[PATCH 0/2] FDT fixes for running on native Open Firmware

[PATCH 0/2] FDT fixes for running on native Open Firmware

[Sascha Silbe]

Two fixes for bugs in the FDT code I discovered while trying to get
the mainline kernel to run on OLPC XO-1.75. XOs are running Open
Firmware natively, not just passing down some blob.

Sascha Silbe (2):
  fdt: correctly handle uncompressed node names
  of: fdt: fix unflattening of FDTs containing uncompressed paths

 drivers/of/fdt.c            | 2 ++
 scripts/dtc/libfdt/fdt_ro.c | 3 +++
 2 files changed, 5 insertions(+)

-- 
2.11.0

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[PATCH 1/2] fdt: correctly handle uncompressed node names

[Sascha Silbe]

When handling uncompressed node names, we need to compare the last
component rather than the entire string.

Signed-off-by: Sascha Silbe <x-linux@infra-silbe.de>
---
 scripts/dtc/libfdt/fdt_ro.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/scripts/dtc/libfdt/fdt_ro.c b/scripts/dtc/libfdt/fdt_ro.c
index 3d00d2eee0e3..ca03ff87429c 100644
--- a/scripts/dtc/libfdt/fdt_ro.c
+++ b/scripts/dtc/libfdt/fdt_ro.c
@@ -64,6 +64,9 @@ static int _fdt_nodename_eq(const void *fdt, int offset,
 		/* short match */
 		return 0;
 
+	if (*p == '/')
+		/* Uncompressed node name. Only compare the last part. */
+		p = strrchr(p, '/') + 1;
 	if (memcmp(p, s, len) != 0)
 		return 0;
 
-- 
2.11.0

Re: [PATCH 1/2] fdt: correctly handle uncompressed node names

[kbuild test robot]

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Hi Sascha,

[auto build test ERROR on robh/for-next]
[also build test ERROR on v4.11 next-20170512]
[cannot apply to glikely/devicetree/next]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Sascha-Silbe/fdt-correctly-handle-uncompressed-node-names/20170513-184012
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
config: arm64-alldefconfig (attached as .config)
compiler: aarch64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm64 

All errors (new ones prefixed by >>):

   ./drivers/firmware/efi/libstub/lib.a(lib-fdt_ro.stub.o): In function `__efistub_fdt_subnode_offset_namelen':
>> __efistub_fdt_ro.c:(.init.text+0x248): undefined reference to `__efistub_strrchr'
   __efistub_fdt_ro.c:(.init.text+0x248): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__efistub_strrchr'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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Re: [PATCH 1/2] fdt: correctly handle uncompressed node names

[kbuild test robot]

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Hi Sascha,

[auto build test ERROR on robh/for-next]
[also build test ERROR on v4.11 next-20170512]
[cannot apply to glikely/devicetree/next]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Sascha-Silbe/fdt-correctly-handle-uncompressed-node-names/20170513-184012
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
config: arm-omap2plus_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm 

All errors (new ones prefixed by >>):

   arch/arm/boot/compressed/fdt_ro.o: In function `fdt_subnode_offset_namelen':
>> arch/arm/boot/compressed/fdt_ro.c:69: undefined reference to `strrchr'
>> arch/arm/boot/compressed/fdt_ro.o:(.debug_addr+0x364): undefined reference to `strrchr'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
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Re: [PATCH 1/2] fdt: correctly handle uncompressed node names

[Rob Herring]

On Sat, May 13, 2017 at 5:22 AM, Sascha Silbe <x-linux@infra-silbe.de> wrote:
> When handling uncompressed node names, we need to compare the last
> component rather than the entire string.
>
> Signed-off-by: Sascha Silbe <x-linux@infra-silbe.de>
> ---
>  scripts/dtc/libfdt/fdt_ro.c | 3 +++
>  1 file changed, 3 insertions(+)

This needs to be a patch against dtc, sent to devicetree-compiler list
and accepted there, then I can pick it up.

>
> diff --git a/scripts/dtc/libfdt/fdt_ro.c b/scripts/dtc/libfdt/fdt_ro.c
> index 3d00d2eee0e3..ca03ff87429c 100644
> --- a/scripts/dtc/libfdt/fdt_ro.c
> +++ b/scripts/dtc/libfdt/fdt_ro.c
> @@ -64,6 +64,9 @@ static int _fdt_nodename_eq(const void *fdt, int offset,
>                 /* short match */
>                 return 0;
>
> +       if (*p == '/')
> +               /* Uncompressed node name. Only compare the last part. */
> +               p = strrchr(p, '/') + 1;

However, you are changing behavior here that I'd guess has existed for
some time. This makes me suspicious that this is correct especially
when it is non-FDT DT you are trying to fix.

Given that 0-day reports an error with EFI stub, you also have to
consider if u-boot, barebox, grub, and all the other libfdt users
provide strrchr.

Rob

[PATCH 2/2] of: fdt: fix unflattening of FDTs containing uncompressed paths

[Sascha Silbe]

Probably since commit dfbd4c6eff35 ("drivers/of: Split
unflatten_dt_node()"), unflattening an FDT containing uncompressed
node names (e.g. "/gpio@d4019000/gpio@0") will abort after scanning
the root node because fpsize wasn't updated to include the path len.

Signed-off-by: Sascha Silbe <x-linux@infra-silbe.de>
---
 drivers/of/fdt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index e5ce4b59e162..2d5414e644b3 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -309,6 +309,8 @@ static unsigned int populate_node(const void *blob,
 			fpsize += l;
 			allocl = fpsize;
 		}
+	} else {
+		fpsize += allocl;
 	}
 
 	np = unflatten_dt_alloc(mem, sizeof(struct device_node) + allocl,
-- 
2.11.0