linux/arch/loongarch/kernel/switch.S
Qing Zhang 93a4fa622e LoongArch: Add STACKTRACE support
1. Use common arch_stack_walk() infrastructure to avoid duplicated code
   and avoid taking care of the stack storage and filtering.
2. Add sched_ra (means sched return address) and sched_cfa (means sched
   call frame address) to thread_info, and store them in switch_to().
3. Add __get_wchan() implementation.

Now we can print the process stack and wait channel by cat /proc/*/stack
and /proc/*/wchan.

Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-08-12 13:10:11 +08:00

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844 B
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/asm-offsets.h>
#include <asm/loongarch.h>
#include <asm/regdef.h>
#include <asm/stackframe.h>
#include <asm/thread_info.h>
/*
* task_struct *__switch_to(task_struct *prev, task_struct *next,
* struct thread_info *next_ti)
*/
.align 5
SYM_FUNC_START(__switch_to)
csrrd t1, LOONGARCH_CSR_PRMD
stptr.d t1, a0, THREAD_CSRPRMD
cpu_save_nonscratch a0
stptr.d ra, a0, THREAD_REG01
stptr.d a3, a0, THREAD_SCHED_RA
stptr.d a4, a0, THREAD_SCHED_CFA
move tp, a2
cpu_restore_nonscratch a1
li.w t0, _THREAD_SIZE - 32
PTR_ADD t0, t0, tp
set_saved_sp t0, t1, t2
ldptr.d t1, a1, THREAD_CSRPRMD
csrwr t1, LOONGARCH_CSR_PRMD
jr ra
SYM_FUNC_END(__switch_to)