On Wed, Apr 10, 2019 at 03:00:43PM -0300, Joao Moreira wrote:
> When -fpatchable-relocation-entry is used, gcc places nops on the
> prologue of each compiled function and creates a section named
> __patchable_function_entries which holds relocation entries for the
> positions in which the nops were placed. As is, gcc creates this
> section without the proper section flags, causing crashes in the
> compiled program during its load.
>
> Given the above, fix the problem by creating the section with the
> SECTION_WRITE and SECTION_RELRO flags.
>
> The problem was noticed while compiling glibc with
> -fpatchable-function-entry compiler flag. After applying the patch,
> this issue was solved.
>
> This was also tested on x86-64 arch without visible problems under
> the gcc standard tests.
Thanks for the patch. Just some nits:
> 2019-04-10 Joao Moreira <jmore...@suse.de>
Two spaces after the name.
>
> * gcc/targhooks.c (default_print_patchable_function_entry): emit
> __patchable_function_entries section with writable flags to allow
> relocation resolution.
Please drop the gcc/ prefix and use capital E in "emit".
> ---
> gcc/targhooks.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/gcc/targhooks.c b/gcc/targhooks.c
> index 318f7e9784a..9fbaa255747 100644
> --- a/gcc/targhooks.c
> +++ b/gcc/targhooks.c
> @@ -1814,7 +1814,7 @@ default_print_patchable_function_entry (FILE *file,
> ASM_GENERATE_INTERNAL_LABEL (buf, "LPFE", patch_area_number);
>
> switch_to_section (get_section ("__patchable_function_entries",
> - 0, NULL));
> + SECTION_WRITE | SECTION_RELRO , NULL));
Redundant space before ,.
Marek
