[LTP] [PATCH] syscalls/mprotect04: Use __builtin___clear_cache() to sync caches

[Jan Stancek]

----- Original Message -----
> From: "Peter Maydell" <peter.maydell@linaro.org>
> To: ltp@lists.linux.it
> Cc: patches@linaro.org, "Cyril Hrubis" <chrubis@suse.cz>, "Jan Stancek" <jstancek@redhat.com>, "Mark Rutland"
> <mark.rutland@arm.com>
> Sent: Tuesday, 26 July, 2016 6:31:05 PM
> Subject: [PATCH] syscalls/mprotect04: Use __builtin___clear_cache() to sync caches
> 
> In commit cf9a0800cd0 code was added to mprotect04 to synchronize
> the instruction and data caches on PowerPC before executing
> the copied code. This is also necessary on other architectures
> which have split instruction and data caches and need explicit
> cache maintenance operations, like ARM.
> 
> The GCC builtin __builtin___clear_cache() will correctly handle
> this for all architectures, so switch to using it. The builtin
> was only implemented at around GCC 4.1, so use a configure
> check so that we will skip the test with TCONF if the compiler
> doesn't support the builtin.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Looks good to me.

> ---
> Disclaimer: untested on PPC.

I don't have such HW available at the moment, but I tested this
on RHEL5.6/6.0/7.2 x86_64. RHEL5.6 exits with TCONF as expected.

Regards,
Jan