xref: /openbmc/linux/arch/arm64/kernel/perf_regs.c (revision e5f586c763a079349398e2b0c7c271386193ac34)
1 #include <linux/errno.h>
2 #include <linux/kernel.h>
3 #include <linux/perf_event.h>
4 #include <linux/bug.h>
5 #include <linux/sched/task_stack.h>
6 
7 #include <asm/compat.h>
8 #include <asm/perf_regs.h>
9 #include <asm/ptrace.h>
10 
11 u64 perf_reg_value(struct pt_regs *regs, int idx)
12 {
13 	if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX))
14 		return 0;
15 
16 	/*
17 	 * Compat (i.e. 32 bit) mode:
18 	 * - PC has been set in the pt_regs struct in kernel_entry,
19 	 * - Handle SP and LR here.
20 	 */
21 	if (compat_user_mode(regs)) {
22 		if ((u32)idx == PERF_REG_ARM64_SP)
23 			return regs->compat_sp;
24 		if ((u32)idx == PERF_REG_ARM64_LR)
25 			return regs->compat_lr;
26 	}
27 
28 	if ((u32)idx == PERF_REG_ARM64_SP)
29 		return regs->sp;
30 
31 	if ((u32)idx == PERF_REG_ARM64_PC)
32 		return regs->pc;
33 
34 	return regs->regs[idx];
35 }
36 
37 #define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1))
38 
39 int perf_reg_validate(u64 mask)
40 {
41 	if (!mask || mask & REG_RESERVED)
42 		return -EINVAL;
43 
44 	return 0;
45 }
46 
47 u64 perf_reg_abi(struct task_struct *task)
48 {
49 	if (is_compat_thread(task_thread_info(task)))
50 		return PERF_SAMPLE_REGS_ABI_32;
51 	else
52 		return PERF_SAMPLE_REGS_ABI_64;
53 }
54 
55 void perf_get_regs_user(struct perf_regs *regs_user,
56 			struct pt_regs *regs,
57 			struct pt_regs *regs_user_copy)
58 {
59 	regs_user->regs = task_pt_regs(current);
60 	regs_user->abi = perf_reg_abi(current);
61 }
62