arch/arm/cpu/armv8/cache.S

/*
 * (C) Copyright 2013
 * David Feng <fenghua@phytium.com.cn>
 *
 * This file is based on sample code from ARMv8 ARM.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <asm-offsets.h>
#include <config.h>
#include <asm/macro.h>
#include <asm/system.h>
#include <linux/linkage.h>

/*
 * void __asm_dcache_level(level)
 *
 * flush or invalidate one level cache.
 *
 * x0: cache level
 * x1: 0 clean & invalidate, 1 invalidate only
 * x2~x9: clobbered
 */
ENTRY(__asm_dcache_level)
	lsl	x12, x0, #1
	msr	csselr_el1, x12		/* select cache level */
	isb				/* sync change of cssidr_el1 */
	mrs	x6, ccsidr_el1		/* read the new cssidr_el1 */
	and	x2, x6, #7		/* x2 <- log2(cache line size)-4 */
	add	x2, x2, #4		/* x2 <- log2(cache line size) */
	mov	x3, #0x3ff
	and	x3, x3, x6, lsr #3	/* x3 <- max number of #ways */
	clz	w5, w3			/* bit position of #ways */
	mov	x4, #0x7fff
	and	x4, x4, x6, lsr #13	/* x4 <- max number of #sets */
	/* x12 <- cache level << 1 */
	/* x2 <- line length offset */
	/* x3 <- number of cache ways - 1 */
	/* x4 <- number of cache sets - 1 */
	/* x5 <- bit position of #ways */

loop_set:
	mov	x6, x3			/* x6 <- working copy of #ways */
loop_way:
	lsl	x7, x6, x5
	orr	x9, x12, x7		/* map way and level to cisw value */
	lsl	x7, x4, x2
	orr	x9, x9, x7		/* map set number to cisw value */
	tbz	w1, #0, 1f
	dc	isw, x9
	b	2f
1:	dc	cisw, x9		/* clean & invalidate by set/way */
2:	subs	x6, x6, #1		/* decrement the way */
	b.ge	loop_way
	subs	x4, x4, #1		/* decrement the set */
	b.ge	loop_set

	ret
ENDPROC(__asm_dcache_level)

/*
 * void __asm_flush_dcache_all(int invalidate_only)
 *
 * x0: 0 clean & invalidate, 1 invalidate only
 *
 * flush or invalidate all data cache by SET/WAY.
 */
ENTRY(__asm_dcache_all)
	mov	x1, x0
	dsb	sy
	mrs	x10, clidr_el1		/* read clidr_el1 */
	lsr	x11, x10, #24
	and	x11, x11, #0x7		/* x11 <- loc */
	cbz	x11, finished		/* if loc is 0, exit */
	mov	x15, lr
	mov	x0, #0			/* start flush at cache level 0 */
	/* x0  <- cache level */
	/* x10 <- clidr_el1 */
	/* x11 <- loc */
	/* x15 <- return address */

loop_level:
	lsl	x12, x0, #1
	add	x12, x12, x0		/* x0 <- tripled cache level */
	lsr	x12, x10, x12
	and	x12, x12, #7		/* x12 <- cache type */
	cmp	x12, #2
	b.lt	skip			/* skip if no cache or icache */
	bl	__asm_dcache_level	/* x1 = 0 flush, 1 invalidate */
skip:
	add	x0, x0, #1		/* increment cache level */
	cmp	x11, x0
	b.gt	loop_level

	mov	x0, #0
	msr	csselr_el1, x0		/* restore csselr_el1 */
	dsb	sy
	isb
	mov	lr, x15

finished:
	ret
ENDPROC(__asm_dcache_all)

ENTRY(__asm_flush_dcache_all)
	mov	x0, #0
	b	__asm_dcache_all
ENDPROC(__asm_flush_dcache_all)

ENTRY(__asm_invalidate_dcache_all)
	mov	x0, #0x1
	b	__asm_dcache_all
ENDPROC(__asm_invalidate_dcache_all)

/*
 * void __asm_flush_dcache_range(start, end)
 *
 * clean & invalidate data cache in the range
 *
 * x0: start address
 * x1: end address
 */
ENTRY(__asm_flush_dcache_range)
	mrs	x3, ctr_el0
	lsr	x3, x3, #16
	and	x3, x3, #0xf
	mov	x2, #4
	lsl	x2, x2, x3		/* cache line size */

	/* x2 <- minimal cache line size in cache system */
	sub	x3, x2, #1
	bic	x0, x0, x3
1:	dc	civac, x0	/* clean & invalidate data or unified cache */
	add	x0, x0, x2
	cmp	x0, x1
	b.lo	1b
	dsb	sy
	ret
ENDPROC(__asm_flush_dcache_range)

/*
 * void __asm_invalidate_icache_all(void)
 *
 * invalidate all tlb entries.
 */
ENTRY(__asm_invalidate_icache_all)
	ic	ialluis
	isb	sy
	ret
ENDPROC(__asm_invalidate_icache_all)

ENTRY(__asm_flush_l3_cache)
	mov	x0, #0			/* return status as success */
	ret
ENDPROC(__asm_flush_l3_cache)
	.weak	__asm_flush_l3_cache

/*
 * void __asm_switch_ttbr(ulong new_ttbr)
 *
 * Safely switches to a new page table.
 */
ENTRY(__asm_switch_ttbr)
	/* x2 = SCTLR (alive throghout the function) */
	switch_el x4, 3f, 2f, 1f
3:	mrs	x2, sctlr_el3
	b	0f
2:	mrs	x2, sctlr_el2
	b	0f
1:	mrs	x2, sctlr_el1
0:

	/* Unset CR_M | CR_C | CR_I from SCTLR to disable all caches */
	movn	x1, #(CR_M | CR_C | CR_I)
	and	x1, x2, x1
	switch_el x4, 3f, 2f, 1f
3:	msr	sctlr_el3, x1
	b	0f
2:	msr	sctlr_el2, x1
	b	0f
1:	msr	sctlr_el1, x1
0:	isb

	/* This call only clobbers x30 (lr) and x9 (unused) */
	mov	x3, x30
	bl	__asm_invalidate_tlb_all

	/* From here on we're running safely with caches disabled */

	/* Set TTBR to our first argument */
	switch_el x4, 3f, 2f, 1f
3:	msr	ttbr0_el3, x0
	b	0f
2:	msr	ttbr0_el2, x0
	b	0f
1:	msr	ttbr0_el1, x0
0:	isb

	/* Restore original SCTLR and thus enable caches again */
	switch_el x4, 3f, 2f, 1f
3:	msr	sctlr_el3, x2
	b	0f
2:	msr	sctlr_el2, x2
	b	0f
1:	msr	sctlr_el1, x2
0:	isb

	ret	x3
ENDPROC(__asm_switch_ttbr)