[PATCH] powerpc: Parse crashkernel= parameter in first kernel

This patch adds code to parse and setup the crash kernel resource in the
first kernel. PPC64 ignores the @x part, we always run at 32 MB.
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/prom.c

@@ -29,6 +29,7 @@
 #include <linux/initrd.h>
 #include <linux/bitops.h>
 #include <linux/module.h>
+#include <linux/kexec.h>
 
 #include <asm/prom.h>
 #include <asm/rtas.h>
@@ -1198,6 +1199,16 @@ static int __init early_init_dt_scan_chosen(unsigned long node,
 	}
 #endif /* CONFIG_PPC_RTAS */
 
+#ifdef CONFIG_KEXEC
+       lprop = (u64*)of_get_flat_dt_prop(node, "linux,crashkernel-base", NULL);
+       if (lprop)
+               crashk_res.start = *lprop;
+
+       lprop = (u64*)of_get_flat_dt_prop(node, "linux,crashkernel-size", NULL);
+       if (lprop)
+               crashk_res.end = crashk_res.start + *lprop - 1;
+#endif
+
 	/* break now */
 	return 1;
 }

arch/powerpc/kernel/prom_init.c

@@ -192,6 +192,11 @@ static unsigned long __initdata alloc_bottom;
 static unsigned long __initdata rmo_top;
 static unsigned long __initdata ram_top;
 
+#ifdef CONFIG_KEXEC
+static unsigned long __initdata prom_crashk_base;
+static unsigned long __initdata prom_crashk_size;
+#endif
+
 static struct mem_map_entry __initdata mem_reserve_map[MEM_RESERVE_MAP_SIZE];
 static int __initdata mem_reserve_cnt;
 
@@ -590,6 +595,34 @@ static void __init early_cmdline_parse(void)
 		RELOC(prom_memory_limit) = ALIGN(RELOC(prom_memory_limit), 0x1000000);
 #endif
 	}
+
+#ifdef CONFIG_KEXEC
+	/*
+	 * crashkernel=size@addr specifies the location to reserve for
+	 * crash kernel.
+	 */
+	opt = strstr(RELOC(prom_cmd_line), RELOC("crashkernel="));
+	if (opt) {
+		opt += 12;
+		RELOC(prom_crashk_size) = prom_memparse(opt, &opt);
+
+		if (ALIGN(RELOC(prom_crashk_size), 0x1000000) !=
+			RELOC(prom_crashk_size)) {
+			prom_printf("Warning: crashkernel size is not "
+					"aligned to 16MB\n");
+		}
+
+		/*
+		 * At present, the crash kernel always run at 32MB.
+		 * Just ignore whatever user passed.
+		 */
+		RELOC(prom_crashk_base) = 0x2000000;
+		if (*opt == '@') {
+			prom_printf("Warning: PPC64 kdump kernel always runs "
+					"at 32 MB\n");
+		}
+	}
+#endif
 }
 
 #ifdef CONFIG_PPC_PSERIES
@@ -1011,6 +1044,12 @@ static void __init prom_init_mem(void)
 	prom_printf("  alloc_top_hi : %x\n", RELOC(alloc_top_high));
 	prom_printf("  rmo_top      : %x\n", RELOC(rmo_top));
 	prom_printf("  ram_top      : %x\n", RELOC(ram_top));
+#ifdef CONFIG_KEXEC
+	if (RELOC(prom_crashk_base)) {
+		prom_printf("  crashk_base  : %x\n",  RELOC(prom_crashk_base));
+		prom_printf("  crashk_size  : %x\n", RELOC(prom_crashk_size));
+	}
+#endif
 }
 
 
@@ -2094,6 +2133,10 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
 	 */
 	prom_init_mem();
 
+#ifdef CONFIG_KEXEC
+	if (RELOC(prom_crashk_base))
+		reserve_mem(RELOC(prom_crashk_base), RELOC(prom_crashk_size));
+#endif
 	/*
 	 * Determine which cpu is actually running right _now_
 	 */
@@ -2150,6 +2193,16 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
 	}
 #endif
 
+#ifdef CONFIG_KEXEC
+	if (RELOC(prom_crashk_base)) {
+		prom_setprop(_prom->chosen, "/chosen", "linux,crashkernel-base",
+			PTRRELOC(&prom_crashk_base),
+			sizeof(RELOC(prom_crashk_base)));
+		prom_setprop(_prom->chosen, "/chosen", "linux,crashkernel-size",
+			PTRRELOC(&prom_crashk_size),
+			sizeof(RELOC(prom_crashk_size)));
+	}
+#endif
 	/*
 	 * Fixup any known bugs in the device-tree
 	 */