From b68239ee746760bd99a68692f4c97a28f08a5d01 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 3 Feb 2006 19:05:47 +1100 Subject: [PATCH] [PATCH] powerpc: Don't overwrite flat device tree with kdump kernel It's possible for prom_init to allocate the flat device tree inside the kdump crash kernel region. If this happens, when we load the kdump kernel we overwrite the flattened device tree, which is bad. We could make prom_init try and avoid allocating inside the crash kernel region, but then we run into issues if the crash kernel region uses all the space inside the RMO. The easiest solution is to move the flat device tree once we're running in the kernel. Signed-off-by: Michael Ellerman Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/prom.c | 27 +++++++++++++++++++++++++++ arch/powerpc/kernel/setup_64.c | 3 +++ include/asm-powerpc/prom.h | 2 ++ 3 files changed, 32 insertions(+) diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index 535a33e4aa..2b062853bc 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -1922,3 +1922,30 @@ int prom_update_property(struct device_node *np, return 0; } + +#ifdef CONFIG_KEXEC +/* We may have allocated the flat device tree inside the crash kernel region + * in prom_init. If so we need to move it out into regular memory. */ +void kdump_move_device_tree(void) +{ + unsigned long start, end; + struct boot_param_header *new; + + start = __pa((unsigned long)initial_boot_params); + end = start + initial_boot_params->totalsize; + + if (end < crashk_res.start || start > crashk_res.end) + return; + + new = (struct boot_param_header*) + __va(lmb_alloc(initial_boot_params->totalsize, PAGE_SIZE)); + + memcpy(new, initial_boot_params, initial_boot_params->totalsize); + + initial_boot_params = new; + + DBG("Flat device tree blob moved to %p\n", initial_boot_params); + + /* XXX should we unreserve the old DT? */ +} +#endif /* CONFIG_KEXEC */ diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index e29b275e09..a717dff695 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -398,6 +398,9 @@ void __init setup_system(void) { DBG(" -> setup_system()\n"); +#ifdef CONFIG_KEXEC + kdump_move_device_tree(); +#endif /* * Unflatten the device-tree passed by prom_init or kexec */ diff --git a/include/asm-powerpc/prom.h b/include/asm-powerpc/prom.h index 5b2bd4eefb..cbd297f44c 100644 --- a/include/asm-powerpc/prom.h +++ b/include/asm-powerpc/prom.h @@ -222,5 +222,7 @@ extern int of_address_to_resource(struct device_node *dev, int index, extern int of_pci_address_to_resource(struct device_node *dev, int bar, struct resource *r); +extern void kdump_move_device_tree(void); + #endif /* __KERNEL__ */ #endif /* _POWERPC_PROM_H */ -- 2.39.5