ARM: 6116/1: kdump: reserve memory for crashkernel

Implemented ARM support for command line option
"crashkernel=size@start" which allows user to reserve some memory
for a dump capture kernel.

Signed-off-by: Mika Westerberg <ext-mika.1.westerberg@nokia.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 51 insertions, 0 deletions

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 648c3c1e16c4..714cbaaab3aa 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -19,6 +19,7 @@
 #include <linux/seq_file.h>
 #include <linux/screen_info.h>
 #include <linux/init.h>
+#include <linux/kexec.h>
 #include <linux/root_dev.h>
 #include <linux/cpu.h>
 #include <linux/interrupt.h>
@@ -680,6 +681,55 @@ static int __init customize_machine(void)
 }
 arch_initcall(customize_machine);
 
+#ifdef CONFIG_KEXEC
+static inline unsigned long long get_total_mem(void)
+{
+        unsigned long total;
+
+        total = max_low_pfn - min_low_pfn;
+        return total << PAGE_SHIFT;
+}
+
+/**
+ * reserve_crashkernel() - reserves memory are for crash kernel
+ *
+ * This function reserves memory area given in "crashkernel=" kernel command
+ * line parameter. The memory reserved is used by a dump capture kernel when
+ * primary kernel is crashing.
+ */
+static void __init reserve_crashkernel(void)
+{
+        unsigned long long crash_size, crash_base;
+        unsigned long long total_mem;
+        int ret;
+
+        total_mem = get_total_mem();
+        ret = parse_crashkernel(boot_command_line, total_mem,
+                                &crash_size, &crash_base);
+        if (ret)
+                return;
+
+        ret = reserve_bootmem(crash_base, crash_size, BOOTMEM_EXCLUSIVE);
+        if (ret < 0) {
+                printk(KERN_WARNING "crashkernel reservation failed - "
+                       "memory is in use (0x%lx)\n", (unsigned long)crash_base);
+                return;
+        }
+
+        printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
+               "for crashkernel (System RAM: %ldMB)\n",
+               (unsigned long)(crash_size >> 20),
+               (unsigned long)(crash_base >> 20),
+               (unsigned long)(total_mem >> 20));
+
+        crashk_res.start = crash_base;
+        crashk_res.end = crash_base + crash_size - 1;
+        insert_resource(&iomem_resource, &crashk_res);
+}
+#else
+static inline void reserve_crashkernel(void) {}
+#endif /* CONFIG_KEXEC */
+
 void __init setup_arch(char **cmdline_p)
 {
         struct tag *tags = (struct tag *)&init_tags;
@@ -739,6 +789,7 @@ void __init setup_arch(char **cmdline_p)
 #ifdef CONFIG_SMP
         smp_init_cpus();
 #endif
+        reserve_crashkernel();
 
         cpu_init();
         tcm_init();