From d9c93813ac17b34ee6eb7a424578acae6f90d759 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 2 May 2007 19:27:05 +0200 Subject: [PATCH] x86-64: Correct max number of CPUs in Kconfig Pointed out by Adrian Bunk Signed-off-by: Andi Kleen --- arch/x86_64/Kconfig | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86_64/Kconfig') diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig index 56eb14c98475..b3dbf11eb82c 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 -- cgit v1.2.2 From 1ab60e0f72f71ec54831e525a3e1154f1c092408 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Wed, 2 May 2007 19:27:07 +0200 Subject: [PATCH] x86-64: Relocatable Kernel Support This patch modifies the x86_64 kernel so that it can be loaded and run at any 2M aligned address, below 512G. The technique used is to compile the decompressor with -fPIC and modify it so the decompressor is fully relocatable. For the main kernel the page tables are modified so the kernel remains at the same virtual address. In addition a variable phys_base is kept that holds the physical address the kernel is loaded at. __pa_symbol is modified to add that when we take the address of a kernel symbol. When loaded with a normal bootloader the decompressor will decompress the kernel to 2M and it will run there. This both ensures the relocation code is always working, and makes it easier to use 2M pages for the kernel and the cpu. AK: changed to not make RELOCATABLE default in Kconfig Signed-off-by: Eric W. Biederman Signed-off-by: Vivek Goyal Signed-off-by: Andi Kleen --- arch/x86_64/Kconfig | 49 +++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 41 insertions(+), 8 deletions(-) (limited to 'arch/x86_64/Kconfig') diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig index b3dbf11eb82c..715632026073 100644 --- a/arch/x86_64/Kconfig +++ b/arch/x86_64/Kconfig @@ -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 -- cgit v1.2.2 From 2136220d00d84e5dd923f23552f75b1864a76f21 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 2 May 2007 19:27:21 +0200 Subject: [PATCH] x86-64: Remove CONFIG_REORDER The option never worked well and functionlist wasn't well maintained. Also it made the build very slow on many binutils version. So just remove it. Cc: arjan@linux.intel.com Signed-off-by: Andi Kleen --- arch/x86_64/Kconfig | 8 -------- 1 file changed, 8 deletions(-) (limited to 'arch/x86_64/Kconfig') diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig index 715632026073..1cad418373c3 100644 --- a/arch/x86_64/Kconfig +++ b/arch/x86_64/Kconfig @@ -660,14 +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) -- cgit v1.2.2