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