1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/errno.h> 3 #include <linux/kernel.h> 4 #include <linux/sched.h> 5 #include <linux/sched/task_stack.h> 6 #include <linux/perf_event.h> 7 #include <linux/bug.h> 8 #include <linux/stddef.h> 9 #include <asm/perf_regs.h> 10 #include <asm/ptrace.h> 11 12 #ifdef CONFIG_X86_32 13 #define PERF_REG_X86_MAX PERF_REG_X86_32_MAX 14 #else 15 #define PERF_REG_X86_MAX PERF_REG_X86_64_MAX 16 #endif 17 18 #define PT_REGS_OFFSET(id, r) [id] = offsetof(struct pt_regs, r) 19 20 static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = { 21 PT_REGS_OFFSET(PERF_REG_X86_AX, ax), 22 PT_REGS_OFFSET(PERF_REG_X86_BX, bx), 23 PT_REGS_OFFSET(PERF_REG_X86_CX, cx), 24 PT_REGS_OFFSET(PERF_REG_X86_DX, dx), 25 PT_REGS_OFFSET(PERF_REG_X86_SI, si), 26 PT_REGS_OFFSET(PERF_REG_X86_DI, di), 27 PT_REGS_OFFSET(PERF_REG_X86_BP, bp), 28 PT_REGS_OFFSET(PERF_REG_X86_SP, sp), 29 PT_REGS_OFFSET(PERF_REG_X86_IP, ip), 30 PT_REGS_OFFSET(PERF_REG_X86_FLAGS, flags), 31 PT_REGS_OFFSET(PERF_REG_X86_CS, cs), 32 PT_REGS_OFFSET(PERF_REG_X86_SS, ss), 33 #ifdef CONFIG_X86_32 34 PT_REGS_OFFSET(PERF_REG_X86_DS, ds), 35 PT_REGS_OFFSET(PERF_REG_X86_ES, es), 36 PT_REGS_OFFSET(PERF_REG_X86_FS, fs), 37 PT_REGS_OFFSET(PERF_REG_X86_GS, gs), 38 #else 39 /* 40 * The pt_regs struct does not store 41 * ds, es, fs, gs in 64 bit mode. 42 */ 43 (unsigned int) -1, 44 (unsigned int) -1, 45 (unsigned int) -1, 46 (unsigned int) -1, 47 #endif 48 #ifdef CONFIG_X86_64 49 PT_REGS_OFFSET(PERF_REG_X86_R8, r8), 50 PT_REGS_OFFSET(PERF_REG_X86_R9, r9), 51 PT_REGS_OFFSET(PERF_REG_X86_R10, r10), 52 PT_REGS_OFFSET(PERF_REG_X86_R11, r11), 53 PT_REGS_OFFSET(PERF_REG_X86_R12, r12), 54 PT_REGS_OFFSET(PERF_REG_X86_R13, r13), 55 PT_REGS_OFFSET(PERF_REG_X86_R14, r14), 56 PT_REGS_OFFSET(PERF_REG_X86_R15, r15), 57 #endif 58 }; 59 60 u64 perf_reg_value(struct pt_regs *regs, int idx) 61 { 62 struct x86_perf_regs *perf_regs; 63 64 if (idx >= PERF_REG_X86_XMM0 && idx < PERF_REG_X86_XMM_MAX) { 65 perf_regs = container_of(regs, struct x86_perf_regs, regs); 66 if (!perf_regs->xmm_regs) 67 return 0; 68 return perf_regs->xmm_regs[idx - PERF_REG_X86_XMM0]; 69 } 70 71 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(pt_regs_offset))) 72 return 0; 73 74 return regs_get_register(regs, pt_regs_offset[idx]); 75 } 76 77 #define PERF_REG_X86_RESERVED (((1ULL << PERF_REG_X86_XMM0) - 1) & \ 78 ~((1ULL << PERF_REG_X86_MAX) - 1)) 79 80 #ifdef CONFIG_X86_32 81 #define REG_NOSUPPORT ((1ULL << PERF_REG_X86_R8) | \ 82 (1ULL << PERF_REG_X86_R9) | \ 83 (1ULL << PERF_REG_X86_R10) | \ 84 (1ULL << PERF_REG_X86_R11) | \ 85 (1ULL << PERF_REG_X86_R12) | \ 86 (1ULL << PERF_REG_X86_R13) | \ 87 (1ULL << PERF_REG_X86_R14) | \ 88 (1ULL << PERF_REG_X86_R15)) 89 90 int perf_reg_validate(u64 mask) 91 { 92 if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED))) 93 return -EINVAL; 94 95 return 0; 96 } 97 98 u64 perf_reg_abi(struct task_struct *task) 99 { 100 return PERF_SAMPLE_REGS_ABI_32; 101 } 102 103 void perf_get_regs_user(struct perf_regs *regs_user, 104 struct pt_regs *regs, 105 struct pt_regs *regs_user_copy) 106 { 107 regs_user->regs = task_pt_regs(current); 108 regs_user->abi = perf_reg_abi(current); 109 } 110 #else /* CONFIG_X86_64 */ 111 #define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) | \ 112 (1ULL << PERF_REG_X86_ES) | \ 113 (1ULL << PERF_REG_X86_FS) | \ 114 (1ULL << PERF_REG_X86_GS)) 115 116 int perf_reg_validate(u64 mask) 117 { 118 if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED))) 119 return -EINVAL; 120 121 return 0; 122 } 123 124 u64 perf_reg_abi(struct task_struct *task) 125 { 126 if (test_tsk_thread_flag(task, TIF_IA32)) 127 return PERF_SAMPLE_REGS_ABI_32; 128 else 129 return PERF_SAMPLE_REGS_ABI_64; 130 } 131 132 void perf_get_regs_user(struct perf_regs *regs_user, 133 struct pt_regs *regs, 134 struct pt_regs *regs_user_copy) 135 { 136 struct pt_regs *user_regs = task_pt_regs(current); 137 138 /* 139 * If we're in an NMI that interrupted task_pt_regs setup, then 140 * we can't sample user regs at all. This check isn't really 141 * sufficient, though, as we could be in an NMI inside an interrupt 142 * that happened during task_pt_regs setup. 143 */ 144 if (regs->sp > (unsigned long)&user_regs->r11 && 145 regs->sp <= (unsigned long)(user_regs + 1)) { 146 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 147 regs_user->regs = NULL; 148 return; 149 } 150 151 /* 152 * These registers are always saved on 64-bit syscall entry. 153 * On 32-bit entry points, they are saved too except r8..r11. 154 */ 155 regs_user_copy->ip = user_regs->ip; 156 regs_user_copy->ax = user_regs->ax; 157 regs_user_copy->cx = user_regs->cx; 158 regs_user_copy->dx = user_regs->dx; 159 regs_user_copy->si = user_regs->si; 160 regs_user_copy->di = user_regs->di; 161 regs_user_copy->r8 = user_regs->r8; 162 regs_user_copy->r9 = user_regs->r9; 163 regs_user_copy->r10 = user_regs->r10; 164 regs_user_copy->r11 = user_regs->r11; 165 regs_user_copy->orig_ax = user_regs->orig_ax; 166 regs_user_copy->flags = user_regs->flags; 167 regs_user_copy->sp = user_regs->sp; 168 regs_user_copy->cs = user_regs->cs; 169 regs_user_copy->ss = user_regs->ss; 170 /* 171 * Store user space frame-pointer value on sample 172 * to facilitate stack unwinding for cases when 173 * user space executable code has such support 174 * enabled at compile time: 175 */ 176 regs_user_copy->bp = user_regs->bp; 177 178 regs_user_copy->bx = -1; 179 regs_user_copy->r12 = -1; 180 regs_user_copy->r13 = -1; 181 regs_user_copy->r14 = -1; 182 regs_user_copy->r15 = -1; 183 /* 184 * For this to be at all useful, we need a reasonable guess for 185 * the ABI. Be careful: we're in NMI context, and we're 186 * considering current to be the current task, so we should 187 * be careful not to look at any other percpu variables that might 188 * change during context switches. 189 */ 190 regs_user->abi = user_64bit_mode(user_regs) ? 191 PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32; 192 193 regs_user->regs = regs_user_copy; 194 } 195 #endif /* CONFIG_X86_32 */ 196