cba595c350
On x86, padding in struct __jmp_buf_tag is used for shadow stack pointer to support Shadow Stack in Intel Control-flow Enforcemen Technology. cancel_jmp_buf has been updated to include saved_mask so that it is as large as struct __jmp_buf_tag. We must suport the old cancel_jmp_buf in existing binaries. Since symbol versioning doesn't work on cancel_jmp_buf, feature_1 is added to tcbhead_t so that setjmp and longjmp can check if shadow stack is enabled. NB: Shadow stack is enabled only if all modules are shadow stack enabled. [BZ #22563] * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New. * sysdeps/i386/nptl/tls.h (tcbhead_t): Add feature_1. * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New. * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Rename __glibc_unused1 to feature_1.