mirror of
https://sourceware.org/git/glibc.git
synced 2025-10-30 10:45:40 +03:00
1bdda52fe9
This patch moves the vDSO setup from libc to loader code, just after the vDSO link_map setup. For static case the initialization is moved to _dl_non_dynamic_init instead. Instead of using the mangled pointer, the vDSO data is set as attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for static). It is read-only even with partial relro. It fixes BZ#24967 now that the vDSO pointer is setup earlier than malloc interposition is called. Also, vDSO calls should not be a problem for static dlopen as indicated by BZ#20802. The vDSO pointer would be zero-initialized and the syscall will be issued instead. Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and sparcv9-linux-gnu. I also run some tests on mips. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
77 lines
2.0 KiB
C
77 lines
2.0 KiB
C
/* RISC-V instruction cache flushing VDSO calls
|
|
Copyright (C) 2017-2020 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/>. */
|
|
|
|
#include <dl-vdso.h>
|
|
#include <stdlib.h>
|
|
#include <atomic.h>
|
|
#include <sys/cachectl.h>
|
|
#if __has_include (<asm/syscalls.h>)
|
|
# include <asm/syscalls.h>
|
|
#else
|
|
# include <asm/unistd.h>
|
|
#endif
|
|
#include <sys/syscall.h>
|
|
|
|
typedef int (*func_type) (void *, void *, unsigned long int);
|
|
|
|
static int
|
|
__riscv_flush_icache_syscall (void *start, void *end, unsigned long int flags)
|
|
{
|
|
return INLINE_SYSCALL (riscv_flush_icache, 3, start, end, flags);
|
|
}
|
|
|
|
static func_type
|
|
__lookup_riscv_flush_icache (void)
|
|
{
|
|
func_type func = dl_vdso_vsym ("__vdso_flush_icache");
|
|
|
|
/* If there is no vDSO entry then call the system call directly. All Linux
|
|
versions provide the vDSO entry, but QEMU's user-mode emulation doesn't
|
|
provide a vDSO. */
|
|
if (!func)
|
|
func = &__riscv_flush_icache_syscall;
|
|
|
|
return func;
|
|
}
|
|
|
|
#ifdef SHARED
|
|
|
|
# define INIT_ARCH()
|
|
libc_ifunc (__riscv_flush_icache, __lookup_riscv_flush_icache ())
|
|
|
|
#else
|
|
|
|
int
|
|
__riscv_flush_icache (void *start, void *end, unsigned long int flags)
|
|
{
|
|
static volatile func_type cached_func;
|
|
|
|
func_type func = atomic_load_relaxed (&cached_func);
|
|
|
|
if (!func)
|
|
{
|
|
func = __lookup_riscv_flush_icache ();
|
|
atomic_store_relaxed (&cached_func, func);
|
|
}
|
|
|
|
return func (start, end, flags);
|
|
}
|
|
|
|
#endif
|