[RFC PATCH] powerpc/mm/radix: Parse disable_radix commandline correctly.

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

kernel parameter disable_radix takes different options
disable_radix=yes|no|1|0  or just disable_radix. When using the later format
we get below error.

 `Malformed early option 'disable_radix'`

We also update the command line parsing in prom_init to handle the new format.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/prom_init.c        | 16 +++++++++++++---
 arch/powerpc/kernel/prom_init_check.sh |  2 +-
 arch/powerpc/mm/init_64.c              |  2 +-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index d22c41c26bb3..77735a7655ee 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -171,7 +171,7 @@ static unsigned long __initdata prom_tce_alloc_start;
 static unsigned long __initdata prom_tce_alloc_end;
 #endif
 
-static bool __initdata prom_radix_disable;
+static bool __initdata prom_radix_disable = !IS_ENABLED(CONFIG_PPC_RADIX_MMU_DEFAULT); 
 
 struct platform_support {
 	bool hash_mmu;
@@ -641,9 +641,19 @@ static void __init early_cmdline_parse(void)
 
 	opt = strstr(prom_cmd_line, "disable_radix");
 	if (opt) {
-		prom_debug("Radix disabled from cmdline\n");
-		prom_radix_disable = true;
+		opt += 13;
+		if (*opt && *opt == '=') {
+			bool val;
+
+			if (kstrtobool(++opt, &val))
+				prom_radix_disable = true;
+			else
+				prom_radix_disable = val;
+		} else
+			prom_radix_disable = true;
 	}
+	if (prom_radix_disable)
+		prom_debug("Radix disabled from cmdline\n");
 }
 
 #if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh
index 12640f7e726b..acb6b9226352 100644
--- a/arch/powerpc/kernel/prom_init_check.sh
+++ b/arch/powerpc/kernel/prom_init_check.sh
@@ -19,7 +19,7 @@
 WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
 _end enter_prom memcpy memset reloc_offset __secondary_hold
 __secondary_hold_acknowledge __secondary_hold_spinloop __start
-strcmp strcpy strlcpy strlen strncmp strstr logo_linux_clut224
+strcmp strcpy strlcpy strlen strncmp strstr kstrtobool logo_linux_clut224
 reloc_got2 kernstart_addr memstart_addr linux_banner _stext
 __prom_init_toc_start __prom_init_toc_end btext_setup_display TOC."
 
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 63470b06c502..51ce091914f9 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -366,7 +366,7 @@ static int __init parse_disable_radix(char *p)
 {
 	bool val;
 
-	if (strlen(p) == 0)
+	if (!p)
 		val = true;
 	else if (kstrtobool(p, &val))
 		return -EINVAL;
-- 
2.14.3