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>

48 files changed, 123 insertions, 38 deletions

diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug
index 23817bc..d2b88a0 100644
--- a/arch/mips/Kconfig.debug
+++ b/arch/mips/Kconfig.debug
@@ -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"
diff --git a/arch/mips/configs/ar7_defconfig b/arch/mips/configs/ar7_defconfig
index 1d5ec3c..5a5b6ba 100644
--- a/arch/mips/configs/ar7_defconfig
+++ b/arch/mips/configs/ar7_defconfig
@@ -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
diff --git a/arch/mips/configs/bcm47xx_defconfig b/arch/mips/configs/bcm47xx_defconfig
index 8715de1..267bd46 100644
--- a/arch/mips/configs/bcm47xx_defconfig
+++ b/arch/mips/configs/bcm47xx_defconfig
@@ -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
diff --git a/arch/mips/configs/bcm63xx_defconfig b/arch/mips/configs/bcm63xx_defconfig
index efa6598..7fee027 100644
--- a/arch/mips/configs/bcm63xx_defconfig
+++ b/arch/mips/configs/bcm63xx_defconfig
@@ -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
diff --git a/arch/mips/configs/bigsur_defconfig b/arch/mips/configs/bigsur_defconfig
index 1f0228d..c2f06e3 100644
--- a/arch/mips/configs/bigsur_defconfig
+++ b/arch/mips/configs/bigsur_defconfig
@@ -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
diff --git a/arch/mips/configs/capcella_defconfig b/arch/mips/configs/capcella_defconfig
index be81bf6..72b7e45 100644
--- a/arch/mips/configs/capcella_defconfig
+++ b/arch/mips/configs/capcella_defconfig
@@ -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
diff --git a/arch/mips/configs/cavium-octeon_defconfig b/arch/mips/configs/cavium-octeon_defconfig
index 22819d9..c8507bc 100644
--- a/arch/mips/configs/cavium-octeon_defconfig
+++ b/arch/mips/configs/cavium-octeon_defconfig
@@ -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
 
diff --git a/arch/mips/configs/cobalt_defconfig b/arch/mips/configs/cobalt_defconfig
index b150286..49e6131 100644
--- a/arch/mips/configs/cobalt_defconfig
+++ b/arch/mips/configs/cobalt_defconfig
@@ -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
diff --git a/arch/mips/configs/db1000_defconfig b/arch/mips/configs/db1000_defconfig
index 63cdea2..68e90cd 100644
--- a/arch/mips/configs/db1000_defconfig
+++ b/arch/mips/configs/db1000_defconfig
@@ -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
diff --git a/arch/mips/configs/db1100_defconfig b/arch/mips/configs/db1100_defconfig
index 7ae0f9a..9081283 100644
--- a/arch/mips/configs/db1100_defconfig
+++ b/arch/mips/configs/db1100_defconfig
@@ -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
diff --git a/arch/mips/configs/db1200_defconfig b/arch/mips/configs/db1200_defconfig
index a6d9e1f..dabf030 100644
--- a/arch/mips/configs/db1200_defconfig
+++ b/arch/mips/configs/db1200_defconfig
@@ -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
diff --git a/arch/mips/configs/db1500_defconfig b/arch/mips/configs/db1500_defconfig
index a3a462b..a151313 100644
--- a/arch/mips/configs/db1500_defconfig
+++ b/arch/mips/configs/db1500_defconfig
@@ -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
diff --git a/arch/mips/configs/db1550_defconfig b/arch/mips/configs/db1550_defconfig
index bfc962ed..6b64339 100644
--- a/arch/mips/configs/db1550_defconfig
+++ b/arch/mips/configs/db1550_defconfig
@@ -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
diff --git a/arch/mips/configs/decstation_defconfig b/arch/mips/configs/decstation_defconfig
index 7eb6d1b..cbb4d86 100644
--- a/arch/mips/configs/decstation_defconfig
+++ b/arch/mips/configs/decstation_defconfig
@@ -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
diff --git a/arch/mips/configs/e55_defconfig b/arch/mips/configs/e55_defconfig
index c6b1d6b..52968c4 100644
--- a/arch/mips/configs/e55_defconfig
+++ b/arch/mips/configs/e55_defconfig
@@ -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
diff --git a/arch/mips/configs/fuloong2e_defconfig b/arch/mips/configs/fuloong2e_defconfig
index 17341a0..a09dd03 100644
--- a/arch/mips/configs/fuloong2e_defconfig
+++ b/arch/mips/configs/fuloong2e_defconfig
@@ -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
diff --git a/arch/mips/configs/ip22_defconfig b/arch/mips/configs/ip22_defconfig
index 3471ac9..222d7ec 100644
--- a/arch/mips/configs/ip22_defconfig
+++ b/arch/mips/configs/ip22_defconfig
@@ -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
diff --git a/arch/mips/configs/ip27_defconfig b/arch/mips/configs/ip27_defconfig
index 26127a8..ed84b4c 100644
--- a/arch/mips/configs/ip27_defconfig
+++ b/arch/mips/configs/ip27_defconfig
@@ -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
diff --git a/arch/mips/configs/ip28_defconfig b/arch/mips/configs/ip28_defconfig
index ac6c850..dab2e5a 100644
--- a/arch/mips/configs/ip28_defconfig
+++ b/arch/mips/configs/ip28_defconfig
@@ -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
diff --git a/arch/mips/configs/ip32_defconfig b/arch/mips/configs/ip32_defconfig
index 56553b1..1841c88 100644
--- a/arch/mips/configs/ip32_defconfig
+++ b/arch/mips/configs/ip32_defconfig
@@ -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
diff --git a/arch/mips/configs/jazz_defconfig b/arch/mips/configs/jazz_defconfig
index 9db23fd..14c2ab3 100644
--- a/arch/mips/configs/jazz_defconfig
+++ b/arch/mips/configs/jazz_defconfig
@@ -1373,7 +1373,7 @@ 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
diff --git a/arch/mips/configs/jmr3927_defconfig b/arch/mips/configs/jmr3927_defconfig
index 11fec0e..4d66c44 100644
--- a/arch/mips/configs/jmr3927_defconfig
+++ b/arch/mips/configs/jmr3927_defconfig
@@ -834,7 +834,7 @@ 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
diff --git a/arch/mips/configs/lasat_defconfig b/arch/mips/configs/lasat_defconfig
index 2fe15a5..08d481e 100644
--- a/arch/mips/configs/lasat_defconfig
+++ b/arch/mips/configs/lasat_defconfig
@@ -797,7 +797,7 @@ CONFIG_MAGIC_SYSRQ=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
diff --git a/arch/mips/configs/lemote2f_defconfig b/arch/mips/configs/lemote2f_defconfig
index ddb1c92..b71a0a4 100644
--- a/arch/mips/configs/lemote2f_defconfig
+++ b/arch/mips/configs/lemote2f_defconfig
@@ -1707,7 +1707,7 @@ CONFIG_TRACING_SUPPORT=y
 # CONFIG_FTRACE is not set
 # CONFIG_SAMPLES is not set
 CONFIG_HAVE_ARCH_KGDB=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set
 
 #
 # Security options
diff --git a/arch/mips/configs/malta_defconfig b/arch/mips/configs/malta_defconfig
index 38d9873..d3c6012 100644
--- a/arch/mips/configs/malta_defconfig
+++ b/arch/mips/configs/malta_defconfig
@@ -1590,7 +1590,7 @@ CONFIG_FRAME_WARN=1024
 # 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
diff --git a/arch/mips/configs/markeins_defconfig b/arch/mips/configs/markeins_defconfig
index 9137571..6a325c0 100644
--- a/arch/mips/configs/markeins_defconfig
+++ b/arch/mips/configs/markeins_defconfig
@@ -1365,7 +1365,9 @@ 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="console=ttyS0,115200 mem=192m ip=bootp root=/dev/nfs rw"
+# CONFIG_CMDLINE_OVERRIDE is not set
 
 #
 # Security options
diff --git a/arch/mips/configs/mipssim_defconfig b/arch/mips/configs/mipssim_defconfig
index 513e9a4..f77a34e 100644
--- a/arch/mips/configs/mipssim_defconfig
+++ b/arch/mips/configs/mipssim_defconfig
@@ -634,7 +634,9 @@ CONFIG_FORCED_INLINING=y
 # CONFIG_RCU_TORTURE_TEST is not set
 # CONFIG_FAULT_INJECTION is not set
 CONFIG_CROSSCOMPILE=y
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="nfsroot=192.168.192.169:/u1/mipsel,timeo=20 ip=dhcp"
+# CONFIG_CMDLINE_OVERRIDE is not set
 # CONFIG_DEBUG_STACK_USAGE is not set
 # CONFIG_RUNTIME_DEBUG is not set
 
diff --git a/arch/mips/configs/mpc30x_defconfig b/arch/mips/configs/mpc30x_defconfig
index b893f9d..1720305 100644
--- a/arch/mips/configs/mpc30x_defconfig
+++ b/arch/mips/configs/mpc30x_defconfig
@@ -816,7 +816,9 @@ 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=ttyVR0,19200 ide0=0x170,0x376,73"
+# CONFIG_CMDLINE_OVERRIDE is not set
 
 #
 # Security options
diff --git a/arch/mips/configs/msp71xx_defconfig b/arch/mips/configs/msp71xx_defconfig
index 89d2b6a..000d185 100644
--- a/arch/mips/configs/msp71xx_defconfig
+++ b/arch/mips/configs/msp71xx_defconfig
@@ -1411,7 +1411,7 @@ CONFIG_FORCED_INLINING=y
 # CONFIG_RCU_TORTURE_TEST is not set
 # CONFIG_FAULT_INJECTION is not set
 CONFIG_CROSSCOMPILE=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set
 # CONFIG_DEBUG_STACK_USAGE is not set
 # CONFIG_RUNTIME_DEBUG is not set
 # CONFIG_MIPS_UNCACHED is not set
diff --git a/arch/mips/configs/mtx1_defconfig b/arch/mips/configs/mtx1_defconfig
index 3199668..144b94d 100644
--- a/arch/mips/configs/mtx1_defconfig
+++ b/arch/mips/configs/mtx1_defconfig
@@ -3017,7 +3017,7 @@ CONFIG_MAGIC_SYSRQ=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
diff --git a/arch/mips/configs/pb1100_defconfig b/arch/mips/configs/pb1100_defconfig
index c36e859..ddf67f6 100644
--- a/arch/mips/configs/pb1100_defconfig
+++ b/arch/mips/configs/pb1100_defconfig
@@ -1082,7 +1082,7 @@ 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
diff --git a/arch/mips/configs/pb1500_defconfig b/arch/mips/configs/pb1500_defconfig
index 4b43e36..5ec6083 100644
--- a/arch/mips/configs/pb1500_defconfig
+++ b/arch/mips/configs/pb1500_defconfig
@@ -1199,7 +1199,7 @@ 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
diff --git a/arch/mips/configs/pb1550_defconfig b/arch/mips/configs/pb1550_defconfig
index 7c8d351..6647642 100644
--- a/arch/mips/configs/pb1550_defconfig
+++ b/arch/mips/configs/pb1550_defconfig
@@ -1192,7 +1192,7 @@ 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
diff --git a/arch/mips/configs/pnx8335-stb225_defconfig b/arch/mips/configs/pnx8335-stb225_defconfig
index 77a75f0..848344d5 100644
--- a/arch/mips/configs/pnx8335-stb225_defconfig
+++ b/arch/mips/configs/pnx8335-stb225_defconfig
@@ -1033,7 +1033,7 @@ CONFIG_FRAME_WARN=1024
 # CONFIG_DEBUG_KERNEL is not set
 # CONFIG_SAMPLES is not set
 # CONFIG_KERNEL_TESTS is not set
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set
 
 #
 # Security options
diff --git a/arch/mips/configs/pnx8550-jbs_defconfig b/arch/mips/configs/pnx8550-jbs_defconfig
index 945b27e..9d721fd 100644
--- a/arch/mips/configs/pnx8550-jbs_defconfig
+++ b/arch/mips/configs/pnx8550-jbs_defconfig
@@ -1214,7 +1214,9 @@ CONFIG_DEBUG_MUTEXES=y
 CONFIG_FORCED_INLINING=y
 # CONFIG_RCU_TORTURE_TEST is not set
 CONFIG_CROSSCOMPILE=y
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyS1,38400n8 root=/dev/nfs ip=bootp"
+# CONFIG_CMDLINE_OVERRIDE is not set
 # CONFIG_DEBUG_STACK_USAGE is not set
 # CONFIG_RUNTIME_DEBUG is not set
 
diff --git a/arch/mips/configs/pnx8550-stb810_defconfig b/arch/mips/configs/pnx8550-stb810_defconfig
index ff0fc0b..ab07ec0 100644
--- a/arch/mips/configs/pnx8550-stb810_defconfig
+++ b/arch/mips/configs/pnx8550-stb810_defconfig
@@ -1204,7 +1204,9 @@ CONFIG_DEBUG_SLAB=y
 CONFIG_FORCED_INLINING=y
 # CONFIG_RCU_TORTURE_TEST is not set
 CONFIG_CROSSCOMPILE=y
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="console=ttyS1,38400n8 root=/dev/nfs ip=bootp"
+# CONFIG_CMDLINE_OVERRIDE is not set
 # CONFIG_DEBUG_STACK_USAGE is not set
 # CONFIG_RUNTIME_DEBUG is not set
 
diff --git a/arch/mips/configs/powertv_defconfig b/arch/mips/configs/powertv_defconfig
index 86c8007..7291633 100644
--- a/arch/mips/configs/powertv_defconfig
+++ b/arch/mips/configs/powertv_defconfig
@@ -1418,7 +1418,9 @@ CONFIG_BRANCH_PROFILE_NONE=y
 CONFIG_HAVE_ARCH_KGDB=y
 # CONFIG_KGDB is not set
 # CONFIG_KMEMCHECK is not set
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="rw dhash_entries=1024 ihash_entries=1024 ip=10.0.1.3:10.0.1.1:10.0.1.1:255.255.255.0:zeus:eth0: root=/dev/nfs nfsroot=/nfsroot/cramfs,wsize=512,rsize=512,tcp nokgdb console=ttyUSB0,115200 memsize=252M"
+# CONFIG_CMDLINE_OVERRIDE is not set
 # CONFIG_DEBUG_STACK_USAGE is not set
 # CONFIG_RUNTIME_DEBUG is not set
 
diff --git a/arch/mips/configs/rb532_defconfig b/arch/mips/configs/rb532_defconfig
index a9408db..57a5048 100644
--- a/arch/mips/configs/rb532_defconfig
+++ b/arch/mips/configs/rb532_defconfig
@@ -1203,7 +1203,7 @@ CONFIG_FRAME_WARN=1024
 # 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
diff --git a/arch/mips/configs/rbtx49xx_defconfig b/arch/mips/configs/rbtx49xx_defconfig
index 1c9a542..21c2022 100644
--- a/arch/mips/configs/rbtx49xx_defconfig
+++ b/arch/mips/configs/rbtx49xx_defconfig
@@ -1061,7 +1061,7 @@ 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
diff --git a/arch/mips/configs/rm200_defconfig b/arch/mips/configs/rm200_defconfig
index 5873fc5..7903628 100644
--- a/arch/mips/configs/rm200_defconfig
+++ b/arch/mips/configs/rm200_defconfig
@@ -1693,7 +1693,7 @@ 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
diff --git a/arch/mips/configs/sb1250-swarm_defconfig b/arch/mips/configs/sb1250-swarm_defconfig
index 5244716..7f07bf0 100644
--- a/arch/mips/configs/sb1250-swarm_defconfig
+++ b/arch/mips/configs/sb1250-swarm_defconfig
@@ -960,7 +960,7 @@ CONFIG_ENABLE_MUST_CHECK=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
 # CONFIG_SB1XXX_CORELIS is not set
 
 #
diff --git a/arch/mips/configs/tb0219_defconfig b/arch/mips/configs/tb0219_defconfig
index 937b47c..c54d112 100644
--- a/arch/mips/configs/tb0219_defconfig
+++ b/arch/mips/configs/tb0219_defconfig
@@ -891,7 +891,9 @@ CONFIG_FRAME_WARN=1024
 # CONFIG_HEADERS_CHECK is not set
 # CONFIG_DEBUG_KERNEL is not set
 # CONFIG_SAMPLES is not set
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="cca=3 mem=64M console=ttyVR0,115200 ip=any root=/dev/nfs"
+# CONFIG_CMDLINE_OVERRIDE is not set
 
 #
 # Security options
diff --git a/arch/mips/configs/tb0226_defconfig b/arch/mips/configs/tb0226_defconfig
index da73584..e7c5cd3 100644
--- a/arch/mips/configs/tb0226_defconfig
+++ b/arch/mips/configs/tb0226_defconfig
@@ -894,7 +894,9 @@ CONFIG_FRAME_WARN=1024
 # CONFIG_HEADERS_CHECK is not set
 # CONFIG_DEBUG_KERNEL is not set
 # CONFIG_SAMPLES is not set
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="cca=3 mem=32M console=ttyVR0,115200"
+# CONFIG_CMDLINE_OVERRIDE is not set
 
 #
 # Security options
diff --git a/arch/mips/configs/tb0287_defconfig b/arch/mips/configs/tb0287_defconfig
index 99a0d21..b50032b 100644
--- a/arch/mips/configs/tb0287_defconfig
+++ b/arch/mips/configs/tb0287_defconfig
@@ -1076,7 +1076,9 @@ CONFIG_FRAME_WARN=1024
 # CONFIG_HEADERS_CHECK is not set
 # CONFIG_DEBUG_KERNEL is not set
 # CONFIG_SAMPLES is not set
+CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE="cca=3 mem=64M console=ttyVR0,115200 ip=any root=/dev/nfs"
+# CONFIG_CMDLINE_OVERRIDE is not set
 
 #
 # Security options
diff --git a/arch/mips/configs/workpad_defconfig b/arch/mips/configs/workpad_defconfig
index d3646ea..c02ba08 100644
--- a/arch/mips/configs/workpad_defconfig
+++ b/arch/mips/configs/workpad_defconfig
@@ -754,7 +754,9 @@ 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=0x170,0x376,49 mem=16M"
+# CONFIG_CMDLINE_OVERRIDE is not set
 
 #
 # Security options
diff --git a/arch/mips/configs/wrppmc_defconfig b/arch/mips/configs/wrppmc_defconfig
index c137831..a35bc41 100644
--- a/arch/mips/configs/wrppmc_defconfig
+++ b/arch/mips/configs/wrppmc_defconfig
@@ -886,7 +886,9 @@ 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="console=ttyS0,115200n8"
+# CONFIG_CMDLINE_OVERRIDE is not set
 
 #
 # Security options
diff --git a/arch/mips/configs/yosemite_defconfig b/arch/mips/configs/yosemite_defconfig
index 4a04f0c..e3d68d6 100644
--- a/arch/mips/configs/yosemite_defconfig
+++ b/arch/mips/configs/yosemite_defconfig
@@ -823,7 +823,7 @@ CONFIG_DEBUG_MUTEXES=y
 CONFIG_FORCED_INLINING=y
 # CONFIG_RCU_TORTURE_TEST is not set
 CONFIG_CROSSCOMPILE=y
-CONFIG_CMDLINE=""
+# CONFIG_CMDLINE_BOOL is not set
 # CONFIG_DEBUG_STACK_USAGE is not set
 # CONFIG_RUNTIME_DEBUG is not set
 
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index bd55f71..f9513f9 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -58,8 +58,12 @@ EXPORT_SYMBOL(mips_machtype);
 
 struct boot_mem_map boot_mem_map;
 
-static char command_line[COMMAND_LINE_SIZE];
-       char arcs_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
+static char __initdata command_line[COMMAND_LINE_SIZE];
+char __initdata arcs_cmdline[COMMAND_LINE_SIZE];
+
+#ifdef CONFIG_CMDLINE_BOOL
+static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
+#endif
 
 /*
  * mips_io_port_base is the begin of the address space to which x86 style
@@ -458,8 +462,20 @@ static void __init arch_mem_init(char **cmdline_p)
 	pr_info("Determined physical RAM map:\n");
 	print_memory_map();
 
-	strlcpy(command_line, arcs_cmdline, sizeof(command_line));
-	strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
+#ifdef CONFIG_CMDLINE_BOOL
+#ifdef CONFIG_CMDLINE_OVERRIDE
+	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+#else
+	if (builtin_cmdline[0]) {
+		strlcat(arcs_cmdline, " ", COMMAND_LINE_SIZE);
+		strlcat(arcs_cmdline, builtin_cmdline, COMMAND_LINE_SIZE);
+	}
+	strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE);
+#endif
+#else
+	strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE);
+#endif
+	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
 
 	*cmdline_p = command_line;