unicore32 core architecture: process/thread related codes
authorGuanXuetao <gxt@mprc.pku.edu.cn>
Sat, 15 Jan 2011 10:16:21 +0000 (18:16 +0800)
committerGuanXuetao <gxt@mprc.pku.edu.cn>
Thu, 17 Mar 2011 01:19:07 +0000 (09:19 +0800)
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>
arch/unicore32/include/asm/stacktrace.h [new file with mode: 0644]
arch/unicore32/include/asm/thread_info.h [new file with mode: 0644]
arch/unicore32/kernel/init_task.c [new file with mode: 0644]
arch/unicore32/kernel/process.c [new file with mode: 0644]
arch/unicore32/kernel/stacktrace.c [new file with mode: 0644]
arch/unicore32/lib/backtrace.S [new file with mode: 0644]

diff --git a/arch/unicore32/include/asm/stacktrace.h b/arch/unicore32/include/asm/stacktrace.h
new file mode 100644 (file)
index 0000000..76edc65
--- /dev/null
@@ -0,0 +1,31 @@
+/*
+ * linux/arch/unicore32/include/asm/stacktrace.h
+ *
+ * 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.
+ */
+
+#ifndef __UNICORE_STACKTRACE_H__
+#define __UNICORE_STACKTRACE_H__
+
+struct stackframe {
+       unsigned long fp;
+       unsigned long sp;
+       unsigned long lr;
+       unsigned long pc;
+};
+
+#ifdef CONFIG_FRAME_POINTER
+extern int unwind_frame(struct stackframe *frame);
+#else
+#define unwind_frame(f) (-EINVAL)
+#endif
+extern void walk_stackframe(struct stackframe *frame,
+                           int (*fn)(struct stackframe *, void *), void *data);
+
+#endif /* __UNICORE_STACKTRACE_H__ */
diff --git a/arch/unicore32/include/asm/thread_info.h b/arch/unicore32/include/asm/thread_info.h
new file mode 100644 (file)
index 0000000..c270e9e
--- /dev/null
@@ -0,0 +1,154 @@
+/*
+ * linux/arch/unicore32/include/asm/thread_info.h
+ *
+ * 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.
+ */
+#ifndef __UNICORE_THREAD_INFO_H__
+#define __UNICORE_THREAD_INFO_H__
+
+#ifdef __KERNEL__
+
+#include <linux/compiler.h>
+#include <asm/fpstate.h>
+
+#define THREAD_SIZE_ORDER      1
+#define THREAD_SIZE            8192
+#define THREAD_START_SP                (THREAD_SIZE - 8)
+
+#ifndef __ASSEMBLY__
+
+struct task_struct;
+struct exec_domain;
+
+#include <asm/types.h>
+
+typedef struct {
+       unsigned long seg;
+} mm_segment_t;
+
+struct cpu_context_save {
+       __u32   r4;
+       __u32   r5;
+       __u32   r6;
+       __u32   r7;
+       __u32   r8;
+       __u32   r9;
+       __u32   r10;
+       __u32   r11;
+       __u32   r12;
+       __u32   r13;
+       __u32   r14;
+       __u32   r15;
+       __u32   r16;
+       __u32   r17;
+       __u32   r18;
+       __u32   r19;
+       __u32   r20;
+       __u32   r21;
+       __u32   r22;
+       __u32   r23;
+       __u32   r24;
+       __u32   r25;
+       __u32   r26;
+       __u32   fp;
+       __u32   sp;
+       __u32   pc;
+};
+
+/*
+ * low level task data that entry.S needs immediate access to.
+ * __switch_to() assumes cpu_context follows immediately after cpu_domain.
+ */
+struct thread_info {
+       unsigned long           flags;          /* low level flags */
+       int                     preempt_count;  /* 0 => preemptable */
+                                               /* <0 => bug */
+       mm_segment_t            addr_limit;     /* address limit */
+       struct task_struct      *task;          /* main task structure */
+       struct exec_domain      *exec_domain;   /* execution domain */
+       __u32                   cpu;            /* cpu */
+       struct cpu_context_save cpu_context;    /* cpu context */
+       __u32                   syscall;        /* syscall number */
+       __u8                    used_cp[16];    /* thread used copro */
+#ifdef CONFIG_UNICORE_FPU_F64
+       struct fp_state         fpstate __attribute__((aligned(8)));
+#endif
+       struct restart_block    restart_block;
+};
+
+#define INIT_THREAD_INFO(tsk)                                          \
+{                                                                      \
+       .task           = &tsk,                                         \
+       .exec_domain    = &default_exec_domain,                         \
+       .flags          = 0,                                            \
+       .preempt_count  = INIT_PREEMPT_COUNT,                           \
+       .addr_limit     = KERNEL_DS,                                    \
+       .restart_block  = {                                             \
+               .fn     = do_no_restart_syscall,                        \
+       },                                                              \
+}
+
+#define init_thread_info       (init_thread_union.thread_info)
+#define init_stack             (init_thread_union.stack)
+
+/*
+ * how to get the thread information struct from C
+ */
+static inline struct thread_info *current_thread_info(void) __attribute_const__;
+
+static inline struct thread_info *current_thread_info(void)
+{
+       register unsigned long sp asm ("sp");
+       return (struct thread_info *)(sp & ~(THREAD_SIZE - 1));
+}
+
+#define thread_saved_pc(tsk)   \
+       ((unsigned long)(task_thread_info(tsk)->cpu_context.pc))
+#define thread_saved_sp(tsk)   \
+       ((unsigned long)(task_thread_info(tsk)->cpu_context.sp))
+#define thread_saved_fp(tsk)   \
+       ((unsigned long)(task_thread_info(tsk)->cpu_context.fp))
+
+#endif
+
+/*
+ * We use bit 30 of the preempt_count to indicate that kernel
+ * preemption is occurring.  See <asm/hardirq.h>.
+ */
+#define PREEMPT_ACTIVE 0x40000000
+
+/*
+ * thread information flags:
+ *  TIF_SYSCALL_TRACE  - syscall trace active
+ *  TIF_SIGPENDING     - signal pending
+ *  TIF_NEED_RESCHED   - rescheduling necessary
+ *  TIF_NOTIFY_RESUME  - callback before returning to user
+ */
+#define TIF_SIGPENDING         0
+#define TIF_NEED_RESCHED       1
+#define TIF_NOTIFY_RESUME      2       /* callback before returning to user */
+#define TIF_SYSCALL_TRACE      8
+#define TIF_MEMDIE             18
+#define TIF_FREEZE             19
+#define TIF_RESTORE_SIGMASK    20
+
+#define _TIF_SIGPENDING                (1 << TIF_SIGPENDING)
+#define _TIF_NEED_RESCHED      (1 << TIF_NEED_RESCHED)
+#define _TIF_NOTIFY_RESUME     (1 << TIF_NOTIFY_RESUME)
+#define _TIF_SYSCALL_TRACE     (1 << TIF_SYSCALL_TRACE)
+#define _TIF_FREEZE            (1 << TIF_FREEZE)
+#define _TIF_RESTORE_SIGMASK   (1 << TIF_RESTORE_SIGMASK)
+
+/*
+ * Change these and you break ASM code in entry-common.S
+ */
+#define _TIF_WORK_MASK         0x000000ff
+
+#endif /* __KERNEL__ */
+#endif /* __UNICORE_THREAD_INFO_H__ */
diff --git a/arch/unicore32/kernel/init_task.c b/arch/unicore32/kernel/init_task.c
new file mode 100644 (file)
index 0000000..a35a1e5
--- /dev/null
@@ -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 (file)
index 0000000..8d4a273
--- /dev/null
@@ -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 (file)
index 0000000..b34030b
--- /dev/null
@@ -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
diff --git a/arch/unicore32/lib/backtrace.S b/arch/unicore32/lib/backtrace.S
new file mode 100644 (file)
index 0000000..ef01d77
--- /dev/null
@@ -0,0 +1,163 @@
+/*
+ * linux/arch/unicore32/lib/backtrace.S
+ *
+ * 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/linkage.h>
+#include <asm/assembler.h>
+               .text
+
+@ fp is 0 or stack frame
+
+#define frame  v4
+#define sv_fp  v5
+#define sv_pc  v6
+#define offset v8
+
+ENTRY(__backtrace)
+               mov     r0, fp
+
+ENTRY(c_backtrace)
+
+#if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK)
+               mov     pc, lr
+ENDPROC(__backtrace)
+ENDPROC(c_backtrace)
+#else
+               stm.w   (v4 - v8, lr), [sp-]    @ Save an extra register
+                                               @ so we have a location...
+               mov.a   frame, r0               @ if frame pointer is zero
+               beq     no_frame                @ we have no stack frames
+
+1:             stm.w   (pc), [sp-]             @ calculate offset of PC stored
+               ldw.w   r0, [sp]+, #4           @ by stmfd for this CPU
+               adr     r1, 1b
+               sub     offset, r0, r1
+
+/*
+ * Stack frame layout:
+ *             optionally saved caller registers (r4 - r10)
+ *             saved fp
+ *             saved sp
+ *             saved lr
+ *    frame => saved pc
+ *             optionally saved arguments (r0 - r3)
+ * saved sp => <next word>
+ *
+ * Functions start with the following code sequence:
+ *                  mov   ip, sp
+ *                  stm.w (r0 - r3), [sp-] (optional)
+ * corrected pc =>  stm.w sp, (..., fp, ip, lr, pc)
+ */
+for_each_frame:
+
+1001:          ldw     sv_pc, [frame+], #0     @ get saved pc
+1002:          ldw     sv_fp, [frame+], #-12   @ get saved fp
+
+               sub     sv_pc, sv_pc, offset    @ Correct PC for prefetching
+
+1003:          ldw     r2, [sv_pc+], #-4       @ if stmfd sp, {args} exists,
+               ldw     r3, .Ldsi+4             @ adjust saved 'pc' back one
+               cxor.a  r3, r2 >> #14           @ instruction
+               beq     201f
+               sub     r0, sv_pc, #4           @ allow for mov
+               b       202f
+201:
+               sub     r0, sv_pc, #8           @ allow for mov + stmia
+202:
+               ldw     r1, [frame+], #-4       @ get saved lr
+               mov     r2, frame
+               b.l     dump_backtrace_entry
+
+               ldw     r1, [sv_pc+], #-4       @ if stmfd sp, {args} exists,
+               ldw     r3, .Ldsi+4
+               cxor.a  r3, r1 >> #14
+               bne     1004f
+               ldw     r0, [frame+], #-8       @ get sp
+               sub     r0, r0, #4              @ point at the last arg
+               b.l     .Ldumpstm               @ dump saved registers
+
+1004:          ldw     r1, [sv_pc+], #0        @ if stmfd {, fp, ip, lr, pc}
+               ldw     r3, .Ldsi               @ instruction exists,
+               cxor.a  r3, r1 >> #14
+               bne     201f
+               sub     r0, frame, #16
+               b.l     .Ldumpstm               @ dump saved registers
+201:
+               cxor.a  sv_fp, #0               @ zero saved fp means
+               beq     no_frame                @ no further frames
+
+               csub.a  sv_fp, frame            @ next frame must be
+               mov     frame, sv_fp            @ above the current frame
+               bua     for_each_frame
+
+1006:          adr     r0, .Lbad
+               mov     r1, frame
+               b.l     printk
+no_frame:      ldm.w   (v4 - v8, pc), [sp]+
+ENDPROC(__backtrace)
+ENDPROC(c_backtrace)
+
+               .pushsection __ex_table,"a"
+               .align  3
+               .long   1001b, 1006b
+               .long   1002b, 1006b
+               .long   1003b, 1006b
+               .long   1004b, 1006b
+               .popsection
+
+#define instr v4
+#define reg   v5
+#define stack v6
+
+.Ldumpstm:     stm.w   (instr, reg, stack, v7, lr), [sp-]
+               mov     stack, r0
+               mov     instr, r1
+               mov     reg, #14
+               mov     v7, #0
+1:             mov     r3, #1
+               csub.a  reg, #8
+               bne     201f
+               sub     reg, reg, #3
+201:
+               cand.a  instr, r3 << reg
+               beq     2f
+               add     v7, v7, #1
+               cxor.a  v7, #6
+               cmoveq  v7, #1
+               cmoveq  r1, #'\n'
+               cmovne  r1, #' '
+               ldw.w   r3, [stack]+, #-4
+               mov     r2, reg
+               csub.a  r2, #8
+               bsl     201f
+               sub     r2, r2, #3
+201:
+               cand.a  instr, #0x40            @ if H is 1, high 16 regs
+               beq     201f
+               add     r2, r2, #0x10           @ so r2 need add 16
+201:
+               adr     r0, .Lfp
+               b.l     printk
+2:             sub.a   reg, reg, #1
+               bns     1b
+               cxor.a  v7, #0
+               beq     201f
+               adr     r0, .Lcr
+               b.l     printk
+201:           ldm.w   (instr, reg, stack, v7, pc), [sp]+
+
+.Lfp:          .asciz  "%cr%d:%08x"
+.Lcr:          .asciz  "\n"
+.Lbad:         .asciz  "Backtrace aborted due to bad frame pointer <%p>\n"
+               .align
+.Ldsi:         .word   0x92eec000 >> 14        @ stm.w sp, (... fp, ip, lr, pc)
+               .word   0x92e10000 >> 14        @ stm.w sp, ()
+
+#endif