[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>

2 files changed, 64 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 9aac77ca3167..fddc9c13bff5 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/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;
 }
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 369e1a6cdd40..2ae860c306d7 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/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
          */