MIPS: Fix and enhance built-in kernel command line

Currently, MIPS kernels silently overwrite kernel command-line parameters hardcoded in CONFIG_CMDLINE by the ones received from firmware. Therefore, using firmware remains the only reliable method to transfer the command-line parameters, which is not always desirable or convenient, and the CONFIG_CMDLINE option is thereby effectively rendered useless. This patch fixes the problem described above and introduces a more flexible scheme of handling the kernel command line, in a manner identical to what is currently used for x86. The default behavior, i.e. when CONFIG_CMDLINE_BOOL is not defined, retains the existing semantics, and firmware command-line arguments override the hardcoded ones. [Ralf: I fixed up all the defconfig files so the stay unaffected by this change.] Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com> Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/689/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2026-05-01 15:00:59 -07:00 · 2009-11-21 22:34:41 +02:00
parent de4148f3ef
commit 6acc7d485c
48 changed files with 123 additions and 38 deletions
@@ -20,15 +20,52 @@ config EARLY_PRINTK
 	  doesn't cooperate with an X server. You should normally say N here,
 	  unless you want to debug such a crash.

+config CMDLINE_BOOL
+	bool "Built-in kernel command line"
+	default n
+	help
+	  For most systems, it is firmware or second stage bootloader that
+	  by default specifies the kernel command line options.  However,
+	  it might be necessary or advantageous to either override the
+	  default kernel command line or add a few extra options to it.
+	  For such cases, this option allows you to hardcode your own
+	  command line options directly into the kernel.  For that, you
+	  should choose 'Y' here, and fill in the extra boot arguments
+	  in CONFIG_CMDLINE.
+
+	  The built-in options will be concatenated to the default command
+	  line if CMDLINE_OVERRIDE is set to 'N'. Otherwise, the default
+	  command line will be ignored and replaced by the built-in string.
+
+	  Most MIPS systems will normally expect 'N' here and rely upon
+	  the command line from the firmware or the second-stage bootloader.
+
 config CMDLINE
 	string "Default kernel command string"
+	depends on CMDLINE_BOOL
 	default ""
 	help
 	  On some platforms, there is currently no way for the boot loader to
-	  pass arguments to the kernel. For these platforms, you can supply
-	  some command-line options at build time by entering them here.  In
-	  other cases you can specify kernel args so that you don't have
-	  to set them up in board prom initialization routines.
+	  pass arguments to the kernel.  For these platforms, and for the cases
+	  when you want to add some extra options to the command line or ignore
+	  the default command line, you can supply some command-line options at
+	  build time by entering them here.  In other cases you can specify
+	  kernel args so that you don't have to set them up in board prom
+	  initialization routines.
+
+	  For more information, see the CMDLINE_BOOL and CMDLINE_OVERRIDE
+	  options.
+
+config CMDLINE_OVERRIDE
+	bool "Built-in command line overrides firware arguments"
+	default n
+	depends on CMDLINE_BOOL
+	help
+	  By setting this option to 'Y' you will have your kernel ignore
+	  command line arguments from firmware or second stage bootloader.
+	  Instead, the built-in command line will be used exclusively.
+
+	  Normally, you will choose 'N' here.

 config DEBUG_STACK_USAGE
 	bool "Enable stack utilization instrumentation"
@@ -1051,7 +1051,9 @@ CONFIG_TRACING_SUPPORT=y
 # CONFIG_DYNAMIC_DEBUG is not set
 # CONFIG_SAMPLES is not set
 CONFIG_HAVE_ARCH_KGDB=y
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="rootfstype=squashfs,jffs2"
+# CONFIG_CMDLINE_OVERRIDE is not set

 #
 # Security options
@@ -1852,7 +1852,7 @@ CONFIG_DEBUG_FS=y
 # CONFIG_HEADERS_CHECK is not set
 # CONFIG_DEBUG_KERNEL is not set
 # CONFIG_SAMPLES is not set
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -941,7 +941,9 @@ CONFIG_TRACING_SUPPORT=y
 # CONFIG_BLK_DEV_IO_TRACE is not set
 # CONFIG_SAMPLES is not set
 CONFIG_HAVE_ARCH_KGDB=y
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyS0,115200"
+# CONFIG_CMDLINE_OVERRIDE is not set

 #
 # Security options
@@ -1236,7 +1236,7 @@ CONFIG_DEBUG_MUTEXES=y
 # CONFIG_BACKTRACE_SELF_TEST is not set
 # CONFIG_FAULT_INJECTION is not set
 # CONFIG_SAMPLES is not set
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set
 # CONFIG_DEBUG_STACK_USAGE is not set
 # CONFIG_SB1XXX_CORELIS is not set
 # CONFIG_RUNTIME_DEBUG is not set
@@ -782,7 +782,9 @@ CONFIG_ENABLE_MUST_CHECK=y
 # CONFIG_HEADERS_CHECK is not set
 # CONFIG_DEBUG_KERNEL is not set
 CONFIG_CROSSCOMPILE=y
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="mem=32M console=ttyVR0,38400"
+# CONFIG_CMDLINE_OVERRIDE is not set

 #
 # Security options
@@ -820,7 +820,7 @@ CONFIG_SYSCTL_SYSCALL_CHECK=y
 # CONFIG_SAMPLES is not set
 CONFIG_HAVE_ARCH_KGDB=y
 # CONFIG_KGDB is not set
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set
 # CONFIG_DEBUG_STACK_USAGE is not set
 # CONFIG_RUNTIME_DEBUG is not set

@@ -1125,7 +1125,7 @@ CONFIG_FRAME_WARN=1024
 # CONFIG_SLUB_STATS is not set
 # CONFIG_DEBUG_MEMORY_INIT is not set
 # CONFIG_SAMPLES is not set
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -1089,7 +1089,7 @@ CONFIG_ENABLE_MUST_CHECK=y
 # CONFIG_DEBUG_KERNEL is not set
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_CROSSCOMPILE=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -1089,7 +1089,7 @@ CONFIG_ENABLE_MUST_CHECK=y
 # CONFIG_DEBUG_KERNEL is not set
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_CROSSCOMPILE=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -1171,7 +1171,9 @@ CONFIG_ENABLE_MUST_CHECK=y
 # CONFIG_DEBUG_KERNEL is not set
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_CROSSCOMPILE=y
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="mem=48M"
+# CONFIG_CMDLINE_OVERRIDE is not set

 #
 # Security options
@@ -1389,7 +1389,7 @@ CONFIG_ENABLE_MUST_CHECK=y
 # CONFIG_DEBUG_KERNEL is not set
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_CROSSCOMPILE=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -1206,7 +1206,7 @@ CONFIG_ENABLE_MUST_CHECK=y
 # CONFIG_DEBUG_KERNEL is not set
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_CROSSCOMPILE=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -881,7 +881,7 @@ CONFIG_MAGIC_SYSRQ=y
 # CONFIG_DEBUG_KERNEL is not set
 CONFIG_LOG_BUF_SHIFT=14
 CONFIG_CROSSCOMPILE=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -560,7 +560,9 @@ CONFIG_ENABLE_MUST_CHECK=y
 # CONFIG_HEADERS_CHECK is not set
 # CONFIG_DEBUG_KERNEL is not set
 CONFIG_CROSSCOMPILE=y
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyVR0,19200 ide0=0x1f0,0x3f6,40 mem=8M"
+# CONFIG_CMDLINE_OVERRIDE is not set

 #
 # Security options
@@ -1710,7 +1710,7 @@ CONFIG_TRACING_SUPPORT=y
 # CONFIG_DYNAMIC_DEBUG is not set
 # CONFIG_SAMPLES is not set
 CONFIG_HAVE_ARCH_KGDB=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -1187,7 +1187,7 @@ CONFIG_DEBUG_MEMORY_INIT=y
 CONFIG_DYNAMIC_PRINTK_DEBUG=y
 # CONFIG_SAMPLES is not set
 CONFIG_HAVE_ARCH_KGDB=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -939,7 +939,7 @@ CONFIG_ENABLE_MUST_CHECK=y
 # CONFIG_HEADERS_CHECK is not set
 # CONFIG_DEBUG_KERNEL is not set
 CONFIG_CROSSCOMPILE=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -815,7 +815,7 @@ CONFIG_MAGIC_SYSRQ=y
 # CONFIG_HEADERS_CHECK is not set
 # CONFIG_DEBUG_KERNEL is not set
 # CONFIG_SAMPLES is not set
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
@@ -1125,7 +1125,7 @@ CONFIG_SYSCTL_SYSCALL_CHECK=y
 # CONFIG_DYNAMIC_PRINTK_DEBUG is not set
 # CONFIG_SAMPLES is not set
 CONFIG_HAVE_ARCH_KGDB=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set

 #
 # Security options
--- a/Show More
+++ b/Show More