2011-03-25 20:31:57

by Mike Frysinger

[permalink] [raw]
Subject: [PATCH] NOMMU: implement access_remote_vm

Recent vm changes brought in a new function which the core procfs code
utilizes. So implement it for nommu systems too to avoid link failures.

Signed-off-by: Mike Frysinger <[email protected]>
---
mm/nommu.c | 52 +++++++++++++++++++++++++++++++++++++++-------------
1 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/mm/nommu.c b/mm/nommu.c
index cb86e7d..c4c542c 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1971,21 +1971,10 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
}
EXPORT_SYMBOL(filemap_fault);

-/*
- * Access another process' address space.
- * - source/target buffer must be kernel space
- */
-int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long addr, void *buf, int len, int write)
{
struct vm_area_struct *vma;
- struct mm_struct *mm;
-
- if (addr + len < addr)
- return 0;
-
- mm = get_task_mm(tsk);
- if (!mm)
- return 0;

down_read(&mm->mmap_sem);

@@ -2010,6 +1999,43 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
}

up_read(&mm->mmap_sem);
+
+ return len;
+}
+
+/**
+ * @access_remote_vm - access another process' address space
+ * @mm: the mm_struct of the target address space
+ * @addr: start address to access
+ * @buf: source or destination buffer
+ * @len: number of bytes to transfer
+ * @write: whether the access is a write
+ *
+ * The caller must hold a reference on @mm.
+ */
+int access_remote_vm(struct mm_struct *mm, unsigned long addr,
+ void *buf, int len, int write)
+{
+ return __access_remote_vm(NULL, mm, addr, buf, len, write);
+}
+
+/*
+ * Access another process' address space.
+ * - source/target buffer must be kernel space
+ */
+int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+{
+ struct mm_struct *mm;
+
+ if (addr + len < addr)
+ return 0;
+
+ mm = get_task_mm(tsk);
+ if (!mm)
+ return 0;
+
+ len = __access_remote_vm(tsk, mm, addr, buf, len, write);
+
mmput(mm);
return len;
}
--
1.7.4.1


2011-03-29 05:54:40

by Simon Horman

[permalink] [raw]
Subject: Re: [PATCH] NOMMU: implement access_remote_vm

On Fri, Mar 25, 2011 at 04:32:28PM -0400, Mike Frysinger wrote:
> Recent vm changes brought in a new function which the core procfs code
> utilizes. So implement it for nommu systems too to avoid link failures.
>
> Signed-off-by: Mike Frysinger <[email protected]>

This resolves a build problem that I observed this afternoon.

Drive-by Tested-by: Simon Horman <[email protected]>

2011-03-29 08:58:37

by Wan ZongShun

[permalink] [raw]
Subject: Re: [PATCH] NOMMU: implement access_remote_vm

2011/3/29 Simon Horman <[email protected]>:
> On Fri, Mar 25, 2011 at 04:32:28PM -0400, Mike Frysinger wrote:
>> Recent vm changes brought in a new function which the core procfs code
>> utilizes.  So implement it for nommu systems too to avoid link failures.
>>
>> Signed-off-by: Mike Frysinger <[email protected]>
>
> This resolves a build problem that I observed this afternoon.

oh, I just find this build error about access_remote_vm, this patch
will fix my issue.

thanks!

>
> Drive-by Tested-by: Simon Horman <[email protected]>
>
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2011-03-29 10:21:22

by Greg Ungerer

[permalink] [raw]
Subject: Re: [PATCH] NOMMU: implement access_remote_vm

On 26/03/11 06:32, Mike Frysinger wrote:
> Recent vm changes brought in a new function which the core procfs code
> utilizes. So implement it for nommu systems too to avoid link failures.
>
> Signed-off-by: Mike Frysinger<[email protected]>

Looks good.

Acked-by: Greg Ungerer <[email protected]>


> ---
> mm/nommu.c | 52 +++++++++++++++++++++++++++++++++++++++-------------
> 1 files changed, 39 insertions(+), 13 deletions(-)
>
> diff --git a/mm/nommu.c b/mm/nommu.c
> index cb86e7d..c4c542c 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -1971,21 +1971,10 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
> }
> EXPORT_SYMBOL(filemap_fault);
>
> -/*
> - * Access another process' address space.
> - * - source/target buffer must be kernel space
> - */
> -int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
> +static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
> + unsigned long addr, void *buf, int len, int write)
> {
> struct vm_area_struct *vma;
> - struct mm_struct *mm;
> -
> - if (addr + len< addr)
> - return 0;
> -
> - mm = get_task_mm(tsk);
> - if (!mm)
> - return 0;
>
> down_read(&mm->mmap_sem);
>
> @@ -2010,6 +1999,43 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
> }
>
> up_read(&mm->mmap_sem);
> +
> + return len;
> +}
> +
> +/**
> + * @access_remote_vm - access another process' address space
> + * @mm: the mm_struct of the target address space
> + * @addr: start address to access
> + * @buf: source or destination buffer
> + * @len: number of bytes to transfer
> + * @write: whether the access is a write
> + *
> + * The caller must hold a reference on @mm.
> + */
> +int access_remote_vm(struct mm_struct *mm, unsigned long addr,
> + void *buf, int len, int write)
> +{
> + return __access_remote_vm(NULL, mm, addr, buf, len, write);
> +}
> +
> +/*
> + * Access another process' address space.
> + * - source/target buffer must be kernel space
> + */
> +int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
> +{
> + struct mm_struct *mm;
> +
> + if (addr + len< addr)
> + return 0;
> +
> + mm = get_task_mm(tsk);
> + if (!mm)
> + return 0;
> +
> + len = __access_remote_vm(tsk, mm, addr, buf, len, write);
> +
> mmput(mm);
> return len;
> }


--
------------------------------------------------------------------------
Greg Ungerer -- Principal Engineer EMAIL: [email protected]
SnapGear Group, McAfee PHONE: +61 7 3435 2888
8 Gardner Close FAX: +61 7 3217 5323
Milton, QLD, 4064, Australia WEB: http://www.SnapGear.com

2011-03-29 10:31:59

by Ithamar R. Adema

[permalink] [raw]
Subject: Re: [uClinux-dev] [PATCH] NOMMU: implement access_remote_vm

On Fri, 2011-03-25 at 16:32 -0400, Mike Frysinger wrote:
> Recent vm changes brought in a new function which the core procfs code
> utilizes. So implement it for nommu systems too to avoid link failures.
>
> Signed-off-by: Mike Frysinger <[email protected]>

This patch fixes the problem for my NXP lpc2k ARM7TDMI architecture that
I'm mainlining currently, so you can add my:

Tested-by: Ithamar Adema <[email protected]>

Regards,

Ithamar.

2011-03-31 06:14:11

by Wan ZongShun

[permalink] [raw]
Subject: Re: [uClinux-dev] Re: [PATCH] NOMMU: implement access_remote_vm

2011/3/29 Greg Ungerer <[email protected]>:
> On 26/03/11 06:32, Mike Frysinger wrote:
>>
>> Recent vm changes brought in a new function which the core procfs code
>> utilizes.  So implement it for nommu systems too to avoid link failures.
>>
>> Signed-off-by: Mike Frysinger<[email protected]>
>
> Looks good.
>
> Acked-by: Greg Ungerer <[email protected]>
>

It applys to my nuc700 arm7tdmi platform, thanks!

Tested-by: Wan ZongShun <[email protected]>

>
>> ---
>>  mm/nommu.c |   52 +++++++++++++++++++++++++++++++++++++++-------------
>>  1 files changed, 39 insertions(+), 13 deletions(-)
>>
>> diff --git a/mm/nommu.c b/mm/nommu.c
>> index cb86e7d..c4c542c 100644
>> --- a/mm/nommu.c
>> +++ b/mm/nommu.c
>> @@ -1971,21 +1971,10 @@ int filemap_fault(struct vm_area_struct *vma,
>> struct vm_fault *vmf)
>>  }
>>  EXPORT_SYMBOL(filemap_fault);
>>
>> -/*
>> - * Access another process' address space.
>> - * - source/target buffer must be kernel space
>> - */
>> -int access_process_vm(struct task_struct *tsk, unsigned long addr, void
>> *buf, int len, int write)
>> +static int __access_remote_vm(struct task_struct *tsk, struct mm_struct
>> *mm,
>> +               unsigned long addr, void *buf, int len, int write)
>>  {
>>        struct vm_area_struct *vma;
>> -       struct mm_struct *mm;
>> -
>> -       if (addr + len<  addr)
>> -               return 0;
>> -
>> -       mm = get_task_mm(tsk);
>> -       if (!mm)
>> -               return 0;
>>
>>        down_read(&mm->mmap_sem);
>>
>> @@ -2010,6 +1999,43 @@ int access_process_vm(struct task_struct *tsk,
>> unsigned long addr, void *buf, in
>>        }
>>
>>        up_read(&mm->mmap_sem);
>> +
>> +       return len;
>> +}
>> +
>> +/**
>> + * @access_remote_vm - access another process' address space
>> + * @mm:                the mm_struct of the target address space
>> + * @addr:      start address to access
>> + * @buf:       source or destination buffer
>> + * @len:       number of bytes to transfer
>> + * @write:     whether the access is a write
>> + *
>> + * The caller must hold a reference on @mm.
>> + */
>> +int access_remote_vm(struct mm_struct *mm, unsigned long addr,
>> +               void *buf, int len, int write)
>> +{
>> +       return __access_remote_vm(NULL, mm, addr, buf, len, write);
>> +}
>> +
>> +/*
>> + * Access another process' address space.
>> + * - source/target buffer must be kernel space
>> + */
>> +int access_process_vm(struct task_struct *tsk, unsigned long addr, void
>> *buf, int len, int write)
>> +{
>> +       struct mm_struct *mm;
>> +
>> +       if (addr + len<  addr)
>> +               return 0;
>> +
>> +       mm = get_task_mm(tsk);
>> +       if (!mm)
>> +               return 0;
>> +
>> +       len = __access_remote_vm(tsk, mm, addr, buf, len, write);
>> +
>>        mmput(mm);
>>        return len;
>>  }
>
>
> --
> ------------------------------------------------------------------------
> Greg Ungerer  --  Principal Engineer        EMAIL:     [email protected]
> SnapGear Group, McAfee                      PHONE:       +61 7 3435 2888
> 8 Gardner Close                             FAX:         +61 7 3217 5323
> Milton, QLD, 4064, Australia                WEB: http://www.SnapGear.com
> _______________________________________________
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