[POWERPC] pseries: phyp dump: Reserve and release memory

Initial patch for reserving memory in early boot, and freeing it
later.  If the previous boot had ended with a crash, the reserved
memory would contain a copy of the crashed kernel data.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index ff600ef0b4d6..e6c022ef12ee 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -51,6 +51,7 @@
 #include <asm/machdep.h>
 #include <asm/pSeries_reconfig.h>
 #include <asm/pci-bridge.h>
+#include <asm/phyp_dump.h>
 #include <asm/kexec.h>
 
 #ifdef DEBUG
@@ -1040,6 +1041,51 @@ static void __init early_reserve_mem(void)
 #endif
 }
 
+#ifdef CONFIG_PHYP_DUMP
+/**
+ * phyp_dump_reserve_mem() - reserve all not-yet-dumped mmemory
+ *
+ * This routine may reserve memory regions in the kernel only
+ * if the system is supported and a dump was taken in last
+ * boot instance or if the hardware is supported and the
+ * scratch area needs to be setup. In other instances it returns
+ * without reserving anything. The memory in case of dump being
+ * active is freed when the dump is collected (by userland tools).
+ */
+static void __init phyp_dump_reserve_mem(void)
+{
+        unsigned long base, size;
+        if (!phyp_dump_info->phyp_dump_configured) {
+                printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
+                return;
+        }
+
+        if (phyp_dump_info->phyp_dump_is_active) {
+                /* Reserve *everything* above RMR.Area freed by userland tools*/
+                base = PHYP_DUMP_RMR_END;
+                size = lmb_end_of_DRAM() - base;
+
+                /* XXX crashed_ram_end is wrong, since it may be beyond
+                 * the memory_limit, it will need to be adjusted. */
+                lmb_reserve(base, size);
+
+                phyp_dump_info->init_reserve_start = base;
+                phyp_dump_info->init_reserve_size = size;
+        } else {
+                size = phyp_dump_info->cpu_state_size +
+                        phyp_dump_info->hpte_region_size +
+                        PHYP_DUMP_RMR_END;
+                base = lmb_end_of_DRAM() - size;
+                lmb_reserve(base, size);
+                phyp_dump_info->init_reserve_start = base;
+                phyp_dump_info->init_reserve_size = size;
+        }
+}
+#else
+static inline void __init phyp_dump_reserve_mem(void) {}
+#endif /* CONFIG_PHYP_DUMP  && CONFIG_PPC_RTAS */
+
+
 void __init early_init_devtree(void *params)
 {
         DBG(" -> early_init_devtree(%p)\n", params);
@@ -1052,6 +1098,11 @@ void __init early_init_devtree(void *params)
         of_scan_flat_dt(early_init_dt_scan_rtas, NULL);
 #endif
 
+#ifdef CONFIG_PHYP_DUMP
+        /* scan tree to see if dump occured during last boot */
+        of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
+#endif
+
         /* Retrieve various informations from the /chosen node of the
          * device-tree, including the platform type, initrd location and
          * size, TCE reserve, and more ...
@@ -1072,6 +1123,7 @@ void __init early_init_devtree(void *params)
         reserve_kdump_trampoline();
         reserve_crashkernel();
         early_reserve_mem();
+        phyp_dump_reserve_mem();
 
         lmb_enforce_memory_limit(memory_limit);
         lmb_analyze();