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| author | H.J. Lu <hjl.tools@gmail.com> | 2024-02-26 06:37:03 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2024-04-01 10:42:25 -0700 |
| commit | a364304718725a31ab141936322855c76c73e35e (patch) | |
| tree | f6a4d2f7684658444d35e45a5d150bc2a2f74de6 /manual | |
| parent | 7fc8242bf87828c935ac5df5cafb9dc7ab635fd9 (diff) | |
| download | glibc-a364304718725a31ab141936322855c76c73e35e.zip glibc-a364304718725a31ab141936322855c76c73e35e.tar.gz glibc-a364304718725a31ab141936322855c76c73e35e.tar.bz2 | |
x86: Update _dl_tlsdesc_dynamic to preserve caller-saved registers
Compiler generates the following instruction sequence for GNU2 dynamic
TLS access:
leaq tls_var@TLSDESC(%rip), %rax
call *tls_var@TLSCALL(%rax)
or
leal tls_var@TLSDESC(%ebx), %eax
call *tls_var@TLSCALL(%eax)
CALL instruction is transparent to compiler which assumes all registers,
except for EFLAGS and RAX/EAX, are unchanged after CALL. When
_dl_tlsdesc_dynamic is called, it calls __tls_get_addr on the slow
path. __tls_get_addr is a normal function which doesn't preserve any
caller-saved registers. _dl_tlsdesc_dynamic saved and restored integer
caller-saved registers, but didn't preserve any other caller-saved
registers. Add _dl_tlsdesc_dynamic IFUNC functions for FNSAVE, FXSAVE,
XSAVE and XSAVEC to save and restore all caller-saved registers. This
fixes BZ #31372.
Add GLRO(dl_x86_64_runtime_resolve) with GLRO(dl_x86_tlsdesc_dynamic)
to optimize elf_machine_runtime_setup.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
(cherry picked from commit 0aac205a814a8511e98d02b91a8dc908f1c53cde)
Diffstat (limited to 'manual')
0 files changed, 0 insertions, 0 deletions