![Nicolas Pitre](/assets/img/avatar_default.png)
The __memzero assembly code is almost identical to memset's except for two orr instructions. The runtime performance of __memset(p, n) and memset(p, 0, n) is accordingly almost identical. However, the memset() macro used to guard against a zero length and to call __memzero at compile time when the fill value is a constant zero interferes with compiler optimizations. Arnd found tha the test against a zero length brings up some new warnings with gcc v8: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82103 And successively rremoving the test against a zero length and the call to __memzero optimization produces the following kernel sizes for defconfig with gcc 6: text data bss dec hex filename 12248142 6278960 413588 18940690 1210312 vmlinux.orig 12244474 6278960 413588 18937022 120f4be vmlinux.no_zero_test 12239160 6278960 413588 18931708 120dffc vmlinux.no_memzero So it is probably not worth keeping __memzero around given that the compiler can do a better job at inlining trivial memset(p,0,n) on its own. And the memset code already handles a zero length just fine. Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
185 lines
4.3 KiB
C
185 lines
4.3 KiB
C
/*
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* linux/arch/arm/kernel/armksyms.c
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*
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* Copyright (C) 2000 Russell King
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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/export.h>
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#include <linux/sched.h>
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#include <linux/string.h>
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#include <linux/cryptohash.h>
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#include <linux/delay.h>
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#include <linux/in6.h>
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#include <linux/syscalls.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <linux/arm-smccc.h>
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#include <asm/checksum.h>
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#include <asm/ftrace.h>
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/*
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* libgcc functions - functions that are used internally by the
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* compiler... (prototypes are not correct though, but that
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* doesn't really matter since they're not versioned).
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*/
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extern void __ashldi3(void);
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extern void __ashrdi3(void);
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extern void __divsi3(void);
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extern void __lshrdi3(void);
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extern void __modsi3(void);
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extern void __muldi3(void);
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extern void __ucmpdi2(void);
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extern void __udivsi3(void);
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extern void __umodsi3(void);
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extern void __do_div64(void);
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extern void __bswapsi2(void);
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extern void __bswapdi2(void);
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extern void __aeabi_idiv(void);
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extern void __aeabi_idivmod(void);
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extern void __aeabi_lasr(void);
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extern void __aeabi_llsl(void);
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extern void __aeabi_llsr(void);
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extern void __aeabi_lmul(void);
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extern void __aeabi_uidiv(void);
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extern void __aeabi_uidivmod(void);
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extern void __aeabi_ulcmp(void);
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extern void fpundefinstr(void);
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void mmioset(void *, unsigned int, size_t);
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void mmiocpy(void *, const void *, size_t);
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/* platform dependent support */
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EXPORT_SYMBOL(arm_delay_ops);
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/* networking */
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EXPORT_SYMBOL(csum_partial);
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EXPORT_SYMBOL(csum_partial_copy_from_user);
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EXPORT_SYMBOL(csum_partial_copy_nocheck);
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EXPORT_SYMBOL(__csum_ipv6_magic);
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/* io */
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#ifndef __raw_readsb
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EXPORT_SYMBOL(__raw_readsb);
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#endif
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#ifndef __raw_readsw
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EXPORT_SYMBOL(__raw_readsw);
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#endif
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#ifndef __raw_readsl
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EXPORT_SYMBOL(__raw_readsl);
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#endif
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#ifndef __raw_writesb
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EXPORT_SYMBOL(__raw_writesb);
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#endif
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#ifndef __raw_writesw
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EXPORT_SYMBOL(__raw_writesw);
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#endif
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#ifndef __raw_writesl
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EXPORT_SYMBOL(__raw_writesl);
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#endif
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/* string / mem functions */
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EXPORT_SYMBOL(strchr);
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EXPORT_SYMBOL(strrchr);
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EXPORT_SYMBOL(memset);
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EXPORT_SYMBOL(__memset32);
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EXPORT_SYMBOL(__memset64);
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EXPORT_SYMBOL(memcpy);
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EXPORT_SYMBOL(memmove);
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EXPORT_SYMBOL(memchr);
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EXPORT_SYMBOL(mmioset);
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EXPORT_SYMBOL(mmiocpy);
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#ifdef CONFIG_MMU
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EXPORT_SYMBOL(copy_page);
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EXPORT_SYMBOL(arm_copy_from_user);
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EXPORT_SYMBOL(arm_copy_to_user);
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EXPORT_SYMBOL(arm_clear_user);
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EXPORT_SYMBOL(__get_user_1);
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EXPORT_SYMBOL(__get_user_2);
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EXPORT_SYMBOL(__get_user_4);
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EXPORT_SYMBOL(__get_user_8);
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#ifdef __ARMEB__
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EXPORT_SYMBOL(__get_user_64t_1);
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EXPORT_SYMBOL(__get_user_64t_2);
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EXPORT_SYMBOL(__get_user_64t_4);
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EXPORT_SYMBOL(__get_user_32t_8);
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#endif
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EXPORT_SYMBOL(__put_user_1);
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EXPORT_SYMBOL(__put_user_2);
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EXPORT_SYMBOL(__put_user_4);
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EXPORT_SYMBOL(__put_user_8);
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#endif
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/* gcc lib functions */
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EXPORT_SYMBOL(__ashldi3);
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EXPORT_SYMBOL(__ashrdi3);
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EXPORT_SYMBOL(__divsi3);
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EXPORT_SYMBOL(__lshrdi3);
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EXPORT_SYMBOL(__modsi3);
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EXPORT_SYMBOL(__muldi3);
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EXPORT_SYMBOL(__ucmpdi2);
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EXPORT_SYMBOL(__udivsi3);
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EXPORT_SYMBOL(__umodsi3);
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EXPORT_SYMBOL(__do_div64);
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EXPORT_SYMBOL(__bswapsi2);
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EXPORT_SYMBOL(__bswapdi2);
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#ifdef CONFIG_AEABI
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EXPORT_SYMBOL(__aeabi_idiv);
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EXPORT_SYMBOL(__aeabi_idivmod);
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EXPORT_SYMBOL(__aeabi_lasr);
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EXPORT_SYMBOL(__aeabi_llsl);
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EXPORT_SYMBOL(__aeabi_llsr);
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EXPORT_SYMBOL(__aeabi_lmul);
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EXPORT_SYMBOL(__aeabi_uidiv);
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EXPORT_SYMBOL(__aeabi_uidivmod);
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EXPORT_SYMBOL(__aeabi_ulcmp);
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#endif
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/* bitops */
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EXPORT_SYMBOL(_set_bit);
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EXPORT_SYMBOL(_test_and_set_bit);
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EXPORT_SYMBOL(_clear_bit);
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EXPORT_SYMBOL(_test_and_clear_bit);
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EXPORT_SYMBOL(_change_bit);
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EXPORT_SYMBOL(_test_and_change_bit);
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EXPORT_SYMBOL(_find_first_zero_bit_le);
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EXPORT_SYMBOL(_find_next_zero_bit_le);
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EXPORT_SYMBOL(_find_first_bit_le);
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EXPORT_SYMBOL(_find_next_bit_le);
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#ifdef __ARMEB__
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EXPORT_SYMBOL(_find_first_zero_bit_be);
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EXPORT_SYMBOL(_find_next_zero_bit_be);
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EXPORT_SYMBOL(_find_first_bit_be);
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EXPORT_SYMBOL(_find_next_bit_be);
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#endif
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#ifdef CONFIG_FUNCTION_TRACER
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#ifdef CONFIG_OLD_MCOUNT
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EXPORT_SYMBOL(mcount);
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#endif
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EXPORT_SYMBOL(__gnu_mcount_nc);
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#endif
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#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
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EXPORT_SYMBOL(__pv_phys_pfn_offset);
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EXPORT_SYMBOL(__pv_offset);
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#endif
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#ifdef CONFIG_HAVE_ARM_SMCCC
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EXPORT_SYMBOL(__arm_smccc_smc);
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EXPORT_SYMBOL(__arm_smccc_hvc);
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#endif
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