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Re: [PATCH] ld.so: Add architecture specific fields
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Date: Wed, 8 Nov 2017 15:03:34 -0800
- Subject: Re: [PATCH] ld.so: Add architecture specific fields
- Authentication-results: sourceware.org; auth=none
- References: <20171031163712.GA10434@gmail.com>
On Tue, Oct 31, 2017 at 9:37 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> To support Intel Control-flow Enforcement Technology (CET) run-time
> control:
>
> 1. An architecture specific field in the writable ld.so namespace is
> needed to indicate if CET features are enabled at run-time.
> 2. An architecture specific field in struct link_map is needed if
> CET features are enabled in an ELF module.
>
> This patch adds dl-procruntime.c to the writable ld.so namespace and
> link_map.h to struct link_map.
>
> Tested on x86-64.
>
> Any comments?
>
> H.J.
> --
> * elf/dl-support.c: Include <dl-procruntime.c>.
> * include/link.h: Include <link_map.h>.
> * sysdeps/generic/dl-procruntime.c: New file.
> * sysdeps/generic/link_map.h: Likewise.
> * sysdeps/generic/ldsodefs.h: Include <dl-procruntime.c> in
> the writable ld.so namespace.
> ---
> elf/dl-support.c | 1 +
> include/link.h | 2 ++
> sysdeps/generic/dl-procruntime.c | 1 +
> sysdeps/generic/ldsodefs.h | 11 +++++++----
> sysdeps/generic/link_map.h | 1 +
> 5 files changed, 12 insertions(+), 4 deletions(-)
> create mode 100644 sysdeps/generic/dl-procruntime.c
> create mode 100644 sysdeps/generic/link_map.h
>
> diff --git a/elf/dl-support.c b/elf/dl-support.c
> index 5e3de90598..235d3a7f46 100644
> --- a/elf/dl-support.c
> +++ b/elf/dl-support.c
> @@ -126,6 +126,7 @@ int _dl_starting_up = 1;
> void *_dl_random;
>
> /* Get architecture specific initializer. */
> +#include <dl-procruntime.c>
> #include <dl-procinfo.c>
>
> /* Initial value of the CPU clock. */
> diff --git a/include/link.h b/include/link.h
> index 3e1b2aefb7..82b77a6b41 100644
> --- a/include/link.h
> +++ b/include/link.h
> @@ -203,6 +203,8 @@ struct link_map
> freed, ie. not allocated with
> the dummy malloc in ld.so. */
>
> +#include <link_map.h>
> +
> /* Collected information about own RPATH directories. */
> struct r_search_path_struct l_rpath_dirs;
>
> diff --git a/sysdeps/generic/dl-procruntime.c b/sysdeps/generic/dl-procruntime.c
> new file mode 100644
> index 0000000000..a056184690
> --- /dev/null
> +++ b/sysdeps/generic/dl-procruntime.c
> @@ -0,0 +1 @@
> +/* No architecture specific definitions. */
> diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
> index 5efae2d96d..52a792a597 100644
> --- a/sysdeps/generic/ldsodefs.h
> +++ b/sysdeps/generic/ldsodefs.h
> @@ -373,6 +373,13 @@ struct rtld_global
> EXTERN void (*_dl_rtld_unlock_recursive) (void *);
> #endif
>
> + /* Get architecture specific definitions. */
> +#define PROCINFO_DECL
> +#ifndef PROCINFO_CLASS
> +# define PROCINFO_CLASS EXTERN
> +#endif
> +#include <dl-procruntime.c>
> +
> /* If loading a shared object requires that we make the stack executable
> when it was not, we do it by calling this function.
> It returns an errno code or zero on success. */
> @@ -529,10 +536,6 @@ struct rtld_global_ro
> #endif
>
> /* Get architecture specific definitions. */
> -#define PROCINFO_DECL
> -#ifndef PROCINFO_CLASS
> -# define PROCINFO_CLASS EXTERN
> -#endif
> #include <dl-procinfo.c>
>
> /* Names of shared object for which the RPATH should be ignored. */
> diff --git a/sysdeps/generic/link_map.h b/sysdeps/generic/link_map.h
> new file mode 100644
> index 0000000000..a056184690
> --- /dev/null
> +++ b/sysdeps/generic/link_map.h
> @@ -0,0 +1 @@
> +/* No architecture specific definitions. */
> --
> 2.13.6
>
I tested it with build-many-glibcs.py. If there are no objections, I will
check it next week.
Thanks.
--
H.J.