1 /* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * vineetg: March 2009 9 * -Implemented task_pt_regs( ) 10 * 11 * Amit Bhor, Sameer Dhavale, Ashwin Chaugule: Codito Technologies 2004 12 */ 13 14 #ifndef __ASM_ARC_PROCESSOR_H 15 #define __ASM_ARC_PROCESSOR_H 16 17 #ifdef __KERNEL__ 18 19 #ifndef __ASSEMBLY__ 20 21 #include <asm/arcregs.h> /* for STATUS_E1_MASK et all */ 22 23 /* Arch specific stuff which needs to be saved per task. 24 * However these items are not so important so as to earn a place in 25 * struct thread_info 26 */ 27 struct thread_struct { 28 unsigned long ksp; /* kernel mode stack pointer */ 29 unsigned long callee_reg; /* pointer to callee regs */ 30 unsigned long fault_address; /* dbls as brkpt holder as well */ 31 unsigned long cause_code; /* Exception Cause Code (ECR) */ 32 #ifdef CONFIG_ARC_FPU_SAVE_RESTORE 33 struct arc_fpu fpu; 34 #endif 35 }; 36 37 #define INIT_THREAD { \ 38 .ksp = sizeof(init_stack) + (unsigned long) init_stack, \ 39 } 40 41 /* Forward declaration, a strange C thing */ 42 struct task_struct; 43 44 /* 45 * Return saved PC of a blocked thread. 46 */ 47 unsigned long thread_saved_pc(struct task_struct *t); 48 49 #define task_pt_regs(p) \ 50 ((struct pt_regs *)(THREAD_SIZE - 4 + (void *)task_stack_page(p)) - 1) 51 52 /* Free all resources held by a thread. */ 53 #define release_thread(thread) do { } while (0) 54 55 /* Prepare to copy thread state - unlazy all lazy status */ 56 #define prepare_to_copy(tsk) do { } while (0) 57 58 #define cpu_relax() do { } while (0) 59 60 #define copy_segments(tsk, mm) do { } while (0) 61 #define release_segments(mm) do { } while (0) 62 63 #define KSTK_EIP(tsk) (task_pt_regs(tsk)->ret) 64 65 /* 66 * Where abouts of Task's sp, fp, blink when it was last seen in kernel mode. 67 * These can't be derived from pt_regs as that would give correp user-mode val 68 */ 69 #define KSTK_ESP(tsk) (tsk->thread.ksp) 70 #define KSTK_BLINK(tsk) (*((unsigned int *)((KSTK_ESP(tsk)) + (13+1+1)*4))) 71 #define KSTK_FP(tsk) (*((unsigned int *)((KSTK_ESP(tsk)) + (13+1)*4))) 72 73 /* 74 * Do necessary setup to start up a newly executed thread. 75 * 76 * E1,E2 so that Interrupts are enabled in user mode 77 * L set, so Loop inhibited to begin with 78 * lp_start and lp_end seeded with bogus non-zero values so to easily catch 79 * the ARC700 sr to lp_start hardware bug 80 */ 81 #define start_thread(_regs, _pc, _usp) \ 82 do { \ 83 set_fs(USER_DS); /* reads from user space */ \ 84 (_regs)->ret = (_pc); \ 85 /* Interrupts enabled in User Mode */ \ 86 (_regs)->status32 = STATUS_U_MASK | STATUS_L_MASK \ 87 | STATUS_E1_MASK | STATUS_E2_MASK; \ 88 (_regs)->sp = (_usp); \ 89 /* bogus seed values for debugging */ \ 90 (_regs)->lp_start = 0x10; \ 91 (_regs)->lp_end = 0x80; \ 92 } while (0) 93 94 extern unsigned int get_wchan(struct task_struct *p); 95 96 /* 97 * Default implementation of macro that returns current 98 * instruction pointer ("program counter"). 99 * Should the PC register be read instead ? This macro does not seem to 100 * be used in many places so this wont be all that bad. 101 */ 102 #define current_text_addr() ({ __label__ _l; _l: &&_l; }) 103 104 #endif /* !__ASSEMBLY__ */ 105 106 /* Kernels Virtual memory area. 107 * Unlike other architectures(MIPS, sh, cris ) ARC 700 does not have a 108 * "kernel translated" region (like KSEG2 in MIPS). So we use a upper part 109 * of the translated bottom 2GB for kernel virtual memory and protect 110 * these pages from user accesses by disabling Ru, Eu and Wu. 111 */ 112 #define VMALLOC_SIZE (0x10000000) /* 256M */ 113 #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) 114 #define VMALLOC_END (PAGE_OFFSET) 115 116 /* Most of the architectures seem to be keeping some kind of padding between 117 * userspace TASK_SIZE and PAGE_OFFSET. i.e TASK_SIZE != PAGE_OFFSET. 118 */ 119 #define USER_KERNEL_GUTTER 0x10000000 120 121 /* User address space: 122 * On ARC700, CPU allows the entire lower half of 32 bit address space to be 123 * translated. Thus potentially 2G (0:0x7FFF_FFFF) could be User vaddr space. 124 * However we steal 256M for kernel addr (0x7000_0000:0x7FFF_FFFF) and another 125 * 256M (0x6000_0000:0x6FFF_FFFF) is gutter between user/kernel spaces 126 * Thus total User vaddr space is (0:0x5FFF_FFFF) 127 */ 128 #define TASK_SIZE (PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER) 129 130 #define STACK_TOP TASK_SIZE 131 #define STACK_TOP_MAX STACK_TOP 132 133 /* This decides where the kernel will search for a free chunk of vm 134 * space during mmap's. 135 */ 136 #define TASK_UNMAPPED_BASE (TASK_SIZE / 3) 137 138 #endif /* __KERNEL__ */ 139 140 #endif /* __ASM_ARC_PROCESSOR_H */ 141