1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/bits.h>
4 #include <linux/perf_event.h>
5 #include <linux/sched/task_stack.h>
6 #include <asm/perf_regs.h>
7
8 #define REG(idx, field) \
9 [PERF_REG_ALPHA_##idx] = offsetof(struct pt_regs, field)
10
11 #define REG_RESERVED (~GENMASK_ULL(PERF_REG_ALPHA_MAX - 1, 0) | \
12 GENMASK_ULL(PERF_REG_ALPHA_R15, PERF_REG_ALPHA_R9))
13
14 static const unsigned int pt_regs_offset[PERF_REG_ALPHA_MAX] = {
15 REG(R0, r0), REG(R1, r1), REG(R2, r2), REG(R3, r3),
16 REG(R4, r4), REG(R5, r5), REG(R6, r6), REG(R7, r7),
17 REG(R8, r8), REG(R16, r16), REG(R17, r17), REG(R18, r18),
18 REG(R19, r19), REG(R20, r20), REG(R21, r21), REG(R22, r22),
19 REG(R23, r23), REG(R24, r24), REG(R25, r25), REG(R26, r26),
20 REG(R27, r27), REG(R28, r28), REG(GP, gp), REG(PC, pc),
21 };
22
perf_reg_value(struct pt_regs * regs,int idx)23 u64 perf_reg_value(struct pt_regs *regs, int idx)
24 {
25 if (idx == PERF_REG_ALPHA_SP) {
26 if (user_mode(regs))
27 return user_stack_pointer(regs);
28 /*
29 * Software events built by perf_fetch_caller_regs() use a
30 * per-CPU pt_regs rather than a trap frame, and pt_regs has
31 * nowhere to record sp, so report none.
32 */
33 if (!object_is_on_stack(regs))
34 return 0;
35 /* Same kernel sp approximation as stacktrace.c. */
36 return (unsigned long)(regs + 1);
37 }
38
39 if (WARN_ON_ONCE((u32)idx >= PERF_REG_ALPHA_MAX ||
40 BIT_ULL(idx) & REG_RESERVED))
41 return 0;
42
43 return *(unsigned long *)((void *)regs + pt_regs_offset[idx]);
44 }
45
perf_reg_validate(u64 mask)46 int perf_reg_validate(u64 mask)
47 {
48 if (!mask || mask & REG_RESERVED)
49 return -EINVAL;
50
51 return 0;
52 }
53
perf_reg_abi(struct task_struct * task)54 u64 perf_reg_abi(struct task_struct *task)
55 {
56 return PERF_SAMPLE_REGS_ABI_64;
57 }
58
perf_get_regs_user(struct perf_regs * regs_user,struct pt_regs * regs)59 void perf_get_regs_user(struct perf_regs *regs_user,
60 struct pt_regs *regs)
61 {
62 regs_user->regs = task_pt_regs(current);
63 regs_user->abi = perf_reg_abi(current);
64 }
65