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-rw-r--r--arch/x86/include/asm/crash.h6
-rw-r--r--arch/x86/kernel/crash.c15
-rw-r--r--arch/x86/realmode/init.c2
3 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/include/asm/crash.h b/arch/x86/include/asm/crash.h
index ef5638f641f2..88eadd08ad70 100644
--- a/arch/x86/include/asm/crash.h
+++ b/arch/x86/include/asm/crash.h
@@ -10,4 +10,10 @@ int crash_setup_memmap_entries(struct kimage *image,
struct boot_params *params);
void crash_smp_send_stop(void);
+#ifdef CONFIG_KEXEC_CORE
+void __init crash_reserve_low_1M(void);
+#else
+static inline void __init crash_reserve_low_1M(void) { }
+#endif
+
#endif /* _ASM_X86_CRASH_H */
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index eb651fbde92a..ff25a2ea271c 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -24,6 +24,7 @@
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
+#include <linux/memblock.h>
#include <asm/processor.h>
#include <asm/hardirq.h>
@@ -39,6 +40,7 @@
#include <asm/virtext.h>
#include <asm/intel_pt.h>
#include <asm/crash.h>
+#include <asm/cmdline.h>
/* Used while preparing memory map entries for second kernel */
struct crash_memmap_data {
@@ -68,6 +70,19 @@ static inline void cpu_crash_vmclear_loaded_vmcss(void)
rcu_read_unlock();
}
+/*
+ * When the crashkernel option is specified, only use the low
+ * 1M for the real mode trampoline.
+ */
+void __init crash_reserve_low_1M(void)
+{
+ if (cmdline_find_option(boot_command_line, "crashkernel", NULL, 0) < 0)
+ return;
+
+ memblock_reserve(0, 1<<20);
+ pr_info("Reserving the low 1M of memory for crashkernel\n");
+}
+
#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 7dce39c8c034..262f83cad355 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -8,6 +8,7 @@
#include <asm/pgtable.h>
#include <asm/realmode.h>
#include <asm/tlbflush.h>
+#include <asm/crash.h>
struct real_mode_header *real_mode_header;
u32 *trampoline_cr4_features;
@@ -34,6 +35,7 @@ void __init reserve_real_mode(void)
memblock_reserve(mem, size);
set_real_mode_mem(mem);
+ crash_reserve_low_1M();
}
static void __init setup_real_mode(void)