cregit-Linux how code gets into the kernel

Release 4.14 arch/hexagon/kernel/vdso.c

/*
 * vDSO implementation for Hexagon
 *
 * Copyright (c) 2011, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#include <linux/err.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/binfmts.h>

#include <asm/vdso.h>


static struct page *vdso_page;

/* Create a vDSO page holding the signal trampoline.
 * We want this for a non-executable stack.
 */

static int __init vdso_init(void) { struct hexagon_vdso *vdso; vdso_page = alloc_page(GFP_KERNEL); if (!vdso_page) panic("Cannot allocate vdso"); vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL); if (!vdso) panic("Cannot map vdso"); clear_page(vdso); /* Install the signal trampoline; currently looks like this: * r6 = #__NR_rt_sigreturn; * trap0(#1); */ vdso->rt_signal_trampoline[0] = __rt_sigtramp_template[0]; vdso->rt_signal_trampoline[1] = __rt_sigtramp_template[1]; vunmap(vdso); return 0; }

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PersonTokensPropCommitsCommitProp
Richard Kuo93100.00%1100.00%
Total93100.00%1100.00%

arch_initcall(vdso_init); /* * Called from binfmt_elf. Create a VMA for the vDSO page. */
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { int ret; unsigned long vdso_base; struct mm_struct *mm = current->mm; if (down_write_killable(&mm->mmap_sem)) return -EINTR; /* Try to get it loaded right near ld.so/glibc. */ vdso_base = STACK_TOP; vdso_base = get_unmapped_area(NULL, vdso_base, PAGE_SIZE, 0, 0); if (IS_ERR_VALUE(vdso_base)) { ret = vdso_base; goto up_fail; } /* MAYWRITE to allow gdb to COW and set breakpoints. */ ret = install_special_mapping(mm, vdso_base, PAGE_SIZE, VM_READ|VM_EXEC| VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, &vdso_page); if (ret) goto up_fail; mm->context.vdso = (void *)vdso_base; up_fail: up_write(&mm->mmap_sem); return ret; }

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PersonTokensPropCommitsCommitProp
Richard Kuo12894.12%150.00%
Michal Hocko85.88%150.00%
Total136100.00%2100.00%


const char *arch_vma_name(struct vm_area_struct *vma) { if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) return "[vdso]"; return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Richard Kuo39100.00%1100.00%
Total39100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Richard Kuo28997.31%375.00%
Michal Hocko82.69%125.00%
Total297100.00%4100.00%
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