
+ " \n"
+ "4: ; --- done --- \n"
+
+ : [val] "=&r" (val),
+ [got_it] "+&r" (got_it)
+ : [rwlock] "r" (&(rw->counter)),
+ [WR_LOCKED] "ir" (0)
+ : "memory", "cc");
+
+ smp_mb();
+
+ return got_it;
+}
+
+static inline void arch_write_lock(arch_rwlock_t *rw)
+{
+ unsigned int val;
+
+ smp_mb();
+
+ /*
+ * If reader(s) hold lock (lock < __ARCH_RW_LOCK_UNLOCKED__),
+ * deny writer. Otherwise if unlocked grant to writer
+ * Hence the claim that Linux rwlocks are unfair to writers.
+ * (can be starved for an indefinite time by readers).
+ *
+ * if (rw->counter == __ARCH_RW_LOCK_UNLOCKED__) {
+ * rw->counter = 0;
+ * ret = 1;
+ * }
+ */
+
+ __asm__ __volatile__(
+ "1: llock %[val], [%[rwlock]] \n"
+ " brne %[val], %[UNLOCKED], 1b \n" /* while !UNLOCKED spin */
+ " mov %[val], %[WR_LOCKED] \n"
+ " scond %[val], [%[rwlock]] \n"
+ " bnz 1b \n"
+ " \n"
+ : [val] "=&r" (val)
+ : [rwlock] "r" (&(rw->counter)),
+ [UNLOCKED] "ir" (__ARCH_RW_LOCK_UNLOCKED__),
+ [WR_LOCKED] "ir" (0)
+ : "memory", "cc");
+
+ smp_mb();
+}
+
+/* 1 - lock taken successfully */
+static inline int arch_write_trylock(arch_rwlock_t *rw)
+{
+ unsigned int val, got_it = 0;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "1: llock %[val], [%[rwlock]] \n"
+ " brne %[val], %[UNLOCKED], 4f \n" /* !UNLOCKED, bail */
+ " mov %[val], %[WR_LOCKED] \n"
+ " scond %[val], [%[rwlock]] \n"
+ " bnz 1b \n" /* retry if collided with someone */
+ " mov %[got_it], 1 \n"
+ " \n"
+ "4: ; --- done --- \n"
+
+ : [val] "=&r" (val),
+ [got_it] "+&r" (got_it)
+ : [rwlock] "r" (&(rw->counter)),
+ [UNLOCKED] "ir" (__ARCH_RW_LOCK_UNLOCKED__),
+ [WR_LOCKED] "ir" (0)
+ : "memory", "cc");
+
+ smp_mb();
+
+ return got_it;
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *rw)
+{
+ unsigned int val;
+
+ smp_mb();
+
+ /*
+ * rw->counter++;
+ */
+ __asm__ __volatile__(
+ "1: llock %[val], [%[rwlock]] \n"
+ " add %[val], %[val], 1 \n"
+ " scond %[val], [%[rwlock]] \n"
+ " bnz 1b \n"
+ " \n"
+ : [val] "=&r" (val)
+ : [rwlock] "r" (&(rw->counter))
+ : "memory", "cc");
+
+ smp_mb();
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *rw)
+{
+ smp_mb();
+
+ rw->counter = __ARCH_RW_LOCK_UNLOCKED__;
+
+ smp_mb();
+}
+
+#else /* CONFIG_ARC_STAR_9000923308 */
+
+/*
+ * HS38x4 could get into a LLOCK/SCOND livelock in case of multiple overlapping
+ * coherency transactions in the SCU. The exclusive line state keeps rotating
+ * among contenting cores leading to a never ending cycle. So break the cycle
+ * by deferring the retry of failed exclusive access (SCOND). The actual delay
+ * needed is function of number of contending cores as well as the unrelated
+ * coherency traffic from other cores. To keep the code simple, start off with
+ * small delay of 1 which would suffice most cases and in case of contention
+ * double the delay. Eventually the delay is sufficient such that the coherency
+ * pipeline is drained, thus a subsequent exclusive access would succeed.
+ */
+
+#define SCOND_FAIL_RETRY_VAR_DEF \
+ unsigned int delay, tmp; \
+
+#define SCOND_FAIL_RETRY_ASM \
+ " ; --- scond fail delay --- \n" \
+ " mov %[tmp], %[delay] \n" /* tmp = delay */ \
+ "2: brne.d %[tmp], 0, 2b \n" /* while (tmp != 0) */ \
+ " sub %[tmp], %[tmp], 1 \n" /* tmp-- */ \
+ " rol %[delay], %[delay] \n" /* delay *= 2 */ \
+ " b 1b \n" /* start over */ \
+ " \n" \
+ "4: ; --- done --- \n" \
+
+#define SCOND_FAIL_RETRY_VARS \
+ ,[delay] "=&r" (delay), [tmp] "=&r" (tmp) \
+
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+ unsigned int val;
+ SCOND_FAIL_RETRY_VAR_DEF;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "0: mov %[delay], 1 \n"
+ "1: llock %[val], [%[slock]] \n"
+ " breq %[val], %[LOCKED], 0b \n" /* spin while LOCKED */
+ " scond %[LOCKED], [%[slock]] \n" /* acquire */
+ " bz 4f \n" /* done */
+ " \n"
+ SCOND_FAIL_RETRY_ASM
+
+ : [val] "=&r" (val)
+ SCOND_FAIL_RETRY_VARS
+ : [slock] "r" (&(lock->slock)),
+ [LOCKED] "r" (__ARCH_SPIN_LOCK_LOCKED__)
+ : "memory", "cc");
+
+ smp_mb();
+}
+
+/* 1 - lock taken successfully */
+static inline int arch_spin_trylock(arch_spinlock_t *lock)
+{
+ unsigned int val, got_it = 0;
+ SCOND_FAIL_RETRY_VAR_DEF;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "0: mov %[delay], 1 \n"
+ "1: llock %[val], [%[slock]] \n"
+ " breq %[val], %[LOCKED], 4f \n" /* already LOCKED, just bail */
+ " scond %[LOCKED], [%[slock]] \n" /* acquire */
+ " bz.d 4f \n"
+ " mov.z %[got_it], 1 \n" /* got it */
+ " \n"
+ SCOND_FAIL_RETRY_ASM
+
+ : [val] "=&r" (val),
+ [got_it] "+&r" (got_it)
+ SCOND_FAIL_RETRY_VARS
+ : [slock] "r" (&(lock->slock)),
+ [LOCKED] "r" (__ARCH_SPIN_LOCK_LOCKED__)
+ : "memory", "cc");
+
+ smp_mb();
+
+ return got_it;
+}
+
+static inline void arch_spin_unlock(arch_spinlock_t *lock)
+{
+ smp_mb();
+
+ lock->slock = __ARCH_SPIN_LOCK_UNLOCKED__;
+
+ smp_mb();
+}
+
+/*
+ * Read-write spinlocks, allowing multiple readers but only one writer.
+ * Unfair locking as Writers could be starved indefinitely by Reader(s)
+ */
+
+static inline void arch_read_lock(arch_rwlock_t *rw)
+{
+ unsigned int val;
+ SCOND_FAIL_RETRY_VAR_DEF;
+
+ smp_mb();
+
+ /*
+ * zero means writer holds the lock exclusively, deny Reader.
+ * Otherwise grant lock to first/subseq reader
+ *
+ * if (rw->counter > 0) {
+ * rw->counter--;
+ * ret = 1;
+ * }
+ */
+
+ __asm__ __volatile__(
+ "0: mov %[delay], 1 \n"
+ "1: llock %[val], [%[rwlock]] \n"
+ " brls %[val], %[WR_LOCKED], 0b\n" /* <= 0: spin while write locked */
+ " sub %[val], %[val], 1 \n" /* reader lock */
+ " scond %[val], [%[rwlock]] \n"
+ " bz 4f \n" /* done */
+ " \n"
+ SCOND_FAIL_RETRY_ASM
+
+ : [val] "=&r" (val)
+ SCOND_FAIL_RETRY_VARS
+ : [rwlock] "r" (&(rw->counter)),
+ [WR_LOCKED] "ir" (0)
+ : "memory", "cc");
+
+ smp_mb();
+}
+
+/* 1 - lock taken successfully */
+static inline int arch_read_trylock(arch_rwlock_t *rw)
+{
+ unsigned int val, got_it = 0;
+ SCOND_FAIL_RETRY_VAR_DEF;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "0: mov %[delay], 1 \n"
+ "1: llock %[val], [%[rwlock]] \n"
+ " brls %[val], %[WR_LOCKED], 4f\n" /* <= 0: already write locked, bail */
+ " sub %[val], %[val], 1 \n" /* counter-- */
+ " scond %[val], [%[rwlock]] \n"
+ " bz.d 4f \n"
+ " mov.z %[got_it], 1 \n" /* got it */
+ " \n"
+ SCOND_FAIL_RETRY_ASM
+
+ : [val] "=&r" (val),
+ [got_it] "+&r" (got_it)
+ SCOND_FAIL_RETRY_VARS
+ : [rwlock] "r" (&(rw->counter)),
+ [WR_LOCKED] "ir" (0)
+ : "memory", "cc");
+
+ smp_mb();
+
+ return got_it;
+}
+
+static inline void arch_write_lock(arch_rwlock_t *rw)
+{
+ unsigned int val;
+ SCOND_FAIL_RETRY_VAR_DEF;
+
+ smp_mb();
+
+ /*
+ * If reader(s) hold lock (lock < __ARCH_RW_LOCK_UNLOCKED__),
+ * deny writer. Otherwise if unlocked grant to writer
+ * Hence the claim that Linux rwlocks are unfair to writers.
+ * (can be starved for an indefinite time by readers).
+ *
+ * if (rw->counter == __ARCH_RW_LOCK_UNLOCKED__) {
+ * rw->counter = 0;
+ * ret = 1;
+ * }
+ */
+
+ __asm__ __volatile__(
+ "0: mov %[delay], 1 \n"
+ "1: llock %[val], [%[rwlock]] \n"
+ " brne %[val], %[UNLOCKED], 0b \n" /* while !UNLOCKED spin */
+ " mov %[val], %[WR_LOCKED] \n"
+ " scond %[val], [%[rwlock]] \n"
+ " bz 4f \n"
+ " \n"
+ SCOND_FAIL_RETRY_ASM
+
+ : [val] "=&r" (val)
+ SCOND_FAIL_RETRY_VARS
+ : [rwlock] "r" (&(rw->counter)),
+ [UNLOCKED] "ir" (__ARCH_RW_LOCK_UNLOCKED__),
+ [WR_LOCKED] "ir" (0)
+ : "memory", "cc");
+
+ smp_mb();
+}
+
+/* 1 - lock taken successfully */
+static inline int arch_write_trylock(arch_rwlock_t *rw)
+{
+ unsigned int val, got_it = 0;
+ SCOND_FAIL_RETRY_VAR_DEF;
+
+ smp_mb();
+
+ __asm__ __volatile__(
+ "0: mov %[delay], 1 \n"
+ "1: llock %[val], [%[rwlock]] \n"
+ " brne %[val], %[UNLOCKED], 4f \n" /* !UNLOCKED, bail */
+ " mov %[val], %[WR_LOCKED] \n"
+ " scond %[val], [%[rwlock]] \n"
+ " bz.d 4f \n"
+ " mov.z %[got_it], 1 \n" /* got it */
+ " \n"
+ SCOND_FAIL_RETRY_ASM
+
+ : [val] "=&r" (val),
+ [got_it] "+&r" (got_it)
+ SCOND_FAIL_RETRY_VARS
+ : [rwlock] "r" (&(rw->counter)),
+ [UNLOCKED] "ir" (__ARCH_RW_LOCK_UNLOCKED__),
+ [WR_LOCKED] "ir" (0)
+ : "memory", "cc");
+
+ smp_mb();
+
+ return got_it;
+}
+
+static inline void arch_read_unlock(arch_rwlock_t *rw)
+{
+ unsigned int val;
+
+ smp_mb();
+
+ /*
+ * rw->counter++;
+ */
+ __asm__ __volatile__(
+ "1: llock %[val], [%[rwlock]] \n"
+ " add %[val], %[val], 1 \n"
+ " scond %[val], [%[rwlock]] \n"
+ " bnz 1b \n"
+ " \n"
+ : [val] "=&r" (val)
+ : [rwlock] "r" (&(rw->counter))
+ : "memory", "cc");
+
+ smp_mb();
+}
+
+static inline void arch_write_unlock(arch_rwlock_t *rw)
+{
+ unsigned int val;
+
+ smp_mb();
+
+ /*
+ * rw->counter = __ARCH_RW_LOCK_UNLOCKED__;
+ */
+ __asm__ __volatile__(
+ "1: llock %[val], [%[rwlock]] \n"
+ " scond %[UNLOCKED], [%[rwlock]]\n"
+ " bnz 1b \n"
+ " \n"
+ : [val] "=&r" (val)
+ : [rwlock] "r" (&(rw->counter)),
+ [UNLOCKED] "r" (__ARCH_RW_LOCK_UNLOCKED__)
+ : "memory", "cc");
+
+ smp_mb();
+}
+
+#undef SCOND_FAIL_RETRY_VAR_DEF
+#undef SCOND_FAIL_RETRY_ASM
+#undef SCOND_FAIL_RETRY_VARS
+
+#endif /* CONFIG_ARC_STAR_9000923308 */
+
+#else /* !CONFIG_ARC_HAS_LLSC */
+
+static inline void arch_spin_lock(arch_spinlock_t *lock)
+{
+ unsigned int val = __ARCH_SPIN_LOCK_LOCKED__;
/*
* This smp_mb() is technically superfluous, we only need the one
@@ -33,7 +542,7 @@ static inline void arch_spin_lock(arch_spinlock_t *lock)
__asm__ __volatile__(
"1: ex %0, [%1] \n"
" breq %0, %2, 1b \n"
- : "+&r" (tmp)
+ : "+&r" (val)
: "r"(&(lock->slock)), "ir"(__ARCH_SPIN_LOCK_LOCKED__)
: "memory");
@@ -48,26 +557,27 @@ static inline void arch_spin_lock(arch_spinlock_t *lock)
smp_mb();
}
+/* 1 - lock taken successfully */
static inline int arch_spin_trylock(arch_spinlock_t *lock)
{
- unsigned int tmp = __ARCH_SPIN_LOCK_LOCKED__;
+ unsigned int val = __ARCH_SPIN_LOCK_LOCKED__;
smp_mb();
__asm__ __volatile__(
"1: ex %0, [%1] \n"
- : "+r" (tmp)
+ : "+r" (val)
: "r"(&(lock->slock))
: "memory");
smp_mb();
- return (tmp == __ARCH_SPIN_LOCK_UNLOCKED__);
+ return (val == __ARCH_SPIN_LOCK_UNLOCKED__);
}
static inline void arch_spin_unlock(arch_spinlock_t *lock)
{
- unsigned int tmp = __ARCH_SPIN_LOCK_UNLOCKED__;
+ unsigned int val = __ARCH_SPIN_LOCK_UNLOCKED__;
/*
* RELEASE barrier: given the instructions avail on ARCv2, full barrier
@@ -77,7 +587,7 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
__asm__ __volatile__(
" ex %0, [%1] \n"
- : "+r" (tmp)
+ : "+r" (val)
: "r"(&(lock->slock))
: "memory");
@@ -90,19 +600,12 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
/*
* Read-write spinlocks, allowing multiple readers but only one writer.
+ * Unfair locking as Writers could be starved indefinitely by Reader(s)
*
* The spinlock itself is contained in @counter and access to it is
* serialized with @lock_mutex.
- *
- * Unfair locking as Writers could be starved indefinitely by Reader(s)
*/
-/* Would read_trylock() succeed? */
-#define arch_read_can_lock(x) ((x)->counter > 0)
-
-/* Would write_trylock() succeed? */
-#define arch_write_can_lock(x) ((x)->counter == __ARCH_RW_LOCK_UNLOCKED__)
-
/* 1 - lock taken successfully */
static inline int arch_read_trylock(arch_rwlock_t *rw)
{
@@ -173,6 +676,11 @@ static inline void arch_write_unlock(arch_rwlock_t *rw)
arch_spin_unlock(&(rw->lock_mutex));
}
+#endif
+
+#define arch_read_can_lock(x) ((x)->counter > 0)
+#define arch_write_can_lock(x) ((x)->counter == __ARCH_RW_LOCK_UNLOCKED__)
+
#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
diff --git a/arch/arc/include/asm/spinlock_types.h b/arch/arc/include/asm/spinlock_types.h
index 662627c..4e1ef5f 100644
--- a/arch/arc/include/asm/spinlock_types.h
+++ b/arch/arc/include/asm/spinlock_types.h
@@ -26,7 +26,9 @@ typedef struct {
*/
typedef struct {
volatile unsigned int counter;
+#ifndef CONFIG_ARC_HAS_LLSC
arch_spinlock_t lock_mutex;
+#endif
} arch_rwlock_t;
#define __ARCH_RW_LOCK_UNLOCKED__ 0x01000000
generated by cgit v0.10.2 at 2024-08-24 18:46:10 (GMT)