| Message ID | 1466682675-5301-1-git-send-email-vgupta@synopsys.com |
|---|---|
| State | Accepted |
| Headers | show |
Hi Vineet, Vineet Gupta wrote, > Currently crt1 takes address of functions (main,_init,_fini) directly > which doesn't generate truely position independent code, but zero based > values instead. e.g. > > | __start: > | ... > | add_s r2,sp,0x4 > | mov_s r0, main > > generates to > > | 000156ec <__start>: > | ... > | 156f4: add_s r2,sp,0x4 > | 156f6: mov_s r0,0x15f7c > | ... > | 00015f7c <main>: > | 15f7c: push_s blink > > This works just fine for the normal (non PIE) dynamic executables since > they are loaded at address 0. However this is not true for PIE > executables. So for Scrt1 we use a true position independent way when > taking function addresses. > > Cc: uclibc@uclibc.org <uclibc@uclibc.org> > Cc: devel@uclibc-ng.org <devel@uclibc-ng.org> > Cc: Cupertino Miranda <cmiranda@synopsys.com> > Signed-off-by: Vineet Gupta <vgupta@synopsys.com> > --- > libc/sysdeps/linux/arc/crt1.S | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) Applied and pushed, thx Waldemar
diff --git a/libc/sysdeps/linux/arc/crt1.S b/libc/sysdeps/linux/arc/crt1.S index 95c41f888850..e38c8e81b2c0 100644 --- a/libc/sysdeps/linux/arc/crt1.S +++ b/libc/sysdeps/linux/arc/crt1.S @@ -41,11 +41,15 @@ __start: mov_s r5, r0 ; rltd_fini add_s r2, sp, 4 ; argv - +#ifdef L_Scrt1 + add r0, pcl, @main@pcl + add r3, pcl, @_init@pcl + add r4, pcl, @_fini@pcl +#else mov_s r0, main mov_s r3, _init mov r4, _fini - +#endif and sp, sp, -8 mov r6, sp
Currently crt1 takes address of functions (main,_init,_fini) directly which doesn't generate truely position independent code, but zero based values instead. e.g. | __start: | ... | add_s r2,sp,0x4 | mov_s r0, main generates to | 000156ec <__start>: | ... | 156f4: add_s r2,sp,0x4 | 156f6: mov_s r0,0x15f7c | ... | 00015f7c <main>: | 15f7c: push_s blink This works just fine for the normal (non PIE) dynamic executables since they are loaded at address 0. However this is not true for PIE executables. So for Scrt1 we use a true position independent way when taking function addresses. Cc: uclibc@uclibc.org <uclibc@uclibc.org> Cc: devel@uclibc-ng.org <devel@uclibc-ng.org> Cc: Cupertino Miranda <cmiranda@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- libc/sysdeps/linux/arc/crt1.S | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)