1/* 2 * Copyright 2010 Tilera Corporation. All Rights Reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation, version 2. 7 * 8 * This program is distributed in the hope that it will be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 11 * NON INFRINGEMENT. See the GNU General Public License for 12 * more details. 13 */ 14 15#include <linux/linkage.h> 16#include <linux/unistd.h> 17#include <asm/irqflags.h> 18#include <asm/processor.h> 19#include <arch/abi.h> 20#include <arch/spr_def.h> 21 22#ifdef __tilegx__ 23#define bnzt bnezt 24#endif 25 26STD_ENTRY(current_text_addr) 27 { move r0, lr; jrp lr } 28 STD_ENDPROC(current_text_addr) 29 30/* 31 * Implement execve(). The i386 code has a note that forking from kernel 32 * space results in no copy on write until the execve, so we should be 33 * careful not to write to the stack here. 34 */ 35STD_ENTRY(kernel_execve) 36 moveli TREG_SYSCALL_NR_NAME, __NR_execve 37 swint1 38 jrp lr 39 STD_ENDPROC(kernel_execve) 40 41/* 42 * We don't run this function directly, but instead copy it to a page 43 * we map into every user process. See vdso_setup(). 44 * 45 * Note that libc has a copy of this function that it uses to compare 46 * against the PC when a stack backtrace ends, so if this code is 47 * changed, the libc implementation(s) should also be updated. 48 */ 49 .pushsection .data 50ENTRY(__rt_sigreturn) 51 moveli TREG_SYSCALL_NR_NAME,__NR_rt_sigreturn 52 swint1 53 ENDPROC(__rt_sigreturn) 54 ENTRY(__rt_sigreturn_end) 55 .popsection 56 57STD_ENTRY(dump_stack) 58 { move r2, lr; lnk r1 } 59 { move r4, r52; addli r1, r1, dump_stack - . } 60 { move r3, sp; j _dump_stack } 61 jrp lr /* keep backtracer happy */ 62 STD_ENDPROC(dump_stack) 63 64STD_ENTRY(KBacktraceIterator_init_current) 65 { move r2, lr; lnk r1 } 66 { move r4, r52; addli r1, r1, KBacktraceIterator_init_current - . } 67 { move r3, sp; j _KBacktraceIterator_init_current } 68 jrp lr /* keep backtracer happy */ 69 STD_ENDPROC(KBacktraceIterator_init_current) 70 71/* 72 * Reset our stack to r1/r2 (sp and ksp0+cpu respectively), then 73 * free the old stack (passed in r0) and re-invoke cpu_idle(). 74 * We update sp and ksp0 simultaneously to avoid backtracer warnings. 75 */ 76STD_ENTRY(cpu_idle_on_new_stack) 77 { 78 move sp, r1 79 mtspr SPR_SYSTEM_SAVE_K_0, r2 80 } 81 jal free_thread_info 82 j cpu_idle 83 STD_ENDPROC(cpu_idle_on_new_stack) 84 85/* Loop forever on a nap during SMP boot. */ 86STD_ENTRY(smp_nap) 87 nap 88 nop /* avoid provoking the icache prefetch with a jump */ 89 j smp_nap /* we are not architecturally guaranteed not to exit nap */ 90 jrp lr /* clue in the backtracer */ 91 STD_ENDPROC(smp_nap) 92 93/* 94 * Enable interrupts racelessly and then nap until interrupted. 95 * Architecturally, we are guaranteed that enabling interrupts via 96 * mtspr to INTERRUPT_CRITICAL_SECTION only interrupts at the next PC. 97 * This function's _cpu_idle_nap address is special; see intvec.S. 98 * When interrupted at _cpu_idle_nap, we bump the PC forward 8, and 99 * as a result return to the function that called _cpu_idle(). 100 */ 101STD_ENTRY(_cpu_idle) 102 movei r1, 1 103 mtspr INTERRUPT_CRITICAL_SECTION, r1 104 IRQ_ENABLE(r2, r3) /* unmask, but still with ICS set */ 105 mtspr INTERRUPT_CRITICAL_SECTION, zero 106 .global _cpu_idle_nap 107_cpu_idle_nap: 108 nap 109 nop /* avoid provoking the icache prefetch with a jump */ 110 jrp lr 111 STD_ENDPROC(_cpu_idle) 112