1#include <linux/errno.h>
2#include <linux/kernel.h>
3#include <linux/sched.h>
4#include <linux/perf_event.h>
5#include <linux/bug.h>
6#include <linux/stddef.h>
7#include <asm/perf_regs.h>
8#include <asm/ptrace.h>
9
10#ifdef CONFIG_X86_32
11#define PERF_REG_X86_MAX PERF_REG_X86_32_MAX
12#else
13#define PERF_REG_X86_MAX PERF_REG_X86_64_MAX
14#endif
15
16#define PT_REGS_OFFSET(id, r) [id] = offsetof(struct pt_regs, r)
17
18static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = {
19	PT_REGS_OFFSET(PERF_REG_X86_AX, ax),
20	PT_REGS_OFFSET(PERF_REG_X86_BX, bx),
21	PT_REGS_OFFSET(PERF_REG_X86_CX, cx),
22	PT_REGS_OFFSET(PERF_REG_X86_DX, dx),
23	PT_REGS_OFFSET(PERF_REG_X86_SI, si),
24	PT_REGS_OFFSET(PERF_REG_X86_DI, di),
25	PT_REGS_OFFSET(PERF_REG_X86_BP, bp),
26	PT_REGS_OFFSET(PERF_REG_X86_SP, sp),
27	PT_REGS_OFFSET(PERF_REG_X86_IP, ip),
28	PT_REGS_OFFSET(PERF_REG_X86_FLAGS, flags),
29	PT_REGS_OFFSET(PERF_REG_X86_CS, cs),
30	PT_REGS_OFFSET(PERF_REG_X86_SS, ss),
31#ifdef CONFIG_X86_32
32	PT_REGS_OFFSET(PERF_REG_X86_DS, ds),
33	PT_REGS_OFFSET(PERF_REG_X86_ES, es),
34	PT_REGS_OFFSET(PERF_REG_X86_FS, fs),
35	PT_REGS_OFFSET(PERF_REG_X86_GS, gs),
36#else
37	/*
38	 * The pt_regs struct does not store
39	 * ds, es, fs, gs in 64 bit mode.
40	 */
41	(unsigned int) -1,
42	(unsigned int) -1,
43	(unsigned int) -1,
44	(unsigned int) -1,
45#endif
46#ifdef CONFIG_X86_64
47	PT_REGS_OFFSET(PERF_REG_X86_R8, r8),
48	PT_REGS_OFFSET(PERF_REG_X86_R9, r9),
49	PT_REGS_OFFSET(PERF_REG_X86_R10, r10),
50	PT_REGS_OFFSET(PERF_REG_X86_R11, r11),
51	PT_REGS_OFFSET(PERF_REG_X86_R12, r12),
52	PT_REGS_OFFSET(PERF_REG_X86_R13, r13),
53	PT_REGS_OFFSET(PERF_REG_X86_R14, r14),
54	PT_REGS_OFFSET(PERF_REG_X86_R15, r15),
55#endif
56};
57
58u64 perf_reg_value(struct pt_regs *regs, int idx)
59{
60	if (WARN_ON_ONCE(idx >= ARRAY_SIZE(pt_regs_offset)))
61		return 0;
62
63	return regs_get_register(regs, pt_regs_offset[idx]);
64}
65
66#define REG_RESERVED (~((1ULL << PERF_REG_X86_MAX) - 1ULL))
67
68#ifdef CONFIG_X86_32
69int perf_reg_validate(u64 mask)
70{
71	if (!mask || mask & REG_RESERVED)
72		return -EINVAL;
73
74	return 0;
75}
76
77u64 perf_reg_abi(struct task_struct *task)
78{
79	return PERF_SAMPLE_REGS_ABI_32;
80}
81
82void perf_get_regs_user(struct perf_regs *regs_user,
83			struct pt_regs *regs,
84			struct pt_regs *regs_user_copy)
85{
86	regs_user->regs = task_pt_regs(current);
87	regs_user->abi = perf_reg_abi(current);
88}
89#else /* CONFIG_X86_64 */
90#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) | \
91		       (1ULL << PERF_REG_X86_ES) | \
92		       (1ULL << PERF_REG_X86_FS) | \
93		       (1ULL << PERF_REG_X86_GS))
94
95int perf_reg_validate(u64 mask)
96{
97	if (!mask || mask & REG_RESERVED)
98		return -EINVAL;
99
100	if (mask & REG_NOSUPPORT)
101		return -EINVAL;
102
103	return 0;
104}
105
106u64 perf_reg_abi(struct task_struct *task)
107{
108	if (test_tsk_thread_flag(task, TIF_IA32))
109		return PERF_SAMPLE_REGS_ABI_32;
110	else
111		return PERF_SAMPLE_REGS_ABI_64;
112}
113
114void perf_get_regs_user(struct perf_regs *regs_user,
115			struct pt_regs *regs,
116			struct pt_regs *regs_user_copy)
117{
118	struct pt_regs *user_regs = task_pt_regs(current);
119
120	/*
121	 * If we're in an NMI that interrupted task_pt_regs setup, then
122	 * we can't sample user regs at all.  This check isn't really
123	 * sufficient, though, as we could be in an NMI inside an interrupt
124	 * that happened during task_pt_regs setup.
125	 */
126	if (regs->sp > (unsigned long)&user_regs->r11 &&
127	    regs->sp <= (unsigned long)(user_regs + 1)) {
128		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
129		regs_user->regs = NULL;
130		return;
131	}
132
133	/*
134	 * These registers are always saved on 64-bit syscall entry.
135	 * On 32-bit entry points, they are saved too except r8..r11.
136	 */
137	regs_user_copy->ip = user_regs->ip;
138	regs_user_copy->ax = user_regs->ax;
139	regs_user_copy->cx = user_regs->cx;
140	regs_user_copy->dx = user_regs->dx;
141	regs_user_copy->si = user_regs->si;
142	regs_user_copy->di = user_regs->di;
143	regs_user_copy->r8 = user_regs->r8;
144	regs_user_copy->r9 = user_regs->r9;
145	regs_user_copy->r10 = user_regs->r10;
146	regs_user_copy->r11 = user_regs->r11;
147	regs_user_copy->orig_ax = user_regs->orig_ax;
148	regs_user_copy->flags = user_regs->flags;
149	regs_user_copy->sp = user_regs->sp;
150	regs_user_copy->cs = user_regs->cs;
151	regs_user_copy->ss = user_regs->ss;
152
153	/*
154	 * Most system calls don't save these registers, don't report them.
155	 */
156	regs_user_copy->bx = -1;
157	regs_user_copy->bp = -1;
158	regs_user_copy->r12 = -1;
159	regs_user_copy->r13 = -1;
160	regs_user_copy->r14 = -1;
161	regs_user_copy->r15 = -1;
162
163	/*
164	 * For this to be at all useful, we need a reasonable guess for
165	 * the ABI.  Be careful: we're in NMI context, and we're
166	 * considering current to be the current task, so we should
167	 * be careful not to look at any other percpu variables that might
168	 * change during context switches.
169	 */
170	regs_user->abi = user_64bit_mode(user_regs) ?
171		PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32;
172
173	regs_user->regs = regs_user_copy;
174}
175#endif /* CONFIG_X86_32 */
176