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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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a6c19dfe39
The core mm code will provide a default gate area based on FIXADDR_USER_START and FIXADDR_USER_END if !defined(__HAVE_ARCH_GATE_AREA) && defined(AT_SYSINFO_EHDR). This default is only useful for ia64. arm64, ppc, s390, sh, tile, 64-bit UML, and x86_32 have their own code just to disable it. arm, 32-bit UML, and x86_64 have gate areas, but they have their own implementations. This gets rid of the default and moves the code into ia64. This should save some code on architectures without a gate area: it's now possible to inline the gate_area functions in the default case. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Nathan Lynch <nathan_lynch@mentor.com> Acked-by: H. Peter Anvin <hpa@linux.intel.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [in principle] Acked-by: Richard Weinberger <richard@nod.at> [for um] Acked-by: Will Deacon <will.deacon@arm.com> [for arm64] Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Nathan Lynch <Nathan_Lynch@mentor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
95 lines
2.2 KiB
C
95 lines
2.2 KiB
C
/*
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* arch/sh/kernel/vsyscall/vsyscall.c
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*
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* Copyright (C) 2006 Paul Mundt
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*
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* vDSO randomization
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* Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/mm.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/gfp.h>
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#include <linux/module.h>
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#include <linux/elf.h>
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#include <linux/sched.h>
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#include <linux/err.h>
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/*
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* Should the kernel map a VDSO page into processes and pass its
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* address down to glibc upon exec()?
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*/
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unsigned int __read_mostly vdso_enabled = 1;
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EXPORT_SYMBOL_GPL(vdso_enabled);
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static int __init vdso_setup(char *s)
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{
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vdso_enabled = simple_strtoul(s, NULL, 0);
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return 1;
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}
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__setup("vdso=", vdso_setup);
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/*
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* These symbols are defined by vsyscall.o to mark the bounds
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* of the ELF DSO images included therein.
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*/
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extern const char vsyscall_trapa_start, vsyscall_trapa_end;
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static struct page *syscall_pages[1];
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int __init vsyscall_init(void)
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{
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void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
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syscall_pages[0] = virt_to_page(syscall_page);
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/*
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* XXX: Map this page to a fixmap entry if we get around
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* to adding the page to ELF core dumps
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*/
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memcpy(syscall_page,
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&vsyscall_trapa_start,
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&vsyscall_trapa_end - &vsyscall_trapa_start);
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return 0;
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}
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/* Setup a VMA at program startup for the vsyscall page */
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int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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{
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struct mm_struct *mm = current->mm;
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unsigned long addr;
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int ret;
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down_write(&mm->mmap_sem);
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addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
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if (IS_ERR_VALUE(addr)) {
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ret = addr;
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goto up_fail;
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}
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ret = install_special_mapping(mm, addr, PAGE_SIZE,
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VM_READ | VM_EXEC |
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
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syscall_pages);
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if (unlikely(ret))
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goto up_fail;
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current->mm->context.vdso = (void *)addr;
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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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