1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Process/processor support for the Hexagon architecture 4 * 5 * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved. 6 */ 7 8 #ifndef _ASM_PROCESSOR_H 9 #define _ASM_PROCESSOR_H 10 11 #ifndef __ASSEMBLY__ 12 13 #include <asm/mem-layout.h> 14 #include <asm/registers.h> 15 #include <asm/hexagon_vm.h> 16 17 /* task_struct, defined elsewhere, is the "process descriptor" */ 18 struct task_struct; 19 20 extern void start_thread(struct pt_regs *, unsigned long, unsigned long); 21 22 /* 23 * thread_struct is supposed to be for context switch data. 24 * Specifically, to hold the state necessary to perform switch_to... 25 */ 26 struct thread_struct { 27 void *switch_sp; 28 }; 29 30 /* 31 * initializes thread_struct 32 * The only thing we have in there is switch_sp 33 * which doesn't really need to be initialized. 34 */ 35 36 #define INIT_THREAD { \ 37 } 38 39 #define cpu_relax() __vmyield() 40 41 /* 42 * Decides where the kernel will search for a free chunk of vm space during 43 * mmaps. 44 * See also arch_get_unmapped_area. 45 * Doesn't affect if you have MAX_FIXED in the page flags set though... 46 * 47 * Apparently the convention is that ld.so will ask for "unmapped" private 48 * memory to be allocated SOMEWHERE, but it also asks for memory explicitly 49 * via MAP_FIXED at the lower * addresses starting at VA=0x0. 50 * 51 * If the two requests collide, you get authentic segfaulting action, so 52 * you have to kick the "unmapped" base requests higher up. 53 */ 54 #define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE/3)) 55 56 57 #define task_pt_regs(task) \ 58 ((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1) 59 60 #define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk))) 61 #define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk))) 62 63 /* Free all resources held by a thread; defined in process.c */ 64 extern void release_thread(struct task_struct *dead_task); 65 66 /* Get wait channel for task P. */ 67 extern unsigned long get_wchan(struct task_struct *p); 68 69 /* The following stuff is pretty HEXAGON specific. */ 70 71 /* This is really just here for __switch_to. 72 Offsets are pulled via asm-offsets.c */ 73 74 /* 75 * No real reason why VM and native switch stacks should be different. 76 * Ultimately this should merge. Note that Rev C. ABI called out only 77 * R24-27 as callee saved GPRs needing explicit attention (R29-31 being 78 * dealt with automagically by allocframe), but the current ABI has 79 * more, R16-R27. By saving more, the worst case is that we waste some 80 * cycles if building with the old compilers. 81 */ 82 83 struct hexagon_switch_stack { 84 union { 85 struct { 86 unsigned long r16; 87 unsigned long r17; 88 }; 89 unsigned long long r1716; 90 }; 91 union { 92 struct { 93 unsigned long r18; 94 unsigned long r19; 95 }; 96 unsigned long long r1918; 97 }; 98 union { 99 struct { 100 unsigned long r20; 101 unsigned long r21; 102 }; 103 unsigned long long r2120; 104 }; 105 union { 106 struct { 107 unsigned long r22; 108 unsigned long r23; 109 }; 110 unsigned long long r2322; 111 }; 112 union { 113 struct { 114 unsigned long r24; 115 unsigned long r25; 116 }; 117 unsigned long long r2524; 118 }; 119 union { 120 struct { 121 unsigned long r26; 122 unsigned long r27; 123 }; 124 unsigned long long r2726; 125 }; 126 127 unsigned long fp; 128 unsigned long lr; 129 }; 130 131 #endif /* !__ASSEMBLY__ */ 132 133 #endif 134