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88 lines
1.9 KiB
88 lines
1.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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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#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 (mmap_write_lock_killable(mm)) |
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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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mmap_write_unlock(mm); |
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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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