| 1 | // SPDX-FileCopyrightText: 2009 Paul E. McKenney, IBM Corporation. |
| 2 | // SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 3 | // |
| 4 | // SPDX-License-Identifier: LGPL-2.1-or-later |
| 5 | |
| 6 | #ifndef _URCU_ARCH_PPC_H |
| 7 | #define _URCU_ARCH_PPC_H |
| 8 | |
| 9 | /* |
| 10 | * arch_ppc.h: trivial definitions for the powerpc architecture. |
| 11 | */ |
| 12 | |
| 13 | #include <urcu/compiler.h> |
| 14 | #include <urcu/config.h> |
| 15 | #include <urcu/syscall-compat.h> |
| 16 | #include <stdint.h> |
| 17 | |
| 18 | #ifdef __cplusplus |
| 19 | extern "C" { |
| 20 | #endif |
| 21 | |
| 22 | /* |
| 23 | * Most powerpc machines have 128 bytes cache lines, but to make sure |
| 24 | * there is no false sharing on all known Power hardware, use the |
| 25 | * largest known cache line size, which is the physical size of POWER5 |
| 26 | * L3 cache lines (256 bytes). |
| 27 | * |
| 28 | * "Each slice [of the L3] is 12-way set-associative, with 4,096 |
| 29 | * congruence classes of 256-byte lines managed as two 128-byte sectors |
| 30 | * to match the L2 line size." |
| 31 | * |
| 32 | * From: "POWER5 system microarchitecture", |
| 33 | * IBM Journal of Research & Development, |
| 34 | * vol. 49, no. 4/5, July/September 2005 |
| 35 | * https://www.eecg.utoronto.ca/~moshovos/ACA08/readings/power5.pdf |
| 36 | * |
| 37 | * This value is a compile-time constant, which prevents us from |
| 38 | * querying the processor for the cache line size at runtime. We |
| 39 | * therefore need to be pessimistic and assume the largest known cache |
| 40 | * line size. |
| 41 | * |
| 42 | * This value is exposed through public headers, so tuning it for |
| 43 | * specific environments is a concern for ABI compatibility between |
| 44 | * applications and liburcu. |
| 45 | */ |
| 46 | #define CAA_CACHE_LINE_SIZE 256 |
| 47 | |
| 48 | #ifdef __NO_LWSYNC__ |
| 49 | #define LWSYNC_OPCODE "sync\n" |
| 50 | #else |
| 51 | #define LWSYNC_OPCODE "lwsync\n" |
| 52 | #endif |
| 53 | |
| 54 | /* |
| 55 | * Use sync for all cmm_mb/rmb/wmb barriers because lwsync does not |
| 56 | * preserve ordering of cacheable vs. non-cacheable accesses, so it |
| 57 | * should not be used to order with respect to MMIO operations. An |
| 58 | * eieio+lwsync pair is also not enough for cmm_rmb, because it will |
| 59 | * order cacheable and non-cacheable memory operations separately---i.e. |
| 60 | * not the latter against the former. |
| 61 | */ |
| 62 | #define cmm_mb() __asm__ __volatile__ ("sync":::"memory") |
| 63 | |
| 64 | /* |
| 65 | * lwsync orders loads in cacheable memory with respect to other loads, |
| 66 | * and stores in cacheable memory with respect to other stores. |
| 67 | * Therefore, use it for barriers ordering accesses to cacheable memory |
| 68 | * only. |
| 69 | */ |
| 70 | #define cmm_smp_rmb() __asm__ __volatile__ (LWSYNC_OPCODE:::"memory") |
| 71 | #define cmm_smp_wmb() __asm__ __volatile__ (LWSYNC_OPCODE:::"memory") |
| 72 | |
| 73 | #define mftbl() \ |
| 74 | __extension__ \ |
| 75 | ({ \ |
| 76 | unsigned long rval; \ |
| 77 | __asm__ __volatile__ ("mftb %0" : "=r" (rval)); \ |
| 78 | rval; \ |
| 79 | }) |
| 80 | |
| 81 | #define mftbu() \ |
| 82 | __extension__ \ |
| 83 | ({ \ |
| 84 | unsigned long rval; \ |
| 85 | __asm__ __volatile__ ("mftbu %0" : "=r" (rval)); \ |
| 86 | rval; \ |
| 87 | }) |
| 88 | |
| 89 | #define mftb() \ |
| 90 | __extension__ \ |
| 91 | ({ \ |
| 92 | unsigned long long rval; \ |
| 93 | __asm__ __volatile__ ("mftb %0" : "=r" (rval)); \ |
| 94 | rval; \ |
| 95 | }) |
| 96 | |
| 97 | #define HAS_CAA_GET_CYCLES |
| 98 | |
| 99 | typedef uint64_t caa_cycles_t; |
| 100 | |
| 101 | #ifdef __powerpc64__ |
| 102 | static inline caa_cycles_t caa_get_cycles(void) |
| 103 | { |
| 104 | return (caa_cycles_t) mftb(); |
| 105 | } |
| 106 | #else |
| 107 | static inline caa_cycles_t caa_get_cycles(void) |
| 108 | { |
| 109 | unsigned long h, l; |
| 110 | |
| 111 | for (;;) { |
| 112 | h = mftbu(); |
| 113 | cmm_barrier(); |
| 114 | l = mftbl(); |
| 115 | cmm_barrier(); |
| 116 | if (mftbu() == h) |
| 117 | return (((caa_cycles_t) h) << 32) + l; |
| 118 | } |
| 119 | } |
| 120 | #endif |
| 121 | |
| 122 | /* |
| 123 | * On Linux, define the membarrier system call number if not yet available in |
| 124 | * the system headers. |
| 125 | */ |
| 126 | #if (defined(__linux__) && !defined(__NR_membarrier)) |
| 127 | #define __NR_membarrier 365 |
| 128 | #endif |
| 129 | |
| 130 | #ifdef __cplusplus |
| 131 | } |
| 132 | #endif |
| 133 | |
| 134 | #include <urcu/arch/generic.h> |
| 135 | |
| 136 | #endif /* _URCU_ARCH_PPC_H */ |