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The pad array in struct pthread_unwind_buf is used by setjmp to save shadow stack register. We assert that size of struct pthread_unwind_buf is no less than offset of shadow stack pointer + shadow stack pointer size. Since functions, like LIBC_START_MAIN, START_THREAD_DEFN as well as these with thread cancellation, call setjmp, but never return after __libc_unwind_longjmp, __libc_unwind_longjmp, which is defined as __libc_longjmp on x86, doesn't need to restore shadow stack register. __libc_longjmp, which is a private interface for thread cancellation implementation in libpthread, is changed to call __longjmp_cancel, instead of __longjmp. __longjmp_cancel is a new internal function in libc, which is similar to __longjmp, but doesn't restore shadow stack register. The compatibility longjmp and siglongjmp in libpthread.so are changed to call __libc_siglongjmp, instead of __libc_longjmp, so that they will restore shadow stack register. Tested with build-many-glibcs.py. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com> * nptl/pthread_create.c (START_THREAD_DEFN): Clear previous handlers after setjmp. * setjmp/longjmp.c (__libc_longjmp): Don't define alias if defined. * sysdeps/unix/sysv/linux/x86/setjmpP.h: Include <libc-pointer-arith.h>. (_JUMP_BUF_SIGSET_BITS_PER_WORD): New. (_JUMP_BUF_SIGSET_NSIG): Changed to 96. (_JUMP_BUF_SIGSET_NWORDS): Changed to use ALIGN_UP and _JUMP_BUF_SIGSET_BITS_PER_WORD. * sysdeps/x86/Makefile (sysdep_routines): Add __longjmp_cancel. * sysdeps/x86/__longjmp_cancel.S: New file. * sysdeps/x86/longjmp.c: Likewise. * sysdeps/x86/nptl/pt-longjmp.c: Likewise. |
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| sh | ||
| sysv/linux | ||
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| clock_gettime.c | ||
| clock_nanosleep.c | ||
| clock_settime.c | ||
| confstr.h | ||
| get_child_max.c | ||
| getlogin_r.c | ||
| getlogin.c | ||
| getpagesize.c | ||
| grantpt.c | ||
| ifreq.c | ||
| Implies | ||
| make-syscalls.sh | ||
| Makefile | ||
| s-proto-cancel.S | ||
| s-proto.S | ||
| setxid.h | ||
| sockatmark.c | ||
| stime.c | ||
| syscall-template.S | ||
| syscall.S | ||
| syscalls.list | ||
| sysdep.h | ||