xtensa: make bootparam parsing optional

A kernel may not need any boot parameters from the bootloader, allow
disabling bootparam parsing in that case.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

3 files changed, 22 insertions, 1 deletions

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 44b20da404be..bc766b6b6344 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -473,6 +473,15 @@ config BUILTIN_DTB
         string "DTB to build into the kernel image"
         depends on OF
 
+config PARSE_BOOTPARAM
+        bool "Parse bootparam block"
+        default y
+        help
+          Parse parameters passed to the kernel from the bootloader. It may
+          be disabled if the kernel is known to run without the bootloader.
+
+          If unsure, say Y.
+
 config BLK_DEV_SIMDISK
         tristate "Host file-based simulated block device support"
         default n
diff --git a/arch/xtensa/boot/boot-elf/bootstrap.S b/arch/xtensa/boot/boot-elf/bootstrap.S
index b6aa85328ac0..718c99dcfe7a 100644
--- a/arch/xtensa/boot/boot-elf/bootstrap.S
+++ b/arch/xtensa/boot/boot-elf/bootstrap.S
@@ -42,7 +42,10 @@ RomInitAddr:
         .word   KERNELOFFSET
 #endif
 RomBootParam:
-        .word _bootparam
+#ifndef CONFIG_PARSE_BOOTPARAM
+        .word   0
+#else
+        .word   _bootparam
 _bootparam:
         .short  BP_TAG_FIRST
         .short  4
@@ -50,6 +53,7 @@ _bootparam:
         .short  BP_TAG_LAST
         .short  0
         .long   0
+#endif
 
         .align  4
 _SetupMMU:
diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index 41618788cc9e..351283b60df6 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -79,6 +79,7 @@ static char __initdata command_line[COMMAND_LINE_SIZE];
 static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
 #endif
 
+#ifdef CONFIG_PARSE_BOOTPARAM
 /*
  * Boot parameter parsing.
  *
@@ -176,6 +177,13 @@ static int __init parse_bootparam(const bp_tag_t* tag)
 
         return 0;
 }
+#else
+static int __init parse_bootparam(const bp_tag_t *tag)
+{
+        pr_info("Ignoring boot parameters at %p\n", tag);
+        return 0;
+}
+#endif
 
 #ifdef CONFIG_OF