[PATCHv1 05/12] unicore32 core architecture: process/thread related code
From: Guan Xuetao
Date: Sat Dec 25 2010 - 13:47:59 EST
From: Guan Xuetao <guanxuetao@xxxxxxxxxxxxxxx>
Patch 5 implements process/thread related codes. Backtrace and stacktrace are here.
Signed-off-by: Guan Xuetao <guanxuetao@xxxxxxxxxxxxxxx>
---
arch/unicore32/include/asm/stacktrace.h | 31 +++
arch/unicore32/include/asm/thread_info.h | 152 ++++++++++++
arch/unicore32/kernel/init_task.c | 44 ++++
arch/unicore32/kernel/process.c | 389 ++++++++++++++++++++++++++++++
arch/unicore32/kernel/stacktrace.c | 131 ++++++++++
arch/unicore32/lib/backtrace.S | 163 +++++++++++++
6 files changed, 910 insertions(+), 0 deletions(-)
diff --git a/arch/unicore32/include/asm/stacktrace.h b/arch/unicore32/include/asm/stacktrace.h
new file mode 100644
index 0000000..76edc65
--- /dev/null
+++ b/arch/unicore32/include/asm/stacktrace.h
@@ -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
index 0000000..06b3bb2
--- /dev/null
+++ b/arch/unicore32/include/asm/thread_info.h
@@ -0,0 +1,152 @@
+/*
+ * 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 unsigned long 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
+ union 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
index 0000000..a35a1e5
--- /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 0000000..c957aab
--- /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)],
+ 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(union 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.soft, 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(®s, 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, ®s, 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 0000000..b34030b
--- /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
diff --git a/arch/unicore32/lib/backtrace.S b/arch/unicore32/lib/backtrace.S
new file mode 100644
index 0000000..ef01d77
--- /dev/null
+++ b/arch/unicore32/lib/backtrace.S
@@ -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
--
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