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Diffstat (limited to 'arch/arm/lib/copy_template.S')
| -rw-r--r-- | arch/arm/lib/copy_template.S | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/arch/arm/lib/copy_template.S b/arch/arm/lib/copy_template.S new file mode 100644 index 000000000..810a805d3 --- /dev/null +++ b/arch/arm/lib/copy_template.S @@ -0,0 +1,294 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * 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. + */ + +/* + * 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. + * + * usave reg1 reg2 + * + * Unwind annotation macro is corresponding for 'enter' macro. + * It tell unwinder that preserved some provided registers on the stack + * and additional data by a prior 'enter' macro. + * + * exit reg1 reg2 + * + * Restore registers with the values previously saved with the + * 'preserv' macro. Called upon code termination. + * + * LDR1W_SHIFT + * STR1W_SHIFT + * + * Correction to be applied to the "ip" register when branching into + * the ldr1w or str1w instructions (some of these macros may expand to + * than one 32bit instruction in Thumb-2) + */ + + + UNWIND( .fnstart ) + enter r4, lr + UNWIND( .fnend ) + + UNWIND( .fnstart ) + usave r4, lr @ in first stmdb block + + 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} + UNWIND( .fnend ) + + UNWIND( .fnstart ) + usave r4, lr + UNWIND( .save {r5 - r8} ) @ in second stmfd block + blt 5f + + CALGN( ands ip, r0, #31 ) + CALGN( rsb r3, ip, #32 ) + CALGN( sbcsne 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 +#if LDR1W_SHIFT > 0 + lsl ip, ip, #LDR1W_SHIFT +#endif + addne pc, pc, ip @ C is always clear here + b 7f +6: + .rept (1 << LDR1W_SHIFT) + W(nop) + .endr + 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 + +#if LDR1W_SHIFT < STR1W_SHIFT + lsl ip, ip, #STR1W_SHIFT - LDR1W_SHIFT +#elif LDR1W_SHIFT > STR1W_SHIFT + lsr ip, ip, #LDR1W_SHIFT - STR1W_SHIFT +#endif + add pc, pc, ip + nop + .rept (1 << STR1W_SHIFT) + W(nop) + .endr + 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} + UNWIND( .fnend ) @ end of second stmfd block + + UNWIND( .fnstart ) + usave r4, lr @ still in first stmdb block +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 + UNWIND( .fnend ) + + + .macro forward_copy_shift pull push + + UNWIND( .fnstart ) + usave r4, lr @ still in first stmdb block + subs r2, r2, #28 + blt 14f + + CALGN( ands ip, r0, #31 ) + CALGN( rsb ip, ip, #32 ) + CALGN( sbcsne r4, ip, r2 ) @ C is always set here + CALGN( subcc r2, r2, ip ) + CALGN( bcc 15f ) + +11: stmfd sp!, {r5 - r9} + UNWIND( .fnend ) + + UNWIND( .fnstart ) + usave r4, lr + UNWIND( .save {r5 - r9} ) @ in new second stmfd block + 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, lspull #\pull + subs r2, r2, #32 + ldr4w r1, r8, r9, ip, lr, abort=19f + orr r3, r3, r4, lspush #\push + mov r4, r4, lspull #\pull + orr r4, r4, r5, lspush #\push + mov r5, r5, lspull #\pull + orr r5, r5, r6, lspush #\push + mov r6, r6, lspull #\pull + orr r6, r6, r7, lspush #\push + mov r7, r7, lspull #\pull + orr r7, r7, r8, lspush #\push + mov r8, r8, lspull #\pull + orr r8, r8, r9, lspush #\push + mov r9, r9, lspull #\pull + orr r9, r9, ip, lspush #\push + mov ip, ip, lspull #\pull + orr ip, ip, lr, lspush #\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} + UNWIND( .fnend ) @ end of the second stmfd block + + UNWIND( .fnstart ) + usave r4, lr @ still in first stmdb block +14: ands ip, r2, #28 + beq 16f + +15: mov r3, lr, lspull #\pull + ldr1w r1, lr, abort=21f + subs ip, ip, #4 + orr r3, r3, lr, lspush #\push + str1w r0, r3, abort=21f + bgt 15b + CALGN( cmp r2, #0 ) + CALGN( bge 11b ) + +16: sub r1, r1, #(\push / 8) + b 8b + UNWIND( .fnend ) + + .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 preamble 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 + |