[3/5] riscv: Add the clone3 wrapper
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Commit Message
It follows the internal signature:
extern int clone3 (struct clone_args *__cl_args, size_t __size,
int (*__func) (void *__arg), void *__arg);
Checked on riscv64-linux-gnu-rv64imafdc-lp64d.
---
sysdeps/unix/sysv/linux/riscv/clone3.S | 80 ++++++++++++++++++++++++++
sysdeps/unix/sysv/linux/riscv/sysdep.h | 1 +
2 files changed, 81 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/riscv/clone3.S
Comments
Ping.
On 03/02/23 14:12, Adhemerval Zanella wrote:
> It follows the internal signature:
>
> extern int clone3 (struct clone_args *__cl_args, size_t __size,
> int (*__func) (void *__arg), void *__arg);
>
> Checked on riscv64-linux-gnu-rv64imafdc-lp64d.
> ---
> sysdeps/unix/sysv/linux/riscv/clone3.S | 80 ++++++++++++++++++++++++++
> sysdeps/unix/sysv/linux/riscv/sysdep.h | 1 +
> 2 files changed, 81 insertions(+)
> create mode 100644 sysdeps/unix/sysv/linux/riscv/clone3.S
>
> diff --git a/sysdeps/unix/sysv/linux/riscv/clone3.S b/sysdeps/unix/sysv/linux/riscv/clone3.S
> new file mode 100644
> index 0000000000..ee5780ee2f
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/riscv/clone3.S
> @@ -0,0 +1,80 @@
> +/* The clone3 syscall wrapper. Linux/RISC-V version.
> + Copyright (C) 2023 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 <asm/errno.h>
> +#include <sys/asm.h>
> +#include <sysdep.h>
> +
> +/* The userland implementation is:
> + int clone3 (struct clone_args *cl_args, size_t size,
> + int (*func)(void *arg), void *arg);
> +
> + the kernel entry is:
> + int clone3 (struct clone_args *cl_args, size_t size);
> +
> + The parameters are passed in registers from userland:
> + a0: cl_args
> + a1: size
> + a2: func
> + a3: arg */
> +
> + .text
> +ENTRY(__clone3)
> + /* Sanity check args. */
> + beqz a0, L(invalid) /* No NULL cl_args pointer. */
> + beqz a2, L(invalid) /* No NULL function pointer. */
> +
> + /* Do the system call, the kernel expects:
> + a7: system call number
> + a0: cl_args
> + a1: size */
> + li a7, __NR_clone3
> + scall
> +
> + bltz a0, L(error)
> + beqz a0, L(thread_start)
> +
> + ret
> +
> +L(invalid):
> + li a0, -EINVAL
> +L(error):
> + tail __syscall_error
> +END (__clone3)
> +
> +ENTRY(__thread_start_clone3)
> +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 (ra)
> +
> + /* Restore the arg for user's function and call the user's
> + function. */
> + mv a1, a2 /* Function pointer. */
> + mv a0, a3 /* Argument pointer. */
> + jalr a1
> +
> + /* Call exit with the function's return value. */
> + li a7, __NR_exit
> + scall
> +END(__thread_start_clone3)
> +
> +libc_hidden_def (__clone3)
> +weak_alias (__clone3, clone3)
> diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.h b/sysdeps/unix/sysv/linux/riscv/sysdep.h
> index 4af5fe5dbc..e96a930409 100644
> --- a/sysdeps/unix/sysv/linux/riscv/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/riscv/sysdep.h
> @@ -151,6 +151,7 @@
>
> /* RV32 does not support the gettime VDSO syscalls. */
> # endif
> +# define HAVE_CLONE3_WRAPPER 1
>
> /* List of system calls which are supported as vsyscalls (for RV32 and
> RV64). */
On Fri, 03 Feb 2023 09:12:35 PST (-0800), adhemerval.zanella@linaro.org wrote:
> It follows the internal signature:
>
> extern int clone3 (struct clone_args *__cl_args, size_t __size,
> int (*__func) (void *__arg), void *__arg);
>
> Checked on riscv64-linux-gnu-rv64imafdc-lp64d.
Due to a bug we only had clone3 on rv64 until 59a4e0d5511b ("RISC-V:
Include clone3() on rv32"), which landed in 5.15 and was then backported
all the way to 5.4.
> ---
> sysdeps/unix/sysv/linux/riscv/clone3.S | 80 ++++++++++++++++++++++++++
> sysdeps/unix/sysv/linux/riscv/sysdep.h | 1 +
> 2 files changed, 81 insertions(+)
> create mode 100644 sysdeps/unix/sysv/linux/riscv/clone3.S
>
> diff --git a/sysdeps/unix/sysv/linux/riscv/clone3.S b/sysdeps/unix/sysv/linux/riscv/clone3.S
> new file mode 100644
> index 0000000000..ee5780ee2f
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/riscv/clone3.S
> @@ -0,0 +1,80 @@
> +/* The clone3 syscall wrapper. Linux/RISC-V version.
> + Copyright (C) 2023 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 <asm/errno.h>
> +#include <sys/asm.h>
> +#include <sysdep.h>
> +
> +/* The userland implementation is:
> + int clone3 (struct clone_args *cl_args, size_t size,
> + int (*func)(void *arg), void *arg);
> +
> + the kernel entry is:
> + int clone3 (struct clone_args *cl_args, size_t size);
> +
> + The parameters are passed in registers from userland:
> + a0: cl_args
> + a1: size
> + a2: func
> + a3: arg */
> +
> + .text
> +ENTRY(__clone3)
> + /* Sanity check args. */
> + beqz a0, L(invalid) /* No NULL cl_args pointer. */
> + beqz a2, L(invalid) /* No NULL function pointer. */
> +
> + /* Do the system call, the kernel expects:
> + a7: system call number
> + a0: cl_args
> + a1: size */
> + li a7, __NR_clone3
IIUC this only builds with kernel headers 5.15 or newer on rv32. I'm
not sure if that's a problem: unless I'm missing something we support
building for those systems now, but rv32 is pretty esoteric so I'm not
sure anyone cares -- maybe someone uses 5.15 on rv32 (some rv64 hardware
is still being released with 5.10-based vendor kernels), but 5.4 is
pretty old for us.
> + scall
> +
> + bltz a0, L(error)
> + beqz a0, L(thread_start)
> +
> + ret
> +
> +L(invalid):
> + li a0, -EINVAL
> +L(error):
> + tail __syscall_error
> +END (__clone3)
> +
> +ENTRY(__thread_start_clone3)
> +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 (ra)
> +
> + /* Restore the arg for user's function and call the user's
> + function. */
> + mv a1, a2 /* Function pointer. */
I think we don't need that mv, we can just call a2 directly? Unless I'm
missing some reason the thread main needs to see a pointer to itself?
> + mv a0, a3 /* Argument pointer. */
> + jalr a1
> +
> + /* Call exit with the function's return value. */
> + li a7, __NR_exit
> + scall
> +END(__thread_start_clone3)
> +
> +libc_hidden_def (__clone3)
> +weak_alias (__clone3, clone3)
> diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.h b/sysdeps/unix/sysv/linux/riscv/sysdep.h
> index 4af5fe5dbc..e96a930409 100644
> --- a/sysdeps/unix/sysv/linux/riscv/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/riscv/sysdep.h
> @@ -151,6 +151,7 @@
>
> /* RV32 does not support the gettime VDSO syscalls. */
> # endif
> +# define HAVE_CLONE3_WRAPPER 1
>
> /* List of system calls which are supported as vsyscalls (for RV32 and
> RV64). */
That's just some minor comments though, so
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Thanks! (and sorry I missed it for a bit)
On 29/05/23 11:04, Palmer Dabbelt wrote:
> On Fri, 03 Feb 2023 09:12:35 PST (-0800), adhemerval.zanella@linaro.org wrote:
>> It follows the internal signature:
>>
>> extern int clone3 (struct clone_args *__cl_args, size_t __size,
>> int (*__func) (void *__arg), void *__arg);
>>
>> Checked on riscv64-linux-gnu-rv64imafdc-lp64d.
>
> Due to a bug we only had clone3 on rv64 until 59a4e0d5511b ("RISC-V: Include clone3() on rv32"), which landed in 5.15 and was then backported all the way to 5.4.
>
>> ---
>> sysdeps/unix/sysv/linux/riscv/clone3.S | 80 ++++++++++++++++++++++++++
>> sysdeps/unix/sysv/linux/riscv/sysdep.h | 1 +
>> 2 files changed, 81 insertions(+)
>> create mode 100644 sysdeps/unix/sysv/linux/riscv/clone3.S
>>
>> diff --git a/sysdeps/unix/sysv/linux/riscv/clone3.S b/sysdeps/unix/sysv/linux/riscv/clone3.S
>> new file mode 100644
>> index 0000000000..ee5780ee2f
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/riscv/clone3.S
>> @@ -0,0 +1,80 @@
>> +/* The clone3 syscall wrapper. Linux/RISC-V version.
>> + Copyright (C) 2023 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 <asm/errno.h>
>> +#include <sys/asm.h>
>> +#include <sysdep.h>
>> +
>> +/* The userland implementation is:
>> + int clone3 (struct clone_args *cl_args, size_t size,
>> + int (*func)(void *arg), void *arg);
>> +
>> + the kernel entry is:
>> + int clone3 (struct clone_args *cl_args, size_t size);
>> +
>> + The parameters are passed in registers from userland:
>> + a0: cl_args
>> + a1: size
>> + a2: func
>> + a3: arg */
>> +
>> + .text
>> +ENTRY(__clone3)
>> + /* Sanity check args. */
>> + beqz a0, L(invalid) /* No NULL cl_args pointer. */
>> + beqz a2, L(invalid) /* No NULL function pointer. */
>> +
>> + /* Do the system call, the kernel expects:
>> + a7: system call number
>> + a0: cl_args
>> + a1: size */
>> + li a7, __NR_clone3
>
> IIUC this only builds with kernel headers 5.15 or newer on rv32. I'm not sure if that's a problem: unless I'm missing something we support building for those systems now, but rv32 is pretty esoteric so I'm not sure anyone cares -- maybe someone uses 5.15 on rv32 (some rv64 hardware is still being released with 5.10-based vendor kernels), but 5.4 is pretty old for us.
The __NR_XXX macros are now provided by arch-syscall.h, which in turn is generated
by the kernel header. And we already have clone3 for rv32 since 3387c40a8bb.
>
>> + scall
>> +
>> + bltz a0, L(error)
>> + beqz a0, L(thread_start)
>> +
>> + ret
>> +
>> +L(invalid):
>> + li a0, -EINVAL
>> +L(error):
>> + tail __syscall_error
>> +END (__clone3)
>> +
>> +ENTRY(__thread_start_clone3)
>> +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 (ra)
>> +
>> + /* Restore the arg for user's function and call the user's
>> + function. */
>> + mv a1, a2 /* Function pointer. */
>
> I think we don't need that mv, we can just call a2 directly? Unless I'm missing some reason the thread main needs to see a pointer to itself?
We can, I will change it.
>
>> + mv a0, a3 /* Argument pointer. */
>> + jalr a1
>> +
>> + /* Call exit with the function's return value. */
>> + li a7, __NR_exit
>> + scall
>> +END(__thread_start_clone3)
>> +
>> +libc_hidden_def (__clone3)
>> +weak_alias (__clone3, clone3)
>> diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.h b/sysdeps/unix/sysv/linux/riscv/sysdep.h
>> index 4af5fe5dbc..e96a930409 100644
>> --- a/sysdeps/unix/sysv/linux/riscv/sysdep.h
>> +++ b/sysdeps/unix/sysv/linux/riscv/sysdep.h
>> @@ -151,6 +151,7 @@
>>
>> /* RV32 does not support the gettime VDSO syscalls. */
>> # endif
>> +# define HAVE_CLONE3_WRAPPER 1
>>
>> /* List of system calls which are supported as vsyscalls (for RV32 and
>> RV64). */
>
> That's just some minor comments though, so
>
> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Thanks.
>
> Thanks! (and sorry I missed it for a bit)
new file mode 100644
@@ -0,0 +1,80 @@
+/* The clone3 syscall wrapper. Linux/RISC-V version.
+ Copyright (C) 2023 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 <asm/errno.h>
+#include <sys/asm.h>
+#include <sysdep.h>
+
+/* The userland implementation is:
+ int clone3 (struct clone_args *cl_args, size_t size,
+ int (*func)(void *arg), void *arg);
+
+ the kernel entry is:
+ int clone3 (struct clone_args *cl_args, size_t size);
+
+ The parameters are passed in registers from userland:
+ a0: cl_args
+ a1: size
+ a2: func
+ a3: arg */
+
+ .text
+ENTRY(__clone3)
+ /* Sanity check args. */
+ beqz a0, L(invalid) /* No NULL cl_args pointer. */
+ beqz a2, L(invalid) /* No NULL function pointer. */
+
+ /* Do the system call, the kernel expects:
+ a7: system call number
+ a0: cl_args
+ a1: size */
+ li a7, __NR_clone3
+ scall
+
+ bltz a0, L(error)
+ beqz a0, L(thread_start)
+
+ ret
+
+L(invalid):
+ li a0, -EINVAL
+L(error):
+ tail __syscall_error
+END (__clone3)
+
+ENTRY(__thread_start_clone3)
+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 (ra)
+
+ /* Restore the arg for user's function and call the user's
+ function. */
+ mv a1, a2 /* Function pointer. */
+ mv a0, a3 /* Argument pointer. */
+ jalr a1
+
+ /* Call exit with the function's return value. */
+ li a7, __NR_exit
+ scall
+END(__thread_start_clone3)
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
@@ -151,6 +151,7 @@
/* RV32 does not support the gettime VDSO syscalls. */
# endif
+# define HAVE_CLONE3_WRAPPER 1
/* List of system calls which are supported as vsyscalls (for RV32 and
RV64). */