[PATCH]powerpc: Force page alignment for early reserved memory

[PATCH]powerpc: Force page alignment for early reserved memory

[Dave Carroll]

When using 64K pages with a separate cpio rootfs, U-Boot will align the roo=
tfs on a 4K
page boundary. When the memory is reserved, and subsequent early memblock_a=
lloc
is called, it will allocate memory between the 64K page alignment and reser=
ved
memory. When the reserved memory is subsequently freed, it is done so by pa=
ges,
causing the early memblock_alloc requests to be re-used, which in my case, =
caused
the device-tree to be clobbered.

This patch forces all early reserved memory to be kernel page aligned, to m=
atch
the mechanism used to free reserved memory.

Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
---
 arch/powerpc/kernel/prom.c |   21 +++++++++++++++++----
 1 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index e74fa12..2744792 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -534,6 +534,19 @@ void __init early_init_dt_setup_initrd_arch(unsigned l=
ong start,
 }
 #endif

+static void __init reserve_mem(u64 base, u64 size)
+{
+       u64 top =3D base + size;
+       if (size =3D=3D 0)
+               return;
+
+       base =3D _ALIGN_DOWN(base, PAGE_SIZE);
+       top =3D _ALIGN_UP(top, PAGE_SIZE);
+       size =3D top - base;
+       memblock_reserve(base, size);
+
+}
+
 static void __init early_reserve_mem(void)
 {
        u64 base, size;
@@ -547,12 +560,12 @@ static void __init early_reserve_mem(void)
        /* before we do anything, lets reserve the dt blob */
        self_base =3D __pa((unsigned long)initial_boot_params);
        self_size =3D initial_boot_params->totalsize;
-       memblock_reserve(self_base, self_size);
+       reserve_mem(self_base, self_size);

 #ifdef CONFIG_BLK_DEV_INITRD
        /* then reserve the initrd, if any */
        if (initrd_start && (initrd_end > initrd_start))
-               memblock_reserve(__pa(initrd_start), initrd_end - initrd_st=
art);
+               reserve_mem(__pa(initrd_start), initrd_end - initrd_start);
 #endif /* CONFIG_BLK_DEV_INITRD */

 #ifdef CONFIG_PPC32
@@ -573,7 +586,7 @@ static void __init early_reserve_mem(void)
                        if (base_32 =3D=3D self_base && size_32 =3D=3D self=
_size)
                                continue;
                        DBG("reserving: %x -> %x\n", base_32, size_32);
-                       memblock_reserve(base_32, size_32);
+                       reserve_mem(base_32, size_32);
                }
                return;
        }
@@ -584,7 +597,7 @@ static void __init early_reserve_mem(void)
                if (size =3D=3D 0)
                        break;
                DBG("reserving: %llx -> %llx\n", base, size);
-               memblock_reserve(base, size);
+               reserve_mem(base, size);
        }
 }

--
1.7.4

Re: [PATCH]powerpc: Force page alignment for early reserved memory

[Benjamin Herrenschmidt]

On Fri, 2011-05-20 at 15:26 -0600, Dave Carroll wrote:
> When using 64K pages with a separate cpio rootfs, U-Boot will align the rootfs on a 4K
> page boundary. When the memory is reserved, and subsequent early memblock_alloc
> is called, it will allocate memory between the 64K page alignment and reserved
> memory. When the reserved memory is subsequently freed, it is done so by pages,
> causing the early memblock_alloc requests to be re-used, which in my case, caused
> the device-tree to be clobbered.
> 
> This patch forces all early reserved memory to be kernel page aligned, to match
> the mechanism used to free reserved memory.

Hrm...

Reserved memory isn't normally freed. The rootfs is a special case here,
shouldn't we special case it and thus align that specific reserve at the
call site ?

Not a huge deal either way now that I fixed memblock_reserve() to cope
with overlaps but could be a problem if we want to backport your patch.

Cheers,
Ben.

> Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
> ---
>  arch/powerpc/kernel/prom.c |   21 +++++++++++++++++----
>  1 files changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
> index e74fa12..2744792 100644
> --- a/arch/powerpc/kernel/prom.c
> +++ b/arch/powerpc/kernel/prom.c
> @@ -534,6 +534,19 @@ void __init early_init_dt_setup_initrd_arch(unsigned long start,
>  }
>  #endif
> 
> +static void __init reserve_mem(u64 base, u64 size)
> +{
> +       u64 top = base + size;
> +       if (size == 0)
> +               return;
> +
> +       base = _ALIGN_DOWN(base, PAGE_SIZE);
> +       top = _ALIGN_UP(top, PAGE_SIZE);
> +       size = top - base;
> +       memblock_reserve(base, size);
> +
> +}
> +
>  static void __init early_reserve_mem(void)
>  {
>         u64 base, size;
> @@ -547,12 +560,12 @@ static void __init early_reserve_mem(void)
>         /* before we do anything, lets reserve the dt blob */
>         self_base = __pa((unsigned long)initial_boot_params);
>         self_size = initial_boot_params->totalsize;
> -       memblock_reserve(self_base, self_size);
> +       reserve_mem(self_base, self_size);
> 
>  #ifdef CONFIG_BLK_DEV_INITRD
>         /* then reserve the initrd, if any */
>         if (initrd_start && (initrd_end > initrd_start))
> -               memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
> +               reserve_mem(__pa(initrd_start), initrd_end - initrd_start);
>  #endif /* CONFIG_BLK_DEV_INITRD */
> 
>  #ifdef CONFIG_PPC32
> @@ -573,7 +586,7 @@ static void __init early_reserve_mem(void)
>                         if (base_32 == self_base && size_32 == self_size)
>                                 continue;
>                         DBG("reserving: %x -> %x\n", base_32, size_32);
> -                       memblock_reserve(base_32, size_32);
> +                       reserve_mem(base_32, size_32);
>                 }
>                 return;
>         }
> @@ -584,7 +597,7 @@ static void __init early_reserve_mem(void)
>                 if (size == 0)
>                         break;
>                 DBG("reserving: %llx -> %llx\n", base, size);
> -               memblock_reserve(base, size);
> +               reserve_mem(base, size);
>         }
>  }
> 
> --
> 1.7.4
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

RE: [PATCH v2]powerpc: Force page alignment for initrd

[Dave Carroll]

When using 64K pages with a separate cpio rootfs, U-Boot will align the roo=
tfs
on a 4K page boundary. When the memory is reserved, and subsequent early
memblock_alloc is called, it will allocate memory between the 64K page alig=
nment
and reserved memory. When the reserved memory is subsequently freed, it is =
done
so by pages, causing the early memblock_alloc requests to be re-used, which=
 in
my case, caused the device-tree to be clobbered.

This patch forces initrd to be kernel page aligned, to match the mechanism =
used
to free reserved memory.

Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
---
 arch/powerpc/kernel/prom.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 48aeb55..7e58f6b 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -555,7 +555,8 @@ static void __init early_reserve_mem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
        /* then reserve the initrd, if any */
        if (initrd_start && (initrd_end > initrd_start))
-               memblock_reserve(__pa(initrd_start), initrd_end - initrd_st=
art);
+               memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE)=
,
+                       PAGE_ALIGN(initrd_end) - _ALIGN_DOWN(initrd_start, =
PAGE_SIZE));
 #endif /* CONFIG_BLK_DEV_INITRD */

 #ifdef CONFIG_PPC32
--
1.7.4

Re: [v2] powerpc: Force page alignment for initrd

[Milton Miller]

On Fri, 20 May 2011 about 13:23:36 -0000, Dave Carroll wrote:
> When using 64K pages with a separate cpio rootfs, U-Boot will align
> the rootfs on a 4K page boundary. When the memory is reserved, and
> subsequent early memblock_alloc is called, it will allocate memory
> between the 64K page alignment and reserved memory. When the reserved
> memory is subsequently freed, it is done so by pages, causing the
> early memblock_alloc requests to be re-used, which in my case, caused
> the device-tree to be clobbered.
> 
> This patch forces initrd to be kernel page aligned, to match the
> mechanism used to free reserved memory.

Actually it is only forcing the memory reserved for the initrd (its
not moving the contents nor filling the extra space).

> 
> @@ -555,7 +555,8 @@ static void __init early_reserve_mem(void)
>  #ifdef CONFIG_BLK_DEV_INITRD
>         /* then reserve the initrd, if any */
>         if (initrd_start && (initrd_end > initrd_start))
> -               memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
> +               memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE),
> +                       PAGE_ALIGN(initrd_end) - _ALIGN_DOWN(initrd_start, PAGE_SIZE));

Please align up the end, then change free_initrd_mem (32 and 64 bit)
to do the same range extension.

Thanks,
milton

[PATCH v3] powerpc: Force page alignment for initrd reserved memory

[Dave Carroll]

When using 64K pages with a separate cpio rootfs, U-Boot will align
the rootfs on a 4K page boundary. When the memory is reserved, and
subsequent early memblock_alloc is called, it will allocate memory
between the 64K page alignment and reserved memory. When the reserved
memory is subsequently freed, it is done so by pages, causing the
early memblock_alloc requests to be re-used, which in my case, caused
the device-tree to be clobbered.

This patch forces the reserved memory for initrd to be kernel page
aligned, and adds the same range extension when freeing initrd.


Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
---
 arch/powerpc/kernel/prom.c |    4 +++-
 arch/powerpc/mm/init_32.c  |    3 +++
 arch/powerpc/mm/init_64.c  |    3 +++
 3 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 48aeb55..397d4a0 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -555,7 +555,9 @@ static void __init early_reserve_mem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
        /* then reserve the initrd, if any */
        if (initrd_start && (initrd_end > initrd_start))
-               memblock_reserve(__pa(initrd_start), initrd_end - initrd_st=
art);
+               memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE)=
,
+                       _ALIGN_UP(initrd_end, PAGE_SIZE) -
+                       _ALIGN_DOWN(initrd_start, PAGE_SIZE));
 #endif /* CONFIG_BLK_DEV_INITRD */

 #ifdef CONFIG_PPC32
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index d65b591..b0791cb 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -226,6 +226,9 @@ void free_initmem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
+       start =3D _ALIGN_DOWN(start, PAGE_SIZE);
+       end =3D _ALIGN_UP(end, PAGE_SIZE);
+
        if (start < end)
                printk ("Freeing initrd memory: %ldk freed\n", (end - start=
) >> 10);
        for (; start < end; start +=3D PAGE_SIZE) {
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 6374b21..07ae936 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -102,6 +102,9 @@ void free_initmem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
+       start =3D _ALIGN_DOWN(start, PAGE_SIZE);
+       end =3D _ALIGN_UP(end, PAGE_SIZE);
+
        if (start < end)
                printk ("Freeing initrd memory: %ldk freed\n", (end - start=
) >> 10);
        for (; start < end; start +=3D PAGE_SIZE) {
--
1.7.4

Re: [PATCH v3] powerpc: Force page alignment for initrd reserved memory, Re: [PATCH v3] powerpc: Force page alignment for initrd reserved memory

['Milton Miller']

On Sat, 21 May 2011 about 11:05:27 -0600, Dave Carroll wrote:
> 
> When using 64K pages with a separate cpio rootfs, U-Boot will align
> the rootfs on a 4K page boundary. When the memory is reserved, and
> subsequent early memblock_alloc is called, it will allocate memory
> between the 64K page alignment and reserved memory. When the reserved
> memory is subsequently freed, it is done so by pages, causing the
> early memblock_alloc requests to be re-used, which in my case, caused
> the device-tree to be clobbered.
> 
> This patch forces the reserved memory for initrd to be kernel page
> aligned, and adds the same range extension when freeing initrd.

Getting better, but

> 
> 
> Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
> ---
>  arch/powerpc/kernel/prom.c |    4 +++-
>  arch/powerpc/mm/init_32.c  |    3 +++
>  arch/powerpc/mm/init_64.c  |    3 +++
>  3 files changed, 9 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
> index 48aeb55..397d4a0 100644
> --- a/arch/powerpc/kernel/prom.c
> +++ b/arch/powerpc/kernel/prom.c
> @@ -555,7 +555,9 @@ static void __init early_reserve_mem(void)
>  #ifdef CONFIG_BLK_DEV_INITRD
>         /* then reserve the initrd, if any */
>         if (initrd_start && (initrd_end > initrd_start))

Here you test the unaligned values

>  void free_initrd_mem(unsigned long start, unsigned long end)
>  {
> +       start = _ALIGN_DOWN(start, PAGE_SIZE);
> +       end = _ALIGN_UP(end, PAGE_SIZE);
> +
>         if (start < end)
>                 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);

But here you test the aligned values.  And they are aligned with
opposite bias.  Which means that if start == end (or is less than,
but within the same page), a page that wasn't reserved (same
32 and 64 bit) gets freed.

I thought "what happens if we are within a page of end, could we
free the last page of bss?", but then I checked vmlinux.lds and we
align end to page size.  I thought other allocations should be safe,
but then remembered: 

The flattened device tree (of which we continue to use the string
table after boot) could be a problem.

milton

RE: [PATCH v3] powerpc: Force page alignment for initrd reserved memory

[Dave Carroll]

>On Sun, 22 May 2011 about 15:17, Milton Miller wrote:
>>On Sat, 21 May 2011 about 11:05:27 -0600, Dave Carroll wrote:>
>> When using 64K pages with a separate cpio rootfs, U-Boot will align
>> the rootfs on a 4K page boundary. When the memory is reserved, and
>> subsequent early memblock_alloc is called, it will allocate memory
>> between the 64K page alignment and reserved memory. When the reserved
>> memory is subsequently freed, it is done so by pages, causing the
>> early memblock_alloc requests to be re-used, which in my case, caused
>> the device-tree to be clobbered.
>>
>> This patch forces the reserved memory for initrd to be kernel page
>> aligned, and adds the same range extension when freeing initrd.
>
>Getting better, but
>
>>
>>
>> Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
>> ---
>>  arch/powerpc/kernel/prom.c |    4 +++-
>>  arch/powerpc/mm/init_32.c  |    3 +++
>>  arch/powerpc/mm/init_64.c  |    3 +++
>>  3 files changed, 9 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
>> index 48aeb55..397d4a0 100644
>> --- a/arch/powerpc/kernel/prom.c
>> +++ b/arch/powerpc/kernel/prom.c
>> @@ -555,7 +555,9 @@ static void __init early_reserve_mem(void)
>>  #ifdef CONFIG_BLK_DEV_INITRD
>>         /* then reserve the initrd, if any */
>>         if (initrd_start && (initrd_end > initrd_start))
>
>Here you test the unaligned values
>
>>  void free_initrd_mem(unsigned long start, unsigned long end)
>>  {
>> +       start =3D _ALIGN_DOWN(start, PAGE_SIZE);
>> +       end =3D _ALIGN_UP(end, PAGE_SIZE);
>> +
>>         if (start < end)
>>                 printk ("Freeing initrd memory: %ldk freed\n", (end - st=
art) >> 10);
>
>But here you test the aligned values.  And they are aligned with
>opposite bias.  Which means that if start =3D=3D end (or is less than,
>but within the same page), a page that wasn't reserved (same
>32 and 64 bit) gets freed.
>

Agreed ... I'll have the but shortly ...

>I thought "what happens if we are within a page of end, could we
>free the last page of bss?", but then I checked vmlinux.lds and we
>align end to page size.  I thought other allocations should be safe,
>but then remembered:
>
>The flattened device tree (of which we continue to use the string
>table after boot) could be a problem.
>

I had previouly looked at free_initrd_mem, and thought the same conditions
should be used to handle the memory release, but as for the explicit alignm=
ent
of the release areas, that seemed to be handled by the fact that all of the
releases are specifically page aligned. The remainder of the free_initrd_me=
m
routine:

        for (; start < end; start +=3D PAGE_SIZE) {
                ClearPageReserved(virt_to_page(start));
                init_page_count(virt_to_page(start));
                free_page(start);
                totalram_pages++;
        }

implicitly aligns down start to a page boundary, and also would implicitly =
align
up the end address. While I would be a proponent of something like;

        if (start && (start < end)) do { remainder of free_initrd_mem }

I'm not sure of the goal in explicitly attempting to align the addresses in=
 the
routine as you proposed.

As for the FDT, if the FDT is packed contiguous with initrd, and the alignm=
ent is on
4K page boundaries, it would have been released before this patch. In my ca=
se (U-Boot),
they are not near each other.

Thanks,
-Dave
>
>milton

[PATCH v4] powerpc: Force page alignment for initrd reserved memory

[Dave Carroll]

When using 64K pages with a separate cpio rootfs, U-Boot will align
the rootfs on a 4K page boundary. When the memory is reserved, and
subsequent early memblock_alloc is called, it will allocate memory
between the 64K page alignment and reserved memory. When the reserved
memory is subsequently freed, it is done so by pages, causing the
early memblock_alloc requests to be re-used, which in my case, caused
the device-tree to be clobbered.

This patch forces the reserved memory for initrd to be kernel page
aligned, and adds the same range extension when freeing initrd.

Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
---

* I think this handles Milton's concerns with the exception of
  a packed FDT next to initrd with mismatched page sizes. That
  would require coordination with the bootloader.

 arch/powerpc/kernel/prom.c |    4 +++-
 arch/powerpc/mm/init_32.c  |   15 +++++++++------
 arch/powerpc/mm/init_64.c  |   15 +++++++++------
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 48aeb55..387e5c9 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -555,7 +555,9 @@ static void __init early_reserve_mem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
        /* then reserve the initrd, if any */
        if (initrd_start && (initrd_end > initrd_start))
-               memblock_reserve(__pa(initrd_start), initrd_end - initrd_st=
art);
+               memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE)=
,
+                       _ALIGN_UP(initrd_end, PAGE_SIZE) -
+                       _ALIGN_DOWN(initrd_start, PAGE_SIZE));
 #endif /* CONFIG_BLK_DEV_INITRD */

 #ifdef CONFIG_PPC32
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index d65b591..1aad444 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -226,13 +226,16 @@ void free_initmem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
-       if (start < end)
+       if (start && (start < end)) {
+               start =3D _ALIGN_DOWN(start, PAGE_SIZE);
+               end =3D _ALIGN_UP(end, PAGE_SIZE);
                printk ("Freeing initrd memory: %ldk freed\n", (end - start=
) >> 10);
-       for (; start < end; start +=3D PAGE_SIZE) {
-               ClearPageReserved(virt_to_page(start));
-               init_page_count(virt_to_page(start));
-               free_page(start);
-               totalram_pages++;
+               for (; start < end; start +=3D PAGE_SIZE) {
+                       ClearPageReserved(virt_to_page(start));
+                       init_page_count(virt_to_page(start));
+                       free_page(start);
+                       totalram_pages++;
+               }
        }
 }
 #endif
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 6374b21..fa9586b 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -102,13 +102,16 @@ void free_initmem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
-       if (start < end)
+       if (start && (start < end)) {
+               start =3D _ALIGN_DOWN(start, PAGE_SIZE);
+               end =3D _ALIGN_UP(end, PAGE_SIZE);
                printk ("Freeing initrd memory: %ldk freed\n", (end - start=
) >> 10);
-       for (; start < end; start +=3D PAGE_SIZE) {
-               ClearPageReserved(virt_to_page(start));
-               init_page_count(virt_to_page(start));
-               free_page(start);
-               totalram_pages++;
+               for (; start < end; start +=3D PAGE_SIZE) {
+                       ClearPageReserved(virt_to_page(start));
+                       init_page_count(virt_to_page(start));
+                       free_page(start);
+                       totalram_pages++;
+               }
        }
 }
 #endif
--
1.7.4

RE: [ v4] powerpc: Force page alignment for initrd reserved memory

[Dave Carroll]

I'm withdrawing this patch for the moment, due to two areas that need furth=
er research;

1) An adjacent FDT blob, as mentioned by Milton Miller, and

2) Potential interaction with the crash kernel, as used in
        init/initramfs.c

If anyone sees other interactions, please feel free to let me know ...

Thanks,
-Dave Carroll

RE: [ v4] powerpc: Force page alignment for initrd reserved memory

[Milton Miller]

On Mon, 23 May 2011 about 10:50:07 -0600, Dave Carroll wrote:
> I'm withdrawing this patch for the moment, due to two areas that need
> further research;
> 
> 1) An adjacent FDT blob, as mentioned by Milton Miller, and
> 

Ok ... by the way, see move_device_tree() in arch/powerpc/kernel/prom.c

> 2) Potential interaction with the crash kernel, as used in
>         init/initramfs.c

which already goes around the start and end of crashk_res, which
is adjusted to PAGE_ALIGN in reserve_crashkernel() in machine_kexec.c

 
> If anyone sees other interactions, please feel free to let me know ...
> 
> Thanks,
> -Dave Carroll

One interaction that I have ignored is preserve_initrd overlapping
crash kernel.  Loading the crash kernel destroys the preserved initrd.
But that is beyond the scope of your current patch (and probably a
seperate patch, with cross-architecture scope).

milton

[PATCH v5] powerpc: Force page alignment for initrd reserved memory

[Dave Carroll]

When using 64K pages with a separate cpio rootfs, U-Boot will align
the rootfs on a 4K page boundary. When the memory is reserved, and
subsequent early memblock_alloc is called, it will allocate memory
between the 64K page alignment and reserved memory. When the reserved
memory is subsequently freed, it is done so by pages, causing the
early memblock_alloc requests to be re-used, which in my case, caused
the device-tree to be clobbered.

This patch forces the reserved memory for initrd to be kernel page
aligned, and adds the same range extension when freeing initrd. It
will also move the device tree if it overlaps with the reserved memory
for initrd.

Many thanks to Milton Miller for his input on this patch.

Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
---
 * This patch is based on Linus' current tree

 arch/powerpc/kernel/prom.c |   11 ++++++++---
 arch/powerpc/mm/init_32.c  |    5 ++++-
 arch/powerpc/mm/init_64.c  |    5 ++++-
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 48aeb55..58871df 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -86,7 +86,8 @@ early_param("mem", early_parse_mem);
  * move_device_tree - move tree to an unused area, if needed.
  *
  * The device tree may be allocated beyond our memory limit, or inside the
- * crash kernel region for kdump. If so, move it out of the way.
+ * crash kernel region for kdump, or within the page aligned range of init=
rd.
+ * If so, move it out of the way.
  */
 static void __init move_device_tree(void)
 {
@@ -99,7 +100,9 @@ static void __init move_device_tree(void)
        size =3D be32_to_cpu(initial_boot_params->totalsize);

        if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit=
) ||
-                       overlaps_crashkernel(start, size)) {
+                       overlaps_crashkernel(start, size) ||
+                       ((start + size) > _ALIGN_DOWN(initrd_start, PAGE_SI=
ZE)
+                       && start <=3D _ALIGN_UP(initrd_end, PAGE_SIZE))) {
                p =3D __va(memblock_alloc(size, PAGE_SIZE));
                memcpy(p, initial_boot_params, size);
                initial_boot_params =3D (struct boot_param_header *)p;
@@ -555,7 +558,9 @@ static void __init early_reserve_mem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
        /* then reserve the initrd, if any */
        if (initrd_start && (initrd_end > initrd_start))
-               memblock_reserve(__pa(initrd_start), initrd_end - initrd_st=
art);
+               memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE)=
,
+                       _ALIGN_UP(initrd_end, PAGE_SIZE) -
+                       _ALIGN_DOWN(initrd_start, PAGE_SIZE));
 #endif /* CONFIG_BLK_DEV_INITRD */

 #ifdef CONFIG_PPC32
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index d65b591..4835c4f 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -226,8 +226,11 @@ void free_initmem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
-       if (start < end)
+       if (start < end) {
+               start =3D _ALIGN_DOWN(start, PAGE_SIZE);
+               end =3D _ALIGN_UP(end, PAGE_SIZE);
                printk ("Freeing initrd memory: %ldk freed\n", (end - start=
) >> 10);
+       }
        for (; start < end; start +=3D PAGE_SIZE) {
                ClearPageReserved(virt_to_page(start));
                init_page_count(virt_to_page(start));
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 6374b21..060c952 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -102,8 +102,11 @@ void free_initmem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
-       if (start < end)
+       if (start < end) {
+               start =3D _ALIGN_DOWN(start, PAGE_SIZE);
+               end =3D _ALIGN_UP(end, PAGE_SIZE);
                printk ("Freeing initrd memory: %ldk freed\n", (end - start=
) >> 10);
+       }
        for (; start < end; start +=3D PAGE_SIZE) {
                ClearPageReserved(virt_to_page(start));
                init_page_count(virt_to_page(start));
--
1.7.4

Re: [v5] powerpc: Force page alignment for initrd reserved memory

[Milton Miller]

On Mon, 23 May 2011 about 12:54:25 -0000, Dave Carroll wrote:
> When using 64K pages with a separate cpio rootfs, U-Boot will align
> the rootfs on a 4K page boundary. When the memory is reserved, and
> subsequent early memblock_alloc is called, it will allocate memory
> between the 64K page alignment and reserved memory. When the reserved
> memory is subsequently freed, it is done so by pages, causing the
> early memblock_alloc requests to be re-used, which in my case, caused
> the device-tree to be clobbered.
> 
> This patch forces the reserved memory for initrd to be kernel page
> aligned, and adds the same range extension when freeing initrd. It
> will also move the device tree if it overlaps with the reserved memory
> for initrd.
> 
> Many thanks to Milton Miller for his input on this patch.
> 
> Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
> 
> ---
> * This patch is based on Linus' current tree

Ben if I had reviewed this closely, so I tried to apply it.  First
it failed because it arrived with

Content-Transfer-Encoding: quoted-printable 

patchwork was nice enough to fix that, but it still didn't apply
because tabs were changed to spaces.

While both of those things can be fixed, It would reduce the burden
to test and apply if you can fix your mailer.

> 
>  arch/powerpc/kernel/prom.c |   11 ++++++++---
>  arch/powerpc/mm/init_32.c  |    5 ++++-
>  arch/powerpc/mm/init_64.c  |    5 ++++-
>  3 files changed, 16 insertions(+), 5 deletions(-)
> 
> --
> 1.7.4
> 
> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
> index 48aeb55..58871df 100644
> --- a/arch/powerpc/kernel/prom.c
> +++ b/arch/powerpc/kernel/prom.c
> @@ -86,7 +86,8 @@ early_param("mem", early_parse_mem);
>   * move_device_tree - move tree to an unused area, if needed.
>   *
>   * The device tree may be allocated beyond our memory limit, or inside the
> - * crash kernel region for kdump. If so, move it out of the way.
> + * crash kernel region for kdump, or within the page aligned range of initrd.
> + * If so, move it out of the way.
>   */
>  static void __init move_device_tree(void)
>  {
> @@ -99,7 +100,9 @@ static void __init move_device_tree(void)
>         size = be32_to_cpu(initial_boot_params->totalsize);
> 
>         if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
> -                       overlaps_crashkernel(start, size)) {
> +                       overlaps_crashkernel(start, size) ||
> +                       ((start + size) > _ALIGN_DOWN(initrd_start, PAGE_SIZE)
> +                       && start <= _ALIGN_UP(initrd_end, PAGE_SIZE))) {

When reviewing that with Ben, I thought the && should have been ||.  But
upon further review and comparison with overlaps_crashkernel, I see &&
is correct; it checks both the end is after the start and start is after end.

But that does point out the expression is too complex to read.  Please
create a helper overlaps_initrd similar to overlaps_crashkernel.  In that
function you should also return false if initrd_start is 0.

>                 p = __va(memblock_alloc(size, PAGE_SIZE));
>                 memcpy(p, initial_boot_params, size);
>                 initial_boot_params = (struct boot_param_header *)p;
> @@ -555,7 +558,9 @@ static void __init early_reserve_mem(void)
>  #ifdef CONFIG_BLK_DEV_INITRD
>         /* then reserve the initrd, if any */
>         if (initrd_start && (initrd_end > initrd_start))
> -               memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
> +               memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE),
> +                       _ALIGN_UP(initrd_end, PAGE_SIZE) -
> +                       _ALIGN_DOWN(initrd_start, PAGE_SIZE));
>  #endif /* CONFIG_BLK_DEV_INITRD */
> 
>  #ifdef CONFIG_PPC32
> diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
> index d65b591..4835c4f 100644
> --- a/arch/powerpc/mm/init_32.c
> +++ b/arch/powerpc/mm/init_32.c
> @@ -226,8 +226,11 @@ void free_initmem(void)
>  #ifdef CONFIG_BLK_DEV_INITRD
>  void free_initrd_mem(unsigned long start, unsigned long end)
>  {
> -       if (start < end)
> +       if (start < end) {
> +               start = _ALIGN_DOWN(start, PAGE_SIZE);
> +               end = _ALIGN_UP(end, PAGE_SIZE);
>                 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
> +       }

With the additional code added, Ben and I both noticed the indent
level can be reduced by reversing the condition and issuing an
early return.  eg:

	if (start >= end)
		return;

This will also bring the printk line back under 80 columns.

>         for (; start < end; start += PAGE_SIZE) {
>                 ClearPageReserved(virt_to_page(start));
>                 init_page_count(virt_to_page(start));
> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
> index 6374b21..060c952 100644
> --- a/arch/powerpc/mm/init_64.c
> +++ b/arch/powerpc/mm/init_64.c
> @@ -102,8 +102,11 @@ void free_initmem(void)
>  #ifdef CONFIG_BLK_DEV_INITRD
>  void free_initrd_mem(unsigned long start, unsigned long end)
>  {
> -       if (start < end)
> +       if (start < end) {
> +               start = _ALIGN_DOWN(start, PAGE_SIZE);
> +               end = _ALIGN_UP(end, PAGE_SIZE);
>                 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
> +       }
>         for (; start < end; start += PAGE_SIZE) {
>                 ClearPageReserved(virt_to_page(start));
>                 init_page_count(virt_to_page(start));

Ben noticed the duplication and asked that the function be moved to
mem.c, which is common for 32 and 64 bit.

I would ask that, in addition, you prepare a second patch that
consolidates the free_initmem functions just above them by
noting that all sections except init were removed in v2.6.15 by
6c45ab992e4299c869fb26427944a8f8ea177024 (powerpc: Remove section
free() and linker script bits), and therefore the bulk of the executed
code is identical.

However, I see its a bit more involved because of that last line in
the 32 bit code which clears ppc_md.progress.  A bit of research shows
we mostly don't call ppc_md.progress after init calls, but powermac
has a late initcall to clear it because they call it from a smp hook,
and the progress function is marked __init.  Further research shows
most are marked init, including somewhat duplicated functions across
64 bit powerpc; the exception seems to be rtas_progress which is
called directly (not through ppc_md) from rtas-proc.c.

So upon further review, clear the ppc_md.progress to NULL at the
beginning of the consolidated function (before we start to release
the pages with the code).  You can then remove the late_initcall in
the powermac code.

Extra credit to create and consolidate a printk_progress companion
to the udbg_progress call (but located somewhere common like
arch/powerpc/kernel/setup-common.c).

Thanks,
milton

[PATCH v6] powerpc: Force page alignment for initrd reserved memory

[Dave Carroll]

From: Dave Carroll <dcarroll@astekcorp.com>

When using 64K pages with a separate cpio rootfs, U-Boot will align
the rootfs on a 4K page boundary. When the memory is reserved, and
subsequent early memblock_alloc is called, it will allocate memory
between the 64K page alignment and reserved memory. When the reserved
memory is subsequently freed, it is done so by pages, causing the
early memblock_alloc requests to be re-used, which in my case, caused
the device-tree to be clobbered.

This patch forces the reserved memory for initrd to be kernel page
aligned, and will move the device tree if it overlaps with the range
extension of initrd. This patch will also consolidate the identical
function free_initrd_mem() from mm/init_32.c, init_64.c to mm/mem.c,
and adds the same range extension when freeing initrd.

Many thanks to Milton Miller for his input on this patch.

Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>

---
 arch/powerpc/kernel/prom.c |   21 ++++++++++++++++++---
 arch/powerpc/mm/init_32.c  |   15 ---------------
 arch/powerpc/mm/init_64.c  |   13 -------------
 arch/powerpc/mm/mem.c      |   19 +++++++++++++++++++
 4 files changed, 37 insertions(+), 31 deletions(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 48aeb55..86966a0 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -81,12 +81,24 @@ static int __init early_parse_mem(char *p)
 	return 0;
 }
 early_param("mem", early_parse_mem);
+/**
+ * overlaps_initrd - check for overlap with page aligned extension of
+ * initrd.
+ */
+static inline int overlaps_initrd(unsigned long start, unsigned long end)
+{
+	if (!initrd_start)
+		return 0;
 
+	return	(start + size) > _ALIGN_DOWN(initrd_start, PAGE_SIZE) &&
+			start <= _ALIGN_UP(initrd_end, PAGE_SIZE);
+}
 /**
  * move_device_tree - move tree to an unused area, if needed.
  *
  * The device tree may be allocated beyond our memory limit, or inside the
- * crash kernel region for kdump. If so, move it out of the way.
+ * crash kernel region for kdump, or within the page aligned range of initrd.
+ * If so, move it out of the way.
  */
 static void __init move_device_tree(void)
 {
@@ -99,7 +111,8 @@ static void __init move_device_tree(void)
 	size = be32_to_cpu(initial_boot_params->totalsize);
 
 	if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
-			overlaps_crashkernel(start, size)) {
+			overlaps_crashkernel(start, size) ||
+			overlaps_initrd(start, size) {
 		p = __va(memblock_alloc(size, PAGE_SIZE));
 		memcpy(p, initial_boot_params, size);
 		initial_boot_params = (struct boot_param_header *)p;
@@ -555,7 +568,9 @@ static void __init early_reserve_mem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 	/* then reserve the initrd, if any */
 	if (initrd_start && (initrd_end > initrd_start))
-		memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
+		memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE),
+			_ALIGN_UP(initrd_end, PAGE_SIZE) -
+			_ALIGN_DOWN(initrd_start, PAGE_SIZE));
 #endif /* CONFIG_BLK_DEV_INITRD */
 
 #ifdef CONFIG_PPC32
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index d65b591..5de0f25 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -223,21 +223,6 @@ void free_initmem(void)
 #undef FREESEC
 }
 
-#ifdef CONFIG_BLK_DEV_INITRD
-void free_initrd_mem(unsigned long start, unsigned long end)
-{
-	if (start < end)
-		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
-	for (; start < end; start += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(start));
-		init_page_count(virt_to_page(start));
-		free_page(start);
-		totalram_pages++;
-	}
-}
-#endif
-
-
 #ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 				phys_addr_t first_memblock_size)
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 6374b21..7591a97 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -99,19 +99,6 @@ void free_initmem(void)
 		((unsigned long)__init_end - (unsigned long)__init_begin) >> 10);
 }
 
-#ifdef CONFIG_BLK_DEV_INITRD
-void free_initrd_mem(unsigned long start, unsigned long end)
-{
-	if (start < end)
-		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
-	for (; start < end; start += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(start));
-		init_page_count(virt_to_page(start));
-		free_page(start);
-		totalram_pages++;
-	}
-}
-#endif
 
 static void pgd_ctor(void *addr)
 {
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 57e545b..f60e44e 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -160,6 +160,25 @@ walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 }
 EXPORT_SYMBOL_GPL(walk_system_ram_range);
 
+#ifdef CONFIG_BLK_DEV_INITRD
+void free_initrd_mem(unsigned long start, unsigned long end)
+{
+	if (start >= end)
+		return;
+
+	start = _ALIGN_DOWN(start, PAGE_SIZE);
+	end = _ALIGN_UP(end, PAGE_SIZE);
+	printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
+			(end - start) >> 10);
+	for (; start < end; start += PAGE_SIZE) {
+		ClearPageReserved(virt_to_page(start));
+		init_page_count(virt_to_page(start));
+		free_page(start);
+		totalram_pages++;
+	}
+}
+#endif
+
 /*
  * Initialize the bootmem system and give it all the memory we
  * have available.  If we are using highmem, we only put the
-- 
1.7.4

[PATCH v7] powerpc: Force page alignment for initrd reserved memory

[Dave Carroll]

From: Dave Carroll <dcarroll@astekcorp.com>

When using 64K pages with a separate cpio rootfs, U-Boot will align
the rootfs on a 4K page boundary. When the memory is reserved, and
subsequent early memblock_alloc is called, it will allocate memory
between the 64K page alignment and reserved memory. When the reserved
memory is subsequently freed, it is done so by pages, causing the
early memblock_alloc requests to be re-used, which in my case, caused
the device-tree to be clobbered.

This patch forces the reserved memory for initrd to be kernel page
aligned, and will move the device tree if it overlaps with the range
extension of initrd. This patch will also consolidate the identical
function free_initrd_mem() from mm/init_32.c, init_64.c to mm/mem.c,
and adds the same range extension when freeing initrd.

Many thanks to Milton Miller for his input on this patch.

Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>

---
 * The previous patch [v6] was the wrong copy, sorry ...
 
 arch/powerpc/kernel/prom.c |   21 ++++++++++++++++++---
 arch/powerpc/mm/init_32.c  |   15 ---------------
 arch/powerpc/mm/init_64.c  |   13 -------------
 arch/powerpc/mm/mem.c      |   19 +++++++++++++++++++
 4 files changed, 37 insertions(+), 31 deletions(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 48aeb55..86966a0 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -81,12 +81,24 @@ static int __init early_parse_mem(char *p)
 	return 0;
 }
 early_param("mem", early_parse_mem);
+/**
+ * overlaps_initrd - check for overlap with page aligned extension of
+ * initrd.
+ */
+static inline int overlaps_initrd(unsigned long start, unsigned long size)
+{
+	if (!initrd_start)
+		return 0;
 
+	return	(start + size) > _ALIGN_DOWN(initrd_start, PAGE_SIZE) &&
+			start <= _ALIGN_UP(initrd_end, PAGE_SIZE);
+}
 /**
  * move_device_tree - move tree to an unused area, if needed.
  *
  * The device tree may be allocated beyond our memory limit, or inside the
- * crash kernel region for kdump. If so, move it out of the way.
+ * crash kernel region for kdump, or within the page aligned range of initrd.
+ * If so, move it out of the way.
  */
 static void __init move_device_tree(void)
 {
@@ -99,7 +111,8 @@ static void __init move_device_tree(void)
 	size = be32_to_cpu(initial_boot_params->totalsize);
 
 	if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
-			overlaps_crashkernel(start, size)) {
+			overlaps_crashkernel(start, size) ||
+			overlaps_initrd(start, size)) {
 		p = __va(memblock_alloc(size, PAGE_SIZE));
 		memcpy(p, initial_boot_params, size);
 		initial_boot_params = (struct boot_param_header *)p;
@@ -555,7 +568,9 @@ static void __init early_reserve_mem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 	/* then reserve the initrd, if any */
 	if (initrd_start && (initrd_end > initrd_start))
-		memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
+		memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE),
+			_ALIGN_UP(initrd_end, PAGE_SIZE) -
+			_ALIGN_DOWN(initrd_start, PAGE_SIZE));
 #endif /* CONFIG_BLK_DEV_INITRD */
 
 #ifdef CONFIG_PPC32
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index d65b591..5de0f25 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -223,21 +223,6 @@ void free_initmem(void)
 #undef FREESEC
 }
 
-#ifdef CONFIG_BLK_DEV_INITRD
-void free_initrd_mem(unsigned long start, unsigned long end)
-{
-	if (start < end)
-		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
-	for (; start < end; start += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(start));
-		init_page_count(virt_to_page(start));
-		free_page(start);
-		totalram_pages++;
-	}
-}
-#endif
-
-
 #ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 				phys_addr_t first_memblock_size)
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 6374b21..7591a97 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -99,19 +99,6 @@ void free_initmem(void)
 		((unsigned long)__init_end - (unsigned long)__init_begin) >> 10);
 }
 
-#ifdef CONFIG_BLK_DEV_INITRD
-void free_initrd_mem(unsigned long start, unsigned long end)
-{
-	if (start < end)
-		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
-	for (; start < end; start += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(start));
-		init_page_count(virt_to_page(start));
-		free_page(start);
-		totalram_pages++;
-	}
-}
-#endif
 
 static void pgd_ctor(void *addr)
 {
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 57e545b..f60e44e 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -160,6 +160,25 @@ walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 }
 EXPORT_SYMBOL_GPL(walk_system_ram_range);
 
+#ifdef CONFIG_BLK_DEV_INITRD
+void free_initrd_mem(unsigned long start, unsigned long end)
+{
+	if (start >= end)
+		return;
+
+	start = _ALIGN_DOWN(start, PAGE_SIZE);
+	end = _ALIGN_UP(end, PAGE_SIZE);
+	printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
+			(end - start) >> 10);
+	for (; start < end; start += PAGE_SIZE) {
+		ClearPageReserved(virt_to_page(start));
+		init_page_count(virt_to_page(start));
+		free_page(start);
+		totalram_pages++;
+	}
+}
+#endif
+
 /*
  * Initialize the bootmem system and give it all the memory we
  * have available.  If we are using highmem, we only put the
-- 
1.7.4

Re: [PATCH v7] powerpc: Force page alignment for initrd reserved memory

[Milton Miller]

On Wed, 25 May 2011 about 20:32:42 -0600, Dave Carroll wrote:

> When using 64K pages with a separate cpio rootfs, U-Boot will align
> the rootfs on a 4K page boundary. When the memory is reserved, and
> subsequent early memblock_alloc is called, it will allocate memory
> between the 64K page alignment and reserved memory. When the reserved
> memory is subsequently freed, it is done so by pages, causing the
> early memblock_alloc requests to be re-used, which in my case, caused
> the device-tree to be clobbered.
> 
> This patch forces the reserved memory for initrd to be kernel page
> aligned, and will move the device tree if it overlaps with the range
> extension of initrd. This patch will also consolidate the identical
> function free_initrd_mem() from mm/init_32.c, init_64.c to mm/mem.c,
> and adds the same range extension when freeing initrd.
> 
> Many thanks to Milton Miller for his input on this patch.
> 

Thanks for the mailer update, it applied cleanly.

> Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 
> ---
>  * The previous patch [v6] was the wrong copy, sorry ...
>  
>  arch/powerpc/kernel/prom.c |   21 ++++++++++++++++++---
>  arch/powerpc/mm/init_32.c  |   15 ---------------
>  arch/powerpc/mm/init_64.c  |   13 -------------
>  arch/powerpc/mm/mem.c      |   19 +++++++++++++++++++
>  4 files changed, 37 insertions(+), 31 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
> index 48aeb55..86966a0 100644
> --- a/arch/powerpc/kernel/prom.c
> +++ b/arch/powerpc/kernel/prom.c
> @@ -81,12 +81,24 @@ static int __init early_parse_mem(char *p)
>  	return 0;
>  }
>  early_param("mem", early_parse_mem);
> +/**
> + * overlaps_initrd - check for overlap with page aligned extension of
> + * initrd.
> + */

1) Please place a blank line after the above early_param before
the comment block.

2) /** says it is kernel doc format, so you need to follow the rules.
The description should fit on one line (I might say: ... with the initrd,
page aligned.)  and you have to document the parameters.  (Or just make
it a simple comment block by removing the second *)

> +static inline int overlaps_initrd(unsigned long start, unsigned long size)
> +{
> +	if (!initrd_start)
> +		return 0;
>  
> +	return	(start + size) > _ALIGN_DOWN(initrd_start, PAGE_SIZE) &&
> +			start <= _ALIGN_UP(initrd_end, PAGE_SIZE);
> +}
>  /**

need a blank line after the function before this comment block too.

>   * move_device_tree - move tree to an unused area, if needed.
>   *
>   * The device tree may be allocated beyond our memory limit, or inside the
> - * crash kernel region for kdump. If so, move it out of the way.
> + * crash kernel region for kdump, or within the page aligned range of initrd.
> + * If so, move it out of the way.

of the initrd.

>   */
>  static void __init move_device_tree(void)
>  {
> @@ -99,7 +111,8 @@ static void __init move_device_tree(void)
>  	size = be32_to_cpu(initial_boot_params->totalsize);
>  
>  	if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
> -			overlaps_crashkernel(start, size)) {
> +			overlaps_crashkernel(start, size) ||
> +			overlaps_initrd(start, size)) {
>  		p = __va(memblock_alloc(size, PAGE_SIZE));
>  		memcpy(p, initial_boot_params, size);
>  		initial_boot_params = (struct boot_param_header *)p;
> @@ -555,7 +568,9 @@ static void __init early_reserve_mem(void)
>  #ifdef CONFIG_BLK_DEV_INITRD
>  	/* then reserve the initrd, if any */
>  	if (initrd_start && (initrd_end > initrd_start))
> -		memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
> +		memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE),
> +			_ALIGN_UP(initrd_end, PAGE_SIZE) -
> +			_ALIGN_DOWN(initrd_start, PAGE_SIZE));
>  #endif /* CONFIG_BLK_DEV_INITRD */
>  
>  #ifdef CONFIG_PPC32
> diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
> index d65b591..5de0f25 100644
> --- a/arch/powerpc/mm/init_32.c
> +++ b/arch/powerpc/mm/init_32.c
> @@ -223,21 +223,6 @@ void free_initmem(void)
>  #undef FREESEC
>  }
>  
> -#ifdef CONFIG_BLK_DEV_INITRD
> -void free_initrd_mem(unsigned long start, unsigned long end)
> -{
> -	if (start < end)
> -		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
> -	for (; start < end; start += PAGE_SIZE) {
> -		ClearPageReserved(virt_to_page(start));
> -		init_page_count(virt_to_page(start));
> -		free_page(start);
> -		totalram_pages++;
> -	}
> -}
> -#endif
> -
> -
>  #ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
>  void setup_initial_memory_limit(phys_addr_t first_memblock_base,
>  				phys_addr_t first_memblock_size)
> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
> index 6374b21..7591a97 100644
> --- a/arch/powerpc/mm/init_64.c
> +++ b/arch/powerpc/mm/init_64.c
> @@ -99,19 +99,6 @@ void free_initmem(void)
>  		((unsigned long)__init_end - (unsigned long)__init_begin) >> 10);
>  }
>  
> -#ifdef CONFIG_BLK_DEV_INITRD
> -void free_initrd_mem(unsigned long start, unsigned long end)
> -{
> -	if (start < end)
> -		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
> -	for (; start < end; start += PAGE_SIZE) {
> -		ClearPageReserved(virt_to_page(start));
> -		init_page_count(virt_to_page(start));
> -		free_page(start);
> -		totalram_pages++;
> -	}
> -}
> -#endif
>  
>  static void pgd_ctor(void *addr)
>  {
> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
> index 57e545b..f60e44e 100644
> --- a/arch/powerpc/mm/mem.c
> +++ b/arch/powerpc/mm/mem.c
> @@ -160,6 +160,25 @@ walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
>  }
>  EXPORT_SYMBOL_GPL(walk_system_ram_range);
>  
> +#ifdef CONFIG_BLK_DEV_INITRD
> +void free_initrd_mem(unsigned long start, unsigned long end)
> +{
> +	if (start >= end)
> +		return;
> +
> +	start = _ALIGN_DOWN(start, PAGE_SIZE);
> +	end = _ALIGN_UP(end, PAGE_SIZE);
> +	printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
> +			(end - start) >> 10);

If you use pr_info then the above again fits on one line. 
(this is what triggered my formatting and whitespace review).

Although I would then add a blank line before the loop for readability.

> +	for (; start < end; start += PAGE_SIZE) {
> +		ClearPageReserved(virt_to_page(start));
> +		init_page_count(virt_to_page(start));
> +		free_page(start);
> +		totalram_pages++;
> +	}
> +}
> +#endif
> +

Nit: Looking at the whole file I would put this after mem_init
because that puts it next to the other code that sets page counts,
clears PageReerved, and hands pages to page_alloc.


>  /*
>   * Initialize the bootmem system and give it all the memory we
>   * have available.  If we are using highmem, we only put the
> -- 
> 1.7.4
> 

milton

[PATCH v8] powerpc: Force page alignment for initrd reserved memory

[Dave Carroll]

From: Dave Carroll <dcarroll@astekcorp.com>

When using 64K pages with a separate cpio rootfs, U-Boot will align
the rootfs on a 4K page boundary. When the memory is reserved, and
subsequent early memblock_alloc is called, it will allocate memory
between the 64K page alignment and reserved memory. When the reserved
memory is subsequently freed, it is done so by pages, causing the
early memblock_alloc requests to be re-used, which in my case, caused
the device-tree to be clobbered.

This patch forces the reserved memory for initrd to be kernel page
aligned, and will move the device tree if it overlaps with the range
extension of initrd. This patch will also consolidate the identical
function free_initrd_mem() from mm/init_32.c, init_64.c to mm/mem.c,
and adds the same range extension when freeing initrd. free_initrd_mem()
is also moved to the __init section.

Many thanks to Milton Miller for his input on this patch.

Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 arch/powerpc/kernel/prom.c |   23 ++++++++++++++++++++---
 arch/powerpc/mm/init_32.c  |   15 ---------------
 arch/powerpc/mm/init_64.c  |   14 --------------
 arch/powerpc/mm/mem.c      |   19 +++++++++++++++++++
 4 files changed, 39 insertions(+), 32 deletions(-)

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 48aeb55..fba012a 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -82,11 +82,25 @@ static int __init early_parse_mem(char *p)
 }
 early_param("mem", early_parse_mem);
 
+/*
+ * overlaps_initrd - check for overlap with page aligned extension of
+ * initrd.
+ */
+static inline int overlaps_initrd(unsigned long start, unsigned long size)
+{
+	if (!initrd_start)
+		return 0;
+
+	return	(start + size) > _ALIGN_DOWN(initrd_start, PAGE_SIZE) &&
+			start <= _ALIGN_UP(initrd_end, PAGE_SIZE);
+}
+
 /**
  * move_device_tree - move tree to an unused area, if needed.
  *
  * The device tree may be allocated beyond our memory limit, or inside the
- * crash kernel region for kdump. If so, move it out of the way.
+ * crash kernel region for kdump, or within the page aligned range of initrd.
+ * If so, move it out of the way.
  */
 static void __init move_device_tree(void)
 {
@@ -99,7 +113,8 @@ static void __init move_device_tree(void)
 	size = be32_to_cpu(initial_boot_params->totalsize);
 
 	if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
-			overlaps_crashkernel(start, size)) {
+			overlaps_crashkernel(start, size) ||
+			overlaps_initrd(start, size)) {
 		p = __va(memblock_alloc(size, PAGE_SIZE));
 		memcpy(p, initial_boot_params, size);
 		initial_boot_params = (struct boot_param_header *)p;
@@ -555,7 +570,9 @@ static void __init early_reserve_mem(void)
 #ifdef CONFIG_BLK_DEV_INITRD
 	/* then reserve the initrd, if any */
 	if (initrd_start && (initrd_end > initrd_start))
-		memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
+		memblock_reserve(_ALIGN_DOWN(__pa(initrd_start), PAGE_SIZE),
+			_ALIGN_UP(initrd_end, PAGE_SIZE) -
+			_ALIGN_DOWN(initrd_start, PAGE_SIZE));
 #endif /* CONFIG_BLK_DEV_INITRD */
 
 #ifdef CONFIG_PPC32
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index d65b591..5de0f25 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -223,21 +223,6 @@ void free_initmem(void)
 #undef FREESEC
 }
 
-#ifdef CONFIG_BLK_DEV_INITRD
-void free_initrd_mem(unsigned long start, unsigned long end)
-{
-	if (start < end)
-		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
-	for (; start < end; start += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(start));
-		init_page_count(virt_to_page(start));
-		free_page(start);
-		totalram_pages++;
-	}
-}
-#endif
-
-
 #ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 				phys_addr_t first_memblock_size)
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 6374b21..f6dbb4c 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -99,20 +99,6 @@ void free_initmem(void)
 		((unsigned long)__init_end - (unsigned long)__init_begin) >> 10);
 }
 
-#ifdef CONFIG_BLK_DEV_INITRD
-void free_initrd_mem(unsigned long start, unsigned long end)
-{
-	if (start < end)
-		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
-	for (; start < end; start += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(start));
-		init_page_count(virt_to_page(start));
-		free_page(start);
-		totalram_pages++;
-	}
-}
-#endif
-
 static void pgd_ctor(void *addr)
 {
 	memset(addr, 0, PGD_TABLE_SIZE);
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 57e545b..29d4dde 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -382,6 +382,25 @@ void __init mem_init(void)
 	mem_init_done = 1;
 }
 
+#ifdef CONFIG_BLK_DEV_INITRD
+void __init free_initrd_mem(unsigned long start, unsigned long end)
+{
+	if (start >= end)
+		return;
+
+	start = _ALIGN_DOWN(start, PAGE_SIZE);
+	end = _ALIGN_UP(end, PAGE_SIZE);
+	pr_info("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
+
+	for (; start < end; start += PAGE_SIZE) {
+		ClearPageReserved(virt_to_page(start));
+		init_page_count(virt_to_page(start));
+		free_page(start);
+		totalram_pages++;
+	}
+}
+#endif
+
 /*
  * This is called when a page has been modified by the kernel.
  * It just marks the page as not i-cache clean.  We do the i-cache
-- 
1.7.4

[PATCH 1/2] powerpc: Move free_initmem to common code

[Dave Carroll]

From: Dave Carroll <dcarroll@astekcorp.com>

The free_initmem function is basically duplicated in mm/init_32,
and init_64, and is moved to the common 32/64-bit mm/mem.c.

All other sections except init were removed in v2.6.15 by
6c45ab992e4299c869fb26427944a8f8ea177024 (powerpc: Remove section
free() and linker script bits), and therefore the bulk of the executed
code is identical.

This patch also removes updating ppc_md.progress to NULL in the powermac
late_initcall.

Suggested-by: Milton Miller <miltonm@bga.com>
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
---
 arch/powerpc/mm/init_32.c               |   32 -------------------------------
 arch/powerpc/mm/init_64.c               |   16 ---------------
 arch/powerpc/mm/mem.c                   |   19 ++++++++++++++++++
 arch/powerpc/platforms/powermac/setup.c |    3 --
 4 files changed, 19 insertions(+), 51 deletions(-)

diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index 5de0f25..c77fef5 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -191,38 +191,6 @@ void __init *early_get_page(void)
 		return __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
 }
 
-/* Free up now-unused memory */
-static void free_sec(unsigned long start, unsigned long end, const char *name)
-{
-	unsigned long cnt = 0;
-
-	while (start < end) {
-		ClearPageReserved(virt_to_page(start));
-		init_page_count(virt_to_page(start));
-		free_page(start);
-		cnt++;
-		start += PAGE_SIZE;
- 	}
-	if (cnt) {
-		printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
-		totalram_pages += cnt;
-	}
-}
-
-void free_initmem(void)
-{
-#define FREESEC(TYPE) \
-	free_sec((unsigned long)(&__ ## TYPE ## _begin), \
-		 (unsigned long)(&__ ## TYPE ## _end), \
-		 #TYPE);
-
-	printk ("Freeing unused kernel memory:");
-	FREESEC(init);
- 	printk("\n");
-	ppc_md.progress = NULL;
-#undef FREESEC
-}
-
 #ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 				phys_addr_t first_memblock_size)
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index f6dbb4c..e94b57f 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -83,22 +83,6 @@ EXPORT_SYMBOL_GPL(memstart_addr);
 phys_addr_t kernstart_addr;
 EXPORT_SYMBOL_GPL(kernstart_addr);
 
-void free_initmem(void)
-{
-	unsigned long addr;
-
-	addr = (unsigned long)__init_begin;
-	for (; addr < (unsigned long)__init_end; addr += PAGE_SIZE) {
-		memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
-		ClearPageReserved(virt_to_page(addr));
-		init_page_count(virt_to_page(addr));
-		free_page(addr);
-		totalram_pages++;
-	}
-	printk ("Freeing unused kernel memory: %luk freed\n",
-		((unsigned long)__init_end - (unsigned long)__init_begin) >> 10);
-}
-
 static void pgd_ctor(void *addr)
 {
 	memset(addr, 0, PGD_TABLE_SIZE);
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 29d4dde..f4e6408 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -382,6 +382,25 @@ void __init mem_init(void)
 	mem_init_done = 1;
 }
 
+void free_initmem(void)
+{
+	unsigned long addr;
+
+	ppc_md.progress = NULL;
+
+	addr = (unsigned long)__init_begin;
+	for (; addr < (unsigned long)__init_end; addr += PAGE_SIZE) {
+		memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
+		ClearPageReserved(virt_to_page(addr));
+		init_page_count(virt_to_page(addr));
+		free_page(addr);
+		totalram_pages++;
+	}
+	pr_info("Freeing unused kernel memory: %luk freed\n",
+		((unsigned long)__init_end -
+		(unsigned long)__init_begin) >> 10);
+}
+
 #ifdef CONFIG_BLK_DEV_INITRD
 void __init free_initrd_mem(unsigned long start, unsigned long end)
 {
diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index aa45281..a028f08 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/arch/powerpc/platforms/powermac/setup.c
@@ -355,9 +355,6 @@ static int initializing = 1;
 static int pmac_late_init(void)
 {
 	initializing = 0;
-	/* this is udbg (which is __init) and we can later use it during
-	 * cpu hotplug (in smp_core99_kick_cpu) */
-	ppc_md.progress = NULL;
 	return 0;
 }
 machine_late_initcall(powermac, pmac_late_init);
-- 
1.7.4

[PATCH 2/2] powerpc: Add printk companion for ppc_md.progress

[Dave Carroll]

From: Dave Carroll <dcarroll@astekcorp.com>

This patch adds a printk companion to replace the udbg progress function
when initmem is freed.

Suggested-by: Milton Miller <miltonm@bga.com>
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Dave Carroll <dcarroll@astekcorp.com>
---
 arch/powerpc/include/asm/setup.h   |    2 ++
 arch/powerpc/kernel/setup-common.c |    5 +++++
 arch/powerpc/mm/mem.c              |    2 +-
 3 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index dae1934..c77cb7a 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -3,4 +3,6 @@
 
 #include <asm-generic/setup.h>
 
+extern void ppc_printk_progress(char *s, unsigned short hex);
+
 #endif	/* _ASM_POWERPC_SETUP_H */
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 79fca26..e053b16 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -704,6 +704,11 @@ static int powerpc_debugfs_init(void)
 arch_initcall(powerpc_debugfs_init);
 #endif
 
+void ppc_printk_progress(char *s, unsigned short hex)
+{
+	pr_info("%s\n", s);
+}
+
 static int ppc_dflt_bus_notify(struct notifier_block *nb,
 				unsigned long action, void *data)
 {
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index f4e6408..e0d2aa0 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -386,7 +386,7 @@ void free_initmem(void)
 {
 	unsigned long addr;
 
-	ppc_md.progress = NULL;
+	ppc_md.progress = ppc_printk_progress;
 
 	addr = (unsigned long)__init_begin;
 	for (; addr < (unsigned long)__init_end; addr += PAGE_SIZE) {
-- 
1.7.4