142 lines
4.1 KiB
ArmAsm
142 lines
4.1 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 <arch/abi.h>
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#include <asm/unistd.h>
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#include <asm/irqflags.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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STD_ENTRY(_sim_syscall)
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/*
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* Wait for r0-r9 to be ready (and lr on the off chance we
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* want the syscall to locate its caller), then make a magic
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* simulator syscall.
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*
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* We carefully stall until the registers are readable in case they
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* are the target of a slow load, etc. so that tile-sim will
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* definitely be able to read all of them inside the magic syscall.
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*
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* Technically this is wrong for r3-r9 and lr, since an interrupt
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* could come in and restore the registers with a slow load right
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* before executing the mtspr. We may need to modify tile-sim to
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* explicitly stall for this case, but we do not yet have
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* a way to implement such a stall.
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*/
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{ and zero, lr, r9 ; and zero, r8, r7 }
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{ and zero, r6, r5 ; and zero, r4, r3 }
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{ and zero, r2, r1 ; mtspr SIM_CONTROL, r0 }
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{ jrp lr }
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STD_ENDPROC(_sim_syscall)
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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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/* Delay a fixed number of cycles. */
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STD_ENTRY(__delay)
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{ addi r0, r0, -1; bnzt r0, . }
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jrp lr
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STD_ENDPROC(__delay)
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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 SYSTEM_SAVE_1_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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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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* 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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{
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lnk r0
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movei r1, 1
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}
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{
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addli r0, r0, _cpu_idle_nap - .
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mtspr INTERRUPT_CRITICAL_SECTION, r1
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}
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IRQ_ENABLE(r2, r3) /* unmask, but still with ICS set */
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mtspr EX_CONTEXT_1_1, r1 /* PL1, ICS clear */
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mtspr EX_CONTEXT_1_0, r0
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iret
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.global _cpu_idle_nap
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_cpu_idle_nap:
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nap
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jrp lr
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STD_ENDPROC(_cpu_idle)
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