[PATCH, Android] Runtime stack protector enabling for Android target

Andrew Pinski pinskia@gmail.com
Fri Jul 6 08:13:00 GMT 2012


On Fri, Jul 6, 2012 at 12:49 AM, Igor Zamyatin <izamyatin@gmail.com> wrote:
> Hi!
>
> For runtime stack protector enabling on x86 for Android we have to
> disable current glibc-based implementation and turn on default one
> since bionic doesn't use value from gs:0x14.
>
> Tested in android environment(x86_64-*-linux-android), also
> bootstrapped and regtested on x86_64-unknown-linux-gnu and i686-linux.
> Ok for trunk?



I think you want flag_android and not ANDROID_DEFAULT since you could
use -mno-android .

Thanks,
Andrew



>
> Thanks,
> Igor
>
>
> ChangeLog:
>
> 2012-07-05 Sergey Melnikov <sergey.melnikov@intel.com>
>
>         * config/i386/i386.md (stack_protect_set): Disable the pattern
>         for Android since Android libc (bionic) does not provide random
>         value for stack protection guard at gs:0x14. Guard value
>         will be provided from external symbol (default implementation).
>         (stack_protect_set_<mode>): Likewise.
>         (stack_protect_test): Likewise.
>         (stack_protect_test_<mode>): Likewise.
>
> diff --git a/gcc-4.6/gcc/config/i386/i386.md b/gcc-4.6/gcc/config/i386/i386.md
> index b1d7e5e..fe0009d 100644
> --- a/gcc-4.6/gcc/config/i386/i386.md
> +++ b/gcc-4.6/gcc/config/i386/i386.md
> @@ -17955,7 +17955,7 @@
>  (define_expand "stack_protect_set"
>    [(match_operand 0 "memory_operand" "")
>     (match_operand 1 "memory_operand" "")]
> -  ""
> +  "!ANDROID_DEFAULT"
>  {
>    rtx (*insn)(rtx, rtx);
>
> @@ -17979,7 +17979,7 @@
>         (unspec:P [(match_operand:P 1 "memory_operand" "m")] UNSPEC_SP_SET))
>     (set (match_scratch:P 2 "=&r") (const_int 0))
>     (clobber (reg:CC FLAGS_REG))]
> -  ""
> +  "!ANDROID_DEFAULT"
>    "mov{<imodesuffix>}\t{%1, %2|%2, %1}\;mov{<imodesuffix>}\t{%2,
> %0|%0, %2}\;xor{l}\t%k2, %k2"
>    [(set_attr "type" "multi")])
>
> @@ -17997,7 +17997,7 @@
>    [(match_operand 0 "memory_operand" "")
>     (match_operand 1 "memory_operand" "")
>     (match_operand 2 "" "")]
> -  ""
> +  "!ANDROID_DEFAULT"
>  {
>    rtx flags = gen_rtx_REG (CCZmode, FLAGS_REG);
>
> @@ -18027,7 +18027,7 @@
>                      (match_operand:P 2 "memory_operand" "m")]
>                     UNSPEC_SP_TEST))
>     (clobber (match_scratch:P 3 "=&r"))]
> -  ""
> +  "!ANDROID_DEFAULT"
>    "mov{<imodesuffix>}\t{%1, %3|%3, %1}\;xor{<imodesuffix>}\t{%2, %3|%3, %2}"
>    [(set_attr "type" "multi")])



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