LoongArch: Add STACKTRACE support

[linux-2.6-microblaze.git] / arch / loongarch / kernel / process.c

diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c
index bfa0dfe..660492f 100644 (file)
--- a/arch/loongarch/kernel/process.c
+++ b/arch/loongarch/kernel/process.c
@@ -44,6 +44,7 @@
 #include <asm/pgtable.h>
 #include <asm/processor.h>
 #include <asm/reg.h>
+#include <asm/unwind.h>
 #include <asm/vdso.h>
 
 /*
@@ -134,6 +135,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
        childregs = (struct pt_regs *) childksp - 1;
        /*  Put the stack after the struct pt_regs.  */
        childksp = (unsigned long) childregs;
+       p->thread.sched_cfa = 0;
        p->thread.csr_euen = 0;
        p->thread.csr_crmd = csr_read32(LOONGARCH_CSR_CRMD);
        p->thread.csr_prmd = csr_read32(LOONGARCH_CSR_PRMD);
@@ -144,6 +146,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
                p->thread.reg23 = (unsigned long)args->fn;
                p->thread.reg24 = (unsigned long)args->fn_arg;
                p->thread.reg01 = (unsigned long)ret_from_kernel_thread;
+               p->thread.sched_ra = (unsigned long)ret_from_kernel_thread;
                memset(childregs, 0, sizeof(struct pt_regs));
                childregs->csr_euen = p->thread.csr_euen;
                childregs->csr_crmd = p->thread.csr_crmd;
@@ -160,6 +163,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 
        p->thread.reg03 = (unsigned long) childregs;
        p->thread.reg01 = (unsigned long) ret_from_fork;
+       p->thread.sched_ra = (unsigned long) ret_from_fork;
 
        /*
         * New tasks lose permission to use the fpu. This accelerates context
@@ -180,7 +184,91 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 
 unsigned long __get_wchan(struct task_struct *task)
 {
-       return 0;
+       unsigned long pc;
+       struct unwind_state state;
+
+       if (!try_get_task_stack(task))
+               return 0;
+
+       unwind_start(&state, task, NULL);
+       state.sp = thread_saved_fp(task);
+       get_stack_info(state.sp, state.task, &state.stack_info);
+       state.pc = thread_saved_ra(task);
+#ifdef CONFIG_UNWINDER_PROLOGUE
+       state.type = UNWINDER_PROLOGUE;
+#endif
+       for (; !unwind_done(&state); unwind_next_frame(&state)) {
+               pc = unwind_get_return_address(&state);
+               if (!pc)
+                       break;
+               if (in_sched_functions(pc))
+                       continue;
+               break;
+       }
+
+       put_task_stack(task);
+
+       return pc;
+}
+
+bool in_irq_stack(unsigned long stack, struct stack_info *info)
+{
+       unsigned long nextsp;
+       unsigned long begin = (unsigned long)this_cpu_read(irq_stack);
+       unsigned long end = begin + IRQ_STACK_START;
+
+       if (stack < begin || stack >= end)
+               return false;
+
+       nextsp = *(unsigned long *)end;
+       if (nextsp & (SZREG - 1))
+               return false;
+
+       info->begin = begin;
+       info->end = end;
+       info->next_sp = nextsp;
+       info->type = STACK_TYPE_IRQ;
+
+       return true;
+}
+
+bool in_task_stack(unsigned long stack, struct task_struct *task,
+                       struct stack_info *info)
+{
+       unsigned long begin = (unsigned long)task_stack_page(task);
+       unsigned long end = begin + THREAD_SIZE - 32;
+
+       if (stack < begin || stack >= end)
+               return false;
+
+       info->begin = begin;
+       info->end = end;
+       info->next_sp = 0;
+       info->type = STACK_TYPE_TASK;
+
+       return true;
+}
+
+int get_stack_info(unsigned long stack, struct task_struct *task,
+                  struct stack_info *info)
+{
+       task = task ? : current;
+
+       if (!stack || stack & (SZREG - 1))
+               goto unknown;
+
+       if (in_task_stack(stack, task, info))
+               return 0;
+
+       if (task != current)
+               goto unknown;
+
+       if (in_irq_stack(stack, info))
+               return 0;
+
+unknown:
+       info->type = STACK_TYPE_UNKNOWN;
+       return -EINVAL;
 }
 
 unsigned long stack_top(void)