xref: /openbmc/linux/arch/s390/kernel/perf_regs.c (revision c000c4f1)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/perf_event.h>
3 #include <linux/perf_regs.h>
4 #include <linux/kernel.h>
5 #include <linux/errno.h>
6 #include <linux/bug.h>
7 #include <asm/ptrace.h>
8 #include <asm/fpu/api.h>
9 #include <asm/fpu/types.h>
10 
11 u64 perf_reg_value(struct pt_regs *regs, int idx)
12 {
13 	freg_t fp;
14 
15 	if (WARN_ON_ONCE((u32)idx >= PERF_REG_S390_MAX))
16 		return 0;
17 
18 	if (idx >= PERF_REG_S390_R0 && idx <= PERF_REG_S390_R15)
19 		return regs->gprs[idx];
20 
21 	if (idx >= PERF_REG_S390_FP0 && idx <= PERF_REG_S390_FP15) {
22 		if (!user_mode(regs))
23 			return 0;
24 
25 		idx -= PERF_REG_S390_FP0;
26 		fp = MACHINE_HAS_VX ? *(freg_t *)(current->thread.fpu.vxrs + idx)
27 				    : current->thread.fpu.fprs[idx];
28 		return fp.ui;
29 	}
30 
31 	if (idx == PERF_REG_S390_MASK)
32 		return regs->psw.mask;
33 	if (idx == PERF_REG_S390_PC)
34 		return regs->psw.addr;
35 
36 	return regs->gprs[idx];
37 }
38 
39 #define REG_RESERVED (~((1UL << PERF_REG_S390_MAX) - 1))
40 
41 int perf_reg_validate(u64 mask)
42 {
43 	if (!mask || mask & REG_RESERVED)
44 		return -EINVAL;
45 
46 	return 0;
47 }
48 
49 u64 perf_reg_abi(struct task_struct *task)
50 {
51 	if (test_tsk_thread_flag(task, TIF_31BIT))
52 		return PERF_SAMPLE_REGS_ABI_32;
53 
54 	return PERF_SAMPLE_REGS_ABI_64;
55 }
56 
57 void perf_get_regs_user(struct perf_regs *regs_user,
58 			struct pt_regs *regs,
59 			struct pt_regs *regs_user_copy)
60 {
61 	/*
62 	 * Use the regs from the first interruption and let
63 	 * perf_sample_regs_intr() handle interrupts (regs == get_irq_regs()).
64 	 *
65 	 * Also save FPU registers for user-space tasks only.
66 	 */
67 	regs_user->regs = task_pt_regs(current);
68 	if (user_mode(regs_user->regs))
69 		save_fpu_regs();
70 	regs_user->abi = perf_reg_abi(current);
71 }
72