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of/flattree: Make unflatten_device_tree() safe to call from any arch
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This patch makes unflatten_device_tree() safe to call from any arch
setup code with the following changes:
- Make sure initial_boot_params actually points to a device tree blob
  before unflattening
- Make sure the initial_boot_params->magic field is correct
- If CONFIG_OF_FLATTREE is not set, then make unflatten_device_tree()
  an empty static inline function.

This patch also adds some additional debug output to the top of
unflatten_device_tree().

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
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Grant Likely committed Apr 29, 2010
1 parent cf32eb8 commit 8bfe9b5
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Showing 2 changed files with 17 additions and 0 deletions.
15 changes: 15 additions & 0 deletions drivers/of/fdt.c
Original file line number Diff line number Diff line change
Expand Up @@ -556,6 +556,21 @@ void __init unflatten_device_tree(void)

pr_debug(" -> unflatten_device_tree()\n");

if (!initial_boot_params) {
pr_debug("No device tree pointer\n");
return;
}

pr_debug("Unflattening device tree:\n");
pr_debug("magic: %08x\n", be32_to_cpu(initial_boot_params->magic));
pr_debug("size: %08x\n", be32_to_cpu(initial_boot_params->totalsize));
pr_debug("version: %08x\n", be32_to_cpu(initial_boot_params->version));

if (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER) {
pr_err("Invalid device tree blob header\n");
return;
}

/* First pass, scan for size */
start = ((unsigned long)initial_boot_params) +
be32_to_cpu(initial_boot_params->off_dt_struct);
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2 changes: 2 additions & 0 deletions include/linux/of_fdt.h
Original file line number Diff line number Diff line change
Expand Up @@ -99,6 +99,8 @@ extern int early_init_dt_scan_root(unsigned long node, const char *uname,
/* Other Prototypes */
extern void unflatten_device_tree(void);
extern void early_init_devtree(void *);
#else /* CONFIG_OF_FLATTREE */
static inline void unflatten_device_tree(void) {}
#endif /* CONFIG_OF_FLATTREE */

#endif /* __ASSEMBLY__ */
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