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Commit 28b2ee20 authored by Rik van Riel's avatar Rik van Riel Committed by Linus Torvalds
Browse files

access_process_vm device memory infrastructure 



In order to be able to debug things like the X server and programs using
the PPC Cell SPUs, the debugger needs to be able to access device memory
through ptrace and /proc/pid/mem.

This patch:

Add the generic_access_phys access function and put the hooks in place
to allow access_process_vm to access device or PPC Cell SPU memory.

[riel@redhat.com: Add documentation for the vm_ops->access function]
Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarBenjamin Herrensmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0d71d10a

Documentation/filesystems/Locking

+7 −0
Original line number Diff line number Diff line
@@ -510,6 +510,7 @@ prototypes: 
	void (*close)(struct vm_area_struct*);

	int (*fault)(struct vm_area_struct*, struct vm_fault *);

	int (*page_mkwrite)(struct vm_area_struct *, struct page *);

	int (*access)(struct vm_area_struct *, unsigned long, void*, int, int);



locking rules:

		BKL	mmap_sem	PageLocked(page)
@@ -517,6 +518,7 @@ open: no yes 
close:		no	yes

fault:		no	yes

page_mkwrite:	no	yes		no

access:		no	yes



	->page_mkwrite() is called when a previously read-only page is

about to become writeable. The file system is responsible for
@@ -525,6 +527,11 @@ taking to lock out truncate, the page range should be verified to be 
within i_size. The page mapping should also be checked that it is not

NULL.



	->access() is called when get_user_pages() fails in

acces_process_vm(), typically used to debug a process through

/proc/pid/mem or ptrace.  This function is needed only for

VM_IO | VM_PFNMAP VMAs.



================================================================================

			Dubious stuff

arch/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -31,6 +31,9 @@ config KRETPROBES 
	def_bool y

	depends on KPROBES && HAVE_KRETPROBES



config HAVE_IOREMAP_PROT

	def_bool n



config HAVE_KPROBES

	def_bool n

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ config X86 
	select HAVE_UNSTABLE_SCHED_CLOCK

	select HAVE_IDE

	select HAVE_OPROFILE

	select HAVE_IOREMAP_PROT

	select HAVE_KPROBES

	select HAVE_KRETPROBES

	select HAVE_DYNAMIC_FTRACE

arch/x86/mm/ioremap.c

+8 −0
Original line number Diff line number Diff line
@@ -330,6 +330,14 @@ static void __iomem *ioremap_default(resource_size_t phys_addr, 
	return (void __iomem *)ret;

}



void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size,

				unsigned long prot_val)

{

	return __ioremap_caller(phys_addr, size, (prot_val & _PAGE_CACHE_MASK),

				__builtin_return_address(0));

}

EXPORT_SYMBOL(ioremap_prot);



/**

 * iounmap - Free a IO remapping

 * @addr: virtual address from ioremap_*

include/asm-x86/io_32.h

+2 −0
Original line number Diff line number Diff line
@@ -110,6 +110,8 @@ static inline void *phys_to_virt(unsigned long address) 
 */

extern void __iomem *ioremap_nocache(resource_size_t offset, unsigned long size);

extern void __iomem *ioremap_cache(resource_size_t offset, unsigned long size);

extern void __iomem *ioremap_prot(resource_size_t offset, unsigned long size,

				unsigned long prot_val);



/*

 * The default ioremap() behavior is non-cached: