1 files changed, 179 insertions, 0 deletions
diff --git a/arch/powerpc/lib/string_64.S b/arch/powerpc/lib/string_64.S
new file mode 100644
index 000000000..a25eb8588
--- /dev/null
+++ b/arch/powerpc/lib/string_64.S
@@ -0,0 +1,179 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *
+ * Copyright (C) IBM Corporation, 2012
+ *
+ * Author: Anton Blanchard <anton@au.ibm.com>
+ */
+
+#include <linux/export.h>
+#include <asm/ppc_asm.h>
+#include <asm/linkage.h>
+#include <asm/asm-offsets.h>
+
+/**
+ * __arch_clear_user: - Zero a block of memory in user space, with less checking.
+ * @to:   Destination address, in user space.
+ * @n:    Number of bytes to zero.
+ *
+ * Zero a block of memory in user space.  Caller must check
+ * the specified block with access_ok() before calling this function.
+ *
+ * Returns number of bytes that could not be cleared.
+ * On success, this will be zero.
+ */
+
+	.macro err1
+100:
+	EX_TABLE(100b,.Ldo_err1)
+	.endm
+
+	.macro err2
+200:
+	EX_TABLE(200b,.Ldo_err2)
+	.endm
+
+	.macro err3
+300:
+	EX_TABLE(300b,.Ldo_err3)
+	.endm
+
+.Ldo_err1:
+	mr	r3,r8
+
+.Ldo_err2:
+	mtctr	r4
+1:
+err3;	stb	r0,0(r3)
+	addi	r3,r3,1
+	addi	r4,r4,-1
+	bdnz	1b
+
+.Ldo_err3:
+	mr	r3,r4
+	blr
+
+_GLOBAL_TOC(__arch_clear_user)
+	cmpdi	r4,32
+	neg	r6,r3
+	li	r0,0
+	blt	.Lshort_clear
+	mr	r8,r3
+	mtocrf	0x01,r6
+	clrldi	r6,r6,(64-3)
+
+	/* Get the destination 8 byte aligned */
+	bf	cr7*4+3,1f
+err1;	stb	r0,0(r3)
+	addi	r3,r3,1
+
+1:	bf	cr7*4+2,2f
+err1;	sth	r0,0(r3)
+	addi	r3,r3,2
+
+2:	bf	cr7*4+1,3f
+err1;	stw	r0,0(r3)
+	addi	r3,r3,4
+
+3:	sub	r4,r4,r6
+
+	cmpdi	r4,32
+	cmpdi	cr1,r4,512
+	blt	.Lshort_clear
+	bgt	cr1,.Llong_clear
+
+.Lmedium_clear:
+	srdi	r6,r4,5
+	mtctr	r6
+
+	/* Do 32 byte chunks */
+4:
+err2;	std	r0,0(r3)
+err2;	std	r0,8(r3)
+err2;	std	r0,16(r3)
+err2;	std	r0,24(r3)
+	addi	r3,r3,32
+	addi	r4,r4,-32
+	bdnz	4b
+
+.Lshort_clear:
+	/* up to 31 bytes to go */
+	cmpdi	r4,16
+	blt	6f
+err2;	std	r0,0(r3)
+err2;	std	r0,8(r3)
+	addi	r3,r3,16
+	addi	r4,r4,-16
+
+	/* Up to 15 bytes to go */
+6:	mr	r8,r3
+	clrldi	r4,r4,(64-4)
+	mtocrf	0x01,r4
+	bf	cr7*4+0,7f
+err1;	std	r0,0(r3)
+	addi	r3,r3,8
+
+7:	bf	cr7*4+1,8f
+err1;	stw	r0,0(r3)
+	addi	r3,r3,4
+
+8:	bf	cr7*4+2,9f
+err1;	sth	r0,0(r3)
+	addi	r3,r3,2
+
+9:	bf	cr7*4+3,10f
+err1;	stb	r0,0(r3)
+
+10:	li	r3,0
+	blr
+
+.Llong_clear:
+	LOAD_REG_ADDR(r5, ppc64_caches)
+
+	bf	cr7*4+0,11f
+err2;	std	r0,0(r3)
+	addi	r3,r3,8
+	addi	r4,r4,-8
+
+	/* Destination is 16 byte aligned, need to get it cache block aligned */
+11:	lwz	r7,DCACHEL1LOGBLOCKSIZE(r5)
+	lwz	r9,DCACHEL1BLOCKSIZE(r5)
+
+	/*
+	 * With worst case alignment the long clear loop takes a minimum
+	 * of 1 byte less than 2 cachelines.
+	 */
+	sldi	r10,r9,2
+	cmpd	r4,r10
+	blt	.Lmedium_clear
+
+	neg	r6,r3
+	addi	r10,r9,-1
+	and.	r5,r6,r10
+	beq	13f
+
+	srdi	r6,r5,4
+	mtctr	r6
+	mr	r8,r3
+12:
+err1;	std	r0,0(r3)
+err1;	std	r0,8(r3)
+	addi	r3,r3,16
+	bdnz	12b
+
+	sub	r4,r4,r5
+
+13:	srd	r6,r4,r7
+	mtctr	r6
+	mr	r8,r3
+14:
+err1;	dcbz	0,r3
+	add	r3,r3,r9
+	bdnz	14b
+
+	and	r4,r4,r10
+
+	cmpdi	r4,32
+	blt	.Lshort_clear
+	b	.Lmedium_clear
+EXPORT_SYMBOL(__arch_clear_user)