glibc/csu, branch master

Add crt1-2.0.o for glibc 2.0 compatibility tests

2024-05-06T14:49:40Z

Starting from glibc 2.1, crt1.o contains _IO_stdin_used which is checked by _IO_check_libio to provide binary compatibility for glibc 2.0. Add crt1-2.0.o for tests against glibc 2.0. Define tests-2.0 for glibc 2.0 compatibility tests. Add and update glibc 2.0 compatibility tests for stderr, matherr and pthread_kill. Reviewed-by: Carlos O'Donell

csu: Reformat Makefile.

2024-02-25T18:38:16Z

Reflow and sort Makefile. Code generation changes present due to link order changes. No regressions on x86_64 and i686.

Update copyright dates with scripts/update-copyrights

2024-01-01T18:53:40Z

Fix all the remaining misspellings -- BZ 25337

2023-06-02T01:39:48Z

elf: Fix GL(dl_phdr) and GL(dl_phnum) for static builds [BZ #29864]

2023-01-12T16:54:34Z

The 73fc4e28b9464f0e refactor did not add the GL(dl_phdr) and GL(dl_phnum) for static build, relying on the __ehdr_start symbol, which is always added by the static linker, to get the correct values. This is problematic in some ways: - The segment may see its in-memory size differ from its in-file size (or the binary may have holes). The Linux has fixed is to provide concise values for both AT_PHDR and AT_PHNUM (commit 0da1d5002745c - "fs/binfmt_elf: Fix AT_PHDR for unusual ELF files") - Some archs (alpha for instance) the hidden weak reference is not correctly pulled by the static linker and __ehdr_start address end up being 0, which makes GL(dl_phdr) and GL(dl_phnum) have both invalid values (and triggering a segfault later on libc.so while accessing TLS variables). The safer fix is to just restore the previous behavior to setup GL(dl_phdr) and GL(dl_phnum) for static based on kernel auxv. The __ehdr_start fallback can also be simplified by not assuming weak linkage (as for PIE). The libc-static.c auxv init logic is moved to dl-support.c, since the later is build without SHARED and then GLRO macro is defined to access the variables directly. The _dl_phdr is also assumed to be always non NULL, since an invalid NULL values does not trigger TLS initialization (which is used in various libc systems). Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu. Reviewed-by: Florian Weimer

Update copyright dates with scripts/update-copyrights

2023-01-06T21:14:39Z

elf: Introduce and call_tls_init_tp (bug 29249)

2022-11-03T16:28:03Z

This makes it more likely that the compiler can compute the strlen argument in _startup_fatal at compile time, which is required to avoid a dependency on strlen this early during process startup. Reviewed-by: Szabolcs Nagy

csu: Disable stack protector for static-reloc for static-pie

2022-10-06T15:52:46Z

For instance on x86_64 with gcc 12.1.1 andwith fstack-protector enabled the empty function still generates a stack protector code sequence: 0000000000000000 <_dl_relocate_static_pie>: 0: 48 83 ec 18 sub $0x18,%rsp 4: 64 48 8b 04 25 28 00 mov %fs:0x28,%rax b: 00 00 d: 48 89 44 24 08 mov %rax,0x8(%rsp) 12: 31 c0 xor %eax,%eax 14: 48 8b 44 24 08 mov 0x8(%rsp),%rax 19: 64 48 2b 04 25 28 00 sub %fs:0x28,%rax 20: 00 00 22: 75 05 jne 29 <_dl_relocate_static_pie+0x29> 24: 48 83 c4 18 add $0x18,%rsp 28: c3 ret 29: e8 00 00 00 00 call 2e <_dl_relocate_static_pie+0x2e> And since the function is called prior thread pointer setup, it triggers a invalid memory access (this is shown with the failure of elf/tst-tls1-static-non-pie). Although it might characterizes as compiler issue or missed optimization, to be safe also disables stack protector on static-reloc object. Checked on x86_64-linux-gnu and sparc64-linux-gnu. Reviewed-by: Siddhesh Poyarekar

Remove kernel version check

2022-05-16T18:03:49Z

The kernel version check is used to avoid glibc to run on older kernels where some syscall are not available and fallback code are not enabled to handle graciously fail. However, it does not prevent if the kernel does not correctly advertise its version through vDSO note, uname or procfs. Also kernel version checks are sometime not desirable by users, where they want to deploy on different system with different kernel version knowing the minimum set of syscall is always presented on such systems. The kernel version check has been removed along with the LD_ASSUME_KERNEL environment variable. The minimum kernel used to built glibc is still provided through NT_GNU_ABI_TAG ELF note and also printed when libc.so is issued. Checked on x86_64-linux-gnu.

csu: Implement and use _dl_early_allocate during static startup

2022-05-16T16:42:03Z

This implements mmap fallback for a brk failure during TLS allocation. scripts/tls-elf-edit.py is updated to support the new patching method. The script no longer requires that in the input object is of ET_DYN type. Reviewed-by: Adhemerval Zanella