[mirror_ubuntu-jammy-kernel.git] / arch / x86 / kernel / perf_regs.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/perf_event.h>
#include <linux/bug.h>
#include <linux/stddef.h>
#include <asm/perf_regs.h>
#include <asm/ptrace.h>

#ifdef CONFIG_X86_32
#define PERF_REG_X86_MAX PERF_REG_X86_32_MAX
#else
#define PERF_REG_X86_MAX PERF_REG_X86_64_MAX
#endif

#define PT_REGS_OFFSET(id, r) [id] = offsetof(struct pt_regs, r)

static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = {
	PT_REGS_OFFSET(PERF_REG_X86_AX, ax),
	PT_REGS_OFFSET(PERF_REG_X86_BX, bx),
	PT_REGS_OFFSET(PERF_REG_X86_CX, cx),
	PT_REGS_OFFSET(PERF_REG_X86_DX, dx),
	PT_REGS_OFFSET(PERF_REG_X86_SI, si),
	PT_REGS_OFFSET(PERF_REG_X86_DI, di),
	PT_REGS_OFFSET(PERF_REG_X86_BP, bp),
	PT_REGS_OFFSET(PERF_REG_X86_SP, sp),
	PT_REGS_OFFSET(PERF_REG_X86_IP, ip),
	PT_REGS_OFFSET(PERF_REG_X86_FLAGS, flags),
	PT_REGS_OFFSET(PERF_REG_X86_CS, cs),
	PT_REGS_OFFSET(PERF_REG_X86_SS, ss),
#ifdef CONFIG_X86_32
	PT_REGS_OFFSET(PERF_REG_X86_DS, ds),
	PT_REGS_OFFSET(PERF_REG_X86_ES, es),
	PT_REGS_OFFSET(PERF_REG_X86_FS, fs),
	PT_REGS_OFFSET(PERF_REG_X86_GS, gs),
#else
	/*
	 * The pt_regs struct does not store
	 * ds, es, fs, gs in 64 bit mode.
	 */
	(unsigned int) -1,
	(unsigned int) -1,
	(unsigned int) -1,
	(unsigned int) -1,
#endif
#ifdef CONFIG_X86_64
	PT_REGS_OFFSET(PERF_REG_X86_R8, r8),
	PT_REGS_OFFSET(PERF_REG_X86_R9, r9),
	PT_REGS_OFFSET(PERF_REG_X86_R10, r10),
	PT_REGS_OFFSET(PERF_REG_X86_R11, r11),
	PT_REGS_OFFSET(PERF_REG_X86_R12, r12),
	PT_REGS_OFFSET(PERF_REG_X86_R13, r13),
	PT_REGS_OFFSET(PERF_REG_X86_R14, r14),
	PT_REGS_OFFSET(PERF_REG_X86_R15, r15),
#endif
};

u64 perf_reg_value(struct pt_regs *regs, int idx)
{
	struct x86_perf_regs *perf_regs;

	if (idx >= PERF_REG_X86_XMM0 && idx < PERF_REG_X86_XMM_MAX) {
		perf_regs = container_of(regs, struct x86_perf_regs, regs);
		if (!perf_regs->xmm_regs)
			return 0;
		return perf_regs->xmm_regs[idx - PERF_REG_X86_XMM0];
	}

	if (WARN_ON_ONCE(idx >= ARRAY_SIZE(pt_regs_offset)))
		return 0;

	return regs_get_register(regs, pt_regs_offset[idx]);
}

#define PERF_REG_X86_RESERVED	(((1ULL << PERF_REG_X86_XMM0) - 1) & \
				 ~((1ULL << PERF_REG_X86_MAX) - 1))

#ifdef CONFIG_X86_32
#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_R8) | \
		       (1ULL << PERF_REG_X86_R9) | \
		       (1ULL << PERF_REG_X86_R10) | \
		       (1ULL << PERF_REG_X86_R11) | \
		       (1ULL << PERF_REG_X86_R12) | \
		       (1ULL << PERF_REG_X86_R13) | \
		       (1ULL << PERF_REG_X86_R14) | \
		       (1ULL << PERF_REG_X86_R15))

int perf_reg_validate(u64 mask)
{
	if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED)))
		return -EINVAL;

	return 0;
}

u64 perf_reg_abi(struct task_struct *task)
{
	return PERF_SAMPLE_REGS_ABI_32;
}

void perf_get_regs_user(struct perf_regs *regs_user,
			struct pt_regs *regs,
			struct pt_regs *regs_user_copy)
{
	regs_user->regs = task_pt_regs(current);
	regs_user->abi = perf_reg_abi(current);
}
#else /* CONFIG_X86_64 */
#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) | \
		       (1ULL << PERF_REG_X86_ES) | \
		       (1ULL << PERF_REG_X86_FS) | \
		       (1ULL << PERF_REG_X86_GS))

int perf_reg_validate(u64 mask)
{
	if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED)))
		return -EINVAL;

	return 0;
}

u64 perf_reg_abi(struct task_struct *task)
{
	if (test_tsk_thread_flag(task, TIF_IA32))
		return PERF_SAMPLE_REGS_ABI_32;
	else
		return PERF_SAMPLE_REGS_ABI_64;
}

void perf_get_regs_user(struct perf_regs *regs_user,
			struct pt_regs *regs,
			struct pt_regs *regs_user_copy)
{
	struct pt_regs *user_regs = task_pt_regs(current);

	/*
	 * If we're in an NMI that interrupted task_pt_regs setup, then
	 * we can't sample user regs at all.  This check isn't really
	 * sufficient, though, as we could be in an NMI inside an interrupt
	 * that happened during task_pt_regs setup.
	 */
	if (regs->sp > (unsigned long)&user_regs->r11 &&
	    regs->sp <= (unsigned long)(user_regs + 1)) {
		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
		regs_user->regs = NULL;
		return;
	}

	/*
	 * These registers are always saved on 64-bit syscall entry.
	 * On 32-bit entry points, they are saved too except r8..r11.
	 */
	regs_user_copy->ip = user_regs->ip;
	regs_user_copy->ax = user_regs->ax;
	regs_user_copy->cx = user_regs->cx;
	regs_user_copy->dx = user_regs->dx;
	regs_user_copy->si = user_regs->si;
	regs_user_copy->di = user_regs->di;
	regs_user_copy->r8 = user_regs->r8;
	regs_user_copy->r9 = user_regs->r9;
	regs_user_copy->r10 = user_regs->r10;
	regs_user_copy->r11 = user_regs->r11;
	regs_user_copy->orig_ax = user_regs->orig_ax;
	regs_user_copy->flags = user_regs->flags;
	regs_user_copy->sp = user_regs->sp;
	regs_user_copy->cs = user_regs->cs;
	regs_user_copy->ss = user_regs->ss;
	/*
	 * Store user space frame-pointer value on sample
	 * to facilitate stack unwinding for cases when
	 * user space executable code has such support
	 * enabled at compile time:
	 */
	regs_user_copy->bp = user_regs->bp;

	regs_user_copy->bx = -1;
	regs_user_copy->r12 = -1;
	regs_user_copy->r13 = -1;
	regs_user_copy->r14 = -1;
	regs_user_copy->r15 = -1;
	/*
	 * For this to be at all useful, we need a reasonable guess for
	 * the ABI.  Be careful: we're in NMI context, and we're
	 * considering current to be the current task, so we should
	 * be careful not to look at any other percpu variables that might
	 * change during context switches.
	 */
	regs_user->abi = user_64bit_mode(user_regs) ?
		PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32;

	regs_user->regs = regs_user_copy;
}
#endif /* CONFIG_X86_32 */
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
c5e63197 JO	2	#include <linux/errno.h>
c5e63197 JO	3	#include <linux/kernel.h>
4018994f	4	#include <linux/sched.h>
68db0cf1	5	#include <linux/sched/task_stack.h>
4018994f	6	#include <linux/perf_event.h>
c5e63197 JO	7	#include <linux/bug.h>
	8	#include <linux/stddef.h>
	9	#include <asm/perf_regs.h>
	10	#include <asm/ptrace.h>
	11
	12	#ifdef CONFIG_X86_32
	13	#define PERF_REG_X86_MAX PERF_REG_X86_32_MAX
	14	#else
	15	#define PERF_REG_X86_MAX PERF_REG_X86_64_MAX
	16	#endif
	17
	18	#define PT_REGS_OFFSET(id, r) [id] = offsetof(struct pt_regs, r)
	19
	20	static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = {
	21	PT_REGS_OFFSET(PERF_REG_X86_AX, ax),
	22	PT_REGS_OFFSET(PERF_REG_X86_BX, bx),
	23	PT_REGS_OFFSET(PERF_REG_X86_CX, cx),
	24	PT_REGS_OFFSET(PERF_REG_X86_DX, dx),
	25	PT_REGS_OFFSET(PERF_REG_X86_SI, si),
	26	PT_REGS_OFFSET(PERF_REG_X86_DI, di),
	27	PT_REGS_OFFSET(PERF_REG_X86_BP, bp),
	28	PT_REGS_OFFSET(PERF_REG_X86_SP, sp),
	29	PT_REGS_OFFSET(PERF_REG_X86_IP, ip),
	30	PT_REGS_OFFSET(PERF_REG_X86_FLAGS, flags),
	31	PT_REGS_OFFSET(PERF_REG_X86_CS, cs),
	32	PT_REGS_OFFSET(PERF_REG_X86_SS, ss),
	33	#ifdef CONFIG_X86_32
	34	PT_REGS_OFFSET(PERF_REG_X86_DS, ds),
	35	PT_REGS_OFFSET(PERF_REG_X86_ES, es),
	36	PT_REGS_OFFSET(PERF_REG_X86_FS, fs),
	37	PT_REGS_OFFSET(PERF_REG_X86_GS, gs),
	38	#else
	39	/*
	40	* The pt_regs struct does not store
	41	* ds, es, fs, gs in 64 bit mode.
	42	*/
	43	(unsigned int) -1,
	44	(unsigned int) -1,
	45	(unsigned int) -1,
	46	(unsigned int) -1,
	47	#endif
	48	#ifdef CONFIG_X86_64
	49	PT_REGS_OFFSET(PERF_REG_X86_R8, r8),
	50	PT_REGS_OFFSET(PERF_REG_X86_R9, r9),
	51	PT_REGS_OFFSET(PERF_REG_X86_R10, r10),
	52	PT_REGS_OFFSET(PERF_REG_X86_R11, r11),
	53	PT_REGS_OFFSET(PERF_REG_X86_R12, r12),
	54	PT_REGS_OFFSET(PERF_REG_X86_R13, r13),
	55	PT_REGS_OFFSET(PERF_REG_X86_R14, r14),
	56	PT_REGS_OFFSET(PERF_REG_X86_R15, r15),
	57	#endif
	58	};
	59
	60	u64 perf_reg_value(struct pt_regs *regs, int idx)
	61	{
878068ea KL	62	struct x86_perf_regs *perf_regs;
	63
	64	if (idx >= PERF_REG_X86_XMM0 && idx < PERF_REG_X86_XMM_MAX) {
	65	perf_regs = container_of(regs, struct x86_perf_regs, regs);
	66	if (!perf_regs->xmm_regs)
	67	return 0;
	68	return perf_regs->xmm_regs[idx - PERF_REG_X86_XMM0];
	69	}
	70
1e6dd8ad	71	if (WARN_ON_ONCE(idx >= ARRAY_SIZE(pt_regs_offset)))
c5e63197 JO	72	return 0;
	73
	74	return regs_get_register(regs, pt_regs_offset[idx]);
	75	}
	76
90d42491 KL	77	#define PERF_REG_X86_RESERVED (((1ULL << PERF_REG_X86_XMM0) - 1) & \
	78	~((1ULL << PERF_REG_X86_MAX) - 1))
	79
c5e63197	80	#ifdef CONFIG_X86_32
878068ea KL	81	#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_R8) \| \
	82	(1ULL << PERF_REG_X86_R9) \| \
	83	(1ULL << PERF_REG_X86_R10) \| \
	84	(1ULL << PERF_REG_X86_R11) \| \
	85	(1ULL << PERF_REG_X86_R12) \| \
	86	(1ULL << PERF_REG_X86_R13) \| \
	87	(1ULL << PERF_REG_X86_R14) \| \
	88	(1ULL << PERF_REG_X86_R15))
	89
c5e63197 JO	90	int perf_reg_validate(u64 mask)
c5e63197 JO	91	{
90d42491	92	if (!mask \|\| (mask & (REG_NOSUPPORT \| PERF_REG_X86_RESERVED)))
c5e63197 JO	93	return -EINVAL;
	94
	95	return 0;
	96	}
4018994f JO	97
	98	u64 perf_reg_abi(struct task_struct *task)
	99	{
	100	return PERF_SAMPLE_REGS_ABI_32;
	101	}
88a7c26a AL	102
	103	void perf_get_regs_user(struct perf_regs *regs_user,
	104	struct pt_regs *regs,
	105	struct pt_regs *regs_user_copy)
	106	{
	107	regs_user->regs = task_pt_regs(current);
	108	regs_user->abi = perf_reg_abi(current);
	109	}
c5e63197 JO	110	#else /* CONFIG_X86_64 */
	111	#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) \| \
	112	(1ULL << PERF_REG_X86_ES) \| \
	113	(1ULL << PERF_REG_X86_FS) \| \
	114	(1ULL << PERF_REG_X86_GS))
	115
	116	int perf_reg_validate(u64 mask)
	117	{
90d42491	118	if (!mask \|\| (mask & (REG_NOSUPPORT \| PERF_REG_X86_RESERVED)))
c5e63197 JO	119	return -EINVAL;
	120
	121	return 0;
	122	}
4018994f JO	123
	124	u64 perf_reg_abi(struct task_struct *task)
	125	{
	126	if (test_tsk_thread_flag(task, TIF_IA32))
	127	return PERF_SAMPLE_REGS_ABI_32;
	128	else
	129	return PERF_SAMPLE_REGS_ABI_64;
	130	}
88a7c26a AL	131
	132	void perf_get_regs_user(struct perf_regs *regs_user,
	133	struct pt_regs *regs,
	134	struct pt_regs *regs_user_copy)
	135	{
86c269fe AL	136	struct pt_regs *user_regs = task_pt_regs(current);
	137
	138	/*
	139	* If we're in an NMI that interrupted task_pt_regs setup, then
	140	* we can't sample user regs at all. This check isn't really
	141	* sufficient, though, as we could be in an NMI inside an interrupt
	142	* that happened during task_pt_regs setup.
	143	*/
	144	if (regs->sp > (unsigned long)&user_regs->r11 &&
	145	regs->sp <= (unsigned long)(user_regs + 1)) {
	146	regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
	147	regs_user->regs = NULL;
	148	return;
	149	}
	150
	151	/*
aa21df04 DV	152	* These registers are always saved on 64-bit syscall entry.
aa21df04 DV	153	* On 32-bit entry points, they are saved too except r8..r11.
86c269fe AL	154	*/
86c269fe AL	155	regs_user_copy->ip = user_regs->ip;
3b75232d	156	regs_user_copy->ax = user_regs->ax;
86c269fe AL	157	regs_user_copy->cx = user_regs->cx;
	158	regs_user_copy->dx = user_regs->dx;
	159	regs_user_copy->si = user_regs->si;
	160	regs_user_copy->di = user_regs->di;
	161	regs_user_copy->r8 = user_regs->r8;
	162	regs_user_copy->r9 = user_regs->r9;
	163	regs_user_copy->r10 = user_regs->r10;
	164	regs_user_copy->r11 = user_regs->r11;
	165	regs_user_copy->orig_ax = user_regs->orig_ax;
	166	regs_user_copy->flags = user_regs->flags;
aa21df04 DV	167	regs_user_copy->sp = user_regs->sp;
	168	regs_user_copy->cs = user_regs->cs;
	169	regs_user_copy->ss = user_regs->ss;
86c269fe	170	/*
10b11050 AB	171	* Store user space frame-pointer value on sample
	172	* to facilitate stack unwinding for cases when
	173	* user space executable code has such support
	174	* enabled at compile time:
86c269fe	175	*/
10b11050 AB	176	regs_user_copy->bp = user_regs->bp;
10b11050 AB	177
86c269fe	178	regs_user_copy->bx = -1;
86c269fe AL	179	regs_user_copy->r12 = -1;
	180	regs_user_copy->r13 = -1;
	181	regs_user_copy->r14 = -1;
	182	regs_user_copy->r15 = -1;
86c269fe AL	183	/*
86c269fe AL	184	* For this to be at all useful, we need a reasonable guess for
aa21df04	185	* the ABI. Be careful: we're in NMI context, and we're
86c269fe AL	186	* considering current to be the current task, so we should
	187	* be careful not to look at any other percpu variables that might
	188	* change during context switches.
	189	*/
32caa060 DV	190	regs_user->abi = user_64bit_mode(user_regs) ?
32caa060 DV	191	PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32;
86c269fe AL	192
86c269fe AL	193	regs_user->regs = regs_user_copy;
88a7c26a	194	}
c5e63197	195	#endif /* CONFIG_X86_32 */