| 1 | /* Shared HTM header. Work around false transactional execution facility |
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| 2 | intrinsics. |
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| 3 | |
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| 4 | Copyright (C) 2016-2024 Free Software Foundation, Inc. |
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| 5 | This file is part of the GNU C Library. |
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| 6 | |
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| 7 | The GNU C Library is free software; you can redistribute it and/or |
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| 8 | modify it under the terms of the GNU Lesser General Public |
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| 9 | License as published by the Free Software Foundation; either |
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| 10 | version 2.1 of the License, or (at your option) any later version. |
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| 11 | |
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| 12 | The GNU C Library is distributed in the hope that it will be useful, |
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| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 15 | Lesser General Public License for more details. |
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| 16 | |
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| 17 | You should have received a copy of the GNU Lesser General Public |
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| 18 | License along with the GNU C Library; if not, see |
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| 19 | <https://www.gnu.org/licenses/>. */ |
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| 20 | |
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| 21 | #ifndef _HTM_H |
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| 22 | #define _HTM_H 1 |
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| 23 | |
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| 24 | #include <htmintrin.h> |
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| 25 | |
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| 26 | #ifdef __s390x__ |
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| 27 | # define TX_FPRS_BYTES 64 |
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| 28 | # define TX_SAVE_FPRS \ |
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| 29 | " std %%f8, 0(%[R_FPRS])\n\t" \ |
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| 30 | " std %%f9, 8(%[R_FPRS])\n\t" \ |
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| 31 | " std %%f10, 16(%[R_FPRS])\n\t" \ |
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| 32 | " std %%f11, 24(%[R_FPRS])\n\t" \ |
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| 33 | " std %%f12, 32(%[R_FPRS])\n\t" \ |
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| 34 | " std %%f13, 40(%[R_FPRS])\n\t" \ |
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| 35 | " std %%f14, 48(%[R_FPRS])\n\t" \ |
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| 36 | " std %%f15, 56(%[R_FPRS])\n\t" |
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| 37 | |
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| 38 | # define TX_RESTORE_FPRS \ |
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| 39 | " ld %%f8, 0(%[R_FPRS])\n\t" \ |
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| 40 | " ld %%f9, 8(%[R_FPRS])\n\t" \ |
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| 41 | " ld %%f10, 16(%[R_FPRS])\n\t" \ |
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| 42 | " ld %%f11, 24(%[R_FPRS])\n\t" \ |
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| 43 | " ld %%f12, 32(%[R_FPRS])\n\t" \ |
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| 44 | " ld %%f13, 40(%[R_FPRS])\n\t" \ |
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| 45 | " ld %%f14, 48(%[R_FPRS])\n\t" \ |
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| 46 | " ld %%f15, 56(%[R_FPRS])\n\t" |
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| 47 | |
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| 48 | #else |
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| 49 | |
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| 50 | # define TX_FPRS_BYTES 16 |
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| 51 | # define TX_SAVE_FPRS \ |
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| 52 | " std %%f4, 0(%[R_FPRS])\n\t" \ |
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| 53 | " std %%f6, 8(%[R_FPRS])\n\t" |
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| 54 | |
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| 55 | # define TX_RESTORE_FPRS \ |
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| 56 | " ld %%f4, 0(%[R_FPRS])\n\t" \ |
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| 57 | " ld %%f6, 8(%[R_FPRS])\n\t" |
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| 58 | |
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| 59 | #endif /* ! __s390x__ */ |
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| 60 | |
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| 61 | /* Use own inline assembly instead of __builtin_tbegin, as tbegin |
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| 62 | has to filter program interruptions which can't be done with the builtin. |
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| 63 | Now the fprs have to be saved / restored here, too. |
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| 64 | The fpc is also not saved / restored with the builtin. |
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| 65 | The used inline assembly does not clobber the volatile fprs / vrs! |
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| 66 | Clobbering the latter ones would force the compiler to save / restore |
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| 67 | the call saved fprs as those overlap with the vrs, but they only need to be |
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| 68 | restored if the transaction fails but not if the transaction is successfully |
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| 69 | started. Thus the user of the tbegin macros in this header file has to |
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| 70 | compile the file / function with -msoft-float. It prevents gcc from using |
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| 71 | fprs / vrs. */ |
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| 72 | #define __libc_tbegin(tdb) __libc_tbegin_base(tdb,,,) |
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| 73 | |
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| 74 | #define __libc_tbegin_retry_output_regs , [R_TX_CNT] "+&d" (__tx_cnt) |
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| 75 | #define __libc_tbegin_retry_input_regs(retry_cnt) , [R_RETRY] "d" (retry_cnt) |
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| 76 | #define __libc_tbegin_retry_abort_path_insn \ |
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| 77 | /* If tbegin returned _HTM_TBEGIN_TRANSIENT, retry immediately so \ |
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| 78 | that max tbegin_cnt transactions are tried. Otherwise return and \ |
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| 79 | let the caller of this macro do the fallback path. */ \ |
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| 80 | " jnh 1f\n\t" /* cc 1/3: jump to fallback path. */ \ |
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| 81 | /* tbegin returned _HTM_TBEGIN_TRANSIENT: retry with transaction. */ \ |
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| 82 | " crje %[R_TX_CNT], %[R_RETRY], 1f\n\t" /* Reached max retries? */ \ |
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| 83 | " ahi %[R_TX_CNT], 1\n\t" \ |
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| 84 | " ppa %[R_TX_CNT], 0, 1\n\t" /* Transaction-Abort Assist. */ \ |
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| 85 | " j 2b\n\t" /* Loop to tbegin. */ |
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| 86 | |
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| 87 | /* Same as __libc_tbegin except if tbegin aborts with _HTM_TBEGIN_TRANSIENT. |
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| 88 | Then this macros restores the fpc, fprs and automatically retries up to |
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| 89 | retry_cnt tbegins. Further saving of the state is omitted as it is already |
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| 90 | saved. This macro calls tbegin at most as retry_cnt + 1 times. */ |
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| 91 | #define __libc_tbegin_retry(tdb, retry_cnt) \ |
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| 92 | ({ int __ret; \ |
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| 93 | int __tx_cnt = 0; \ |
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| 94 | __ret = __libc_tbegin_base(tdb, \ |
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| 95 | __libc_tbegin_retry_abort_path_insn, \ |
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| 96 | __libc_tbegin_retry_output_regs, \ |
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| 97 | __libc_tbegin_retry_input_regs(retry_cnt)); \ |
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| 98 | __ret; \ |
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| 99 | }) |
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| 100 | |
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| 101 | #define __libc_tbegin_base(tdb, abort_path_insn, output_regs, input_regs) \ |
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| 102 | ({ int __ret; \ |
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| 103 | int __fpc; \ |
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| 104 | char __fprs[TX_FPRS_BYTES]; \ |
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| 105 | __asm__ __volatile__ (".machine push\n\t" \ |
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| 106 | ".machinemode \"zarch_nohighgprs\"\n\t" \ |
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| 107 | ".machine \"all\"\n\t" \ |
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| 108 | /* Save state at the outermost transaction. \ |
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| 109 | As extracting nesting depth is expensive \ |
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| 110 | on at least zEC12, save fprs at inner \ |
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| 111 | transactions, too. \ |
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| 112 | The fpc and fprs are saved here as they \ |
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| 113 | are not saved by tbegin. There exist no \ |
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| 114 | call-saved vrs, thus they are not saved \ |
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| 115 | here. */ \ |
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| 116 | " efpc %[R_FPC]\n\t" \ |
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| 117 | TX_SAVE_FPRS \ |
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| 118 | /* Begin transaction: save all gprs, allow \ |
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| 119 | ar modification and fp operations. Some \ |
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| 120 | program-interruptions (e.g. a null \ |
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| 121 | pointer access) are filtered and the \ |
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| 122 | transaction will abort. In this case \ |
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| 123 | the normal lock path will execute it \ |
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| 124 | again and result in a core dump which does \ |
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| 125 | now show at tbegin but the real executed \ |
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| 126 | instruction. \ |
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| 127 | However it is not guaranteed that this \ |
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| 128 | retry operate on the same data and thus \ |
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| 129 | may not end in an program-interruption. \ |
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| 130 | Note: This could also be used to probe \ |
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| 131 | memory for being accessible! */ \ |
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| 132 | "2: tbegin 0, 0xFF0E\n\t" \ |
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| 133 | /* Branch away in abort case (this is the \ |
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| 134 | preferred sequence. See PoP in chapter 5 \ |
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| 135 | Transactional-Execution Facility \ |
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| 136 | Operation). */ \ |
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| 137 | " jnz 0f\n\t" \ |
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| 138 | /* Transaction has successfully started. */ \ |
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| 139 | " lhi %[R_RET], 0\n\t" \ |
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| 140 | " j 1f\n\t" \ |
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| 141 | /* Transaction has aborted. Now we are at \ |
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| 142 | the outermost transaction. Restore fprs \ |
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| 143 | and fpc. */ \ |
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| 144 | "0: ipm %[R_RET]\n\t" \ |
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| 145 | " srl %[R_RET], 28\n\t" \ |
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| 146 | " sfpc %[R_FPC]\n\t" \ |
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| 147 | TX_RESTORE_FPRS \ |
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| 148 | abort_path_insn \ |
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| 149 | "1:\n\t" \ |
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| 150 | ".machine pop\n" \ |
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| 151 | : [R_RET] "=&d" (__ret), \ |
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| 152 | [R_FPC] "=&d" (__fpc) \ |
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| 153 | output_regs \ |
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| 154 | : [R_FPRS] "a" (__fprs) \ |
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| 155 | input_regs \ |
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| 156 | : "cc", "memory"); \ |
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| 157 | __ret; \ |
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| 158 | }) |
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| 159 | |
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| 160 | /* These builtins are usable in context of glibc lock elision code without any |
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| 161 | changes. Use them. */ |
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| 162 | #define __libc_tend() \ |
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| 163 | ({ __asm__ __volatile__ (".machine push\n\t" \ |
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| 164 | ".machinemode \"zarch_nohighgprs\"\n\t" \ |
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| 165 | ".machine \"all\"\n\t"); \ |
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| 166 | int __ret = __builtin_tend (); \ |
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| 167 | __asm__ __volatile__ (".machine pop"); \ |
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| 168 | __ret; \ |
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| 169 | }) |
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| 170 | |
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| 171 | #define __libc_tabort(abortcode) \ |
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| 172 | __asm__ __volatile__ (".machine push\n\t" \ |
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| 173 | ".machinemode \"zarch_nohighgprs\"\n\t" \ |
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| 174 | ".machine \"all\"\n\t"); \ |
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| 175 | __builtin_tabort (abortcode); \ |
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| 176 | __asm__ __volatile__ (".machine pop") |
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| 177 | |
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| 178 | #define __libc_tx_nesting_depth() \ |
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| 179 | ({ __asm__ __volatile__ (".machine push\n\t" \ |
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| 180 | ".machinemode \"zarch_nohighgprs\"\n\t" \ |
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| 181 | ".machine \"all\"\n\t"); \ |
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| 182 | int __ret = __builtin_tx_nesting_depth (); \ |
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| 183 | __asm__ __volatile__ (".machine pop"); \ |
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| 184 | __ret; \ |
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| 185 | }) |
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| 186 | |
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| 187 | #endif |
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| 188 | |
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