1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright 2016, Cyril Bur, IBM Corp. 4 * 5 * Test the kernel's signal frame code. 6 * 7 * The kernel sets up two sets of ucontexts if the signal was to be 8 * delivered while the thread was in a transaction (referred too as 9 * first and second contexts). 10 * Expected behaviour is that the checkpointed state is in the user 11 * context passed to the signal handler (first context). The speculated 12 * state can be accessed with the uc_link pointer (second context). 13 * 14 * The rationale for this is that if TM unaware code (which linked 15 * against TM libs) installs a signal handler it will not know of the 16 * speculative nature of the 'live' registers and may infer the wrong 17 * thing. 18 */ 19 20 #include <stdlib.h> 21 #include <stdio.h> 22 #include <string.h> 23 #include <signal.h> 24 #include <unistd.h> 25 26 #include <altivec.h> 27 28 #include "utils.h" 29 #include "tm.h" 30 31 #define MAX_ATTEMPT 500000 32 33 #define NV_VSX_REGS 12 /* Number of VSX registers to check. */ 34 #define VSX20 20 /* First VSX register to check in vsr20-vsr31 subset */ 35 #define FPR20 20 /* FPR20 overlaps VSX20 most significant doubleword */ 36 37 long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss); 38 39 static sig_atomic_t fail, broken; 40 41 /* Test only 12 vsx registers from vsr20 to vsr31 */ 42 vector int vsxs[] = { 43 /* First context will be set with these values, i.e. non-speculative */ 44 /* VSX20 , VSX21 , ... */ 45 { 1, 2, 3, 4},{ 5, 6, 7, 8},{ 9,10,11,12}, 46 {13,14,15,16},{17,18,19,20},{21,22,23,24}, 47 {25,26,27,28},{29,30,31,32},{33,34,35,36}, 48 {37,38,39,40},{41,42,43,44},{45,46,47,48}, 49 /* Second context will be set with these values, i.e. speculative */ 50 /* VSX20 , VSX21 , ... */ 51 {-1, -2, -3, -4 },{-5, -6, -7, -8 },{-9, -10,-11,-12}, 52 {-13,-14,-15,-16},{-17,-18,-19,-20},{-21,-22,-23,-24}, 53 {-25,-26,-27,-28},{-29,-30,-31,-32},{-33,-34,-35,-36}, 54 {-37,-38,-39,-40},{-41,-42,-43,-44},{-45,-46,-47,-48} 55 }; 56 57 static void signal_usr1(int signum, siginfo_t *info, void *uc) 58 { 59 int i, j; 60 uint8_t vsx[sizeof(vector int)]; 61 uint8_t vsx_tm[sizeof(vector int)]; 62 ucontext_t *ucp = uc; 63 ucontext_t *tm_ucp = ucp->uc_link; 64 65 /* 66 * FP registers and VMX registers overlap the VSX registers. 67 * 68 * FP registers (f0-31) overlap the most significant 64 bits of VSX 69 * registers vsr0-31, whilst VMX registers vr0-31, being 128-bit like 70 * the VSX registers, overlap fully the other half of VSX registers, 71 * i.e. vr0-31 overlaps fully vsr32-63. 72 * 73 * Due to compatibility and historical reasons (VMX/Altivec support 74 * appeared first on the architecture), VMX registers vr0-31 (so VSX 75 * half vsr32-63 too) are stored right after the v_regs pointer, in an 76 * area allocated for 'vmx_reverse' array (please see 77 * arch/powerpc/include/uapi/asm/sigcontext.h for details about the 78 * mcontext_t structure on Power). 79 * 80 * The other VSX half (vsr0-31) is hence stored below vr0-31/vsr32-63 81 * registers, but only the least significant 64 bits of vsr0-31. The 82 * most significant 64 bits of vsr0-31 (f0-31), as it overlaps the FP 83 * registers, is kept in fp_regs. 84 * 85 * v_regs is a 16 byte aligned pointer at the start of vmx_reserve 86 * (vmx_reserve may or may not be 16 aligned) where the v_regs structure 87 * exists, so v_regs points to where vr0-31 / vsr32-63 registers are 88 * fully stored. Since v_regs type is elf_vrregset_t, v_regs + 1 89 * skips all the slots used to store vr0-31 / vsr32-64 and points to 90 * part of one VSX half, i.e. v_regs + 1 points to the least significant 91 * 64 bits of vsr0-31. The other part of this half (the most significant 92 * part of vsr0-31) is stored in fp_regs. 93 * 94 */ 95 /* Get pointer to least significant doubleword of vsr0-31 */ 96 long *vsx_ptr = (long *)(ucp->uc_mcontext.v_regs + 1); 97 long *tm_vsx_ptr = (long *)(tm_ucp->uc_mcontext.v_regs + 1); 98 99 /* Check first context. Print all mismatches. */ 100 for (i = 0; i < NV_VSX_REGS; i++) { 101 /* 102 * Copy VSX most significant doubleword from fp_regs and 103 * copy VSX least significant one from 64-bit slots below 104 * saved VMX registers. 105 */ 106 memcpy(vsx, &ucp->uc_mcontext.fp_regs[FPR20 + i], 8); 107 memcpy(vsx + 8, &vsx_ptr[VSX20 + i], 8); 108 109 fail = memcmp(vsx, &vsxs[i], sizeof(vector int)); 110 111 if (fail) { 112 broken = 1; 113 printf("VSX%d (1st context) == 0x", VSX20 + i); 114 for (j = 0; j < 16; j++) 115 printf("%02x", vsx[j]); 116 printf(" instead of 0x"); 117 for (j = 0; j < 4; j++) 118 printf("%08x", vsxs[i][j]); 119 printf(" (expected)\n"); 120 } 121 } 122 123 /* Check second context. Print all mismatches. */ 124 for (i = 0; i < NV_VSX_REGS; i++) { 125 /* 126 * Copy VSX most significant doubleword from fp_regs and 127 * copy VSX least significant one from 64-bit slots below 128 * saved VMX registers. 129 */ 130 memcpy(vsx_tm, &tm_ucp->uc_mcontext.fp_regs[FPR20 + i], 8); 131 memcpy(vsx_tm + 8, &tm_vsx_ptr[VSX20 + i], 8); 132 133 fail = memcmp(vsx_tm, &vsxs[NV_VSX_REGS + i], sizeof(vector int)); 134 135 if (fail) { 136 broken = 1; 137 printf("VSX%d (2nd context) == 0x", VSX20 + i); 138 for (j = 0; j < 16; j++) 139 printf("%02x", vsx_tm[j]); 140 printf(" instead of 0x"); 141 for (j = 0; j < 4; j++) 142 printf("%08x", vsxs[NV_VSX_REGS + i][j]); 143 printf("(expected)\n"); 144 } 145 } 146 } 147 148 static int tm_signal_context_chk() 149 { 150 struct sigaction act; 151 int i; 152 long rc; 153 pid_t pid = getpid(); 154 155 SKIP_IF(!have_htm()); 156 SKIP_IF(htm_is_synthetic()); 157 158 act.sa_sigaction = signal_usr1; 159 sigemptyset(&act.sa_mask); 160 act.sa_flags = SA_SIGINFO; 161 if (sigaction(SIGUSR1, &act, NULL) < 0) { 162 perror("sigaction sigusr1"); 163 exit(1); 164 } 165 166 i = 0; 167 while (i < MAX_ATTEMPT && !broken) { 168 /* 169 * tm_signal_self_context_load will set both first and second 170 * contexts accordingly to the values passed through non-NULL 171 * array pointers to it, in that case 'vsxs', and invoke the 172 * signal handler installed for SIGUSR1. 173 */ 174 rc = tm_signal_self_context_load(pid, NULL, NULL, NULL, vsxs); 175 FAIL_IF(rc != pid); 176 i++; 177 } 178 179 return (broken); 180 } 181 182 int main(void) 183 { 184 return test_harness(tm_signal_context_chk, "tm_signal_context_chk_vsx"); 185 } 186