Re: [PATCH for-7.0] linux-user: Fix syscall parameter handling for MIPS n32

[Philippe Mathieu-Daudé]

On 20/3/22 06:22, WANG Xuerui wrote:
> The MIPS n32 ABI is basically n64 with the address space (i.e. pointer
> width) shrinked to 32 bits. Meanwhile the current code treats it as
> o32-like based on TARGET_ABI_BITS, which causes problems with n32
> syscalls utilizing 64-bit offsets, like pread64, affecting most (if not
> all) recently built n32 binaries.
>
> This partially solves issue #909 ("qemu-mipsn32(el) user mode emulator
> fails to execute any recently built n32 binaries"); with this change
> applied, the built qemu-mipsn32el is able to progress beyond the
> pread64, and finish _dl_start_user for the "getting ld.so load libc.so"
> case. The program later dies with SIGBUS, though, due to _dl_start_user
> not maintaining stack alignment after removing ld.so itself from argv,
> and qemu-user starting to enforce alignment recently, but that is
> orthogonal to the issue here; the more common case of chrooting is
> working, verified with my own-built Gentoo n32 sysroot. (Depending on
> the exact ISA used, one may have to explicitly specify QEMU_CPU, which
> is the case for my chroot.)
>
> Buglink: https://gitlab.com/qemu-project/qemu/-/issues/909

Very nice analysis there!

"Buglink" doesn't seem to match GitLab autoclose regexp:
https://docs.gitlab.com/ee/administration/issue_closing_pattern.html#change-the-issue-closing-pattern

> Signed-off-by: WANG Xuerui <xen0n@gentoo.org>
> Cc: Laurent Vivier <laurent@vivier.eu>
> Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
> Cc: Andreas K. Hüttel <dilfridge@gentoo.org>
> ---
>
> P.S. This patch is done with my Gentoo hat on, so I'm not using my
> usual xen0n.name address. I'd like to add a mailmap entry for correct
> shortlog display though, but it seems there's no category for "merely
> preference" mappings yet. What should I do in this case?

The last section seems to match your case:

  # Also list preferred name forms where people have changed their
  # git author config, or had utf8/latin1 encoding issues.

>   linux-user/user-internals.h | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>