The patch titled
access_process_vm device memory infrastructure
has been added to the -mm tree. Its filename is
access_process_vm-device-memory-infrastructure.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: access_process_vm device memory infrastructure
From: Rik van Riel <riel@xxxxxxxxxx>
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.
Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Benjamin Herrensmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/Kconfig | 3
arch/x86/Kconfig | 1
arch/x86/mm/ioremap.c | 8 ++
include/asm-x86/io_32.h | 2
include/asm-x86/io_64.h | 2
include/linux/mm.h | 8 ++
mm/memory.c | 131 ++++++++++++++++++++++++++++++++------
7 files changed, 137 insertions(+), 18 deletions(-)
diff -puN arch/Kconfig~access_process_vm-device-memory-infrastructure arch/Kconfig
--- a/arch/Kconfig~access_process_vm-device-memory-infrastructure
+++ a/arch/Kconfig
@@ -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
diff -puN arch/x86/Kconfig~access_process_vm-device-memory-infrastructure arch/x86/Kconfig
--- a/arch/x86/Kconfig~access_process_vm-device-memory-infrastructure
+++ a/arch/x86/Kconfig
@@ -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_FTRACE
diff -puN arch/x86/mm/ioremap.c~access_process_vm-device-memory-infrastructure arch/x86/mm/ioremap.c
--- a/arch/x86/mm/ioremap.c~access_process_vm-device-memory-infrastructure
+++ a/arch/x86/mm/ioremap.c
@@ -307,6 +307,14 @@ void __iomem *ioremap_cache(resource_siz
}
EXPORT_SYMBOL(ioremap_cache);
+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_*
diff -puN include/asm-x86/io_32.h~access_process_vm-device-memory-infrastructure include/asm-x86/io_32.h
--- a/include/asm-x86/io_32.h~access_process_vm-device-memory-infrastructure
+++ a/include/asm-x86/io_32.h
@@ -110,6 +110,8 @@ static inline void *phys_to_virt(unsigne
*/
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:
diff -puN include/asm-x86/io_64.h~access_process_vm-device-memory-infrastructure include/asm-x86/io_64.h
--- a/include/asm-x86/io_64.h~access_process_vm-device-memory-infrastructure
+++ a/include/asm-x86/io_64.h
@@ -175,6 +175,8 @@ extern void early_iounmap(void *addr, un
*/
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:
diff -puN include/linux/mm.h~access_process_vm-device-memory-infrastructure include/linux/mm.h
--- a/include/linux/mm.h~access_process_vm-device-memory-infrastructure
+++ a/include/linux/mm.h
@@ -169,6 +169,12 @@ struct vm_operations_struct {
/* notification that a previously read-only page is about to become
* writable, if an error is returned it will cause a SIGBUS */
int (*page_mkwrite)(struct vm_area_struct *vma, struct page *page);
+
+ /* called by access_process_vm when get_user_pages() fails, typically
+ * for use by special VMAs that can switch between memory and hardware
+ */
+ int (*access)(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write);
#ifdef CONFIG_NUMA
/*
* set_policy() op must add a reference to any non-NULL @new mempolicy
@@ -769,6 +775,8 @@ int copy_page_range(struct mm_struct *ds
struct vm_area_struct *vma);
void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen, int even_cows);
+int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write);
static inline void unmap_shared_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen)
diff -puN mm/memory.c~access_process_vm-device-memory-infrastructure mm/memory.c
--- a/mm/memory.c~access_process_vm-device-memory-infrastructure
+++ a/mm/memory.c
@@ -2688,6 +2688,86 @@ int in_gate_area_no_task(unsigned long a
#endif /* __HAVE_ARCH_GATE_AREA */
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+static resource_size_t follow_phys(struct vm_area_struct *vma,
+ unsigned long address, unsigned int flags,
+ unsigned long *prot)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *ptep, pte;
+ spinlock_t *ptl;
+ resource_size_t phys_addr = 0;
+ struct mm_struct *mm = vma->vm_mm;
+
+ VM_BUG_ON(!(vma->vm_flags & (VM_IO | VM_PFNMAP)));
+
+ pgd = pgd_offset(mm, address);
+ if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
+ goto no_page_table;
+
+ pud = pud_offset(pgd, address);
+ if (pud_none(*pud) || unlikely(pud_bad(*pud)))
+ goto no_page_table;
+
+ pmd = pmd_offset(pud, address);
+ if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
+ goto no_page_table;
+
+ /* We cannot handle huge page PFN maps. Luckily they don't exist. */
+ if (pmd_huge(*pmd))
+ goto no_page_table;
+
+ ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
+ if (!ptep)
+ goto out;
+
+ pte = *ptep;
+ if (!pte_present(pte))
+ goto unlock;
+ if ((flags & FOLL_WRITE) && !pte_write(pte))
+ goto unlock;
+ phys_addr = pte_pfn(pte);
+ phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */
+
+ *prot = pgprot_val(pte_pgprot(pte));
+
+unlock:
+ pte_unmap_unlock(ptep, ptl);
+out:
+ return phys_addr;
+no_page_table:
+ return 0;
+}
+
+int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write)
+{
+ resource_size_t phys_addr;
+ unsigned long prot = 0;
+ void *maddr;
+ int offset = addr & (PAGE_SIZE-1);
+
+ if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+ return -EINVAL;
+
+ phys_addr = follow_phys(vma, addr, write, &prot);
+
+ if (!phys_addr)
+ return -EINVAL;
+
+ maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
+ if (write)
+ memcpy_toio(maddr + offset, buf, len);
+ else
+ memcpy_fromio(buf, maddr + offset, len);
+ iounmap(maddr);
+
+ return len;
+}
+#endif
+
/*
* Access another process' address space.
* Source/target buffer must be kernel space,
@@ -2697,7 +2777,6 @@ int access_process_vm(struct task_struct
{
struct mm_struct *mm;
struct vm_area_struct *vma;
- struct page *page;
void *old_buf = buf;
mm = get_task_mm(tsk);
@@ -2709,28 +2788,44 @@ int access_process_vm(struct task_struct
while (len) {
int bytes, ret, offset;
void *maddr;
+ struct page *page = NULL;
ret = get_user_pages(tsk, mm, addr, 1,
write, 1, &page, &vma);
- if (ret <= 0)
- break;
-
- bytes = len;
- offset = addr & (PAGE_SIZE-1);
- if (bytes > PAGE_SIZE-offset)
- bytes = PAGE_SIZE-offset;
-
- maddr = kmap(page);
- if (write) {
- copy_to_user_page(vma, page, addr,
- maddr + offset, buf, bytes);
- set_page_dirty_lock(page);
+ if (ret <= 0) {
+ /*
+ * Check if this is a VM_IO | VM_PFNMAP VMA, which
+ * we can access using slightly different code.
+ */
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+ vma = find_vma(mm, addr);
+ if (!vma)
+ break;
+ if (vma->vm_ops && vma->vm_ops->access)
+ ret = vma->vm_ops->access(vma, addr, buf,
+ len, write);
+ if (ret <= 0)
+#endif
+ break;
+ bytes = ret;
} else {
- copy_from_user_page(vma, page, addr,
- buf, maddr + offset, bytes);
+ bytes = len;
+ offset = addr & (PAGE_SIZE-1);
+ if (bytes > PAGE_SIZE-offset)
+ bytes = PAGE_SIZE-offset;
+
+ maddr = kmap(page);
+ if (write) {
+ copy_to_user_page(vma, page, addr,
+ maddr + offset, buf, bytes);
+ set_page_dirty_lock(page);
+ } else {
+ copy_from_user_page(vma, page, addr,
+ buf, maddr + offset, bytes);
+ }
+ kunmap(page);
+ page_cache_release(page);
}
- kunmap(page);
- page_cache_release(page);
len -= bytes;
buf += bytes;
addr += bytes;
_
Patches currently in -mm which might be from riel@xxxxxxxxxx are
access_process_vm-device-memory-infrastructure.patch
use-generic_access_phys-for-dev-mem-mappings.patch
use-generic_access_phys-for-pci-mmap-on-x86.patch
powerpc-ioremap_prot.patch
spufs-use-the-new-vm_ops-access.patch
vmscan-give-referenced-active-and-unmapped-pages-a-second-trip-around-the-lru.patch
idr-change-the-idr-structure.patch
idr-rename-some-of-the-idr-apis-internal-routines.patch
idr-fix-a-printk-call.patch
idr-error-checking-factorization.patch
idr-make-idr_get_new-rcu-safe.patch
idr-make-idr_find-rcu-safe.patch
idr-make-idr_remove-rcu-safe.patch
ipc-call-idr_find-without-locking-in-ipc_lock.patch
ipc-get-rid-of-ipc_lock_down.patch
make-mm-rmapc-anon_vma_cachep-static.patch
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