linux/arch/arm/mm/copypage-fa.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/arch/arm/lib/copypage-fa.S
 *
 *  Copyright (C) 2005 Faraday Corp.
 *  Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
 *
 * Based on copypage-v4wb.S:
 *  Copyright (C) 1995-1999 Russell King
 */
#include <linux/init.h>
#include <linux/highmem.h>

/*
 * Faraday optimised copy_user_page
 */
static void fa_copy_user_page(void *kto, const void *kfrom)
{
	int tmp;

	asm volatile ("\
1:	ldmia	%1!, {r3, r4, ip, lr}		@ 4\n\
	stmia	%0, {r3, r4, ip, lr}		@ 4\n\
	mcr	p15, 0, %0, c7, c14, 1		@ 1   clean and invalidate D line\n\
	add	%0, %0, #16			@ 1\n\
	ldmia	%1!, {r3, r4, ip, lr}		@ 4\n\
	stmia	%0, {r3, r4, ip, lr}		@ 4\n\
	mcr	p15, 0, %0, c7, c14, 1		@ 1   clean and invalidate D line\n\
	add	%0, %0, #16			@ 1\n\
	subs	%2, %2, #1			@ 1\n\
	bne	1b				@ 1\n\
	mcr	p15, 0, %2, c7, c10, 4		@ 1   drain WB"
	: "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
	: "2" (PAGE_SIZE / 32)
	: "r3", "r4", "ip", "lr");
}

void fa_copy_user_highpage(struct page *to, struct page *from,
	unsigned long vaddr, struct vm_area_struct *vma)
{
	void *kto, *kfrom;

	kto = kmap_atomic(to);
	kfrom = kmap_atomic(from);
	fa_copy_user_page(kto, kfrom);
	kunmap_atomic(kfrom);
	kunmap_atomic(kto);
}

/*
 * Faraday optimised clear_user_page
 *
 * Same story as above.
 */
void fa_clear_user_highpage(struct page *page, unsigned long vaddr)
{
	void *ptr, *kaddr = kmap_atomic(page);
	asm volatile("\
	mov	r1, %2				@ 1\n\
	mov	r2, #0				@ 1\n\
	mov	r3, #0				@ 1\n\
	mov	ip, #0				@ 1\n\
	mov	lr, #0				@ 1\n\
1:	stmia	%0, {r2, r3, ip, lr}		@ 4\n\
	mcr	p15, 0, %0, c7, c14, 1		@ 1   clean and invalidate D line\n\
	add	%0, %0, #16			@ 1\n\
	stmia	%0, {r2, r3, ip, lr}		@ 4\n\
	mcr	p15, 0, %0, c7, c14, 1		@ 1   clean and invalidate D line\n\
	add	%0, %0, #16			@ 1\n\
	subs	r1, r1, #1			@ 1\n\
	bne	1b				@ 1\n\
	mcr	p15, 0, r1, c7, c10, 4		@ 1   drain WB"
	: "=r" (ptr)
	: "0" (kaddr), "I" (PAGE_SIZE / 32)
	: "r1", "r2", "r3", "ip", "lr");
	kunmap_atomic(kaddr);
}

struct cpu_user_fns fa_user_fns __initdata = {
	.cpu_clear_user_highpage = fa_clear_user_highpage,
	.cpu_copy_user_highpage	= fa_copy_user_highpage,
};