[POWERPC] pseries: phyp dump: Disable phyp-dump through boot-var

This adds a kernel command line option "phyp_dump", which takes a 0/1
value for disabling/ enabling phyp_dump at boot time.  Kdump can use
this on cmdline (phyp_dump=0) to disable phyp-dump during boot when
enabling itself.  This will ensure only one dumping mechanism is active
at any given time.

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

3 files changed, 24 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index e6c022ef12ee..9330920265f3 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -1060,6 +1060,11 @@ static void __init phyp_dump_reserve_mem(void)
                 return;
         }
 
+        if (!phyp_dump_info->phyp_dump_at_boot) {
+                printk(KERN_INFO "Phyp-dump disabled at boot time\n");
+                return;
+        }
+
         if (phyp_dump_info->phyp_dump_is_active) {
                 /* Reserve *everything* above RMR.Area freed by userland tools*/
                 base = PHYP_DUMP_RMR_END;
diff --git a/arch/powerpc/platforms/pseries/phyp_dump.c b/arch/powerpc/platforms/pseries/phyp_dump.c
index 034fe1b54dd9..f80f8606c6b8 100644
--- a/arch/powerpc/platforms/pseries/phyp_dump.c
+++ b/arch/powerpc/platforms/pseries/phyp_dump.c
@@ -460,3 +460,21 @@ int __init early_init_dt_scan_phyp_dump(unsigned long node,
                                                 *((unsigned long *)&sizes[4]);
         return 1;
 }
+
+/* Look for phyp_dump= cmdline option */
+static int __init early_phyp_dump_enabled(char *p)
+{
+        phyp_dump_info->phyp_dump_at_boot = 1;
+
+        if (!p)
+                return 0;
+
+        if (strncmp(p, "1", 1) == 0)
+                phyp_dump_info->phyp_dump_at_boot = 1;
+        else if (strncmp(p, "0", 1) == 0)
+                phyp_dump_info->phyp_dump_at_boot = 0;
+
+        return 0;
+}
+early_param("phyp_dump", early_phyp_dump_enabled);
+
diff --git a/include/asm-powerpc/phyp_dump.h b/include/asm-powerpc/phyp_dump.h
index b454de45b2ca..209a98913d9d 100644
--- a/include/asm-powerpc/phyp_dump.h
+++ b/include/asm-powerpc/phyp_dump.h
@@ -25,6 +25,7 @@ struct phyp_dump {
         unsigned long init_reserve_start;
         unsigned long init_reserve_size;
         /* Check status during boot if dump supported, active & present*/
+        unsigned long phyp_dump_at_boot;
         unsigned long phyp_dump_configured;
         unsigned long phyp_dump_is_active;
         /* store cpu & hpte size */