[linux-2.6-block.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)
{
	if (WARN_ON_ONCE(idx >= ARRAY_SIZE(pt_regs_offset)))
		return 0;

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

#define REG_RESERVED (~((1ULL << PERF_REG_X86_MAX) - 1ULL))

#ifdef CONFIG_X86_32
int perf_reg_validate(u64 mask)
{
	if (!mask || mask & REG_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_RESERVED)
		return -EINVAL;

	if (mask & REG_NOSUPPORT)
		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;

	/*
	 * Most system calls don't save these registers, don't report them.
	 */
	regs_user_copy->bx = -1;
	regs_user_copy->bp = -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	{
1e6dd8ad	62	if (WARN_ON_ONCE(idx >= ARRAY_SIZE(pt_regs_offset)))
c5e63197 JO	63	return 0;
	64
	65	return regs_get_register(regs, pt_regs_offset[idx]);
	66	}
	67
	68	#define REG_RESERVED (~((1ULL << PERF_REG_X86_MAX) - 1ULL))
	69
	70	#ifdef CONFIG_X86_32
	71	int perf_reg_validate(u64 mask)
	72	{
	73	if (!mask \|\| mask & REG_RESERVED)
	74	return -EINVAL;
	75
	76	return 0;
	77	}
4018994f JO	78
	79	u64 perf_reg_abi(struct task_struct *task)
	80	{
	81	return PERF_SAMPLE_REGS_ABI_32;
	82	}
88a7c26a AL	83
	84	void perf_get_regs_user(struct perf_regs *regs_user,
	85	struct pt_regs *regs,
	86	struct pt_regs *regs_user_copy)
	87	{
	88	regs_user->regs = task_pt_regs(current);
	89	regs_user->abi = perf_reg_abi(current);
	90	}
c5e63197 JO	91	#else /* CONFIG_X86_64 */
	92	#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) \| \
	93	(1ULL << PERF_REG_X86_ES) \| \
	94	(1ULL << PERF_REG_X86_FS) \| \
	95	(1ULL << PERF_REG_X86_GS))
	96
	97	int perf_reg_validate(u64 mask)
	98	{
	99	if (!mask \|\| mask & REG_RESERVED)
	100	return -EINVAL;
	101
	102	if (mask & REG_NOSUPPORT)
	103	return -EINVAL;
	104
	105	return 0;
	106	}
4018994f JO	107
	108	u64 perf_reg_abi(struct task_struct *task)
	109	{
	110	if (test_tsk_thread_flag(task, TIF_IA32))
	111	return PERF_SAMPLE_REGS_ABI_32;
	112	else
	113	return PERF_SAMPLE_REGS_ABI_64;
	114	}
88a7c26a AL	115
	116	void perf_get_regs_user(struct perf_regs *regs_user,
	117	struct pt_regs *regs,
	118	struct pt_regs *regs_user_copy)
	119	{
86c269fe AL	120	struct pt_regs *user_regs = task_pt_regs(current);
	121
	122	/*
	123	* If we're in an NMI that interrupted task_pt_regs setup, then
	124	* we can't sample user regs at all. This check isn't really
	125	* sufficient, though, as we could be in an NMI inside an interrupt
	126	* that happened during task_pt_regs setup.
	127	*/
	128	if (regs->sp > (unsigned long)&user_regs->r11 &&
	129	regs->sp <= (unsigned long)(user_regs + 1)) {
	130	regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
	131	regs_user->regs = NULL;
	132	return;
	133	}
	134
	135	/*
aa21df04 DV	136	* These registers are always saved on 64-bit syscall entry.
aa21df04 DV	137	* On 32-bit entry points, they are saved too except r8..r11.
86c269fe AL	138	*/
86c269fe AL	139	regs_user_copy->ip = user_regs->ip;
3b75232d	140	regs_user_copy->ax = user_regs->ax;
86c269fe AL	141	regs_user_copy->cx = user_regs->cx;
	142	regs_user_copy->dx = user_regs->dx;
	143	regs_user_copy->si = user_regs->si;
	144	regs_user_copy->di = user_regs->di;
	145	regs_user_copy->r8 = user_regs->r8;
	146	regs_user_copy->r9 = user_regs->r9;
	147	regs_user_copy->r10 = user_regs->r10;
	148	regs_user_copy->r11 = user_regs->r11;
	149	regs_user_copy->orig_ax = user_regs->orig_ax;
	150	regs_user_copy->flags = user_regs->flags;
aa21df04 DV	151	regs_user_copy->sp = user_regs->sp;
	152	regs_user_copy->cs = user_regs->cs;
	153	regs_user_copy->ss = user_regs->ss;
86c269fe AL	154
86c269fe AL	155	/*
aa21df04	156	* Most system calls don't save these registers, don't report them.
86c269fe AL	157	*/
	158	regs_user_copy->bx = -1;
	159	regs_user_copy->bp = -1;
	160	regs_user_copy->r12 = -1;
	161	regs_user_copy->r13 = -1;
	162	regs_user_copy->r14 = -1;
	163	regs_user_copy->r15 = -1;
	164
	165	/*
	166	* For this to be at all useful, we need a reasonable guess for
aa21df04	167	* the ABI. Be careful: we're in NMI context, and we're
86c269fe AL	168	* considering current to be the current task, so we should
	169	* be careful not to look at any other percpu variables that might
	170	* change during context switches.
	171	*/
32caa060 DV	172	regs_user->abi = user_64bit_mode(user_regs) ?
32caa060 DV	173	PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32;
86c269fe AL	174
86c269fe AL	175	regs_user->regs = regs_user_copy;
88a7c26a	176	}
c5e63197	177	#endif /* CONFIG_X86_32 */