[mirror_ubuntu-eoan-kernel.git] / arch / arm / include / asm / tls.h

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

#include <linux/compiler.h>
#include <asm/thread_info.h>

#ifdef __ASSEMBLY__
#include <asm/asm-offsets.h>
	.macro switch_tls_none, base, tp, tpuser, tmp1, tmp2
	.endm

	.macro switch_tls_v6k, base, tp, tpuser, tmp1, tmp2
	mrc	p15, 0, \tmp2, c13, c0, 2	@ get the user r/w register
	mcr	p15, 0, \tp, c13, c0, 3		@ set TLS register
	mcr	p15, 0, \tpuser, c13, c0, 2	@ and the user r/w register
	str	\tmp2, [\base, #TI_TP_VALUE + 4] @ save it
	.endm

	.macro switch_tls_v6, base, tp, tpuser, tmp1, tmp2
	ldr	\tmp1, =elf_hwcap
	ldr	\tmp1, [\tmp1, #0]
	mov	\tmp2, #0xffff0fff
	tst	\tmp1, #HWCAP_TLS		@ hardware TLS available?
	streq	\tp, [\tmp2, #-15]		@ set TLS value at 0xffff0ff0
	mrcne	p15, 0, \tmp2, c13, c0, 2	@ get the user r/w register
	mcrne	p15, 0, \tp, c13, c0, 3		@ yes, set TLS register
	mcrne	p15, 0, \tpuser, c13, c0, 2	@ set user r/w register
	strne	\tmp2, [\base, #TI_TP_VALUE + 4] @ save it
	.endm

	.macro switch_tls_software, base, tp, tpuser, tmp1, tmp2
	mov	\tmp1, #0xffff0fff
	str	\tp, [\tmp1, #-15]		@ set TLS value at 0xffff0ff0
	.endm
#endif

#ifdef CONFIG_TLS_REG_EMUL
#define tls_emu		1
#define has_tls_reg		1
#define switch_tls	switch_tls_none
#elif defined(CONFIG_CPU_V6)
#define tls_emu		0
#define has_tls_reg		(elf_hwcap & HWCAP_TLS)
#define switch_tls	switch_tls_v6
#elif defined(CONFIG_CPU_32v6K)
#define tls_emu		0
#define has_tls_reg		1
#define switch_tls	switch_tls_v6k
#else
#define tls_emu		0
#define has_tls_reg		0
#define switch_tls	switch_tls_software
#endif

#ifndef __ASSEMBLY__

static inline void set_tls(unsigned long val)
{
	struct thread_info *thread;

	thread = current_thread_info();

	thread->tp_value[0] = val;

	/*
	 * This code runs with preemption enabled and therefore must
	 * be reentrant with respect to switch_tls.
	 *
	 * We need to ensure ordering between the shadow state and the
	 * hardware state, so that we don't corrupt the hardware state
	 * with a stale shadow state during context switch.
	 *
	 * If we're preempted here, switch_tls will load TPIDRURO from
	 * thread_info upon resuming execution and the following mcr
	 * is merely redundant.
	 */
	barrier();

	if (!tls_emu) {
		if (has_tls_reg) {
			asm("mcr p15, 0, %0, c13, c0, 3"
			    : : "r" (val));
		} else {
#ifdef CONFIG_KUSER_HELPERS
			/*
			 * User space must never try to access this
			 * directly.  Expect your app to break
			 * eventually if you do so.  The user helper
			 * at 0xffff0fe0 must be used instead.  (see
			 * entry-armv.S for details)
			 */
			*((unsigned int *)0xffff0ff0) = val;
#endif
		}

	}
}

static inline unsigned long get_tpuser(void)
{
	unsigned long reg = 0;

	if (has_tls_reg && !tls_emu)
		__asm__("mrc p15, 0, %0, c13, c0, 2" : "=r" (reg));

	return reg;
}

static inline void set_tpuser(unsigned long val)
{
	/* Since TPIDRURW is fully context-switched (unlike TPIDRURO),
	 * we need not update thread_info.
	 */
	if (has_tls_reg && !tls_emu) {
		asm("mcr p15, 0, %0, c13, c0, 2"
		    : : "r" (val));
	}
}

static inline void flush_tls(void)
{
	set_tls(0);
	set_tpuser(0);
}

#endif
#endif	/* __ASMARM_TLS_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
f159f4ed TL	2	#ifndef __ASMARM_TLS_H
	3	#define __ASMARM_TLS_H
	4
fbfb872f NL	5	#include <linux/compiler.h>
	6	#include <asm/thread_info.h>
	7
f159f4ed	8	#ifdef __ASSEMBLY__
a4780ade AH	9	#include <asm/asm-offsets.h>
a4780ade AH	10	.macro switch_tls_none, base, tp, tpuser, tmp1, tmp2
f159f4ed TL	11	.endm
f159f4ed TL	12
a4780ade AH	13	.macro switch_tls_v6k, base, tp, tpuser, tmp1, tmp2
a4780ade AH	14	mrc p15, 0, \tmp2, c13, c0, 2 @ get the user r/w register
f159f4ed	15	mcr p15, 0, \tp, c13, c0, 3 @ set TLS register
a4780ade AH	16	mcr p15, 0, \tpuser, c13, c0, 2 @ and the user r/w register
a4780ade AH	17	str \tmp2, [\base, #TI_TP_VALUE + 4] @ save it
f159f4ed TL	18	.endm
f159f4ed TL	19
a4780ade	20	.macro switch_tls_v6, base, tp, tpuser, tmp1, tmp2
f159f4ed TL	21	ldr \tmp1, =elf_hwcap
	22	ldr \tmp1, [\tmp1, #0]
	23	mov \tmp2, #0xffff0fff
	24	tst \tmp1, #HWCAP_TLS @ hardware TLS available?
f159f4ed	25	streq \tp, [\tmp2, #-15] @ set TLS value at 0xffff0ff0
a4780ade AH	26	mrcne p15, 0, \tmp2, c13, c0, 2 @ get the user r/w register
	27	mcrne p15, 0, \tp, c13, c0, 3 @ yes, set TLS register
	28	mcrne p15, 0, \tpuser, c13, c0, 2 @ set user r/w register
	29	strne \tmp2, [\base, #TI_TP_VALUE + 4] @ save it
f159f4ed TL	30	.endm
f159f4ed TL	31
a4780ade	32	.macro switch_tls_software, base, tp, tpuser, tmp1, tmp2
f159f4ed TL	33	mov \tmp1, #0xffff0fff
	34	str \tp, [\tmp1, #-15] @ set TLS value at 0xffff0ff0
	35	.endm
	36	#endif
	37
	38	#ifdef CONFIG_TLS_REG_EMUL
	39	#define tls_emu 1
	40	#define has_tls_reg 1
a4780ade	41	#define switch_tls switch_tls_none
37bc618f	42	#elif defined(CONFIG_CPU_V6)
f159f4ed TL	43	#define tls_emu 0
f159f4ed TL	44	#define has_tls_reg (elf_hwcap & HWCAP_TLS)
a4780ade	45	#define switch_tls switch_tls_v6
37bc618f RK	46	#elif defined(CONFIG_CPU_32v6K)
	47	#define tls_emu 0
	48	#define has_tls_reg 1
a4780ade	49	#define switch_tls switch_tls_v6k
f159f4ed TL	50	#else
	51	#define tls_emu 0
	52	#define has_tls_reg 0
a4780ade	53	#define switch_tls switch_tls_software
f159f4ed TL	54	#endif
f159f4ed TL	55
a4780ade	56	#ifndef __ASSEMBLY__
fbfb872f NL	57
	58	static inline void set_tls(unsigned long val)
	59	{
	60	struct thread_info *thread;
	61
	62	thread = current_thread_info();
	63
	64	thread->tp_value[0] = val;
	65
	66	/*
	67	* This code runs with preemption enabled and therefore must
	68	* be reentrant with respect to switch_tls.
	69	*
	70	* We need to ensure ordering between the shadow state and the
	71	* hardware state, so that we don't corrupt the hardware state
	72	* with a stale shadow state during context switch.
	73	*
	74	* If we're preempted here, switch_tls will load TPIDRURO from
	75	* thread_info upon resuming execution and the following mcr
	76	* is merely redundant.
	77	*/
	78	barrier();
	79
	80	if (!tls_emu) {
	81	if (has_tls_reg) {
	82	asm("mcr p15, 0, %0, c13, c0, 3"
	83	: : "r" (val));
	84	} else {
9cc6d9e5	85	#ifdef CONFIG_KUSER_HELPERS
fbfb872f NL	86	/*
	87	* User space must never try to access this
	88	* directly. Expect your app to break
	89	* eventually if you do so. The user helper
	90	* at 0xffff0fe0 must be used instead. (see
	91	* entry-armv.S for details)
	92	*/
	93	((unsigned int )0xffff0ff0) = val;
9cc6d9e5	94	#endif
fbfb872f NL	95	}
	96
	97	}
	98	}
	99
a4780ade AH	100	static inline unsigned long get_tpuser(void)
	101	{
	102	unsigned long reg = 0;
	103
	104	if (has_tls_reg && !tls_emu)
	105	__asm__("mrc p15, 0, %0, c13, c0, 2" : "=r" (reg));
	106
	107	return reg;
	108	}
fbfb872f NL	109
	110	static inline void set_tpuser(unsigned long val)
	111	{
	112	/* Since TPIDRURW is fully context-switched (unlike TPIDRURO),
	113	* we need not update thread_info.
	114	*/
	115	if (has_tls_reg && !tls_emu) {
	116	asm("mcr p15, 0, %0, c13, c0, 2"
	117	: : "r" (val));
	118	}
	119	}
	120
	121	static inline void flush_tls(void)
	122	{
	123	set_tls(0);
	124	set_tpuser(0);
	125	}
	126
a4780ade	127	#endif
f159f4ed	128	#endif /* __ASMARM_TLS_H */