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-rw-r--r--arch/x86_64/Kconfig61
1 files changed, 43 insertions, 18 deletions
diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index e9b4f058a49..145bb824b2a 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -415,13 +415,13 @@ config OUT_OF_LINE_PFN_TO_PAGE
depends on DISCONTIGMEM
config NR_CPUS
- int "Maximum number of CPUs (2-256)"
+ int "Maximum number of CPUs (2-255)"
range 2 255
depends on SMP
default "8"
help
This allows you to specify the maximum number of CPUs which this
- kernel will support. Current maximum is 256 CPUs due to
+ kernel will support. Current maximum is 255 CPUs due to
APIC addressing limits. Less depending on the hardware.
This is purely to save memory - each supported CPU requires
@@ -565,23 +565,56 @@ config CRASH_DUMP
PHYSICAL_START.
For more details see Documentation/kdump/kdump.txt
+config RELOCATABLE
+ bool "Build a relocatable kernel(EXPERIMENTAL)"
+ depends on EXPERIMENTAL
+ help
+ Builds a relocatable kernel. This enables loading and running
+ a kernel binary from a different physical address than it has
+ been compiled for.
+
+ One use is for the kexec on panic case where the recovery kernel
+ must live at a different physical address than the primary
+ kernel.
+
+ Note: If CONFIG_RELOCATABLE=y, then kernel run from the address
+ it has been loaded at and compile time physical address
+ (CONFIG_PHYSICAL_START) is ignored.
+
config PHYSICAL_START
hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
- default "0x1000000" if CRASH_DUMP
default "0x200000"
help
- This gives the physical address where the kernel is loaded. Normally
- for regular kernels this value is 0x200000 (2MB). But in the case
- of kexec on panic the fail safe kernel needs to run at a different
- address than the panic-ed kernel. This option is used to set the load
- address for kernels used to capture crash dump on being kexec'ed
- after panic. The default value for crash dump kernels is
- 0x1000000 (16MB). This can also be set based on the "X" value as
+ This gives the physical address where the kernel is loaded. It
+ should be aligned to 2MB boundary.
+
+ If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
+ bzImage will decompress itself to above physical address and
+ run from there. Otherwise, bzImage will run from the address where
+ it has been loaded by the boot loader and will ignore above physical
+ address.
+
+ In normal kdump cases one does not have to set/change this option
+ as now bzImage can be compiled as a completely relocatable image
+ (CONFIG_RELOCATABLE=y) and be used to load and run from a different
+ address. This option is mainly useful for the folks who don't want
+ to use a bzImage for capturing the crash dump and want to use a
+ vmlinux instead.
+
+ So if you are using bzImage for capturing the crash dump, leave
+ the value here unchanged to 0x200000 and set CONFIG_RELOCATABLE=y.
+ Otherwise if you plan to use vmlinux for capturing the crash dump
+ change this value to start of the reserved region (Typically 16MB
+ 0x1000000). In other words, it can be set based on the "X" value as
specified in the "crashkernel=YM@XM" command line boot parameter
passed to the panic-ed kernel. Typically this parameter is set as
crashkernel=64M@16M. Please take a look at
Documentation/kdump/kdump.txt for more details about crash dumps.
+ Usage of bzImage for capturing the crash dump is advantageous as
+ one does not have to build two kernels. Same kernel can be used
+ as production kernel and capture kernel.
+
Don't change this unless you know what you are doing.
config SECCOMP
@@ -627,14 +660,6 @@ config CC_STACKPROTECTOR_ALL
source kernel/Kconfig.hz
-config REORDER
- bool "Function reordering"
- default n
- help
- This option enables the toolchain to reorder functions for a more
- optimal TLB usage. If you have pretty much any version of binutils,
- this can increase your kernel build time by roughly one minute.
-
config K8_NB
def_bool y
depends on AGP_AMD64 || IOMMU || (PCI && NUMA)