powerpc/mm/radix: Update command line parsing for disable_radix

kernel parameter disable_radix takes different options
disable_radix=yes|no|1|0  or just disable_radix.

prom_init parsing is not supporting these options.

Fixes: 1fd6c0220710 ("powerpc/mm: Add a CONFIG option to choose if radix is used by default")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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 prom_radix_disable __initdata = !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 = false;
+			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)

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."