![Chris Zankel](/assets/img/avatar_default.png)
The original implementation could clobber registers under certain conditions. The Xtensa processor architecture uses windowed registers and the original implementation was using a4 as a temporary register, which under certain conditions could be register a0 of the oldest window frame, and didn't always restore the content correctly. By moving the _spill_registers routine inside the fast system call, it frees up one more register (the return address is not required anymore) for the spill routine. Signed-off-by: Chris Zankel <chris@zankel.net>
130 lines
2.8 KiB
C
130 lines
2.8 KiB
C
/*
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* arch/xtensa/kernel/xtensa_ksyms.c
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*
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* Export Xtensa-specific functions for loadable modules.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2001 - 2005 Tensilica Inc.
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*
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* Joe Taylor <joe@tensilica.com>
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*/
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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#include <asm/irq.h>
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#include <linux/in6.h>
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#include <asm/uaccess.h>
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#include <asm/checksum.h>
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#include <asm/dma.h>
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#include <asm/io.h>
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#include <asm/page.h>
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#include <asm/pgalloc.h>
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#include <asm/ftrace.h>
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#ifdef CONFIG_BLK_DEV_FD
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#include <asm/floppy.h>
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#endif
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#ifdef CONFIG_NET
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#include <net/checksum.h>
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#endif /* CONFIG_NET */
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/*
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* String functions
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*/
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EXPORT_SYMBOL(memset);
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EXPORT_SYMBOL(memcpy);
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EXPORT_SYMBOL(memmove);
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EXPORT_SYMBOL(__strncpy_user);
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EXPORT_SYMBOL(clear_page);
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EXPORT_SYMBOL(copy_page);
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EXPORT_SYMBOL(empty_zero_page);
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/*
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* gcc internal math functions
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*/
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extern long long __ashrdi3(long long, int);
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extern long long __ashldi3(long long, int);
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extern long long __lshrdi3(long long, int);
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extern int __divsi3(int, int);
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extern int __modsi3(int, int);
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extern long long __muldi3(long long, long long);
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extern int __mulsi3(int, int);
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extern unsigned int __udivsi3(unsigned int, unsigned int);
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extern unsigned int __umodsi3(unsigned int, unsigned int);
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extern unsigned long long __umoddi3(unsigned long long, unsigned long long);
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extern unsigned long long __udivdi3(unsigned long long, unsigned long long);
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extern int __ucmpdi2(int, int);
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EXPORT_SYMBOL(__ashldi3);
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EXPORT_SYMBOL(__ashrdi3);
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EXPORT_SYMBOL(__lshrdi3);
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EXPORT_SYMBOL(__divsi3);
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EXPORT_SYMBOL(__modsi3);
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EXPORT_SYMBOL(__muldi3);
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EXPORT_SYMBOL(__mulsi3);
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EXPORT_SYMBOL(__udivsi3);
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EXPORT_SYMBOL(__umodsi3);
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EXPORT_SYMBOL(__udivdi3);
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EXPORT_SYMBOL(__umoddi3);
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EXPORT_SYMBOL(__ucmpdi2);
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void __xtensa_libgcc_window_spill(void)
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{
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BUG();
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}
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EXPORT_SYMBOL(__xtensa_libgcc_window_spill);
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unsigned long __sync_fetch_and_and_4(unsigned long *p, unsigned long v)
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{
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BUG();
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}
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EXPORT_SYMBOL(__sync_fetch_and_and_4);
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unsigned long __sync_fetch_and_or_4(unsigned long *p, unsigned long v)
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{
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BUG();
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}
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EXPORT_SYMBOL(__sync_fetch_and_or_4);
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#ifdef CONFIG_NET
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/*
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* Networking support
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*/
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EXPORT_SYMBOL(csum_partial);
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EXPORT_SYMBOL(csum_partial_copy_generic);
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#endif /* CONFIG_NET */
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/*
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* Architecture-specific symbols
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*/
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EXPORT_SYMBOL(__xtensa_copy_user);
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/*
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* Kernel hacking ...
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*/
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#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
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// FIXME EXPORT_SYMBOL(screen_info);
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#endif
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EXPORT_SYMBOL(outsb);
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EXPORT_SYMBOL(outsw);
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EXPORT_SYMBOL(outsl);
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EXPORT_SYMBOL(insb);
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EXPORT_SYMBOL(insw);
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EXPORT_SYMBOL(insl);
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extern long common_exception_return;
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EXPORT_SYMBOL(common_exception_return);
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#ifdef CONFIG_FUNCTION_TRACER
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EXPORT_SYMBOL(_mcount);
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#endif
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