Re: [RFC PATCH 9/9] hurd, htl: Add some more x86_64-specific code

[Samuel Thibault <samuel.thibault@gnu.org>]

Sergey Bugaev, le sam. 18 févr. 2023 23:37:17 +0300, a ecrit:
> diff --git a/sysdeps/mach/hurd/x86_64/tls.h b/sysdeps/mach/hurd/x86_64/tls.h
> new file mode 100644
> index 00000000..644dcb1a
> --- /dev/null
> +++ b/sysdeps/mach/hurd/x86_64/tls.h
> @@ -0,0 +1,257 @@
> +# define TCB_ALIGNMENT	64

Please copy the comment about the penalty of non-64-aligned accesses.

> +# define TLS_INIT_TP(descr) _hurd_tls_init ((tcbhead_t *) (descr))
> +
> +# if __GNUC_PREREQ (6, 0)
> +
> +#  define THREAD_SELF							\
> +  (*(tcbhead_t * __seg_fs *) offsetof (tcbhead_t, tcb))
> +#  define THREAD_GETMEM(descr, member)					\
> +  (*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member))
> +#  define THREAD_SETMEM(descr, member, value)				\
> +  (*(__typeof (descr->member) __seg_fs *) offsetof (tcbhead_t, member) = value)
> +
> +# else

I'd say don't bother keeping the non-gcc-6 case, since x86_64-gnu got
added to gcc only recently.

> +/* Set the stack guard field in TCB head.  */
> +# define THREAD_SET_STACK_GUARD(value)					\
> +  THREAD_SETMEM (THREAD_SELF, stack_guard, value)
> +# define THREAD_COPY_STACK_GUARD(descr)					\
> +  ((descr)->stack_guard							\
> +   = THREAD_GETMEM (THREAD_SELF, stack_guard))
> +
> +/* Set the pointer guard field in the TCB head.  */
> +# define THREAD_SET_POINTER_GUARD(value)				\
> +  THREAD_SETMEM (THREAD_SELF, pointer_guard, value)
> +# define THREAD_COPY_POINTER_GUARD(descr)				\
> +  ((descr)->pointer_guard						\
> +   = THREAD_GETMEM (THREAD_SELF, pointer_guard))
> +
> +/* Install new dtv for current thread.  */
> +# define INSTALL_NEW_DTV(dtvp) THREAD_SETMEM (THREAD_SELF, dtv, dtvp)
> +
> +/* Return the address of the dtv for the current thread.  */
> +# define THREAD_DTV() THREAD_GETMEM (THREAD_SELF, dtv)

Please keep #define order coherent with i386/tls.h

> diff --git a/sysdeps/x86_64/htl/pt-machdep.h b/sysdeps/x86_64/htl/pt-machdep.h
> new file mode 100644
> index 00000000..2e2846fa
> --- /dev/null
> +++ b/sysdeps/x86_64/htl/pt-machdep.h

I don't think this is needed since we already have sysdeps/x86/htl/pt-machdep.h
?

Samuel