[U-Boot] [RFC PATCH] common: fdt_support: Remove fdt_add_mem_rsv in fdt_shrink_to_minimum
With introduction of commit:
a156c47e39ad: tftp: prevent overwriting reserved memory
tftp with loadaddr is failing for Images of the size bigger than SPL. The issue is that SPL image is located at bootaddr and dtb is allocated at bootaddr + spl_size.
The region where dtb is present is marked reserved.
So when the tftp tries to load the Image it tries to find a location from loadaddr to the first reserved memory region which is the dtb base address. The max_size obtained is pretty less and hence tftp fails with the below error:
TFTP error: trying to overwrite reserved memory...
Signed-off-by: Keerthy j-keerthy@ti.com ---
I am sure there are better solutions so just wanted to know if there is one.
common/fdt_support.c | 5 ----- 1 file changed, 5 deletions(-)
diff --git a/common/fdt_support.c b/common/fdt_support.c index 42583e3ed8..2bb101e56e 100644 --- a/common/fdt_support.c +++ b/common/fdt_support.c @@ -633,11 +633,6 @@ int fdt_shrink_to_minimum(void *blob, uint extrasize) /* Change the fdt header to reflect the correct size */ fdt_set_totalsize(blob, actualsize);
- /* Add the new reservation */ - ret = fdt_add_mem_rsv(blob, map_to_sysmem(blob), actualsize); - if (ret < 0) - return ret; - return actualsize; }
Hi Keerthy,
On Wed, 30 Jan 2019 at 06:41, Keerthy j-keerthy@ti.com wrote:
With introduction of commit:
a156c47e39ad: tftp: prevent overwriting reserved memory
tftp with loadaddr is failing for Images of the size bigger than SPL. The issue is that SPL image is located at bootaddr and dtb is allocated at bootaddr + spl_size.
The region where dtb is present is marked reserved.
So when the tftp tries to load the Image it tries to find a location from loadaddr to the first reserved memory region which is the dtb base address. The max_size obtained is pretty less and hence tftp fails with the below error:
TFTP error: trying to overwrite reserved memory...
I don't quite get this. Are you saying that we load U-Boot to loadaddr, overwriting the SPL DT?
Simon Goldschmidt, any thoughts?
Regards, Simon
Signed-off-by: Keerthy j-keerthy@ti.com
I am sure there are better solutions so just wanted to know if there is one.
common/fdt_support.c | 5 ----- 1 file changed, 5 deletions(-)
diff --git a/common/fdt_support.c b/common/fdt_support.c index 42583e3ed8..2bb101e56e 100644 --- a/common/fdt_support.c +++ b/common/fdt_support.c @@ -633,11 +633,6 @@ int fdt_shrink_to_minimum(void *blob, uint extrasize) /* Change the fdt header to reflect the correct size */ fdt_set_totalsize(blob, actualsize);
/* Add the new reservation */ret = fdt_add_mem_rsv(blob, map_to_sysmem(blob), actualsize);if (ret < 0)return ret;return actualsize;}
-- 2.17.1
On 4/12/2019 7:39 AM, Simon Glass wrote:
Hi Keerthy,
On Wed, 30 Jan 2019 at 06:41, Keerthy j-keerthy@ti.com wrote:
With introduction of commit:
a156c47e39ad: tftp: prevent overwriting reserved memory
tftp with loadaddr is failing for Images of the size bigger than SPL. The issue is that SPL image is located at bootaddr and dtb is allocated at bootaddr + spl_size.
The region where dtb is present is marked reserved.
So when the tftp tries to load the Image it tries to find a location from loadaddr to the first reserved memory region which is the dtb base address. The max_size obtained is pretty less and hence tftp fails with the below error:
TFTP error: trying to overwrite reserved memory...
I don't quite get this. Are you saying that we load U-Boot to loadaddr, overwriting the SPL DT?
Simon,
No. Basically when we try to load kernel to bootaddr using tftp there is dtb present at bootaddr+spl_size and its marked as reserved. So TFTP fails. IMHO post relocation it should not be marked as reserved. Basically we will never be able to find enough space between bootaddr and dtb address for us to fit kernel Image and tftp will always fail for bootaddr.
Hope i am clear now.
Regards, Keerthy
Simon Goldschmidt, any thoughts?
Regards, Simon
Signed-off-by: Keerthy j-keerthy@ti.com
I am sure there are better solutions so just wanted to know if there is one.
common/fdt_support.c | 5 ----- 1 file changed, 5 deletions(-)
diff --git a/common/fdt_support.c b/common/fdt_support.c index 42583e3ed8..2bb101e56e 100644 --- a/common/fdt_support.c +++ b/common/fdt_support.c @@ -633,11 +633,6 @@ int fdt_shrink_to_minimum(void *blob, uint extrasize) /* Change the fdt header to reflect the correct size */ fdt_set_totalsize(blob, actualsize);
/* Add the new reservation */ret = fdt_add_mem_rsv(blob, map_to_sysmem(blob), actualsize);if (ret < 0)return ret;return actualsize;-- 2.17.1
Hi Keerthy, Kumar,
On Thu, 11 Apr 2019 at 21:41, keerthy j-keerthy@ti.com wrote:
On 4/12/2019 7:39 AM, Simon Glass wrote:
Hi Keerthy,
On Wed, 30 Jan 2019 at 06:41, Keerthy j-keerthy@ti.com wrote:
With introduction of commit:
a156c47e39ad: tftp: prevent overwriting reserved memory
tftp with loadaddr is failing for Images of the size bigger than SPL. The issue is that SPL image is located at bootaddr and dtb is allocated at bootaddr + spl_size.
The region where dtb is present is marked reserved.
So when the tftp tries to load the Image it tries to find a location from loadaddr to the first reserved memory region which is the dtb base address. The max_size obtained is pretty less and hence tftp fails with the below error:
TFTP error: trying to overwrite reserved memory...
I don't quite get this. Are you saying that we load U-Boot to loadaddr, overwriting the SPL DT?
Simon,
No. Basically when we try to load kernel to bootaddr using tftp there is dtb present at bootaddr+spl_size and its marked as reserved. So TFTP fails. IMHO post relocation it should not be marked as reserved. Basically we will never be able to find enough space between bootaddr and dtb address for us to fit kernel Image and tftp will always fail for bootaddr.
Hope i am clear now.
It looks like this code was added from PowerPC by Kumar Gala galak@kernel.crashing.org, now copied.
3082d2348c fdt: refactor fdt resize code
I don't really understand why the tftp command is looking at reserved memory in the DT. Is this due to the recent improvements to enforce reserved memory that Simon Goldschmidt did?
I'm sorry but I cannot really help with reviewing this. Perhaps Tom knows more.
Regards, Simon
Regards, Keerthy
Simon Goldschmidt, any thoughts?
Regards, Simon
Signed-off-by: Keerthy j-keerthy@ti.com
I am sure there are better solutions so just wanted to know if there is one.
common/fdt_support.c | 5 ----- 1 file changed, 5 deletions(-)
diff --git a/common/fdt_support.c b/common/fdt_support.c index 42583e3ed8..2bb101e56e 100644 --- a/common/fdt_support.c +++ b/common/fdt_support.c @@ -633,11 +633,6 @@ int fdt_shrink_to_minimum(void *blob, uint extrasize) /* Change the fdt header to reflect the correct size */ fdt_set_totalsize(blob, actualsize);
/* Add the new reservation */ret = fdt_add_mem_rsv(blob, map_to_sysmem(blob), actualsize);if (ret < 0)return ret;return actualsize;-- 2.17.1
On Fri, Apr 12, 2019 at 2:25 PM Simon Glass sjg@chromium.org wrote:
Hi Keerthy, Kumar,
On Thu, 11 Apr 2019 at 21:41, keerthy j-keerthy@ti.com wrote:
On 4/12/2019 7:39 AM, Simon Glass wrote:
Hi Keerthy,
On Wed, 30 Jan 2019 at 06:41, Keerthy j-keerthy@ti.com wrote:
With introduction of commit:
a156c47e39ad: tftp: prevent overwriting reserved memory
tftp with loadaddr is failing for Images of the size bigger than SPL. The issue is that SPL image is located at bootaddr and dtb is allocated at bootaddr + spl_size.
The region where dtb is present is marked reserved.
So when the tftp tries to load the Image it tries to find a location from loadaddr to the first reserved memory region which is the dtb base address. The max_size obtained is pretty less and hence tftp fails with the below error:
TFTP error: trying to overwrite reserved memory...
I don't quite get this. Are you saying that we load U-Boot to loadaddr, overwriting the SPL DT?
Simon,
No. Basically when we try to load kernel to bootaddr using tftp there is dtb present at bootaddr+spl_size and its marked as reserved. So TFTP fails. IMHO post relocation it should not be marked as reserved. Basically we will never be able to find enough space between bootaddr and dtb address for us to fit kernel Image and tftp will always fail for bootaddr.
Hope i am clear now.
It looks like this code was added from PowerPC by Kumar Gala galak@kernel.crashing.org, now copied.
3082d2348c fdt: refactor fdt resize code
I don't really understand why the tftp command is looking at reserved memory in the DT. Is this due to the recent improvements to enforce reserved memory that Simon Goldschmidt did?
The tftp command looks at reserved memory in the DT because in many situations, we have to prevent writing to that memory to prevent security issues where reserved memory gets overwritten before we have checked the signature of a loaded binary.
That being said, I don't really understand the boot flow and what's going wrong, could someone please explain this to me further?
Why is the region of the SPL dtb marked as reserved?
Regards, Simon
I'm sorry but I cannot really help with reviewing this. Perhaps Tom knows more.
Regards, Simon
Regards, Keerthy
Simon Goldschmidt, any thoughts?
Regards, Simon
Signed-off-by: Keerthy j-keerthy@ti.com
I am sure there are better solutions so just wanted to know if there is one.
common/fdt_support.c | 5 ----- 1 file changed, 5 deletions(-)
diff --git a/common/fdt_support.c b/common/fdt_support.c index 42583e3ed8..2bb101e56e 100644 --- a/common/fdt_support.c +++ b/common/fdt_support.c @@ -633,11 +633,6 @@ int fdt_shrink_to_minimum(void *blob, uint extrasize) /* Change the fdt header to reflect the correct size */ fdt_set_totalsize(blob, actualsize);
/* Add the new reservation */ret = fdt_add_mem_rsv(blob, map_to_sysmem(blob), actualsize);if (ret < 0)return ret;return actualsize;-- 2.17.1
participants (4)
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Keerthy -
keerthy
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Simon Glass -
Simon Goldschmidt