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 #ifdef CONFIG_X86_32 78 #define REG_NOSUPPORT ((1ULL << PERF_REG_X86_R8) | \ 79 (1ULL << PERF_REG_X86_R9) | \ 80 (1ULL << PERF_REG_X86_R10) | \ 81 (1ULL << PERF_REG_X86_R11) | \ 82 (1ULL << PERF_REG_X86_R12) | \ 83 (1ULL << PERF_REG_X86_R13) | \ 84 (1ULL << PERF_REG_X86_R14) | \ 85 (1ULL << PERF_REG_X86_R15)) 86 87 int perf_reg_validate(u64 mask) 88 { 89 if (!mask || (mask & REG_NOSUPPORT)) 90 return -EINVAL; 91 92 return 0; 93 } 94 95 u64 perf_reg_abi(struct task_struct *task) 96 { 97 return PERF_SAMPLE_REGS_ABI_32; 98 } 99 100 void perf_get_regs_user(struct perf_regs *regs_user, 101 struct pt_regs *regs, 102 struct pt_regs *regs_user_copy) 103 { 104 regs_user->regs = task_pt_regs(current); 105 regs_user->abi = perf_reg_abi(current); 106 } 107 #else /* CONFIG_X86_64 */ 108 #define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) | \ 109 (1ULL << PERF_REG_X86_ES) | \ 110 (1ULL << PERF_REG_X86_FS) | \ 111 (1ULL << PERF_REG_X86_GS)) 112 113 int perf_reg_validate(u64 mask) 114 { 115 if (!mask || (mask & REG_NOSUPPORT)) 116 return -EINVAL; 117 118 return 0; 119 } 120 121 u64 perf_reg_abi(struct task_struct *task) 122 { 123 if (test_tsk_thread_flag(task, TIF_IA32)) 124 return PERF_SAMPLE_REGS_ABI_32; 125 else 126 return PERF_SAMPLE_REGS_ABI_64; 127 } 128 129 void perf_get_regs_user(struct perf_regs *regs_user, 130 struct pt_regs *regs, 131 struct pt_regs *regs_user_copy) 132 { 133 struct pt_regs *user_regs = task_pt_regs(current); 134 135 /* 136 * If we're in an NMI that interrupted task_pt_regs setup, then 137 * we can't sample user regs at all. This check isn't really 138 * sufficient, though, as we could be in an NMI inside an interrupt 139 * that happened during task_pt_regs setup. 140 */ 141 if (regs->sp > (unsigned long)&user_regs->r11 && 142 regs->sp <= (unsigned long)(user_regs + 1)) { 143 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 144 regs_user->regs = NULL; 145 return; 146 } 147 148 /* 149 * These registers are always saved on 64-bit syscall entry. 150 * On 32-bit entry points, they are saved too except r8..r11. 151 */ 152 regs_user_copy->ip = user_regs->ip; 153 regs_user_copy->ax = user_regs->ax; 154 regs_user_copy->cx = user_regs->cx; 155 regs_user_copy->dx = user_regs->dx; 156 regs_user_copy->si = user_regs->si; 157 regs_user_copy->di = user_regs->di; 158 regs_user_copy->r8 = user_regs->r8; 159 regs_user_copy->r9 = user_regs->r9; 160 regs_user_copy->r10 = user_regs->r10; 161 regs_user_copy->r11 = user_regs->r11; 162 regs_user_copy->orig_ax = user_regs->orig_ax; 163 regs_user_copy->flags = user_regs->flags; 164 regs_user_copy->sp = user_regs->sp; 165 regs_user_copy->cs = user_regs->cs; 166 regs_user_copy->ss = user_regs->ss; 167 /* 168 * Store user space frame-pointer value on sample 169 * to facilitate stack unwinding for cases when 170 * user space executable code has such support 171 * enabled at compile time: 172 */ 173 regs_user_copy->bp = user_regs->bp; 174 175 regs_user_copy->bx = -1; 176 regs_user_copy->r12 = -1; 177 regs_user_copy->r13 = -1; 178 regs_user_copy->r14 = -1; 179 regs_user_copy->r15 = -1; 180 /* 181 * For this to be at all useful, we need a reasonable guess for 182 * the ABI. Be careful: we're in NMI context, and we're 183 * considering current to be the current task, so we should 184 * be careful not to look at any other percpu variables that might 185 * change during context switches. 186 */ 187 regs_user->abi = user_64bit_mode(user_regs) ? 188 PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32; 189 190 regs_user->regs = regs_user_copy; 191 } 192 #endif /* CONFIG_X86_32 */ 193