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f441882a52
ARMv6+ processors do not use CONFIG_CPU_USE_DOMAINS and use privileged
ldr/str instructions in copy_{from/to}_user. They are currently
unnecessarily using single ldr/str instructions and can use ldm/stm
instructions instead like memcpy does (but with appropriate fixup
tables).
This speeds up a "dd if=foo of=bar bs=32k" on a tmpfs filesystem by
about 4% on my Cortex-A9.
before:134217728 bytes (128.0MB) copied, 0.543848 seconds, 235.4MB/s
before:134217728 bytes (128.0MB) copied, 0.538610 seconds, 237.6MB/s
before:134217728 bytes (128.0MB) copied, 0.544356 seconds, 235.1MB/s
before:134217728 bytes (128.0MB) copied, 0.544364 seconds, 235.1MB/s
before:134217728 bytes (128.0MB) copied, 0.537130 seconds, 238.3MB/s
before:134217728 bytes (128.0MB) copied, 0.533443 seconds, 240.0MB/s
before:134217728 bytes (128.0MB) copied, 0.545691 seconds, 234.6MB/s
before:134217728 bytes (128.0MB) copied, 0.534695 seconds, 239.4MB/s
before:134217728 bytes (128.0MB) copied, 0.540561 seconds, 236.8MB/s
before:134217728 bytes (128.0MB) copied, 0.541025 seconds, 236.6MB/s
after:134217728 bytes (128.0MB) copied, 0.520445 seconds, 245.9MB/s
after:134217728 bytes (128.0MB) copied, 0.527846 seconds, 242.5MB/s
after:134217728 bytes (128.0MB) copied, 0.519510 seconds, 246.4MB/s
after:134217728 bytes (128.0MB) copied, 0.527231 seconds, 242.8MB/s
after:134217728 bytes (128.0MB) copied, 0.525030 seconds, 243.8MB/s
after:134217728 bytes (128.0MB) copied, 0.524236 seconds, 244.2MB/s
after:134217728 bytes (128.0MB) copied, 0.523659 seconds, 244.4MB/s
after:134217728 bytes (128.0MB) copied, 0.525018 seconds, 243.8MB/s
after:134217728 bytes (128.0MB) copied, 0.519249 seconds, 246.5MB/s
after:134217728 bytes (128.0MB) copied, 0.518527 seconds, 246.9MB/s
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
133 lines
2.6 KiB
ArmAsm
133 lines
2.6 KiB
ArmAsm
/*
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* linux/arch/arm/lib/copy_from_user.S
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*
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* Author: Nicolas Pitre
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* Created: Sep 29, 2005
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* Copyright: MontaVista Software, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/unwind.h>
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/*
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* Prototype:
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*
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* size_t arm_copy_from_user(void *to, const void *from, size_t n)
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*
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* Purpose:
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*
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* copy a block to kernel memory from user memory
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*
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* Params:
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*
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* to = kernel memory
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* from = user memory
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* n = number of bytes to copy
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*
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* Return value:
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*
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* Number of bytes NOT copied.
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*/
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#ifdef CONFIG_CPU_USE_DOMAINS
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#ifndef CONFIG_THUMB2_KERNEL
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#define LDR1W_SHIFT 0
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#else
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#define LDR1W_SHIFT 1
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#endif
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.macro ldr1w ptr reg abort
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ldrusr \reg, \ptr, 4, abort=\abort
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.endm
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.macro ldr4w ptr reg1 reg2 reg3 reg4 abort
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ldr1w \ptr, \reg1, \abort
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ldr1w \ptr, \reg2, \abort
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ldr1w \ptr, \reg3, \abort
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ldr1w \ptr, \reg4, \abort
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.endm
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.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
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ldr4w \ptr, \reg1, \reg2, \reg3, \reg4, \abort
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ldr4w \ptr, \reg5, \reg6, \reg7, \reg8, \abort
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.endm
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#else
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#define LDR1W_SHIFT 0
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.macro ldr1w ptr reg abort
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USERL(\abort, W(ldr) \reg, [\ptr], #4)
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.endm
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.macro ldr4w ptr reg1 reg2 reg3 reg4 abort
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USERL(\abort, ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4})
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.endm
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.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
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USERL(\abort, ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8})
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.endm
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#endif /* CONFIG_CPU_USE_DOMAINS */
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.macro ldr1b ptr reg cond=al abort
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ldrusr \reg, \ptr, 1, \cond, abort=\abort
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.endm
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#define STR1W_SHIFT 0
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.macro str1w ptr reg abort
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W(str) \reg, [\ptr], #4
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.endm
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.macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
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stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
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.endm
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.macro str1b ptr reg cond=al abort
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str\cond\()b \reg, [\ptr], #1
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.endm
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.macro enter reg1 reg2
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mov r3, #0
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stmdb sp!, {r0, r2, r3, \reg1, \reg2}
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.endm
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.macro usave reg1 reg2
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UNWIND( .save {r0, r2, r3, \reg1, \reg2} )
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.endm
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.macro exit reg1 reg2
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add sp, sp, #8
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ldmfd sp!, {r0, \reg1, \reg2}
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.endm
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.text
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ENTRY(arm_copy_from_user)
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#ifdef CONFIG_CPU_SPECTRE
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get_thread_info r3
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ldr r3, [r3, #TI_ADDR_LIMIT]
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uaccess_mask_range_ptr r1, r2, r3, ip
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#endif
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#include "copy_template.S"
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ENDPROC(arm_copy_from_user)
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.pushsection .fixup,"ax"
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.align 0
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copy_abort_preamble
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ldmfd sp!, {r1, r2, r3}
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sub r0, r0, r1
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rsb r0, r0, r2
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copy_abort_end
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.popsection
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