LoongArch: Use the generic shmlab.h.

The shmlba.h file related to the LoongArch architecture was introduced
in commit 3eed5f3a1ee to address the mismatch in the SHMLBA definition
between glibc and the kernel. See [1].  The SHMLBA definition was later
updated in commit d23b77953f5a. See [2].  Now, we adopt the definition
from the common layer.

[1]:
commit 3eed5f3a1ee356969afb403a1cf18d06f8d2d98a
Author: caiyinyu <caiyinyu@loongson.cn>
Date:   Thu May 25 17:01:11 2023 +0800

    LoongArch: Fix inconsistency in SHMLBA macro values between glibc and kernel

    The LoongArch glibc was using the value of the SHMLBA macro from common code,
    which is __getpagesize() (16k), but this was inconsistent with the value of
    the SHMLBA macro in the kernel, which is SZ_64K (64k). This caused several
    shmat-related tests in LTP (Linux Test Project) to fail. This commit fixes
    the issue by ensuring that the glibc's SHMLBA macro value matches the value
    used in the kernel like other architectures.

[2]:
commit d23b77953f5a4fbf94c05157b186aac2a247ae32
Author: Huacai Chen <chenhuacai@kernel.org>
Date:   Wed Jan 17 12:43:08 2024 +0800

    LoongArch: Change SHMLBA from SZ_64K to PAGE_SIZE

    LoongArch has hardware page coloring for L1 Cache, so we don't have
    cache aliases. But SFB (Store Fill Buffer) still has aliases. So we
    define SHMLBA to SZ_64K previously. But there are losts of applications
    use PAGE_SIZE rather than SHMLBA to mmap() file pages and shared pages.
    Of course we can fix them one by one, but not easy.

    On the other hand, we can simply disable SFB for 4KB page size to fix
    cache alias (there will be performance decrease, but acceptable), and
    in future we will fix SFB in hardware. So we can safely define SHMLBA to
    PAGE_SIZE (use the generic shmparam.h) to make life easier.

Signed-off-by: caiyinyu <caiyinyu@loongson.cn>
Reported-by: lixing <lixing@loongson.cn>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

diff --git a/sysdeps/unix/sysv/linux/loongarch/bits/shmlba.h b/sysdeps/unix/sysv/linux/loongarch/bits/shmlba.h
deleted file mode 100644 (file)
index e74644d..0000000
--- a/sysdeps/unix/sysv/linux/loongarch/bits/shmlba.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* Define SHMLBA.  LoongArch version.
-   Copyright (C) 2023-2025 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#ifndef _SYS_SHM_H
-# error "Never use <bits/shmlba.h> directly; include <sys/shm.h> instead."
-#endif
-
-/* Segment low boundary address multiple.  */
-#define SHMLBA         0x10000