linux/arch/loongarch/kernel/entry.S
Qing Zhang e14dd07696 LoongArch: Add basic KGDB & KDB support
KGDB is intended to be used as a source level debugger for the Linux
kernel. It is used along with gdb to debug a Linux kernel. GDB can be
used to "break in" to the kernel to inspect memory, variables and regs
similar to the way an application developer would use GDB to debug an
application. KDB is a frontend of KGDB which is similar to GDB.

By now, in addition to the generic KGDB features, the LoongArch KGDB
implements the following features:
- Hardware breakpoints/watchpoints;
- Software single-step support for KDB.

Signed-off-by: Qing Zhang <zhangqing@loongson.cn>   # Framework & CoreFeature
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn> # BreakPoint & SingleStep
Signed-off-by: Hui Li <lihui@loongson.cn>           # Some Minor Improvements
Signed-off-by: Randy Dunlap <rdunlap@infradead.org> # Some Build Error Fixes
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-09-06 22:53:55 +08:00

96 lines
2.0 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*
* Derived from MIPS:
* Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2001 MIPS Technologies, Inc.
*/
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/loongarch.h>
#include <asm/regdef.h>
#include <asm/stackframe.h>
#include <asm/thread_info.h>
.text
.cfi_sections .debug_frame
.align 5
SYM_FUNC_START(handle_syscall)
csrrd t0, PERCPU_BASE_KS
la.pcrel t1, kernelsp
add.d t1, t1, t0
move t2, sp
ld.d sp, t1, 0
addi.d sp, sp, -PT_SIZE
cfi_st t2, PT_R3
cfi_rel_offset sp, PT_R3
st.d zero, sp, PT_R0
csrrd t2, LOONGARCH_CSR_PRMD
st.d t2, sp, PT_PRMD
csrrd t2, LOONGARCH_CSR_CRMD
st.d t2, sp, PT_CRMD
csrrd t2, LOONGARCH_CSR_EUEN
st.d t2, sp, PT_EUEN
csrrd t2, LOONGARCH_CSR_ECFG
st.d t2, sp, PT_ECFG
csrrd t2, LOONGARCH_CSR_ESTAT
st.d t2, sp, PT_ESTAT
cfi_st ra, PT_R1
cfi_st a0, PT_R4
cfi_st a1, PT_R5
cfi_st a2, PT_R6
cfi_st a3, PT_R7
cfi_st a4, PT_R8
cfi_st a5, PT_R9
cfi_st a6, PT_R10
cfi_st a7, PT_R11
csrrd ra, LOONGARCH_CSR_ERA
st.d ra, sp, PT_ERA
cfi_rel_offset ra, PT_ERA
cfi_st tp, PT_R2
cfi_st u0, PT_R21
cfi_st fp, PT_R22
SAVE_STATIC
#ifdef CONFIG_KGDB
li.w t1, CSR_CRMD_WE
csrxchg t1, t1, LOONGARCH_CSR_CRMD
#endif
move u0, t0
li.d tp, ~_THREAD_MASK
and tp, tp, sp
move a0, sp
bl do_syscall
RESTORE_ALL_AND_RET
SYM_FUNC_END(handle_syscall)
_ASM_NOKPROBE(handle_syscall)
SYM_CODE_START(ret_from_fork)
bl schedule_tail # a0 = struct task_struct *prev
move a0, sp
bl syscall_exit_to_user_mode
RESTORE_STATIC
RESTORE_SOME
RESTORE_SP_AND_RET
SYM_CODE_END(ret_from_fork)
SYM_CODE_START(ret_from_kernel_thread)
bl schedule_tail # a0 = struct task_struct *prev
move a0, s1
jirl ra, s0, 0
move a0, sp
bl syscall_exit_to_user_mode
RESTORE_STATIC
RESTORE_SOME
RESTORE_SP_AND_RET
SYM_CODE_END(ret_from_kernel_thread)