diff options
| author | H.J. Lu <hjl.tools@gmail.com> | 2017-07-19 14:32:42 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2017-08-07 13:05:12 -0700 |
| commit | 99dd28489e425c6f654126871f89d514331aa69f (patch) | |
| tree | e1186383fb3bac831a4f78aaafe3420cb2064365 /csu/libc-tls.c | |
| parent | 57a72fa3502673754d14707da02c7c44e83b8d20 (diff) | |
| download | glibc-hjl/pr21913/master.tar.gz glibc-hjl/pr21913/master.tar.xz glibc-hjl/pr21913/master.zip | |
i386: Add <startup.h> [BZ #21913] hjl/pr21913/master
On Linux/i386, there are 3 ways to make a system call: 1. call *%gs:SYSINFO_OFFSET. This requires TLS initialization. 2. call *_dl_sysinfo. This requires relocation of _dl_sysinfo. 3. int $0x80. This is slower than #2 and #3, but works everywhere. When an object file is compiled with PIC, #1 is prefered since it is faster than #3 and doesn't require relocation of _dl_sysinfo. For dynamic executables, ld.so initializes TLS. However, for static executables, before TLS is initialized by __libc_setup_tls, #3 should be used for syscalls. This patch adds <startup.h> which defines _startup_fatal and defaults it to __libc_fatal. It replaces __libc_fatal with _startup_fatal in static executables where it is called before __libc_setup_tls is called. This header file is included in all files containing functions which are called before __libc_setup_tls is called. On Linux/i386, when PIE is enabled by default, _startup_fatal is turned into ABORT_INSTRUCTION and I386_USE_SYSENTER is defined to 0 so that "int $0x80" is used for system calls before __libc_setup_tls is called. [BZ #21913] * config.h.in (BUILD_PIE_DEFAULT): New. * csu/libc-tls.c: Include <startup.h>. * elf/dl-tunables.c: Likewise. * sysdeps/unix/sysv/linux/i386/brk.c: Likewise. * csu/libc-tls.c: Include <startup.h>. (__libc_setup_tls): Call _startup_fatal instead of __libc_fatal. * sysdeps/generic/startup.h: New file. * sysdeps/unix/sysv/linux/i386/startup.h: Likewise.
Diffstat (limited to 'csu/libc-tls.c')
| -rw-r--r-- | csu/libc-tls.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/csu/libc-tls.c b/csu/libc-tls.c index 3c897bf28b..00138eb43a 100644 --- a/csu/libc-tls.c +++ b/csu/libc-tls.c @@ -16,6 +16,7 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ +#include <startup.h> #include <errno.h> #include <ldsodefs.h> #include <tls.h> @@ -193,7 +194,7 @@ __libc_setup_tls (void) # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" #endif if (__builtin_expect (lossage != NULL, 0)) - __libc_fatal (lossage); + _startup_fatal (lossage); /* Update the executable's link map with enough information to make the TLS routines happy. */ |