forked from luck/tmp_suning_uos_patched
8c92ba6c32
This avoids the hardware istream prefetcher doing unnecessary work. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
112 lines
3.4 KiB
ArmAsm
112 lines
3.4 KiB
ArmAsm
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#include <linux/linkage.h>
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#include <linux/unistd.h>
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#include <asm/irqflags.h>
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#include <asm/processor.h>
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#include <arch/abi.h>
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#include <arch/spr_def.h>
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#ifdef __tilegx__
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#define bnzt bnezt
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#endif
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STD_ENTRY(current_text_addr)
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{ move r0, lr; jrp lr }
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STD_ENDPROC(current_text_addr)
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/*
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* Implement execve(). The i386 code has a note that forking from kernel
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* space results in no copy on write until the execve, so we should be
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* careful not to write to the stack here.
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*/
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STD_ENTRY(kernel_execve)
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moveli TREG_SYSCALL_NR_NAME, __NR_execve
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swint1
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jrp lr
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STD_ENDPROC(kernel_execve)
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/*
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* We don't run this function directly, but instead copy it to a page
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* we map into every user process. See vdso_setup().
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*
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* Note that libc has a copy of this function that it uses to compare
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* against the PC when a stack backtrace ends, so if this code is
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* changed, the libc implementation(s) should also be updated.
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*/
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.pushsection .data
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ENTRY(__rt_sigreturn)
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moveli TREG_SYSCALL_NR_NAME,__NR_rt_sigreturn
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swint1
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ENDPROC(__rt_sigreturn)
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ENTRY(__rt_sigreturn_end)
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.popsection
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STD_ENTRY(dump_stack)
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{ move r2, lr; lnk r1 }
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{ move r4, r52; addli r1, r1, dump_stack - . }
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{ move r3, sp; j _dump_stack }
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jrp lr /* keep backtracer happy */
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STD_ENDPROC(dump_stack)
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STD_ENTRY(KBacktraceIterator_init_current)
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{ move r2, lr; lnk r1 }
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{ move r4, r52; addli r1, r1, KBacktraceIterator_init_current - . }
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{ move r3, sp; j _KBacktraceIterator_init_current }
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jrp lr /* keep backtracer happy */
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STD_ENDPROC(KBacktraceIterator_init_current)
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/*
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* Reset our stack to r1/r2 (sp and ksp0+cpu respectively), then
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* free the old stack (passed in r0) and re-invoke cpu_idle().
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* We update sp and ksp0 simultaneously to avoid backtracer warnings.
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*/
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STD_ENTRY(cpu_idle_on_new_stack)
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{
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move sp, r1
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mtspr SPR_SYSTEM_SAVE_K_0, r2
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}
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jal free_thread_info
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j cpu_idle
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STD_ENDPROC(cpu_idle_on_new_stack)
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/* Loop forever on a nap during SMP boot. */
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STD_ENTRY(smp_nap)
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nap
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nop /* avoid provoking the icache prefetch with a jump */
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j smp_nap /* we are not architecturally guaranteed not to exit nap */
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jrp lr /* clue in the backtracer */
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STD_ENDPROC(smp_nap)
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/*
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* Enable interrupts racelessly and then nap until interrupted.
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* Architecturally, we are guaranteed that enabling interrupts via
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* mtspr to INTERRUPT_CRITICAL_SECTION only interrupts at the next PC.
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* This function's _cpu_idle_nap address is special; see intvec.S.
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* When interrupted at _cpu_idle_nap, we bump the PC forward 8, and
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* as a result return to the function that called _cpu_idle().
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*/
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STD_ENTRY(_cpu_idle)
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movei r1, 1
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mtspr INTERRUPT_CRITICAL_SECTION, r1
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IRQ_ENABLE(r2, r3) /* unmask, but still with ICS set */
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mtspr INTERRUPT_CRITICAL_SECTION, zero
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.global _cpu_idle_nap
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_cpu_idle_nap:
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nap
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nop /* avoid provoking the icache prefetch with a jump */
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jrp lr
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STD_ENDPROC(_cpu_idle)
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