[mirror_ubuntu-kernels.git] / arch / x86 / include / asm / pvclock.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_PVCLOCK_H
#define _ASM_X86_PVCLOCK_H

#include <linux/clocksource.h>
#include <asm/pvclock-abi.h>

#ifdef CONFIG_KVM_GUEST
extern struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void);
#else
static inline struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void)
{
	return NULL;
}
#endif

/* some helper functions for xen and kvm pv clock sources */
u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
void pvclock_set_flags(u8 flags);
unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
			    struct pvclock_vcpu_time_info *vcpu,
			    struct timespec *ts);
void pvclock_resume(void);

void pvclock_touch_watchdogs(void);

static __always_inline
unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src)
{
	unsigned version = src->version & ~1;
	/* Make sure that the version is read before the data. */
	virt_rmb();
	return version;
}

static __always_inline
bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src,
			unsigned version)
{
	/* Make sure that the version is re-read after the data. */
	virt_rmb();
	return unlikely(version != src->version);
}

/*
 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
 * yielding a 64-bit result.
 */
static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
{
	u64 product;
#ifdef __i386__
	u32 tmp1, tmp2;
#else
	ulong tmp;
#endif

	if (shift < 0)
		delta >>= -shift;
	else
		delta <<= shift;

#ifdef __i386__
	__asm__ (
		"mul  %5       ; "
		"mov  %4,%%eax ; "
		"mov  %%edx,%4 ; "
		"mul  %5       ; "
		"xor  %5,%5    ; "
		"add  %4,%%eax ; "
		"adc  %5,%%edx ; "
		: "=A" (product), "=r" (tmp1), "=r" (tmp2)
		: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
#elif defined(__x86_64__)
	__asm__ (
		"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
		: [lo]"=a"(product),
		  [hi]"=d"(tmp)
		: "0"(delta),
		  [mul_frac]"rm"((u64)mul_frac));
#else
#error implement me!
#endif

	return product;
}

static __always_inline
u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc)
{
	u64 delta = tsc - src->tsc_timestamp;
	u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul,
					     src->tsc_shift);
	return src->system_time + offset;
}

struct pvclock_vsyscall_time_info {
	struct pvclock_vcpu_time_info pvti;
} __attribute__((__aligned__(SMP_CACHE_BYTES)));

#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)

#endif /* _ASM_X86_PVCLOCK_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1965aae3 PA	2	#ifndef _ASM_X86_PVCLOCK_H
1965aae3 PA	3	#define _ASM_X86_PVCLOCK_H
7af192c9 GH	4
	5	#include <linux/clocksource.h>
	6	#include <asm/pvclock-abi.h>
	7
8705d603	8	#ifdef CONFIG_KVM_GUEST
dac16fba AL	9	extern struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void);
	10	#else
	11	static inline struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void)
	12	{
	13	return NULL;
	14	}
	15	#endif
	16
7af192c9	17	/* some helper functions for xen and kvm pv clock sources */
a5a1d1c2	18	u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
2697902b	19	u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
424c32f1	20	void pvclock_set_flags(u8 flags);
3807f345	21	unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
7af192c9 GH	22	void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
	23	struct pvclock_vcpu_time_info *vcpu,
	24	struct timespec *ts);
e7a3481c	25	void pvclock_resume(void);
7af192c9	26
d63285e9 MT	27	void pvclock_touch_watchdogs(void);
d63285e9 MT	28
3aed64f6 PB	29	static __always_inline
	30	unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src)
	31	{
	32	unsigned version = src->version & ~1;
	33	/* Make sure that the version is read before the data. */
	34	virt_rmb();
	35	return version;
	36	}
	37
	38	static __always_inline
	39	bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src,
	40	unsigned version)
	41	{
	42	/* Make sure that the version is re-read after the data. */
	43	virt_rmb();
	44	return unlikely(version != src->version);
	45	}
	46
347bb444 ZA	47	/*
	48	* Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
	49	* yielding a 64-bit result.
	50	*/
	51	static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
	52	{
	53	u64 product;
	54	#ifdef __i386__
	55	u32 tmp1, tmp2;
de2d1a52 ZA	56	#else
de2d1a52 ZA	57	ulong tmp;
347bb444 ZA	58	#endif
	59
	60	if (shift < 0)
	61	delta >>= -shift;
	62	else
	63	delta <<= shift;
	64
	65	#ifdef __i386__
	66	__asm__ (
	67	"mul %5 ; "
	68	"mov %4,%%eax ; "
	69	"mov %%edx,%4 ; "
	70	"mul %5 ; "
	71	"xor %5,%5 ; "
	72	"add %4,%%eax ; "
	73	"adc %5,%%edx ; "
	74	: "=A" (product), "=r" (tmp1), "=r" (tmp2)
	75	: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
	76	#elif defined(__x86_64__)
	77	__asm__ (
3b217116	78	"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
de2d1a52 ZA	79	: [lo]"=a"(product),
	80	[hi]"=d"(tmp)
	81	: "0"(delta),
	82	[mul_frac]"rm"((u64)mul_frac));
347bb444 ZA	83	#else
	84	#error implement me!
	85	#endif
	86
	87	return product;
	88	}
	89
dce2db0a	90	static __always_inline
a5a1d1c2	91	u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc)
dce2db0a	92	{
108b249c	93	u64 delta = tsc - src->tsc_timestamp;
a5a1d1c2	94	u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul,
3aed64f6 PB	95	src->tsc_shift);
3aed64f6 PB	96	return src->system_time + offset;
dce2db0a MT	97	}
dce2db0a MT	98
71056ae2 MT	99	struct pvclock_vsyscall_time_info {
71056ae2 MT	100	struct pvclock_vcpu_time_info pvti;
71056ae2 MT	101	} __attribute__((__aligned__(SMP_CACHE_BYTES)));
	102
	103	#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
71056ae2	104
1965aae3	105	#endif /* _ASM_X86_PVCLOCK_H */