bianbu-linux-6.6/arch/loongarch/kernel/entry.S
Huacai Chen be769645a2 LoongArch: Add system call support
Add system call support and related uaccess.h for LoongArch.

Q: Why keep _ARCH_WANT_SYS_CLONE definition while there is clone3:
A: The latest glibc release has some basic support for clone3 but it is
   not complete. E.g., pthread_create() and spawni() have converted to
   use clone3 but fork() will still use clone. Moreover, some seccomp
   related applications can still not work perfectly with clone3. E.g.,
   Chromium sandbox cannot work at all and there is no solution for it,
   which is more terrible than the fork() story [1].

[1] https://chromium-review.googlesource.com/c/chromium/src/+/2936184

Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-06-03 20:09:28 +08:00

89 lines
1.8 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.abs 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
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)
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)