Re: [PATCH v2 08/14] LoongArch: Linux Syscall Interface

[caiyinyu <caiyinyu@loongson.cn>]

在 2022/1/4 下午10:20, Adhemerval Zanella 写道:
> On 31/12/2021 03:44, caiyinyu wrote:
>> Contains the Linux system call interface, as well as the definitions of
>> a handful of system calls.
>> ---
>>   sysdeps/loongarch/abort-instr.h               |   2 +
>>   sysdeps/loongarch/hp-timing.h                 |  42 +++
>>   sysdeps/loongarch/nptl/nptl-sysdep.S          |   2 +
>>   .../unix/sysv/linux/loongarch/arch-syscall.h  | 302 ++++++++++++++++
>>   .../unix/sysv/linux/loongarch/bits/signum.h   |  58 ++++
>>   sysdeps/unix/sysv/linux/loongarch/clone.S     | 100 ++++++
>>   sysdeps/unix/sysv/linux/loongarch/clone3.S    |  87 +++++
>>   sysdeps/unix/sysv/linux/loongarch/ipc_priv.h  |  22 ++
>>   sysdeps/unix/sysv/linux/loongarch/syscall.c   |  35 ++
>>   sysdeps/unix/sysv/linux/loongarch/sysdep.S    |  53 +++
>>   sysdeps/unix/sysv/linux/loongarch/sysdep.h    | 321 ++++++++++++++++++
>>   sysdeps/unix/sysv/linux/loongarch/vfork.S     |  50 +++
>>   12 files changed, 1074 insertions(+)
>>   create mode 100644 sysdeps/loongarch/abort-instr.h
>>   create mode 100644 sysdeps/loongarch/hp-timing.h
>>   create mode 100644 sysdeps/loongarch/nptl/nptl-sysdep.S
>>   create mode 100644 sysdeps/unix/sysv/linux/loongarch/arch-syscall.h
>>   create mode 100644 sysdeps/unix/sysv/linux/loongarch/bits/signum.h
>>   create mode 100644 sysdeps/unix/sysv/linux/loongarch/clone.S
>>   create mode 100644 sysdeps/unix/sysv/linux/loongarch/clone3.S
>>   create mode 100644 sysdeps/unix/sysv/linux/loongarch/ipc_priv.h
>>   create mode 100644 sysdeps/unix/sysv/linux/loongarch/syscall.c
>>   create mode 100644 sysdeps/unix/sysv/linux/loongarch/sysdep.S
>>   create mode 100644 sysdeps/unix/sysv/linux/loongarch/sysdep.h
>>   create mode 100644 sysdeps/unix/sysv/linux/loongarch/vfork.S
>>
>> diff --git a/sysdeps/loongarch/abort-instr.h b/sysdeps/loongarch/abort-instr.h
>> new file mode 100644
>> index 0000000000..92e22edfea
>> --- /dev/null
>> +++ b/sysdeps/loongarch/abort-instr.h
>> @@ -0,0 +1,2 @@
>> +/* An instruction which should crash any program is a breakpoint.  */
>> +#define ABORT_INSTRUCTION asm("break 0")
> Missing space after asm.
Fixed.
>> diff --git a/sysdeps/loongarch/hp-timing.h b/sysdeps/loongarch/hp-timing.h
>> new file mode 100644
>> index 0000000000..7b36a539f1
>> --- /dev/null
>> +++ b/sysdeps/loongarch/hp-timing.h
>> @@ -0,0 +1,42 @@
>> +/* High precision, low overhead timing functions.
>> +   Copyright (C) 2021 Free Software Foundation, Inc.
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library; if not, see
>> +<https://www.gnu.org/licenses/>.  */
>> +
>> +#ifndef _HP_TIMING_H
>> +#define _HP_TIMING_H 1
>> +
>> +/* We always assume having the timestamp register.  */
>> +#define HP_TIMING_AVAIL (1)
>> +#define HP_SMALL_TIMING_AVAIL (1)
>> +
>> +/* We indeed have inlined functions.  */
>> +#define HP_TIMING_INLINE (1)
>> +
>> +/* We use 64bit values for the times.  */
>> +typedef unsigned long long int hp_timing_t;
>> +
>> +/* Read the stable counter.  */
>> +#define HP_TIMING_NOW(Var) \
>> +  ({ \
>> +    unsigned long long int _count; \
>> +    asm volatile("rdtime.d\t%0,$r0" : "=r"(_count)); \
> Missing space after volatile.
Fixed.
>> +    (Var) = _count; \
>> +  })
>> +
>> +#include <hp-timing-common.h>
>> +
>> +#endif /* hp-timing.h */
>> diff --git a/sysdeps/loongarch/nptl/nptl-sysdep.S b/sysdeps/loongarch/nptl/nptl-sysdep.S
>> new file mode 100644
>> index 0000000000..3f5c2a364a
>> --- /dev/null
>> +++ b/sysdeps/loongarch/nptl/nptl-sysdep.S
>> @@ -0,0 +1,2 @@
>> +/* Pull in __syscall_error.  */
>> +#include <sysdep.S>
> Why do you need this file?  Newer Linux ports should have libpthread function
> on libc.so.
Removed.
>> diff --git a/sysdeps/unix/sysv/linux/loongarch/bits/signum.h b/sysdeps/unix/sysv/linux/loongarch/bits/signum.h
>> new file mode 100644
>> index 0000000000..111759778b
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/loongarch/bits/signum.h
>> @@ -0,0 +1,58 @@
>> +/* Signal number definitions.  Linux version.
>> +   Copyright (C) 2021 Free Software Foundation, Inc.
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library; if not, see
>> +<https://www.gnu.org/licenses/>.  */
>> +
>> +#ifndef _BITS_SIGNUM_H
>> +#define _BITS_SIGNUM_H 1
>> +
>> +#ifndef _SIGNAL_H
>> +#error "Never include <bits/signum.h> directly; use <signal.h> instead."
>> +#endif
>> +
>> +#include <bits/signum-generic.h>
>> +
>> +/* Adjustments and additions to the signal number constants for
>> +   most Linux systems.  */
>> +
>> +#define SIGSTKFLT 16 /* Stack fault (obsolete).  */
>> +#define SIGPWR 30    /* Power failure imminent.  */
>> +
>> +#undef SIGBUS
>> +#define SIGBUS 7
>> +#undef SIGUSR1
>> +#define SIGUSR1 10
>> +#undef SIGUSR2
>> +#define SIGUSR2 12
>> +#undef SIGCHLD
>> +#define SIGCHLD 17
>> +#undef SIGCONT
>> +#define SIGCONT 18
>> +#undef SIGSTOP
>> +#define SIGSTOP 19
>> +#undef SIGTSTP
>> +#define SIGTSTP 20
>> +#undef SIGURG
>> +#define SIGURG 23
>> +#undef SIGPOLL
>> +#define SIGPOLL 29
>> +#undef SIGSYS
>> +#define SIGSYS 31
>> +
>> +#undef __SIGRTMAX
>> +#define __SIGRTMAX 64
>> +
>> +#endif /* <signal.h> included.  */
> This file has been refactore by e4e11b1dba261cb650e6 (2.32), now ports that
> deviate from Linux generic ABI should provide a signum-arch.h header. And
> this seems not to be the case here.
Removed.
>
>> diff --git a/sysdeps/unix/sysv/linux/loongarch/clone.S b/sysdeps/unix/sysv/linux/loongarch/clone.S
>> new file mode 100644
>> index 0000000000..d2bed24440
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/loongarch/clone.S
>> @@ -0,0 +1,100 @@
>> +/* The clone syscall wrapper.
>> +   Copyright (C) 2021 Free Software Foundation, Inc.
>> +
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library.  If not, see
>> +<https://www.gnu.org/licenses/>.  */
>> +
>> +/* clone() is even more special than fork() as it mucks with stacks
>> +   and invokes a function in the right context after its all over.  */
>> +
>> +#include <sys/asm.h>
>> +#include <sysdep.h>
>> +#define _ERRNO_H  1
>> +#include <bits/errno.h>
>> +#include <tls.h>
>> +#include "tcb-offsets.h"
>> +
>> +/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
>> +   void *parent_tidptr, void *tls, void *child_tidptr) */
>> +
>> +ENTRY (__clone)
>> +
>> +	/* Align stack to 16 or 8 bytes per the ABI.  */
>> +#ifdef __loongarch_lp64
>> +	bstrins.d	a1, zero, 3, 0
>> +#else
>> +#error "32bit LoongArch systems are not supported"
>> +#endif
> As before, I think we should move the LP64 ABI tests to configure time
> instead of adding multiple checks on arch-specific code.
Fixed.
>> +
>> +	/* Sanity check arguments.  */
>> +	beqz		a0, L (invalid) /* No NULL function pointers.  */
>> +	beqz		a1, L (invalid) /* No NULL stack pointers.  */
>> +
>> +	addi.d 		a1, a1, -16 /* Reserve argument save space.  */
>> +	st.d		a0, a1, 0   /* Save function pointer.  */
>> +	st.d		a3, a1, SZREG   /* Save argument pointer.  */
>> +
>> +	/* The syscall expects the args to be in different slots.  */
>> +	or		a0, a2, zero
>> +	or		a2, a4, zero
>> +	or		a3, a6, zero
>> +	or		a4, a5, zero
>> +
>> +	/* Do the system call.  */
>> +	li.d		a7,__NR_clone
>> +	syscall		0
>> +
>> +	blt		a0, zero ,L (error)
>> +	beqz		a0,L (thread_start)
>> +
>> +	/* Successful return from the parent.  */
>> +	ret
>> +
>> +L (invalid):
>> +	li.d		a0, -EINVAL
>> +
>> +	/* Something bad happened -- no child created.  */
>> +L (error):
>> +	b		__syscall_error
>> +
>> +END (__clone)
>> +
>> +/* Load up the arguments to the function.  Put this block of code in
>> +   its own function so that we can terminate the stack trace with our
>> +   debug info.  */
>> +ENTRY (__thread_start)
>> +L (thread_start):
>> +
>> +/* Terminate call stack by noting ra is undefined.  Use a dummy
>> +   .cfi_label to force starting the FDE.  */
>> +	.cfi_label .Ldummy
>> +	cfi_undefined (1)
>> +
>> +	/* Restore the arg for user's function.  */
>> +	ld.d		a1, sp, 0   /* Function pointer.  */
>> +	ld.d		a0, sp, SZREG   /* Argument pointer.  */
>> +
>> +	/* Call the user's function.  */
>> +	jirl		ra, a1, 0
>> +
>> +	/* Call exit with the function's return value.  */
>> +	li.d		a7, __NR_exit
>> +	syscall		0
>> +
>> +	END (__thread_start)
>> +
>> +libc_hidden_def (__clone)
>> +weak_alias (__clone, clone)
>> diff --git a/sysdeps/unix/sysv/linux/loongarch/ipc_priv.h b/sysdeps/unix/sysv/linux/loongarch/ipc_priv.h
>> new file mode 100644
>> index 0000000000..dde8fa6989
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/loongarch/ipc_priv.h
>> @@ -0,0 +1,22 @@
>> +/* Old SysV permission definition for Linux.
>> +   Copyright (C) 2021 Loongson Technology, Inc.
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library; if not, see
>> +<https://www.gnu.org/licenses/>.  */
>> +
>> +#include <sys/ipc.h> /* For __key_t  */
>> +
>> +#define __IPC_64 0x0
>> +#include <sysdeps/unix/sysv/linux/ipc_priv.h>
> Why can't you use the generic sysdeps/unix/sysv/linux/ipc_priv.h here?
> I woudl asusme that LoongArch will have __ASSUME_SYSVIPC_DEFAULT_IPC_64
> defined and thus __IPC_64 will be 0x0.
Fixed by using generic Linux files.
>> diff --git a/sysdeps/unix/sysv/linux/loongarch/syscall.c b/sysdeps/unix/sysv/linux/loongarch/syscall.c
>> new file mode 100644
>> index 0000000000..d0067bc2d0
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/loongarch/syscall.c
>> @@ -0,0 +1,35 @@
>> +/* system call interface.
>> +   Copyright (C) 2021 Free Software Foundation, Inc.
>> +
>> +   This file is part of the GNU C Library.
>> +
>> +   The GNU C Library is free software; you can redistribute it and/or
>> +   modify it under the terms of the GNU Lesser General Public
>> +   License as published by the Free Software Foundation; either
>> +   version 2.1 of the License, or (at your option) any later version.
>> +
>> +   The GNU C Library is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +   Lesser General Public License for more details.
>> +
>> +   You should have received a copy of the GNU Lesser General Public
>> +   License along with the GNU C Library.  If not, see
>> +<https://www.gnu.org/licenses/>.  */
>> +
>> +#include <sysdep.h>
>> +
>> +long int
>> +syscall (long int syscall_number, long int arg1, long int arg2, long int arg3,
>> +	 long int arg4, long int arg5, long int arg6, long int arg7)
>> +{
>> +  long int ret;
>> +
>> +  ret = INTERNAL_SYSCALL_NCS (syscall_number, 7, arg1, arg2, arg3, arg4, arg5,
>> +			      arg6, arg7);
>> +
>> +  if (INTERNAL_SYSCALL_ERROR_P (ret))
>> +    return __syscall_error (ret);
>> +
>> +  return ret;
>> +}
> Do you really need 7 arguments for syscall? Otherwise you should use the generic
> interface.
Fixed by removing syscall.c.