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Commit c13e4ca2 authored by Roland McGrath's avatar Roland McGrath Committed by Linus Torvalds
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[PATCH] powerpc vDSO: use install_special_mapping 



This patch uses install_special_mapping for the powerpc vDSO setup,
consolidating duplicated code.

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent dc5882b2

arch/powerpc/kernel/vdso.c

+27 −77
Original line number Diff line number Diff line
@@ -49,9 +49,13 @@ 
/* Max supported size for symbol names */

#define MAX_SYMNAME	64



#define VDSO32_MAXPAGES	(((0x3000 + PAGE_MASK) >> PAGE_SHIFT) + 2)

#define VDSO64_MAXPAGES	(((0x3000 + PAGE_MASK) >> PAGE_SHIFT) + 2)



extern char vdso32_start, vdso32_end;

static void *vdso32_kbase = &vdso32_start;

unsigned int vdso32_pages;

static struct page *vdso32_pagelist[VDSO32_MAXPAGES];

unsigned long vdso32_sigtramp;

unsigned long vdso32_rt_sigtramp;
@@ -59,6 +63,7 @@ unsigned long vdso32_rt_sigtramp; 
extern char vdso64_start, vdso64_end;

static void *vdso64_kbase = &vdso64_start;

unsigned int vdso64_pages;

static struct page *vdso64_pagelist[VDSO64_MAXPAGES];

unsigned long vdso64_rt_sigtramp;

#endif /* CONFIG_PPC64 */
@@ -164,55 +169,6 @@ static void dump_vdso_pages(struct vm_area_struct * vma) 
}

#endif /* DEBUG */



/*

 * Keep a dummy vma_close for now, it will prevent VMA merging.

 */

static void vdso_vma_close(struct vm_area_struct * vma)

{

}



/*

 * Our nopage() function, maps in the actual vDSO kernel pages, they will

 * be mapped read-only by do_no_page(), and eventually COW'ed, either

 * right away for an initial write access, or by do_wp_page().

 */

static struct page * vdso_vma_nopage(struct vm_area_struct * vma,

				     unsigned long address, int *type)

{

	unsigned long offset = address - vma->vm_start;

	struct page *pg;

#ifdef CONFIG_PPC64

	void *vbase = (vma->vm_mm->task_size > TASK_SIZE_USER32) ?

		vdso64_kbase : vdso32_kbase;

#else

	void *vbase = vdso32_kbase;

#endif



	DBG("vdso_vma_nopage(current: %s, address: %016lx, off: %lx)\n",

	    current->comm, address, offset);



	if (address < vma->vm_start || address > vma->vm_end)

		return NOPAGE_SIGBUS;



	/*

	 * Last page is systemcfg.

	 */

	if ((vma->vm_end - address) <= PAGE_SIZE)

		pg = virt_to_page(vdso_data);

	else

		pg = virt_to_page(vbase + offset);



	get_page(pg);

	DBG(" ->page count: %d\n", page_count(pg));



	return pg;

}



static struct vm_operations_struct vdso_vmops = {

	.close	= vdso_vma_close,

	.nopage	= vdso_vma_nopage,

};



/*

 * This is called from binfmt_elf, we create the special vma for the

 * vDSO and insert it into the mm struct tree
@@ -221,20 +177,23 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, 
				int executable_stack)

{

	struct mm_struct *mm = current->mm;

	struct vm_area_struct *vma;

	struct page **vdso_pagelist;

	unsigned long vdso_pages;

	unsigned long vdso_base;

	int rc;



#ifdef CONFIG_PPC64

	if (test_thread_flag(TIF_32BIT)) {

		vdso_pagelist = vdso32_pagelist;

		vdso_pages = vdso32_pages;

		vdso_base = VDSO32_MBASE;

	} else {

		vdso_pagelist = vdso64_pagelist;

		vdso_pages = vdso64_pages;

		vdso_base = VDSO64_MBASE;

	}

#else

	vdso_pagelist = vdso32_pagelist;

	vdso_pages = vdso32_pages;

	vdso_base = VDSO32_MBASE;

#endif
@@ -262,17 +221,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, 
		goto fail_mmapsem;

	}





	/* Allocate a VMA structure and fill it up */

	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);

	if (vma == NULL) {

		rc = -ENOMEM;

		goto fail_mmapsem;

	}

	vma->vm_mm = mm;

	vma->vm_start = vdso_base;

	vma->vm_end = vma->vm_start + (vdso_pages << PAGE_SHIFT);



	/*

	 * our vma flags don't have VM_WRITE so by default, the process isn't

	 * allowed to write those pages.
@@ -282,32 +230,26 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, 
	 * and your nice userland gettimeofday will be totally dead.

	 * It's fine to use that for setting breakpoints in the vDSO code

	 * pages though

	 */

	vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC;

	/*

	 *

	 * Make sure the vDSO gets into every core dump.

	 * Dumping its contents makes post-mortem fully interpretable later

	 * without matching up the same kernel and hardware config to see

	 * what PC values meant.

	 */

	vma->vm_flags |= VM_ALWAYSDUMP;

	vma->vm_flags |= mm->def_flags;

	vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];

	vma->vm_ops = &vdso_vmops;



	/* Insert new VMA */

	rc = insert_vm_struct(mm, vma);

	rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,

				     VM_READ|VM_EXEC|

				     VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|

				     VM_ALWAYSDUMP,

				     vdso_pagelist);

	if (rc)

		goto fail_vma;

		goto fail_mmapsem;



	/* Put vDSO base into mm struct and account for memory usage */

	/* Put vDSO base into mm struct */

	current->mm->context.vdso_base = vdso_base;

	mm->total_vm += (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;



	up_write(&mm->mmap_sem);

	return 0;



 fail_vma:

	kmem_cache_free(vm_area_cachep, vma);

 fail_mmapsem:

	up_write(&mm->mmap_sem);

	return rc;
@@ -778,18 +720,26 @@ void __init vdso_init(void) 
	}



	/* Make sure pages are in the correct state */

	BUG_ON(vdso32_pages + 2 > VDSO32_MAXPAGES);

	for (i = 0; i < vdso32_pages; i++) {

		struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);

		ClearPageReserved(pg);

		get_page(pg);



		vdso32_pagelist[i] = pg;

	}

	vdso32_pagelist[i++] = virt_to_page(vdso_data);

	vdso32_pagelist[i] = NULL;



#ifdef CONFIG_PPC64

	BUG_ON(vdso64_pages + 2 > VDSO64_MAXPAGES);

	for (i = 0; i < vdso64_pages; i++) {

		struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);

		ClearPageReserved(pg);

		get_page(pg);

		vdso64_pagelist[i] = pg;

	}

	vdso64_pagelist[i++] = virt_to_page(vdso_data);

	vdso64_pagelist[i] = NULL;

#endif /* CONFIG_PPC64 */



	get_page(virt_to_page(vdso_data));