aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorLey Foon Tan <lftan@altera.com>2014-11-06 02:19:47 -0500
committerLey Foon Tan <lftan@altera.com>2014-12-07 23:55:53 -0500
commit71995e4d004f6afbc86cc4a80c4a281f6c00b07f (patch)
tree68139e7bb9dfee02e23384224e2fa20082e55653
parentcbd15b3fadc27e81a6e8a3d38ce13cde5ce7cb71 (diff)
nios2: Process management
This patch adds support for thread creation and context switching. Signed-off-by: Ley Foon Tan <lftan@altera.com>
Diffstat
-rw-r--r--arch/nios2/include/asm/mmu_context.h66
-rw-r--r--arch/nios2/include/asm/processor.h103
-rw-r--r--arch/nios2/include/asm/switch_to.h31
-rw-r--r--arch/nios2/include/asm/thread_info.h120
-rw-r--r--arch/nios2/kernel/process.c258
-rw-r--r--arch/nios2/mm/mmu_context.c116
6 files changed, 694 insertions, 0 deletions
diff --git a/arch/nios2/include/asm/mmu_context.h b/arch/nios2/include/asm/mmu_context.h
new file mode 100644
index 000000000000..294b4b1f81d4
--- /dev/null
+++ b/arch/nios2/include/asm/mmu_context.h
@@ -0,0 +1,66 @@
1/*
2 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
3 * Copyright (C) 1996, 1997, 1998, 1999 by Ralf Baechle
4 * Copyright (C) 1999 Silicon Graphics, Inc.
5 *
6 * based on MIPS asm/mmu_context.h
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License. See the file "COPYING" in the main directory of this archive
10 * for more details.
11 */
12
13#ifndef _ASM_NIOS2_MMU_CONTEXT_H
14#define _ASM_NIOS2_MMU_CONTEXT_H
15
16#include <asm-generic/mm_hooks.h>
17
18extern void mmu_context_init(void);
19extern unsigned long get_pid_from_context(mm_context_t *ctx);
20
21/*
22 * For the fast tlb miss handlers, we keep a pointer to the current pgd.
23 * processor.
24 */
25extern pgd_t *pgd_current;
26
27static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
28{
29}
30
31/*
32 * Initialize the context related info for a new mm_struct instance.
33 *
34 * Set all new contexts to 0, that way the generation will never match
35 * the currently running generation when this context is switched in.
36 */
37static inline int init_new_context(struct task_struct *tsk,
38 struct mm_struct *mm)
39{
40 mm->context = 0;
41 return 0;
42}
43
44/*
45 * Destroy context related info for an mm_struct that is about
46 * to be put to rest.
47 */
48static inline void destroy_context(struct mm_struct *mm)
49{
50}
51
52void switch_mm(struct mm_struct *prev, struct mm_struct *next,
53 struct task_struct *tsk);
54
55static inline void deactivate_mm(struct task_struct *tsk,
56 struct mm_struct *mm)
57{
58}
59
60/*
61 * After we have set current->mm to a new value, this activates
62 * the context for the new mm so we see the new mappings.
63 */
64void activate_mm(struct mm_struct *prev, struct mm_struct *next);
65
66#endif /* _ASM_NIOS2_MMU_CONTEXT_H */
diff --git a/arch/nios2/include/asm/processor.h b/arch/nios2/include/asm/processor.h
new file mode 100644
index 000000000000..3bd349473b06
--- /dev/null
+++ b/arch/nios2/include/asm/processor.h
@@ -0,0 +1,103 @@
1/*
2 * Copyright (C) 2013 Altera Corporation
3 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
4 * Copyright (C) 2004 Microtronix Datacom Ltd
5 * Copyright (C) 2001 Ken Hill (khill@microtronix.com)
6 * Vic Phillips (vic@microtronix.com)
7 *
8 * based on SPARC asm/processor_32.h which is:
9 *
10 * Copyright (C) 1994 David S. Miller
11 *
12 * This file is subject to the terms and conditions of the GNU General Public
13 * License. See the file "COPYING" in the main directory of this archive
14 * for more details.
15 */
16
17#ifndef _ASM_NIOS2_PROCESSOR_H
18#define _ASM_NIOS2_PROCESSOR_H
19
20#include <asm/ptrace.h>
21#include <asm/registers.h>
22#include <asm/page.h>
23
24#define NIOS2_FLAG_KTHREAD 0x00000001 /* task is a kernel thread */
25
26#define NIOS2_OP_NOP 0x1883a
27#define NIOS2_OP_BREAK 0x3da03a
28
29#ifdef __KERNEL__
30
31#define STACK_TOP TASK_SIZE
32#define STACK_TOP_MAX STACK_TOP
33
34#endif /* __KERNEL__ */
35
36/* Kuser helpers is mapped to this user space address */
37#define KUSER_BASE 0x1000
38#define KUSER_SIZE (PAGE_SIZE)
39#ifndef __ASSEMBLY__
40
41/*
42 * Default implementation of macro that returns current
43 * instruction pointer ("program counter").
44 */
45#define current_text_addr() ({ __label__ _l; _l: &&_l; })
46
47# define TASK_SIZE 0x7FFF0000UL
48# define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 3))
49
50/* The Nios processor specific thread struct. */
51struct thread_struct {
52 struct pt_regs *kregs;
53
54 /* Context switch saved kernel state. */
55 unsigned long ksp;
56 unsigned long kpsr;
57};
58
59#define INIT_MMAP \
60 { &init_mm, (0), (0), __pgprot(0x0), VM_READ | VM_WRITE | VM_EXEC }
61
62# define INIT_THREAD { \
63 .kregs = NULL, \
64 .ksp = 0, \
65 .kpsr = 0, \
66}
67
68extern void start_thread(struct pt_regs *regs, unsigned long pc,
69 unsigned long sp);
70
71struct task_struct;
72
73/* Free all resources held by a thread. */
74static inline void release_thread(struct task_struct *dead_task)
75{
76}
77
78/* Free current thread data structures etc.. */
79static inline void exit_thread(void)
80{
81}
82
83/* Return saved PC of a blocked thread. */
84#define thread_saved_pc(tsk) ((tsk)->thread.kregs->ea)
85
86extern unsigned long get_wchan(struct task_struct *p);
87
88/* Prepare to copy thread state - unlazy all lazy status */
89#define prepare_to_copy(tsk) do { } while (0)
90
91#define task_pt_regs(p) \
92 ((struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1)
93
94/* Used by procfs */
95#define KSTK_EIP(tsk) ((tsk)->thread.kregs->ea)
96#define KSTK_ESP(tsk) ((tsk)->thread.kregs->sp)
97
98#define cpu_relax() barrier()
99#define cpu_relax_lowlatency() cpu_relax()
100
101#endif /* __ASSEMBLY__ */
102
103#endif /* _ASM_NIOS2_PROCESSOR_H */
diff --git a/arch/nios2/include/asm/switch_to.h b/arch/nios2/include/asm/switch_to.h
new file mode 100644
index 000000000000..c47b3f4afbcd
--- /dev/null
+++ b/arch/nios2/include/asm/switch_to.h
@@ -0,0 +1,31 @@
1/*
2 * Copyright (C) 2004 Microtronix Datacom Ltd.
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 */
8#ifndef _ASM_NIOS2_SWITCH_TO_H
9#define _ASM_NIOS2_SWITCH_TO_H
10
11/*
12 * switch_to(n) should switch tasks to task ptr, first checking that
13 * ptr isn't the current task, in which case it does nothing. This
14 * also clears the TS-flag if the task we switched to has used the
15 * math co-processor latest.
16 */
17#define switch_to(prev, next, last) \
18{ \
19 void *_last; \
20 __asm__ __volatile__ ( \
21 "mov r4, %1\n" \
22 "mov r5, %2\n" \
23 "call resume\n" \
24 "mov %0,r4\n" \
25 : "=r" (_last) \
26 : "r" (prev), "r" (next) \
27 : "r4", "r5", "r7", "r8", "ra"); \
28 (last) = _last; \
29}
30
31#endif /* _ASM_NIOS2_SWITCH_TO_H */
diff --git a/arch/nios2/include/asm/thread_info.h b/arch/nios2/include/asm/thread_info.h
new file mode 100644
index 000000000000..1f266575beb5
--- /dev/null
+++ b/arch/nios2/include/asm/thread_info.h
@@ -0,0 +1,120 @@
1/*
2 * NiosII low-level thread information
3 *
4 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
5 * Copyright (C) 2004 Microtronix Datacom Ltd.
6 *
7 * Based on asm/thread_info_no.h from m68k which is:
8 *
9 * Copyright (C) 2002 David Howells <dhowells@redhat.com>
10 *
11 * This file is subject to the terms and conditions of the GNU General Public
12 * License. See the file "COPYING" in the main directory of this archive
13 * for more details.
14 */
15
16#ifndef _ASM_NIOS2_THREAD_INFO_H
17#define _ASM_NIOS2_THREAD_INFO_H
18
19#ifdef __KERNEL__
20
21/*
22 * Size of the kernel stack for each process.
23 */
24#define THREAD_SIZE_ORDER 1
25#define THREAD_SIZE 8192 /* 2 * PAGE_SIZE */
26
27#ifndef __ASSEMBLY__
28
29typedef struct {
30 unsigned long seg;
31} mm_segment_t;
32
33/*
34 * low level task data that entry.S needs immediate access to
35 * - this struct should fit entirely inside of one cache line
36 * - this struct shares the supervisor stack pages
37 * - if the contents of this structure are changed, the assembly constants
38 * must also be changed
39 */
40struct thread_info {
41 struct task_struct *task; /* main task structure */
42 struct exec_domain *exec_domain; /* execution domain */
43 unsigned long flags; /* low level flags */
44 __u32 cpu; /* current CPU */
45 int preempt_count; /* 0 => preemptable,<0 => BUG */
46 mm_segment_t addr_limit; /* thread address space:
47 0-0x7FFFFFFF for user-thead
48 0-0xFFFFFFFF for kernel-thread
49 */
50 struct restart_block restart_block;
51 struct pt_regs *regs;
52};
53
54/*
55 * macros/functions for gaining access to the thread information structure
56 *
57 * preempt_count needs to be 1 initially, until the scheduler is functional.
58 */
59#define INIT_THREAD_INFO(tsk) \
60{ \
61 .task = &tsk, \
62 .exec_domain = &default_exec_domain, \
63 .flags = 0, \
64 .cpu = 0, \
65 .preempt_count = INIT_PREEMPT_COUNT, \
66 .addr_limit = KERNEL_DS, \
67 .restart_block = { \
68 .fn = do_no_restart_syscall, \
69 }, \
70}
71
72#define init_thread_info (init_thread_union.thread_info)
73#define init_stack (init_thread_union.stack)
74
75/* how to get the thread information struct from C */
76static inline struct thread_info *current_thread_info(void)
77{
78 register unsigned long sp asm("sp");
79
80 return (struct thread_info *)(sp & ~(THREAD_SIZE - 1));
81}
82#endif /* !__ASSEMBLY__ */
83
84/*
85 * thread information flags
86 * - these are process state flags that various assembly files may need to
87 * access
88 * - pending work-to-be-done flags are in LSW
89 * - other flags in MSW
90 */
91#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
92#define TIF_NOTIFY_RESUME 1 /* resumption notification requested */
93#define TIF_SIGPENDING 2 /* signal pending */
94#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
95#define TIF_MEMDIE 4 /* is terminating due to OOM killer */
96#define TIF_SECCOMP 5 /* secure computing */
97#define TIF_SYSCALL_AUDIT 6 /* syscall auditing active */
98#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal() */
99
100#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling
101 TIF_NEED_RESCHED */
102
103#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
104#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
105#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
106#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
107#define _TIF_SECCOMP (1 << TIF_SECCOMP)
108#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
109#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
110#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
111
112/* work to do on interrupt/exception return */
113#define _TIF_WORK_MASK 0x0000FFFE
114
115/* work to do on any return to u-space */
116# define _TIF_ALLWORK_MASK 0x0000FFFF
117
118#endif /* __KERNEL__ */
119
120#endif /* _ASM_NIOS2_THREAD_INFO_H */
diff --git a/arch/nios2/kernel/process.c b/arch/nios2/kernel/process.c
new file mode 100644
index 000000000000..0e075b5ad2a5
--- /dev/null
+++ b/arch/nios2/kernel/process.c
@@ -0,0 +1,258 @@
1/*
2 * Architecture-dependent parts of process handling.
3 *
4 * Copyright (C) 2013 Altera Corporation
5 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
6 * Copyright (C) 2009 Wind River Systems Inc
7 * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
8 * Copyright (C) 2004 Microtronix Datacom Ltd
9 *
10 * This file is subject to the terms and conditions of the GNU General Public
11 * License. See the file "COPYING" in the main directory of this archive
12 * for more details.
13 */
14
15#include <linux/export.h>
16#include <linux/sched.h>
17#include <linux/tick.h>
18#include <linux/uaccess.h>
19
20#include <asm/unistd.h>
21#include <asm/traps.h>
22#include <asm/cpuinfo.h>
23
24asmlinkage void ret_from_fork(void);
25asmlinkage void ret_from_kernel_thread(void);
26
27void (*pm_power_off)(void) = NULL;
28EXPORT_SYMBOL(pm_power_off);
29
30void arch_cpu_idle(void)
31{
32 local_irq_enable();
33}
34
35/*
36 * The development boards have no way to pull a board reset. Just jump to the
37 * cpu reset address and let the boot loader or the code in head.S take care of
38 * resetting peripherals.
39 */
40void machine_restart(char *__unused)
41{
42 pr_notice("Machine restart (%08x)...\n", cpuinfo.reset_addr);
43 local_irq_disable();
44 __asm__ __volatile__ (
45 "jmp %0\n\t"
46 :
47 : "r" (cpuinfo.reset_addr)
48 : "r4");
49}
50
51void machine_halt(void)
52{
53 pr_notice("Machine halt...\n");
54 local_irq_disable();
55 for (;;)
56 ;
57}
58
59/*
60 * There is no way to power off the development boards. So just spin for now. If
61 * we ever have a way of resetting a board using a GPIO we should add that here.
62 */
63void machine_power_off(void)
64{
65 pr_notice("Machine power off...\n");
66 local_irq_disable();
67 for (;;)
68 ;
69}
70
71void show_regs(struct pt_regs *regs)
72{
73 pr_notice("\n");
74 show_regs_print_info(KERN_DEFAULT);
75
76 pr_notice("r1: %08lx r2: %08lx r3: %08lx r4: %08lx\n",
77 regs->r1, regs->r2, regs->r3, regs->r4);
78
79 pr_notice("r5: %08lx r6: %08lx r7: %08lx r8: %08lx\n",
80 regs->r5, regs->r6, regs->r7, regs->r8);
81
82 pr_notice("r9: %08lx r10: %08lx r11: %08lx r12: %08lx\n",
83 regs->r9, regs->r10, regs->r11, regs->r12);
84
85 pr_notice("r13: %08lx r14: %08lx r15: %08lx\n",
86 regs->r13, regs->r14, regs->r15);
87
88 pr_notice("ra: %08lx fp: %08lx sp: %08lx gp: %08lx\n",
89 regs->ra, regs->fp, regs->sp, regs->gp);
90
91 pr_notice("ea: %08lx estatus: %08lx\n",
92 regs->ea, regs->estatus);
93}
94
95void flush_thread(void)
96{
97 set_fs(USER_DS);
98}
99
100int copy_thread(unsigned long clone_flags,
101 unsigned long usp, unsigned long arg, struct task_struct *p)
102{
103 struct pt_regs *childregs = task_pt_regs(p);
104 struct pt_regs *regs;
105 struct switch_stack *stack;
106 struct switch_stack *childstack =
107 ((struct switch_stack *)childregs) - 1;
108
109 if (unlikely(p->flags & PF_KTHREAD)) {
110 memset(childstack, 0,
111 sizeof(struct switch_stack) + sizeof(struct pt_regs));
112
113 childstack->r16 = usp; /* fn */
114 childstack->r17 = arg;
115 childstack->ra = (unsigned long) ret_from_kernel_thread;
116 childregs->estatus = STATUS_PIE;
117 childregs->sp = (unsigned long) childstack;
118
119 p->thread.ksp = (unsigned long) childstack;
120 p->thread.kregs = childregs;
121 return 0;
122 }
123
124 regs = current_pt_regs();
125 *childregs = *regs;
126 childregs->r2 = 0; /* Set the return value for the child. */
127 childregs->r7 = 0;
128
129 stack = ((struct switch_stack *) regs) - 1;
130 *childstack = *stack;
131 childstack->ra = (unsigned long)ret_from_fork;
132 p->thread.kregs = childregs;
133 p->thread.ksp = (unsigned long) childstack;
134
135 if (usp)
136 childregs->sp = usp;
137
138 /* Initialize tls register. */
139 if (clone_flags & CLONE_SETTLS)
140 childstack->r23 = regs->r8;
141
142 return 0;
143}
144
145/*
146 * Generic dumping code. Used for panic and debug.
147 */
148void dump(struct pt_regs *fp)
149{
150 unsigned long *sp;
151 unsigned char *tp;
152 int i;
153
154 pr_emerg("\nCURRENT PROCESS:\n\n");
155 pr_emerg("COMM=%s PID=%d\n", current->comm, current->pid);
156
157 if (current->mm) {
158 pr_emerg("TEXT=%08x-%08x DATA=%08x-%08x BSS=%08x-%08x\n",
159 (int) current->mm->start_code,
160 (int) current->mm->end_code,
161 (int) current->mm->start_data,
162 (int) current->mm->end_data,
163 (int) current->mm->end_data,
164 (int) current->mm->brk);
165 pr_emerg("USER-STACK=%08x KERNEL-STACK=%08x\n\n",
166 (int) current->mm->start_stack,
167 (int)(((unsigned long) current) + THREAD_SIZE));
168 }
169
170 pr_emerg("PC: %08lx\n", fp->ea);
171 pr_emerg("SR: %08lx SP: %08lx\n",
172 (long) fp->estatus, (long) fp);
173
174 pr_emerg("r1: %08lx r2: %08lx r3: %08lx\n",
175 fp->r1, fp->r2, fp->r3);
176
177 pr_emerg("r4: %08lx r5: %08lx r6: %08lx r7: %08lx\n",
178 fp->r4, fp->r5, fp->r6, fp->r7);
179 pr_emerg("r8: %08lx r9: %08lx r10: %08lx r11: %08lx\n",
180 fp->r8, fp->r9, fp->r10, fp->r11);
181 pr_emerg("r12: %08lx r13: %08lx r14: %08lx r15: %08lx\n",
182 fp->r12, fp->r13, fp->r14, fp->r15);
183 pr_emerg("or2: %08lx ra: %08lx fp: %08lx sp: %08lx\n",
184 fp->orig_r2, fp->ra, fp->fp, fp->sp);
185 pr_emerg("\nUSP: %08x TRAPFRAME: %08x\n",
186 (unsigned int) fp->sp, (unsigned int) fp);
187
188 pr_emerg("\nCODE:");
189 tp = ((unsigned char *) fp->ea) - 0x20;
190 for (sp = (unsigned long *) tp, i = 0; (i < 0x40); i += 4) {
191 if ((i % 0x10) == 0)
192 pr_emerg("\n%08x: ", (int) (tp + i));
193 pr_emerg("%08x ", (int) *sp++);
194 }
195 pr_emerg("\n");
196
197 pr_emerg("\nKERNEL STACK:");
198 tp = ((unsigned char *) fp) - 0x40;
199 for (sp = (unsigned long *) tp, i = 0; (i < 0xc0); i += 4) {
200 if ((i % 0x10) == 0)
201 pr_emerg("\n%08x: ", (int) (tp + i));
202 pr_emerg("%08x ", (int) *sp++);
203 }
204 pr_emerg("\n");
205 pr_emerg("\n");
206
207 pr_emerg("\nUSER STACK:");
208 tp = (unsigned char *) (fp->sp - 0x10);
209 for (sp = (unsigned long *) tp, i = 0; (i < 0x80); i += 4) {
210 if ((i % 0x10) == 0)
211 pr_emerg("\n%08x: ", (int) (tp + i));
212 pr_emerg("%08x ", (int) *sp++);
213 }
214 pr_emerg("\n\n");
215}
216
217unsigned long get_wchan(struct task_struct *p)
218{
219 unsigned long fp, pc;
220 unsigned long stack_page;
221 int count = 0;
222
223 if (!p || p == current || p->state == TASK_RUNNING)
224 return 0;
225
226 stack_page = (unsigned long)p;
227 fp = ((struct switch_stack *)p->thread.ksp)->fp; /* ;dgt2 */
228 do {
229 if (fp < stack_page+sizeof(struct task_struct) ||
230 fp >= 8184+stack_page) /* ;dgt2;tmp */
231 return 0;
232 pc = ((unsigned long *)fp)[1];
233 if (!in_sched_functions(pc))
234 return pc;
235 fp = *(unsigned long *) fp;
236 } while (count++ < 16); /* ;dgt2;tmp */
237 return 0;
238}
239
240/*
241 * Do necessary setup to start up a newly executed thread.
242 * Will startup in user mode (status_extension = 0).
243 */
244void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
245{
246 memset((void *) regs, 0, sizeof(struct pt_regs));
247 regs->estatus = ESTATUS_EPIE | ESTATUS_EU;
248 regs->ea = pc;
249 regs->sp = sp;
250}
251
252#include <linux/elfcore.h>
253
254/* Fill in the FPU structure for a core dump. */
255int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r)
256{
257 return 0; /* Nios2 has no FPU and thus no FPU registers */
258}
diff --git a/arch/nios2/mm/mmu_context.c b/arch/nios2/mm/mmu_context.c
new file mode 100644
index 000000000000..45d6b9c58d67
--- /dev/null
+++ b/arch/nios2/mm/mmu_context.c
@@ -0,0 +1,116 @@
1/*
2 * MMU context handling.
3 *
4 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
5 * Copyright (C) 2009 Wind River Systems Inc
6 * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License. See the file "COPYING" in the main directory of this archive
10 * for more details.
11 */
12
13#include <linux/mm.h>
14
15#include <asm/cpuinfo.h>
16#include <asm/mmu_context.h>
17#include <asm/tlb.h>
18
19/* The pids position and mask in context */
20#define PID_SHIFT 0
21#define PID_BITS (cpuinfo.tlb_pid_num_bits)
22#define PID_MASK ((1UL << PID_BITS) - 1)
23
24/* The versions position and mask in context */
25#define VERSION_BITS (32 - PID_BITS)
26#define VERSION_SHIFT (PID_SHIFT + PID_BITS)
27#define VERSION_MASK ((1UL << VERSION_BITS) - 1)
28
29/* Return the version part of a context */
30#define CTX_VERSION(c) (((c) >> VERSION_SHIFT) & VERSION_MASK)
31
32/* Return the pid part of a context */
33#define CTX_PID(c) (((c) >> PID_SHIFT) & PID_MASK)
34
35/* Value of the first context (version 1, pid 0) */
36#define FIRST_CTX ((1UL << VERSION_SHIFT) | (0 << PID_SHIFT))
37
38static mm_context_t next_mmu_context;
39
40/*
41 * Initialize MMU context management stuff.
42 */
43void __init mmu_context_init(void)
44{
45 /* We need to set this here because the value depends on runtime data
46 * from cpuinfo */
47 next_mmu_context = FIRST_CTX;
48}
49
50/*
51 * Set new context (pid), keep way
52 */
53static void set_context(mm_context_t context)
54{
55 set_mmu_pid(CTX_PID(context));
56}
57
58static mm_context_t get_new_context(void)
59{
60 /* Return the next pid */
61 next_mmu_context += (1UL << PID_SHIFT);
62
63 /* If the pid field wraps around we increase the version and
64 * flush the tlb */
65 if (unlikely(CTX_PID(next_mmu_context) == 0)) {
66 /* Version is incremented since the pid increment above
67 * overflows info version */
68 flush_cache_all();
69 flush_tlb_all();
70 }
71
72 /* If the version wraps we start over with the first generation, we do
73 * not need to flush the tlb here since it's always done above */
74 if (unlikely(CTX_VERSION(next_mmu_context) == 0))
75 next_mmu_context = FIRST_CTX;
76
77 return next_mmu_context;
78}
79
80void switch_mm(struct mm_struct *prev, struct mm_struct *next,
81 struct task_struct *tsk)
82{
83 unsigned long flags;
84
85 local_irq_save(flags);
86
87 /* If the process context we are swapping in has a different context
88 * generation then we have it should get a new generation/pid */
89 if (unlikely(CTX_VERSION(next->context) !=
90 CTX_VERSION(next_mmu_context)))
91 next->context = get_new_context();
92
93 /* Save the current pgd so the fast tlb handler can find it */
94 pgd_current = next->pgd;
95
96 /* Set the current context */
97 set_context(next->context);
98
99 local_irq_restore(flags);
100}
101
102/*
103 * After we have set current->mm to a new value, this activates
104 * the context for the new mm so we see the new mappings.
105 */
106void activate_mm(struct mm_struct *prev, struct mm_struct *next)
107{
108 next->context = get_new_context();
109 set_context(next->context);
110 pgd_current = next->pgd;
111}
112
113unsigned long get_pid_from_context(mm_context_t *context)
114{
115 return CTX_PID((*context));
116}
generated by cgit v1.2.2 (git 2.25.0) at 2025-08-12 05:02:10 -0400