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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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6904817607
most architectures are relying on mmap_sem for write in their arch_setup_additional_pages. If the waiting task gets killed by the oom killer it would block oom_reaper from asynchronous address space reclaim and reduce the chances of timely OOM resolving. Wait for the lock in the killable mode and return with EINTR if the task got killed while waiting. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Andy Lutomirski <luto@amacapital.net> [x86 vdso] Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
/*
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* vDSO implementation for Hexagon
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*
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* Copyright (c) 2011, The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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#include <linux/err.h>
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#include <linux/mm.h>
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#include <linux/vmalloc.h>
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#include <linux/binfmts.h>
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#include <asm/vdso.h>
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static struct page *vdso_page;
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/* Create a vDSO page holding the signal trampoline.
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* We want this for a non-executable stack.
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*/
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static int __init vdso_init(void)
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{
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struct hexagon_vdso *vdso;
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vdso_page = alloc_page(GFP_KERNEL);
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if (!vdso_page)
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panic("Cannot allocate vdso");
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vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL);
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if (!vdso)
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panic("Cannot map vdso");
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clear_page(vdso);
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/* Install the signal trampoline; currently looks like this:
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* r6 = #__NR_rt_sigreturn;
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* trap0(#1);
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*/
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vdso->rt_signal_trampoline[0] = __rt_sigtramp_template[0];
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vdso->rt_signal_trampoline[1] = __rt_sigtramp_template[1];
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vunmap(vdso);
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return 0;
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}
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arch_initcall(vdso_init);
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/*
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* Called from binfmt_elf. Create a VMA for the vDSO page.
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*/
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int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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{
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int ret;
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unsigned long vdso_base;
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struct mm_struct *mm = current->mm;
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if (down_write_killable(&mm->mmap_sem))
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return -EINTR;
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/* Try to get it loaded right near ld.so/glibc. */
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vdso_base = STACK_TOP;
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vdso_base = get_unmapped_area(NULL, vdso_base, PAGE_SIZE, 0, 0);
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if (IS_ERR_VALUE(vdso_base)) {
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ret = vdso_base;
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goto up_fail;
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}
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/* MAYWRITE to allow gdb to COW and set breakpoints. */
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ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
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VM_READ|VM_EXEC|
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VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
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&vdso_page);
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if (ret)
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goto up_fail;
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mm->context.vdso = (void *)vdso_base;
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up_fail:
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up_write(&mm->mmap_sem);
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return ret;
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}
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const char *arch_vma_name(struct vm_area_struct *vma)
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{
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if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
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return "[vdso]";
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return NULL;
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}
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