xref: /openbmc/linux/arch/arm64/kernel/perf_regs.c (revision cfbb9be8)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/errno.h>
3 #include <linux/kernel.h>
4 #include <linux/perf_event.h>
5 #include <linux/bug.h>
6 #include <linux/sched/task_stack.h>
7 
8 #include <asm/compat.h>
9 #include <asm/perf_regs.h>
10 #include <asm/ptrace.h>
11 
12 u64 perf_reg_value(struct pt_regs *regs, int idx)
13 {
14 	if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX))
15 		return 0;
16 
17 	/*
18 	 * Compat (i.e. 32 bit) mode:
19 	 * - PC has been set in the pt_regs struct in kernel_entry,
20 	 * - Handle SP and LR here.
21 	 */
22 	if (compat_user_mode(regs)) {
23 		if ((u32)idx == PERF_REG_ARM64_SP)
24 			return regs->compat_sp;
25 		if ((u32)idx == PERF_REG_ARM64_LR)
26 			return regs->compat_lr;
27 	}
28 
29 	if ((u32)idx == PERF_REG_ARM64_SP)
30 		return regs->sp;
31 
32 	if ((u32)idx == PERF_REG_ARM64_PC)
33 		return regs->pc;
34 
35 	return regs->regs[idx];
36 }
37 
38 #define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1))
39 
40 int perf_reg_validate(u64 mask)
41 {
42 	if (!mask || mask & REG_RESERVED)
43 		return -EINVAL;
44 
45 	return 0;
46 }
47 
48 u64 perf_reg_abi(struct task_struct *task)
49 {
50 	if (is_compat_thread(task_thread_info(task)))
51 		return PERF_SAMPLE_REGS_ABI_32;
52 	else
53 		return PERF_SAMPLE_REGS_ABI_64;
54 }
55 
56 void perf_get_regs_user(struct perf_regs *regs_user,
57 			struct pt_regs *regs,
58 			struct pt_regs *regs_user_copy)
59 {
60 	regs_user->regs = task_pt_regs(current);
61 	regs_user->abi = perf_reg_abi(current);
62 }
63