kernel.git/arch/powerpc/kernel/prom.c, branch linux-2.6.28.y

powerpc: Make the 64-bit kernel as a position-independent executable

2008-09-15T18:08:38Z

This implements CONFIG_RELOCATABLE for 64-bit by making the kernel as a position-independent executable (PIE) when it is set. This involves processing the dynamic relocations in the image in the early stages of booting, even if the kernel is being run at the address it is linked at, since the linker does not necessarily fill in words in the image for which there are dynamic relocations. (In fact the linker does fill in such words for 64-bit executables, though not for 32-bit executables, so in principle we could avoid calling relocate() entirely when we're running a 64-bit kernel at the linked address.) The dynamic relocations are processed by a new function relocate(addr), where the addr parameter is the virtual address where the image will be run. In fact we call it twice; once before calling prom_init, and again when starting the main kernel. This means that reloc_offset() returns 0 in prom_init (since it has been relocated to the address it is running at), which necessitated a few adjustments. This also changes __va and __pa to use an equivalent definition that is simpler. With the relocatable kernel, PAGE_OFFSET and MEMORY_START are constants (for 64-bit) whereas PHYSICAL_START is a variable (and KERNELBASE ideally should be too, but isn't yet). With this, relocatable kernels still copy themselves down to physical address 0 and run there. Signed-off-by: Paul Mackerras

powerpc: Add support for dynamic reconfiguration memory in kexec/kdump kernels

2008-09-15T18:07:58Z

Kdump kernel needs to use only those memory regions that it is allowed to use (crashkernel, rtas, tce, etc.). Each of these regions have their own sizes and are currently added under 'linux,usable-memory' property under each memory@xxx node of the device tree. The ibm,dynamic-memory property of ibm,dynamic-reconfiguration-memory node (on POWER6) now stores in it the representation for most of the logical memory blocks with the size of each memory block being a constant (lmb_size). If one or more or part of the above mentioned regions lie under one of the lmb from ibm,dynamic-memory property, there is a need to identify those regions within the given lmb. This makes the kernel recognize a new 'linux,drconf-usable-memory' property added by kexec-tools. Each entry in this property is of the form of a count followed by that many (base, size) pairs for the above mentioned regions. The number of cells in the count value is given by the #size-cells property of the root node. Signed-off-by: Chandru Siddalingappa Signed-off-by: Paul Mackerras

powerpc: Add VSX CPU feature

2008-07-01T01:28:47Z

Add a VSX CPU feature. Also add code to detect if VSX is available from the device tree. Signed-off-by: Michael Neuling Signed-off-by: Joel Schopp Signed-off-by: Paul Mackerras

[POWERPC] 85xx: Add support for relocatable kernel (and booting at non-zero)

2008-04-24T10:58:01Z

Added support to allow an 85xx kernel to be run from a non-zero physical address (useful for cooperative asymmetric multiprocessing situations and kdump). The support can be configured at compile time by setting CONFIG_PAGE_OFFSET, CONFIG_KERNEL_START, and CONFIG_PHYSICAL_START as desired. Alternatively, the kernel build can set CONFIG_RELOCATABLE. Setting this config option causes the kernel to determine at runtime the physical addresses of CONFIG_PAGE_OFFSET and CONFIG_KERNEL_START. If CONFIG_RELOCATABLE is set, then CONFIG_PHYSICAL_START has no meaning. However, CONFIG_PHYSICAL_START will always be used to set the LOAD program header physical address field in the resulting ELF image. Currently we are limited to running at a physical address that is a multiple of 256M. This is due to how we map TLBs to cover lowmem. This should be fixed to allow 64M or maybe even 16M alignment in the future. It is considered an error to try and run a kernel at a non-aligned physical address. All the magic for this support is accomplished by proper initialization of the kernel memory subsystem and use of ARCH_PFN_OFFSET. The use of ARCH_PFN_OFFSET only affects normal memory and not IO mappings. ioremap uses map_page and isn't affected by ARCH_PFN_OFFSET. /dev/mem continues to allow access to any physical address in the system regardless of how CONFIG_PHYSICAL_START is set. Signed-off-by: Kumar Gala Signed-off-by: Paul Mackerras

[POWERPC] Fix device-tree locking vs. interrupts

2008-04-18T05:37:16Z

Lockdep found out that we can occasionally take the device-tree lock for reading from softirq time (from rtas_token called by the rtas real time clock code called by the NTP code), while we take it occasionally for writing without masking interrupts. The combination of those two can thus deadlock. While some of those cases of interrupt read lock could be fixed (such as caching the RTAS tokens) I figured that taking the lock for writing is so rare (device-tree modification) that we may as well penalize that case and allow reading from interrupts. Thus, this turns all the writers to take the lock with irqs masked to avoid the situation. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras

[POWERPC] pseries/phyp dump: Reserve a variable amount of space at boot

2008-04-16T21:46:14Z

This changes the way we calculate how much space to reserve for the pHyp dump. Currently we reserve 256MB only. With this change, the code first checks to see if an amount has been specified on the boot command line with the "phyp_dump_reserve_size" option, and if so, uses that much. Otherwise it computes 5% of total ram and rounds it down to a multiple of 256MB, and uses the larger of that or 256MB. This is for large systems with a lot of memory (10GB or more). The aim is to have more space available for the kernel on reboot on machines with more resources. Although the dump will be collected pretty fast and the memory released really early on allowing the machine to have the full memory available, this alleviates any issues that can be caused by having way too little memory on very very large systems during those few minutes. Signed-off-by: Manish Ahuja Signed-off-by: Paul Mackerras

[POWERPC] move_device_tree() should be __init

2008-04-01T09:43:08Z

WARNING: vmlinux.o(.text+0x1e4c0): Section mismatch in reference from the function .move_device_tree() to the function .init.text:.lmb_alloc_base() The function .move_device_tree() references the function __init .lmb_alloc_base(). This is often because .move_device_tree lacks a __init annotation or the annotation of .lmb_alloc_base is wrong. move_device_tree() is called from early_init_devtree() only, which is __init Signed-off-by: Geert Uytterhoeven Signed-off-by: Paul Mackerras

[POWERPC] pseries: phyp dump: Disable phyp-dump through boot-var

2008-03-25T21:44:07Z

This adds a kernel command line option "phyp_dump", which takes a 0/1 value for disabling/ enabling phyp_dump at boot time. Kdump can use this on cmdline (phyp_dump=0) to disable phyp-dump during boot when enabling itself. This will ensure only one dumping mechanism is active at any given time. Signed-off-by: Manish Ahuja Signed-off-by: Paul Mackerras

[POWERPC] pseries: phyp dump: Reserve and release memory

2008-03-25T21:44:06Z

Initial patch for reserving memory in early boot, and freeing it later. If the previous boot had ended with a crash, the reserved memory would contain a copy of the crashed kernel data. Signed-off-by: Manish Ahuja Signed-off-by: Linas Vepstas Signed-off-by: Paul Mackerras

Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/lmb-2.6

2008-02-26T10:08:45Z