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authorNicolas Pitre <nicolas.pitre@linaro.org>2011-02-21 06:57:33 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-02-23 16:14:25 +0000
commit3572bea8cbc57f0bef1e0f4580c01717df7026d8 (patch)
treeaa48782419dad9dbd005783ff7af349e980b1de4 /arch/arm/kernel/setup.c
parentdce72dd08c976c9e5e1367bf994b306b15ae87fe (diff)
ARM: 6748/1: ignore mdesc->boot_params if out of range
The initial MMU table created in head.S contains a 1 MB mapping at the start of memory to let the early kernel boot code access the boot params specified by mdesc->boot_params. When using CONFIG_ARM_PATCH_PHYS_VIRT it is possible for the kernel to have a different idea of where the start of memory is at run time, making the compile-time determined mdesc->boot_params pointing to a memory area which is not mapped. Any access to the boot params in that case will fault and silently hang the kernel at that point. It is therefore a better idea to simply ignore mdesc->boot_params in that case and give the kernel a chance to print some diagnostic on the console later. If the bootloader provides a valid pointer in r2 to the kernel then this is used instead of mdesc->boot_params, and an explicit mapping is already created in the initial MMU table for it. It is therefore a good idea to use that facility when using a relocated kernel. Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/setup.c')
-rw-r--r--arch/arm/kernel/setup.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 6ce80106316e..f43f041a0977 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -839,8 +839,25 @@ void __init setup_arch(char **cmdline_p)
if (__atags_pointer)
tags = phys_to_virt(__atags_pointer);
- else if (mdesc->boot_params)
- tags = phys_to_virt(mdesc->boot_params);
+ else if (mdesc->boot_params) {
+#ifdef CONFIG_MMU
+ /*
+ * We still are executing with a minimal MMU mapping created
+ * with the presumption that the machine default for this
+ * is located in the first MB of RAM. Anything else will
+ * fault and silently hang the kernel at this point.
+ */
+ if (mdesc->boot_params < PHYS_OFFSET ||
+ mdesc->boot_params >= PHYS_OFFSET + SZ_1M) {
+ printk(KERN_WARNING
+ "Default boot params at physical 0x%08lx out of reach\n",
+ mdesc->boot_params);
+ } else
+#endif
+ {
+ tags = phys_to_virt(mdesc->boot_params);
+ }
+ }
#if defined(CONFIG_DEPRECATED_PARAM_STRUCT)
/*