On 02/03/23 13:10, Pavel Kozlov via Libc-alpha wrote:
> From: Pavel Kozlov <pavel.koz...@synopsys.com>
>
> For better debug experience use separate code block with extra
> cfi_* directives to run child (same as in __clone3).
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zane...@linaro.org>
> ---
> sysdeps/unix/sysv/linux/arc/clone.S | 40 ++++++++++++++++++-----------
> 1 file changed, 25 insertions(+), 15 deletions(-)
>
> diff --git a/sysdeps/unix/sysv/linux/arc/clone.S
> b/sysdeps/unix/sysv/linux/arc/clone.S
> index 766649625658..0029aaeb8170 100644
> --- a/sysdeps/unix/sysv/linux/arc/clone.S
> +++ b/sysdeps/unix/sysv/linux/arc/clone.S
> @@ -20,9 +20,6 @@
> #include <sysdep.h>
> #define _ERRNO_H 1
> #include <bits/errno.h>
> -#include <tcb-offsets.h>
> -
> -#define CLONE_SETTLS 0x00080000
>
> /* int clone(int (*fn)(void *), void *child_stack,
> int flags, void *arg, ...
> @@ -63,19 +60,9 @@ ENTRY (__clone)
> ARC_TRAP_INSN
>
> cmp r0, 0 /* return code : 0 new process, !0 parent. */
> + beq thread_start_clone
> blt L (__sys_err2) /* < 0 (signed) error. */
> - jnz [blink] /* Parent returns. */
> -
> - /* child jumps off to @fn with @arg as argument
> - TP register already set by kernel. */
> - jl.d [r10]
> - mov r0, r11
> -
> - /* exit() with result from @fn (already in r0). */
> - mov r8, __NR_exit
> - ARC_TRAP_INSN
> - /* In case it ever came back. */
> - flag 1
> + j [blink] /* Parent returns. */
>
> L (__sys_err):
> mov r0, -EINVAL
> @@ -89,5 +76,28 @@ L (__sys_err2):
> position independent. */
> b __syscall_error
> PSEUDO_END (__clone)
> +
> +
> + .align 4
> + .type thread_start_clone, %function
> +thread_start_clone:
> + cfi_startproc
> + /* Terminate call stack by noting ra is undefined. */
> + cfi_undefined (blink)
> +
> + /* Child jumps off to @fn with @arg as argument. */
> + jl.d [r10]
> + mov r0, r11
> +
> + /* exit() with result from @fn (already in r0). */
> + mov r8, __NR_exit
> + ARC_TRAP_INSN
> +
> + /* In case it ever came back. */
> + flag 1
> +
> + cfi_endproc
> + .size thread_start_clone, .-thread_start_clone
> +
> libc_hidden_def (__clone)
> weak_alias (__clone, clone)
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