[Bug dynamic-link/31372] _dl_tlsdesc_dynamic doesn't preserve all caller-saved registers

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=31372

--- Comment #10 from Sourceware Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by H.J. Lu <hjl@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=0aac205a814a8511e98d02b91a8dc908f1c53cde

commit 0aac205a814a8511e98d02b91a8dc908f1c53cde
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Feb 26 06:37:03 2024 -0800

    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>

-- 
You are receiving this mail because:
You are on the CC list for the bug.