aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/lib/copy_template.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/lib/copy_template.S')
-rw-r--r--arch/arm/lib/copy_template.S255
1 files changed, 255 insertions, 0 deletions
diff --git a/arch/arm/lib/copy_template.S b/arch/arm/lib/copy_template.S
new file mode 100644
index 00000000000..838e435e492
--- /dev/null
+++ b/arch/arm/lib/copy_template.S
@@ -0,0 +1,255 @@
+/*
+ * linux/arch/arm/lib/copy_template.s
+ *
+ * Code template for optimized memory copy functions
+ *
+ * Author: Nicolas Pitre
+ * Created: Sep 28, 2005
+ * Copyright: MontaVista Software, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * This can be used to enable code to cacheline align the source pointer.
+ * Experiments on tested architectures (StrongARM and XScale) didn't show
+ * this a worthwhile thing to do. That might be different in the future.
+ */
+//#define CALGN(code...) code
+#define CALGN(code...)
+
+/*
+ * Theory of operation
+ * -------------------
+ *
+ * This file provides the core code for a forward memory copy used in
+ * the implementation of memcopy(), copy_to_user() and copy_from_user().
+ *
+ * The including file must define the following accessor macros
+ * according to the need of the given function:
+ *
+ * ldr1w ptr reg abort
+ *
+ * This loads one word from 'ptr', stores it in 'reg' and increments
+ * 'ptr' to the next word. The 'abort' argument is used for fixup tables.
+ *
+ * ldr4w ptr reg1 reg2 reg3 reg4 abort
+ * ldr8w ptr, reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+ *
+ * This loads four or eight words starting from 'ptr', stores them
+ * in provided registers and increments 'ptr' past those words.
+ * The'abort' argument is used for fixup tables.
+ *
+ * ldr1b ptr reg cond abort
+ *
+ * Similar to ldr1w, but it loads a byte and increments 'ptr' one byte.
+ * It also must apply the condition code if provided, otherwise the
+ * "al" condition is assumed by default.
+ *
+ * str1w ptr reg abort
+ * str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
+ * str1b ptr reg cond abort
+ *
+ * Same as their ldr* counterparts, but data is stored to 'ptr' location
+ * rather than being loaded.
+ *
+ * enter reg1 reg2
+ *
+ * Preserve the provided registers on the stack plus any additional
+ * data as needed by the implementation including this code. Called
+ * upon code entry.
+ *
+ * exit reg1 reg2
+ *
+ * Restore registers with the values previously saved with the
+ * 'preserv' macro. Called upon code termination.
+ */
+
+
+ enter r4, lr
+
+ subs r2, r2, #4
+ blt 8f
+ ands ip, r0, #3
+ PLD( pld [r1, #0] )
+ bne 9f
+ ands ip, r1, #3
+ bne 10f
+
+1: subs r2, r2, #(28)
+ stmfd sp!, {r5 - r8}
+ blt 5f
+
+ CALGN( ands ip, r1, #31 )
+ CALGN( rsb r3, ip, #32 )
+ CALGN( sbcnes r4, r3, r2 ) @ C is always set here
+ CALGN( bcs 2f )
+ CALGN( adr r4, 6f )
+ CALGN( subs r2, r2, r3 ) @ C gets set
+ CALGN( add pc, r4, ip )
+
+ PLD( pld [r1, #0] )
+2: PLD( subs r2, r2, #96 )
+ PLD( pld [r1, #28] )
+ PLD( blt 4f )
+ PLD( pld [r1, #60] )
+ PLD( pld [r1, #92] )
+
+3: PLD( pld [r1, #124] )
+4: ldr8w r1, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f
+ subs r2, r2, #32
+ str8w r0, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f
+ bge 3b
+ PLD( cmn r2, #96 )
+ PLD( bge 4b )
+
+5: ands ip, r2, #28
+ rsb ip, ip, #32
+ addne pc, pc, ip @ C is always clear here
+ b 7f
+6: nop
+ ldr1w r1, r3, abort=20f
+ ldr1w r1, r4, abort=20f
+ ldr1w r1, r5, abort=20f
+ ldr1w r1, r6, abort=20f
+ ldr1w r1, r7, abort=20f
+ ldr1w r1, r8, abort=20f
+ ldr1w r1, lr, abort=20f
+
+ add pc, pc, ip
+ nop
+ nop
+ str1w r0, r3, abort=20f
+ str1w r0, r4, abort=20f
+ str1w r0, r5, abort=20f
+ str1w r0, r6, abort=20f
+ str1w r0, r7, abort=20f
+ str1w r0, r8, abort=20f
+ str1w r0, lr, abort=20f
+
+ CALGN( bcs 2b )
+
+7: ldmfd sp!, {r5 - r8}
+
+8: movs r2, r2, lsl #31
+ ldr1b r1, r3, ne, abort=21f
+ ldr1b r1, r4, cs, abort=21f
+ ldr1b r1, ip, cs, abort=21f
+ str1b r0, r3, ne, abort=21f
+ str1b r0, r4, cs, abort=21f
+ str1b r0, ip, cs, abort=21f
+
+ exit r4, pc
+
+9: rsb ip, ip, #4
+ cmp ip, #2
+ ldr1b r1, r3, gt, abort=21f
+ ldr1b r1, r4, ge, abort=21f
+ ldr1b r1, lr, abort=21f
+ str1b r0, r3, gt, abort=21f
+ str1b r0, r4, ge, abort=21f
+ subs r2, r2, ip
+ str1b r0, lr, abort=21f
+ blt 8b
+ ands ip, r1, #3
+ beq 1b
+
+10: bic r1, r1, #3
+ cmp ip, #2
+ ldr1w r1, lr, abort=21f
+ beq 17f
+ bgt 18f
+
+
+ .macro forward_copy_shift pull push
+
+ subs r2, r2, #28
+ blt 14f
+
+ CALGN( ands ip, r1, #31 )
+ CALGN( rsb ip, ip, #32 )
+ CALGN( sbcnes r4, ip, r2 ) @ C is always set here
+ CALGN( subcc r2, r2, ip )
+ CALGN( bcc 15f )
+
+11: stmfd sp!, {r5 - r9}
+
+ PLD( pld [r1, #0] )
+ PLD( subs r2, r2, #96 )
+ PLD( pld [r1, #28] )
+ PLD( blt 13f )
+ PLD( pld [r1, #60] )
+ PLD( pld [r1, #92] )
+
+12: PLD( pld [r1, #124] )
+13: ldr4w r1, r4, r5, r6, r7, abort=19f
+ mov r3, lr, pull #\pull
+ subs r2, r2, #32
+ ldr4w r1, r8, r9, ip, lr, abort=19f
+ orr r3, r3, r4, push #\push
+ mov r4, r4, pull #\pull
+ orr r4, r4, r5, push #\push
+ mov r5, r5, pull #\pull
+ orr r5, r5, r6, push #\push
+ mov r6, r6, pull #\pull
+ orr r6, r6, r7, push #\push
+ mov r7, r7, pull #\pull
+ orr r7, r7, r8, push #\push
+ mov r8, r8, pull #\pull
+ orr r8, r8, r9, push #\push
+ mov r9, r9, pull #\pull
+ orr r9, r9, ip, push #\push
+ mov ip, ip, pull #\pull
+ orr ip, ip, lr, push #\push
+ str8w r0, r3, r4, r5, r6, r7, r8, r9, ip, , abort=19f
+ bge 12b
+ PLD( cmn r2, #96 )
+ PLD( bge 13b )
+
+ ldmfd sp!, {r5 - r9}
+
+14: ands ip, r2, #28
+ beq 16f
+
+15: mov r3, lr, pull #\pull
+ ldr1w r1, lr, abort=21f
+ subs ip, ip, #4
+ orr r3, r3, lr, push #\push
+ str1w r0, r3, abort=21f
+ bgt 15b
+ CALGN( cmp r2, #0 )
+ CALGN( bge 11b )
+
+16: sub r1, r1, #(\push / 8)
+ b 8b
+
+ .endm
+
+
+ forward_copy_shift pull=8 push=24
+
+17: forward_copy_shift pull=16 push=16
+
+18: forward_copy_shift pull=24 push=8
+
+
+/*
+ * Abort preanble and completion macros.
+ * If a fixup handler is required then those macros must surround it.
+ * It is assumed that the fixup code will handle the private part of
+ * the exit macro.
+ */
+
+ .macro copy_abort_preamble
+19: ldmfd sp!, {r5 - r9}
+ b 21f
+20: ldmfd sp!, {r5 - r8}
+21:
+ .endm
+
+ .macro copy_abort_end
+ ldmfd sp!, {r4, pc}
+ .endm
+