Date: Fri, 1 Aug 2014 22:28:36 +0000 (UTC) From: Ian Lepore <ian@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r269403 - head/sys/arm/include Message-ID: <201408012228.s71MSaIA048059@svn.freebsd.org>
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Author: ian Date: Fri Aug 1 22:28:36 2014 New Revision: 269403 URL: http://svnweb.freebsd.org/changeset/base/269403 Log: Add 64-bit atomic ops for armv6. The only safe way to access a 64-bit value shared across multiple cores is with atomic_load_64() and atomic_store_64(), because the normal 64-bit load/store instructions are not atomic on 32-bit arm. Luckily the ldrexd/strexd instructions that are atomic are fairly cheap on armv6. Because it's fairly simple to do, this implements all the ops for 64-bit, not just load/store. Reviewed by: andrew, cognet Modified: head/sys/arm/include/atomic.h Modified: head/sys/arm/include/atomic.h ============================================================================== --- head/sys/arm/include/atomic.h Fri Aug 1 21:40:42 2014 (r269402) +++ head/sys/arm/include/atomic.h Fri Aug 1 22:28:36 2014 (r269403) @@ -146,6 +146,28 @@ atomic_set_32(volatile uint32_t *address } static __inline void +atomic_set_64(volatile uint64_t *p, uint64_t val) +{ + uint64_t tmp; + uint32_t exflag; + + __asm __volatile( + "1: \n" + " ldrexd %[tmp], [%[ptr]]\n" + " orr %Q[tmp], %Q[val]\n" + " orr %R[tmp], %R[val]\n" + " strexd %[exf], %[tmp], [%[ptr]]\n" + " teq %[exf], #0\n" + " it ne \n" + " bne 1b\n" + : [exf] "=&r" (exflag), + [tmp] "=&r" (tmp) + : [ptr] "r" (p), + [val] "r" (val) + : "cc", "memory"); +} + +static __inline void atomic_set_long(volatile u_long *address, u_long setmask) { u_long tmp = 0, tmp2 = 0; @@ -177,6 +199,28 @@ atomic_clear_32(volatile uint32_t *addre } static __inline void +atomic_clear_64(volatile uint64_t *p, uint64_t val) +{ + uint64_t tmp; + uint32_t exflag; + + __asm __volatile( + "1: \n" + " ldrexd %[tmp], [%[ptr]]\n" + " bic %Q[tmp], %Q[val]\n" + " bic %R[tmp], %R[val]\n" + " strexd %[exf], %[tmp], [%[ptr]]\n" + " teq %[exf], #0\n" + " it ne \n" + " bne 1b\n" + : [exf] "=&r" (exflag), + [tmp] "=&r" (tmp) + : [ptr] "r" (p), + [val] "r" (val) + : "cc", "memory"); +} + +static __inline void atomic_clear_long(volatile u_long *address, u_long setmask) { u_long tmp = 0, tmp2 = 0; @@ -213,6 +257,35 @@ atomic_cmpset_32(volatile u_int32_t *p, return (ret); } +static __inline int +atomic_cmpset_64(volatile uint64_t *p, uint64_t cmpval, uint64_t newval) +{ + uint64_t tmp; + uint32_t ret; + + __asm __volatile( + "1: \n" + " ldrexd %[tmp], [%[ptr]]\n" + " teq %Q[tmp], %Q[cmp]\n" + " itee eq \n" + " teqeq %R[tmp], %R[cmp]\n" + " movne %[ret], #0\n" + " bne 2f\n" + " strexd %[ret], %[new], [%[ptr]]\n" + " teq %[ret], #0\n" + " it ne \n" + " bne 1b\n" + " mov %[ret], #1\n" + "2: \n" + : [ret] "=&r" (ret), + [tmp] "=&r" (tmp) + : [ptr] "r" (p), + [cmp] "r" (cmpval), + [new] "r" (newval) + : "cc", "memory"); + return (ret); +} + static __inline u_long atomic_cmpset_long(volatile u_long *p, volatile u_long cmpval, volatile u_long newval) { @@ -244,6 +317,15 @@ atomic_cmpset_acq_32(volatile u_int32_t return (ret); } +static __inline uint64_t +atomic_cmpset_acq_64(volatile uint64_t *p, volatile uint64_t cmpval, volatile uint64_t newval) +{ + uint64_t ret = atomic_cmpset_64(p, cmpval, newval); + + __do_dmb(); + return (ret); +} + static __inline u_long atomic_cmpset_acq_long(volatile u_long *p, volatile u_long cmpval, volatile u_long newval) { @@ -261,6 +343,14 @@ atomic_cmpset_rel_32(volatile u_int32_t return (atomic_cmpset_32(p, cmpval, newval)); } +static __inline uint64_t +atomic_cmpset_rel_64(volatile uint64_t *p, volatile uint64_t cmpval, volatile uint64_t newval) +{ + + __do_dmb(); + return (atomic_cmpset_64(p, cmpval, newval)); +} + static __inline u_long atomic_cmpset_rel_long(volatile u_long *p, volatile u_long cmpval, volatile u_long newval) { @@ -286,6 +376,28 @@ atomic_add_32(volatile u_int32_t *p, u_i } static __inline void +atomic_add_64(volatile uint64_t *p, uint64_t val) +{ + uint64_t tmp; + uint32_t exflag; + + __asm __volatile( + "1: \n" + " ldrexd %[tmp], [%[ptr]]\n" + " adds %Q[tmp], %Q[val]\n" + " adc %R[tmp], %R[val]\n" + " strexd %[exf], %[tmp], [%[ptr]]\n" + " teq %[exf], #0\n" + " it ne \n" + " bne 1b\n" + : [exf] "=&r" (exflag), + [tmp] "=&r" (tmp) + : [ptr] "r" (p), + [val] "r" (val) + : "cc", "memory"); +} + +static __inline void atomic_add_long(volatile u_long *p, u_long val) { u_long tmp = 0, tmp2 = 0; @@ -316,6 +428,28 @@ atomic_subtract_32(volatile u_int32_t *p } static __inline void +atomic_subtract_64(volatile uint64_t *p, uint64_t val) +{ + uint64_t tmp; + uint32_t exflag; + + __asm __volatile( + "1: \n" + " ldrexd %[tmp], [%[ptr]]\n" + " subs %Q[tmp], %Q[val]\n" + " sbc %R[tmp], %R[val]\n" + " strexd %[exf], %[tmp], [%[ptr]]\n" + " teq %[exf], #0\n" + " it ne \n" + " bne 1b\n" + : [exf] "=&r" (exflag), + [tmp] "=&r" (tmp) + : [ptr] "r" (p), + [val] "r" (val) + : "cc", "memory"); +} + +static __inline void atomic_subtract_long(volatile u_long *p, u_long val) { u_long tmp = 0, tmp2 = 0; @@ -334,6 +468,10 @@ ATOMIC_ACQ_REL(clear, 32) ATOMIC_ACQ_REL(add, 32) ATOMIC_ACQ_REL(subtract, 32) ATOMIC_ACQ_REL(set, 32) +ATOMIC_ACQ_REL(clear, 64) +ATOMIC_ACQ_REL(add, 64) +ATOMIC_ACQ_REL(subtract, 64) +ATOMIC_ACQ_REL(set, 64) ATOMIC_ACQ_REL_LONG(clear) ATOMIC_ACQ_REL_LONG(add) ATOMIC_ACQ_REL_LONG(subtract) @@ -392,6 +530,116 @@ atomic_store_rel_32(volatile uint32_t *p *p = v; } +static __inline uint64_t +atomic_fetchadd_64(volatile uint64_t *p, uint64_t val) +{ + uint64_t ret, tmp; + uint32_t exflag; + + __asm __volatile( + "1: \n" + " ldrexd %[ret], [%[ptr]]\n" + " adds %Q[tmp], %Q[ret], %Q[val]\n" + " adc %R[tmp], %R[ret], %R[val]\n" + " strexd %[exf], %[tmp], [%[ptr]]\n" + " teq %[exf], #0\n" + " it ne \n" + " bne 1b\n" + : [ret] "=&r" (ret), + [exf] "=&r" (exflag), + [tmp] "=&r" (tmp) + : [ptr] "r" (p), + [val] "r" (val) + : "cc", "memory"); + return (ret); +} + +static __inline uint64_t +atomic_readandclear_64(volatile uint64_t *p) +{ + uint64_t ret, tmp; + uint32_t exflag; + + __asm __volatile( + "1: \n" + " ldrexd %[ret], [%[ptr]]\n" + " mov %Q[tmp], #0\n" + " mov %R[tmp], #0\n" + " strexd %[exf], %[tmp], [%[ptr]]\n" + " teq %[exf], #0\n" + " it ne \n" + " bne 1b\n" + : [ret] "=&r" (ret), + [exf] "=&r" (exflag), + [tmp] "=&r" (tmp) + : [ptr] "r" (p) + : "cc", "memory"); + return (ret); +} + +static __inline uint64_t +atomic_load_64(volatile uint64_t *p) +{ + uint64_t ret; + + /* + * The only way to atomically load 64 bits is with LDREXD which puts the + * exclusive monitor into the open state, so reset it with CLREX because + * we don't actually need to store anything. + */ + __asm __volatile( + "1: \n" + " ldrexd %[ret], [%[ptr]]\n" + " clrex \n" + : [ret] "=&r" (ret) + : [ptr] "r" (p) + : "cc", "memory"); + return (ret); +} + +static __inline uint64_t +atomic_load_acq_64(volatile uint64_t *p) +{ + uint64_t ret; + + ret = atomic_load_64(p); + __do_dmb(); + return (ret); +} + +static __inline void +atomic_store_64(volatile uint64_t *p, uint64_t val) +{ + uint64_t tmp; + uint32_t exflag; + + /* + * The only way to atomically store 64 bits is with STREXD, which will + * succeed only if paired up with a preceeding LDREXD using the same + * address, so we read and discard the existing value before storing. + */ + __asm __volatile( + "1: \n" + " ldrexd %[tmp], [%[ptr]]\n" + " strexd %[exf], %[val], [%[ptr]]\n" + " teq %[exf], #0\n" + " it ne \n" + " bne 1b\n" + : [tmp] "=&r" (tmp), + [exf] "=&r" (exflag) + : [ptr] "r" (p), + [val] "r" (val) + : "cc", "memory"); +} + +static __inline void +atomic_store_rel_64(volatile uint64_t *p, uint64_t val) +{ + + __do_dmb(); + atomic_store_64(p, val); +} + static __inline u_long atomic_fetchadd_long(volatile u_long *p, u_long val) {
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