diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/x86/setjmpP.h')
| -rw-r--r-- | sysdeps/unix/sysv/linux/x86/setjmpP.h | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/x86/setjmpP.h b/sysdeps/unix/sysv/linux/x86/setjmpP.h new file mode 100644 index 0000000000..6b2608453d --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86/setjmpP.h @@ -0,0 +1,128 @@ +/* Internal header file for <setjmp.h>. Linux/x86 version. + Copyright (C) 2017-2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#ifndef _SETJMPP_H +#define _SETJMPP_H 1 + +#include <bits/types/__sigset_t.h> +#include <libc-pointer-arith.h> + +/* <setjmp/setjmp.h> has + +struct __jmp_buf_tag + { + __jmp_buf __jmpbuf; + int __mask_was_saved; + __sigset_t __saved_mask; + }; + + struct __jmp_buf_tag is 32 bits aligned on i386 and is 64 bits + aligned on x32 and x86-64. __saved_mask is aligned to 32 bits + on i386/x32 without padding and is aligned to 64 bits on x86-64 + with 32 bit padding. + + and <nptl/descr.h> has + +struct pthread_unwind_buf +{ + struct + { + __jmp_buf jmp_buf; + int mask_was_saved; + } cancel_jmp_buf[1]; + + union + { + void *pad[4]; + struct + { + struct pthread_unwind_buf *prev; + struct _pthread_cleanup_buffer *cleanup; + int canceltype; + } data; + } priv; +}; + + struct pthread_unwind_buf is 32 bits aligned on i386 and 64 bits + aligned on x32/x86-64. cancel_jmp_buf is aligned to 32 bits on + i386 and is aligned to 64 bits on x32/x86-64. + + The pad array in struct pthread_unwind_buf is used by setjmp to save + shadow stack register. The usable space in __saved_mask for sigset + and shadow stack pointer: + 1. i386: The 4x4 byte pad array which can be used for 4 byte shadow + stack pointer and maximum 12 byte sigset. + 2. x32: 4 byte padding + the 4x4 byte pad array which can be used + for 8 byte shadow stack pointer and maximum 12 byte sigset. + 3. x86-64: The 4x8 byte pad array which can be used for 8 byte + shadow stack pointer and maximum 24 byte sigset. + + NB: We use setjmp in thread cancellation and this saves the shadow + stack register, but __libc_unwind_longjmp doesn't restore the shadow + stack register since cancellation never returns after longjmp. */ + +/* Number of bits per long. */ +#define _JUMP_BUF_SIGSET_BITS_PER_WORD (8 * sizeof (unsigned long int)) +/* The biggest signal number. As of kernel 4.14, x86 _NSIG is 64. The + common maximum sigset for i386, x32 and x86-64 is 12 bytes (96 bits). + Define it to 96 to leave some rooms for future use. */ +#define _JUMP_BUF_SIGSET_NSIG 96 +/* Number of longs to hold all signals. */ +#define _JUMP_BUF_SIGSET_NWORDS \ + (ALIGN_UP (_JUMP_BUF_SIGSET_NSIG, _JUMP_BUF_SIGSET_BITS_PER_WORD) \ + / _JUMP_BUF_SIGSET_BITS_PER_WORD) + +typedef struct + { + unsigned long int __val[_JUMP_BUF_SIGSET_NWORDS]; + } __jmp_buf_sigset_t; + +typedef union + { + __sigset_t __saved_mask_compat; + struct + { + __jmp_buf_sigset_t __saved_mask; + /* Used for shadow stack pointer. NB: Shadow stack pointer + must have the same alignment as __saved_mask. Otherwise + offset of __saved_mask will be changed. */ + unsigned long int __shadow_stack_pointer; + } __saved; + } __jmpbuf_arch_t; + +#undef __sigset_t +#define __sigset_t __jmpbuf_arch_t +#include <setjmp.h> +#undef __saved_mask +#define __saved_mask __saved_mask.__saved.__saved_mask + +#include <signal.h> + +#define _SIGPROCMASK_NSIG_WORDS (_NSIG / (8 * sizeof (unsigned long int))) + +typedef struct + { + unsigned long int __val[_SIGPROCMASK_NSIG_WORDS]; + } __sigprocmask_sigset_t; + +extern jmp_buf ___buf; +extern __typeof (___buf[0].__saved_mask) ___saved_mask; +_Static_assert (sizeof (___saved_mask) >= sizeof (__sigprocmask_sigset_t), + "size of ___saved_mask < size of __sigprocmask_sigset_t"); + +#endif /* setjmpP.h */ |