unicore32 core architecture: process/thread related codes

This patch implements process/thread related codes. Backtrace and stacktrace are here.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

3 files changed, 564 insertions, 0 deletions

diff --git a/arch/unicore32/kernel/init_task.c b/arch/unicore32/kernel/init_task.c
new file mode 100644
index 000000000000..a35a1e50e4f4
--- /dev/null
+++ b/arch/unicore32/kernel/init_task.c
@@ -0,0 +1,44 @@
+/*
+ * linux/arch/unicore32/kernel/init_task.c
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/init_task.h>
+#include <linux/mqueue.h>
+#include <linux/uaccess.h>
+
+#include <asm/pgtable.h>
+
+static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
+static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
+/*
+ * Initial thread structure.
+ *
+ * We need to make sure that this is 8192-byte aligned due to the
+ * way process stacks are handled. This is done by making sure
+ * the linker maps this in the .text segment right after head.S,
+ * and making head.S ensure the proper alignment.
+ *
+ * The things we do for performance..
+ */
+union thread_union init_thread_union __init_task_data = {
+        INIT_THREAD_INFO(init_task) };
+
+/*
+ * Initial task structure.
+ *
+ * All other task structs will be allocated on slabs in fork.c
+ */
+struct task_struct init_task = INIT_TASK(init_task);
+EXPORT_SYMBOL(init_task);
diff --git a/arch/unicore32/kernel/process.c b/arch/unicore32/kernel/process.c
new file mode 100644
index 000000000000..8d4a273ae086
--- /dev/null
+++ b/arch/unicore32/kernel/process.c
@@ -0,0 +1,389 @@
+/*
+ * linux/arch/unicore32/kernel/process.c
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <stdarg.h>
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+#include <linux/interrupt.h>
+#include <linux/kallsyms.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
+#include <linux/elfcore.h>
+#include <linux/pm.h>
+#include <linux/tick.h>
+#include <linux/utsname.h>
+#include <linux/uaccess.h>
+#include <linux/random.h>
+#include <linux/gpio.h>
+#include <linux/stacktrace.h>
+
+#include <asm/cacheflush.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/stacktrace.h>
+
+#include "setup.h"
+
+static const char * const processor_modes[] = {
+        "UK00", "UK01", "UK02", "UK03", "UK04", "UK05", "UK06", "UK07",
+        "UK08", "UK09", "UK0A", "UK0B", "UK0C", "UK0D", "UK0E", "UK0F",
+        "USER", "REAL", "INTR", "PRIV", "UK14", "UK15", "UK16", "ABRT",
+        "UK18", "UK19", "UK1A", "EXTN", "UK1C", "UK1D", "UK1E", "SUSR"
+};
+
+/*
+ * The idle thread, has rather strange semantics for calling pm_idle,
+ * but this is what x86 does and we need to do the same, so that
+ * things like cpuidle get called in the same way.
+ */
+void cpu_idle(void)
+{
+        /* endless idle loop with no priority at all */
+        while (1) {
+                tick_nohz_stop_sched_tick(1);
+                while (!need_resched()) {
+                        local_irq_disable();
+                        stop_critical_timings();
+                        cpu_do_idle();
+                        local_irq_enable();
+                        start_critical_timings();
+                }
+                tick_nohz_restart_sched_tick();
+                preempt_enable_no_resched();
+                schedule();
+                preempt_disable();
+        }
+}
+
+static char reboot_mode = 'h';
+
+int __init reboot_setup(char *str)
+{
+        reboot_mode = str[0];
+        return 1;
+}
+
+__setup("reboot=", reboot_setup);
+
+void machine_halt(void)
+{
+        gpio_set_value(GPO_SOFT_OFF, 0);
+}
+
+/*
+ * Function pointers to optional machine specific functions
+ */
+void (*pm_power_off)(void) = NULL;
+
+void machine_power_off(void)
+{
+        if (pm_power_off)
+                pm_power_off();
+        machine_halt();
+}
+
+void machine_restart(char *cmd)
+{
+        /* Disable interrupts first */
+        local_irq_disable();
+
+        /*
+         * Tell the mm system that we are going to reboot -
+         * we may need it to insert some 1:1 mappings so that
+         * soft boot works.
+         */
+        setup_mm_for_reboot(reboot_mode);
+
+        /* Clean and invalidate caches */
+        flush_cache_all();
+
+        /* Turn off caching */
+        cpu_proc_fin();
+
+        /* Push out any further dirty data, and ensure cache is empty */
+        flush_cache_all();
+
+        /*
+         * Now handle reboot code.
+         */
+        if (reboot_mode == 's') {
+                /* Jump into ROM at address 0xffff0000 */
+                cpu_reset(VECTORS_BASE);
+        } else {
+                PM_PLLSYSCFG = 0x00002001; /* cpu clk = 250M */
+                PM_PLLDDRCFG = 0x00100800; /* ddr clk =  44M */
+                PM_PLLVGACFG = 0x00002001; /* vga clk = 250M */
+
+                /* Use on-chip reset capability */
+                /* following instructions must be in one icache line */
+                __asm__ __volatile__(
+                        "       .align 5\n\t"
+                        "       stw     %1, [%0]\n\t"
+                        "201:   ldw     r0, [%0]\n\t"
+                        "       cmpsub.a        r0, #0\n\t"
+                        "       bne     201b\n\t"
+                        "       stw     %3, [%2]\n\t"
+                        "       nop; nop; nop\n\t"
+                        /* prefetch 3 instructions at most */
+                        :
+                        : "r" ((unsigned long)&PM_PMCR),
+                          "r" (PM_PMCR_CFBSYS | PM_PMCR_CFBDDR
+                                | PM_PMCR_CFBVGA),
+                          "r" ((unsigned long)&RESETC_SWRR),
+                          "r" (RESETC_SWRR_SRB)
+                        : "r0", "memory");
+        }
+
+        /*
+         * Whoops - the architecture was unable to reboot.
+         * Tell the user!
+         */
+        mdelay(1000);
+        printk(KERN_EMERG "Reboot failed -- System halted\n");
+        do { } while (1);
+}
+
+void __show_regs(struct pt_regs *regs)
+{
+        unsigned long flags;
+        char buf[64];
+
+        printk(KERN_DEFAULT "CPU: %d    %s  (%s %.*s)\n",
+                raw_smp_processor_id(), print_tainted(),
+                init_utsname()->release,
+                (int)strcspn(init_utsname()->version, " "),
+                init_utsname()->version);
+        print_symbol("PC is at %s\n", instruction_pointer(regs));
+        print_symbol("LR is at %s\n", regs->UCreg_lr);
+        printk(KERN_DEFAULT "pc : [<%08lx>]    lr : [<%08lx>]    psr: %08lx\n"
+               "sp : %08lx  ip : %08lx  fp : %08lx\n",
+                regs->UCreg_pc, regs->UCreg_lr, regs->UCreg_asr,
+                regs->UCreg_sp, regs->UCreg_ip, regs->UCreg_fp);
+        printk(KERN_DEFAULT "r26: %08lx  r25: %08lx  r24: %08lx\n",
+                regs->UCreg_26, regs->UCreg_25,
+                regs->UCreg_24);
+        printk(KERN_DEFAULT "r23: %08lx  r22: %08lx  r21: %08lx  r20: %08lx\n",
+                regs->UCreg_23, regs->UCreg_22,
+                regs->UCreg_21, regs->UCreg_20);
+        printk(KERN_DEFAULT "r19: %08lx  r18: %08lx  r17: %08lx  r16: %08lx\n",
+                regs->UCreg_19, regs->UCreg_18,
+                regs->UCreg_17, regs->UCreg_16);
+        printk(KERN_DEFAULT "r15: %08lx  r14: %08lx  r13: %08lx  r12: %08lx\n",
+                regs->UCreg_15, regs->UCreg_14,
+                regs->UCreg_13, regs->UCreg_12);
+        printk(KERN_DEFAULT "r11: %08lx  r10: %08lx  r9 : %08lx  r8 : %08lx\n",
+                regs->UCreg_11, regs->UCreg_10,
+                regs->UCreg_09, regs->UCreg_08);
+        printk(KERN_DEFAULT "r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
+                regs->UCreg_07, regs->UCreg_06,
+                regs->UCreg_05, regs->UCreg_04);
+        printk(KERN_DEFAULT "r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
+                regs->UCreg_03, regs->UCreg_02,
+                regs->UCreg_01, regs->UCreg_00);
+
+        flags = regs->UCreg_asr;
+        buf[0] = flags & PSR_S_BIT ? 'S' : 's';
+        buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
+        buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
+        buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
+        buf[4] = '\0';
+
+        printk(KERN_DEFAULT "Flags: %s  INTR o%s  REAL o%s  Mode %s  Segment %s\n",
+                buf, interrupts_enabled(regs) ? "n" : "ff",
+                fast_interrupts_enabled(regs) ? "n" : "ff",
+                processor_modes[processor_mode(regs)],
+                segment_eq(get_fs(), get_ds()) ? "kernel" : "user");
+        {
+                unsigned int ctrl;
+
+                buf[0] = '\0';
+                {
+                        unsigned int transbase;
+                        asm("movc %0, p0.c2, #0\n"
+                            : "=r" (transbase));
+                        snprintf(buf, sizeof(buf), "  Table: %08x", transbase);
+                }
+                asm("movc %0, p0.c1, #0\n" : "=r" (ctrl));
+
+                printk(KERN_DEFAULT "Control: %08x%s\n", ctrl, buf);
+        }
+}
+
+void show_regs(struct pt_regs *regs)
+{
+        printk(KERN_DEFAULT "\n");
+        printk(KERN_DEFAULT "Pid: %d, comm: %20s\n",
+                        task_pid_nr(current), current->comm);
+        __show_regs(regs);
+        __backtrace();
+}
+
+/*
+ * Free current thread data structures etc..
+ */
+void exit_thread(void)
+{
+}
+
+void flush_thread(void)
+{
+        struct thread_info *thread = current_thread_info();
+        struct task_struct *tsk = current;
+
+        memset(thread->used_cp, 0, sizeof(thread->used_cp));
+        memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
+#ifdef CONFIG_UNICORE_FPU_F64
+        memset(&thread->fpstate, 0, sizeof(struct fp_state));
+#endif
+}
+
+void release_thread(struct task_struct *dead_task)
+{
+}
+
+asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
+
+int
+copy_thread(unsigned long clone_flags, unsigned long stack_start,
+            unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
+{
+        struct thread_info *thread = task_thread_info(p);
+        struct pt_regs *childregs = task_pt_regs(p);
+
+        *childregs = *regs;
+        childregs->UCreg_00 = 0;
+        childregs->UCreg_sp = stack_start;
+
+        memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
+        thread->cpu_context.sp = (unsigned long)childregs;
+        thread->cpu_context.pc = (unsigned long)ret_from_fork;
+
+        if (clone_flags & CLONE_SETTLS)
+                childregs->UCreg_16 = regs->UCreg_03;
+
+        return 0;
+}
+
+/*
+ * Fill in the task's elfregs structure for a core dump.
+ */
+int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
+{
+        elf_core_copy_regs(elfregs, task_pt_regs(t));
+        return 1;
+}
+
+/*
+ * fill in the fpe structure for a core dump...
+ */
+int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fp)
+{
+        struct thread_info *thread = current_thread_info();
+        int used_math = thread->used_cp[1] | thread->used_cp[2];
+
+#ifdef CONFIG_UNICORE_FPU_F64
+        if (used_math)
+                memcpy(fp, &thread->fpstate, sizeof(*fp));
+#endif
+        return used_math != 0;
+}
+EXPORT_SYMBOL(dump_fpu);
+
+/*
+ * Shuffle the argument into the correct register before calling the
+ * thread function.  r1 is the thread argument, r2 is the pointer to
+ * the thread function, and r3 points to the exit function.
+ */
+asm(".pushsection .text\n"
+"       .align\n"
+"       .type   kernel_thread_helper, #function\n"
+"kernel_thread_helper:\n"
+"       mov.a   asr, r7\n"
+"       mov     r0, r4\n"
+"       mov     lr, r6\n"
+"       mov     pc, r5\n"
+"       .size   kernel_thread_helper, . - kernel_thread_helper\n"
+"       .popsection");
+
+/*
+ * Create a kernel thread.
+ */
+pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
+{
+        struct pt_regs regs;
+
+        memset(&regs, 0, sizeof(regs));
+
+        regs.UCreg_04 = (unsigned long)arg;
+        regs.UCreg_05 = (unsigned long)fn;
+        regs.UCreg_06 = (unsigned long)do_exit;
+        regs.UCreg_07 = PRIV_MODE;
+        regs.UCreg_pc = (unsigned long)kernel_thread_helper;
+        regs.UCreg_asr = regs.UCreg_07 | PSR_I_BIT;
+
+        return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
+}
+EXPORT_SYMBOL(kernel_thread);
+
+unsigned long get_wchan(struct task_struct *p)
+{
+        struct stackframe frame;
+        int count = 0;
+        if (!p || p == current || p->state == TASK_RUNNING)
+                return 0;
+
+        frame.fp = thread_saved_fp(p);
+        frame.sp = thread_saved_sp(p);
+        frame.lr = 0;                   /* recovered from the stack */
+        frame.pc = thread_saved_pc(p);
+        do {
+                int ret = unwind_frame(&frame);
+                if (ret < 0)
+                        return 0;
+                if (!in_sched_functions(frame.pc))
+                        return frame.pc;
+        } while ((count++) < 16);
+        return 0;
+}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+        unsigned long range_end = mm->brk + 0x02000000;
+        return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
+}
+
+/*
+ * The vectors page is always readable from user space for the
+ * atomic helpers and the signal restart code.  Let's declare a mapping
+ * for it so it is visible through ptrace and /proc/<pid>/mem.
+ */
+
+int vectors_user_mapping(void)
+{
+        struct mm_struct *mm = current->mm;
+        return install_special_mapping(mm, 0xffff0000, PAGE_SIZE,
+                                       VM_READ | VM_EXEC |
+                                       VM_MAYREAD | VM_MAYEXEC |
+                                       VM_ALWAYSDUMP | VM_RESERVED,
+                                       NULL);
+}
+
+const char *arch_vma_name(struct vm_area_struct *vma)
+{
+        return (vma->vm_start == 0xffff0000) ? "[vectors]" : NULL;
+}
diff --git a/arch/unicore32/kernel/stacktrace.c b/arch/unicore32/kernel/stacktrace.c
new file mode 100644
index 000000000000..b34030bdabe3
--- /dev/null
+++ b/arch/unicore32/kernel/stacktrace.c
@@ -0,0 +1,131 @@
+/*
+ * linux/arch/unicore32/kernel/stacktrace.c
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+
+#include <asm/stacktrace.h>
+
+#if defined(CONFIG_FRAME_POINTER)
+/*
+ * Unwind the current stack frame and store the new register values in the
+ * structure passed as argument. Unwinding is equivalent to a function return,
+ * hence the new PC value rather than LR should be used for backtrace.
+ *
+ * With framepointer enabled, a simple function prologue looks like this:
+ *      mov     ip, sp
+ *      stmdb   sp!, {fp, ip, lr, pc}
+ *      sub     fp, ip, #4
+ *
+ * A simple function epilogue looks like this:
+ *      ldm     sp, {fp, sp, pc}
+ *
+ * Note that with framepointer enabled, even the leaf functions have the same
+ * prologue and epilogue, therefore we can ignore the LR value in this case.
+ */
+int notrace unwind_frame(struct stackframe *frame)
+{
+        unsigned long high, low;
+        unsigned long fp = frame->fp;
+
+        /* only go to a higher address on the stack */
+        low = frame->sp;
+        high = ALIGN(low, THREAD_SIZE);
+
+        /* check current frame pointer is within bounds */
+        if (fp < (low + 12) || fp + 4 >= high)
+                return -EINVAL;
+
+        /* restore the registers from the stack frame */
+        frame->fp = *(unsigned long *)(fp - 12);
+        frame->sp = *(unsigned long *)(fp - 8);
+        frame->pc = *(unsigned long *)(fp - 4);
+
+        return 0;
+}
+#endif
+
+void notrace walk_stackframe(struct stackframe *frame,
+                     int (*fn)(struct stackframe *, void *), void *data)
+{
+        while (1) {
+                int ret;
+
+                if (fn(frame, data))
+                        break;
+                ret = unwind_frame(frame);
+                if (ret < 0)
+                        break;
+        }
+}
+EXPORT_SYMBOL(walk_stackframe);
+
+#ifdef CONFIG_STACKTRACE
+struct stack_trace_data {
+        struct stack_trace *trace;
+        unsigned int no_sched_functions;
+        unsigned int skip;
+};
+
+static int save_trace(struct stackframe *frame, void *d)
+{
+        struct stack_trace_data *data = d;
+        struct stack_trace *trace = data->trace;
+        unsigned long addr = frame->pc;
+
+        if (data->no_sched_functions && in_sched_functions(addr))
+                return 0;
+        if (data->skip) {
+                data->skip--;
+                return 0;
+        }
+
+        trace->entries[trace->nr_entries++] = addr;
+
+        return trace->nr_entries >= trace->max_entries;
+}
+
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+        struct stack_trace_data data;
+        struct stackframe frame;
+
+        data.trace = trace;
+        data.skip = trace->skip;
+
+        if (tsk != current) {
+                data.no_sched_functions = 1;
+                frame.fp = thread_saved_fp(tsk);
+                frame.sp = thread_saved_sp(tsk);
+                frame.lr = 0;           /* recovered from the stack */
+                frame.pc = thread_saved_pc(tsk);
+        } else {
+                register unsigned long current_sp asm("sp");
+
+                data.no_sched_functions = 0;
+                frame.fp = (unsigned long)__builtin_frame_address(0);
+                frame.sp = current_sp;
+                frame.lr = (unsigned long)__builtin_return_address(0);
+                frame.pc = (unsigned long)save_stack_trace_tsk;
+        }
+
+        walk_stackframe(&frame, save_trace, &data);
+        if (trace->nr_entries < trace->max_entries)
+                trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+
+void save_stack_trace(struct stack_trace *trace)
+{
+        save_stack_trace_tsk(current, trace);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+#endif