Re: [PATCH v3 1/2] MIPS: convert syscall to generic entry

[WANG Xuerui <i.kernel@xen0n.name>]

Hi Feiyang,

On 2021/10/14 16:32, Feiyang Chen wrote:
> Convert MIPS syscall to use the generic entry infrastructure from
> kernel/entry/*.
>
> There are a few special things on MIPS:
>
> - There is one type of syscall on MIPS32 (scall32-o32) and three types
> of syscalls on MIPS64 (scall64-o32, scall64-n32 and scall64-n64). Now
> convert to C code to handle different types of syscalls.
>
> - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
> save_static_function() wrapper is used to save static registers. Now
> SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
> save_static_function() wrapper can be removed.
>
> - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
> jump to syscall_exit directly for skipping setting the error flag and
> restoring all registers. Now use regs->regs[27] to mark whether to
> handle the error flag and restore all registers in handle_sys, so these
> functions can return normally as other architecture.
>
> Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
> Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
> Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
> ---
>  arch/mips/Kconfig                         |   1 +
>  arch/mips/include/asm/entry-common.h      |  13 ++
>  arch/mips/include/asm/ptrace.h            |   8 +-
>  arch/mips/include/asm/sim.h               |  70 -------
>  arch/mips/include/asm/syscall.h           |   5 +
>  arch/mips/include/asm/thread_info.h       |  17 +-
>  arch/mips/include/uapi/asm/ptrace.h       |   7 +-
>  arch/mips/kernel/Makefile                 |  14 +-
>  arch/mips/kernel/entry.S                  |  75 ++------
>  arch/mips/kernel/linux32.c                |   1 -
>  arch/mips/kernel/ptrace.c                 |  78 --------
>  arch/mips/kernel/scall.S                  | 137 +++++++++++++
>  arch/mips/kernel/scall32-o32.S            | 223 ----------------------
>  arch/mips/kernel/scall64-n32.S            | 107 -----------
>  arch/mips/kernel/scall64-n64.S            | 116 -----------
>  arch/mips/kernel/scall64-o32.S            | 221 ---------------------
>  arch/mips/kernel/signal.c                 |  37 ++--
>  arch/mips/kernel/signal_n32.c             |  16 +-
>  arch/mips/kernel/signal_o32.c             |  31 +--
>  arch/mips/kernel/syscall.c                | 148 +++++++++++---
>  arch/mips/kernel/syscalls/syscall_n32.tbl |   8 +-
>  arch/mips/kernel/syscalls/syscall_n64.tbl |   8 +-
>  arch/mips/kernel/syscalls/syscall_o32.tbl |   8 +-
>  23 files changed, 354 insertions(+), 995 deletions(-)
>  create mode 100644 arch/mips/include/asm/entry-common.h
>  delete mode 100644 arch/mips/include/asm/sim.h
>  create mode 100644 arch/mips/kernel/scall.S
>  delete mode 100644 arch/mips/kernel/scall32-o32.S
>  delete mode 100644 arch/mips/kernel/scall64-n32.S
>  delete mode 100644 arch/mips/kernel/scall64-n64.S
>  delete mode 100644 arch/mips/kernel/scall64-o32.S
>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index 1291774a2fa5..debd125100ad 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -32,6 +32,7 @@ config MIPS
>  	select GENERIC_ATOMIC64 if !64BIT
>  	select GENERIC_CMOS_UPDATE
>  	select GENERIC_CPU_AUTOPROBE
> +	select GENERIC_ENTRY
>  	select GENERIC_GETTIMEOFDAY
>  	select GENERIC_IOMAP
>  	select GENERIC_IRQ_PROBE
> diff --git a/arch/mips/include/asm/entry-common.h b/arch/mips/include/asm/entry-common.h
> new file mode 100644
> index 000000000000..0fe2a098ded9
> --- /dev/null
> +++ b/arch/mips/include/asm/entry-common.h
> @@ -0,0 +1,13 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef ARCH_LOONGARCH_ENTRY_COMMON_H
> +#define ARCH_LOONGARCH_ENTRY_COMMON_H
Do you intend to say "MIPS"? ;-)
> +
> +#include <linux/sched.h>
> +#include <linux/processor.h>
> +
> +static inline bool on_thread_stack(void)
> +{
> +	return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1));
> +}
> +
> +#endif