xref: /openbmc/linux/arch/arm64/kernel/perf_regs.c (revision 9cfc5c90)
1 #include <linux/errno.h>
2 #include <linux/kernel.h>
3 #include <linux/perf_event.h>
4 #include <linux/bug.h>
5 
6 #include <asm/compat.h>
7 #include <asm/perf_regs.h>
8 #include <asm/ptrace.h>
9 
10 u64 perf_reg_value(struct pt_regs *regs, int idx)
11 {
12 	if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX))
13 		return 0;
14 
15 	/*
16 	 * Compat (i.e. 32 bit) mode:
17 	 * - PC has been set in the pt_regs struct in kernel_entry,
18 	 * - Handle SP and LR here.
19 	 */
20 	if (compat_user_mode(regs)) {
21 		if ((u32)idx == PERF_REG_ARM64_SP)
22 			return regs->compat_sp;
23 		if ((u32)idx == PERF_REG_ARM64_LR)
24 			return regs->compat_lr;
25 	}
26 
27 	if ((u32)idx == PERF_REG_ARM64_SP)
28 		return regs->sp;
29 
30 	if ((u32)idx == PERF_REG_ARM64_PC)
31 		return regs->pc;
32 
33 	return regs->regs[idx];
34 }
35 
36 #define REG_RESERVED (~((1ULL << PERF_REG_ARM64_MAX) - 1))
37 
38 int perf_reg_validate(u64 mask)
39 {
40 	if (!mask || mask & REG_RESERVED)
41 		return -EINVAL;
42 
43 	return 0;
44 }
45 
46 u64 perf_reg_abi(struct task_struct *task)
47 {
48 	if (is_compat_thread(task_thread_info(task)))
49 		return PERF_SAMPLE_REGS_ABI_32;
50 	else
51 		return PERF_SAMPLE_REGS_ABI_64;
52 }
53 
54 void perf_get_regs_user(struct perf_regs *regs_user,
55 			struct pt_regs *regs,
56 			struct pt_regs *regs_user_copy)
57 {
58 	regs_user->regs = task_pt_regs(current);
59 	regs_user->abi = perf_reg_abi(current);
60 }
61