[PATCH] drivers/of: Fix build warning in populate_node()

Gavin Shan
2016-05-13T11:32:23Z

Function populate_node() is used to unflatten FDT blob to device
tree. It supports maximal 64 level of device nodes. There is one
array @fpsizes[64] tracking the full name length of last unflattened
device node in the corresponding level (index of element in the
array - 1). Build warning is seen with CONFIG_FRAME_WARN=1024 like
below on ARM64 as Geert reported. The issue can be reproduced on
PPC64 as well.

$ make drivers/of/fdt.o
drivers/of/fdt.c:443:1: warning: the frame size of 1136 bytes is \
larger than 1024 bytes [-Wframe-larger-than=]

This changes the data type of @fpsizes[i] from "unsigned long" to
"unsigned int" to avoid the build warning. The return value type
of populate_node() and its @fpsize argument is adjusted accordingly.
With this applied, 256 bytes saved from the stack frame on ARM64 and
PPC64 platforms and the above warning isn't seen.

Fixes: 9ffa9eb ("drivers/of: Avoid recursively calling unflatten_dt_node()")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
drivers/of/fdt.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index c95054c..34344a8 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -264,13 +264,13 @@ static void populate_properties(const void *blob,
*pprev = NULL;
}

-static unsigned long populate_node(const void *blob,
- int offset,
- void **mem,
- struct device_node *dad,
- unsigned long fpsize,
- struct device_node **pnp,
- bool dryrun)
+static unsigned int populate_node(const void *blob,
+ int offset,
+ void **mem,
+ struct device_node *dad,
+ unsigned int fpsize,
+ struct device_node **pnp,
+ bool dryrun)
{
struct device_node *np;
const char *pathp;
@@ -397,7 +397,7 @@ static int unflatten_dt_nodes(const void *blob,
struct device_node *root;
int offset = 0, depth = 0;
#define FDT_MAX_DEPTH 64
- unsigned long fpsizes[FDT_MAX_DEPTH];
+ unsigned int fpsizes[FDT_MAX_DEPTH];
struct device_node *nps[FDT_MAX_DEPTH];
void *base = mem;
bool dryrun = !base;
--
2.1.0