3 files changed, 93 insertions, 48 deletions

diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 653901042ad7d..2c9b8c0adf229 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -26,13 +26,14 @@ obj-$(CONFIG_PPC_BOOK3S_64) += copyuser_power7.o copypage_power7.o \
 			       memcpy_power7.o
 
 obj64-y	+= copypage_64.o copyuser_64.o mem_64.o hweight_64.o \
-	   string_64.o memcpy_64.o memcmp_64.o pmem.o
+	   memcpy_64.o memcmp_64.o pmem.o
 
 obj64-$(CONFIG_SMP)	+= locks.o
 obj64-$(CONFIG_ALTIVEC)	+= vmx-helper.o
 obj64-$(CONFIG_KPROBES_SANITY_TEST) += test_emulate_step.o
 
-obj-y			+= checksum_$(BITS).o checksum_wrappers.o
+obj-y			+= checksum_$(BITS).o checksum_wrappers.o \
+			   string_$(BITS).o
 
 obj-y			+= sstep.o ldstfp.o quad.o
 obj64-y			+= quad.o
diff --git a/arch/powerpc/lib/string.S b/arch/powerpc/lib/string.S
index 0378def28d411..5343a88e619e9 100644
--- a/arch/powerpc/lib/string.S
+++ b/arch/powerpc/lib/string.S
@@ -8,8 +8,6 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
-#include <asm/processor.h>
-#include <asm/errno.h>
 #include <asm/ppc_asm.h>
 #include <asm/export.h>
 #include <asm/cache.h>
@@ -86,47 +84,3 @@ _GLOBAL(memchr)
 2:	li	r3,0
 	blr
 EXPORT_SYMBOL(memchr)
-
-#ifdef CONFIG_PPC32
-_GLOBAL(__clear_user)
-	addi	r6,r3,-4
-	li	r3,0
-	li	r5,0
-	cmplwi	0,r4,4
-	blt	7f
-	/* clear a single word */
-11:	stwu	r5,4(r6)
-	beqlr
-	/* clear word sized chunks */
-	andi.	r0,r6,3
-	add	r4,r0,r4
-	subf	r6,r0,r6
-	srwi	r0,r4,2
-	andi.	r4,r4,3
-	mtctr	r0
-	bdz	7f
-1:	stwu	r5,4(r6)
-	bdnz	1b
-	/* clear byte sized chunks */
-7:	cmpwi	0,r4,0
-	beqlr
-	mtctr	r4
-	addi	r6,r6,3
-8:	stbu	r5,1(r6)
-	bdnz	8b
-	blr
-90:	mr	r3,r4
-	blr
-91:	mfctr	r3
-	slwi	r3,r3,2
-	add	r3,r3,r4
-	blr
-92:	mfctr	r3
-	blr
-
-	EX_TABLE(11b, 90b)
-	EX_TABLE(1b, 91b)
-	EX_TABLE(8b, 92b)
-
-EXPORT_SYMBOL(__clear_user)
-#endif
diff --git a/arch/powerpc/lib/string_32.S b/arch/powerpc/lib/string_32.S
new file mode 100644
index 0000000000000..f69a6aab7bfbb
--- /dev/null
+++ b/arch/powerpc/lib/string_32.S
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * String handling functions for PowerPC32
+ *
+ * Copyright (C) 1996 Paul Mackerras.
+ *
+ */
+
+#include <asm/ppc_asm.h>
+#include <asm/export.h>
+#include <asm/cache.h>
+
+	.text
+
+CACHELINE_BYTES = L1_CACHE_BYTES
+LG_CACHELINE_BYTES = L1_CACHE_SHIFT
+CACHELINE_MASK = (L1_CACHE_BYTES-1)
+
+_GLOBAL(__clear_user)
+/*
+ * Use dcbz on the complete cache lines in the destination
+ * to set them to zero.  This requires that the destination
+ * area is cacheable.
+ */
+	cmplwi	cr0, r4, 4
+	mr	r10, r3
+	li	r3, 0
+	blt	7f
+
+11:	stw	r3, 0(r10)
+	beqlr
+	andi.	r0, r10, 3
+	add	r11, r0, r4
+	subf	r6, r0, r10
+
+	clrlwi	r7, r6, 32 - LG_CACHELINE_BYTES
+	add	r8, r7, r11
+	srwi	r9, r8, LG_CACHELINE_BYTES
+	addic.	r9, r9, -1	/* total number of complete cachelines */
+	ble	2f
+	xori	r0, r7, CACHELINE_MASK & ~3
+	srwi.	r0, r0, 2
+	beq	3f
+	mtctr	r0
+4:	stwu	r3, 4(r6)
+	bdnz	4b
+3:	mtctr	r9
+	li	r7, 4
+10:	dcbz	r7, r6
+	addi	r6, r6, CACHELINE_BYTES
+	bdnz	10b
+	clrlwi	r11, r8, 32 - LG_CACHELINE_BYTES
+	addi	r11, r11, 4
+
+2:	srwi	r0 ,r11 ,2
+	mtctr	r0
+	bdz	6f
+1:	stwu	r3, 4(r6)
+	bdnz	1b
+6:	andi.	r11, r11, 3
+	beqlr
+	mtctr	r11
+	addi	r6, r6, 3
+8:	stbu	r3, 1(r6)
+	bdnz	8b
+	blr
+
+7:	cmpwi	cr0, r4, 0
+	beqlr
+	mtctr	r4
+	addi	r6, r10, -1
+9:	stbu	r3, 1(r6)
+	bdnz	9b
+	blr
+
+90:	mr	r3, r4
+	blr
+91:	add	r3, r10, r4
+	subf	r3, r6, r3
+	blr
+
+	EX_TABLE(11b, 90b)
+	EX_TABLE(4b, 91b)
+	EX_TABLE(10b, 91b)
+	EX_TABLE(1b, 91b)
+	EX_TABLE(8b, 91b)
+	EX_TABLE(9b, 91b)
+
+EXPORT_SYMBOL(__clear_user)