kernel.git/arch/powerpc/kernel/paca.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: Make it possible to move the interrupt handlers away from the kernel

2008-09-15T18:08:08Z

This changes the way that the exception prologs transfer control to the handlers in 64-bit kernels with the aim of making it possible to have the prologs separate from the main body of the kernel. Now, instead of computing the address of the handler by taking the top 32 bits of the paca address (to get the 0xc0000000........ part) and ORing in something in the bottom 16 bits, we get the base address of the kernel by doing a load from the paca and add an offset. This also replaces an mfmsr and an ori to compute the MSR value for the handler with a load from the paca. That makes it unnecessary to have a separate version of EXCEPTION_PROLOG_PSERIES that forces 64-bit mode. We can no longer use a direct branches in the exception prolog code, which means that the SLB miss handlers can't branch directly to .slb_miss_realmode any more. Instead we have to compute the address and do an indirect branch. This is conditional on CONFIG_RELOCATABLE; for non-relocatable kernels we use a direct branch as before. (A later change will allow CONFIG_RELOCATABLE to be set on 64-bit powerpc.) Since the secondary CPUs on pSeries start execution in the first 0x100 bytes of real memory and then have to get to wherever the kernel is, we can't use a direct branch to get there. Instead this changes __secondary_hold_spinloop from a flag to a function pointer. When it is set to a non-NULL value, the secondary CPUs jump to the function pointed to by that value. Finally this eliminates one code difference between 32-bit and 64-bit by making __secondary_hold be the text address of the secondary CPU spinloop rather than a function descriptor for it. Signed-off-by: Paul Mackerras

[POWERPC] Raise the upper limit of NR_CPUS and move the pacas into the BSS

2008-04-24T10:58:04Z

This adds the required functionality to fill in all pacas at runtime. With NR_CPUS=1024 text data bss dec hex filename 137 1704032 0 1704169 1a00e9 arch/powerpc/kernel/paca.o :Before 121 1179744 524288 1704153 1a00d9 arch/powerpc/kernel/paca.o :After Also remove unneeded #includes from arch/powerpc/kernel/paca.c Signed-off-by: Tony Breeds Signed-off-by: Paul Mackerras

[POWERPC] Initialize paca->current earlier

2008-04-16T21:46:10Z

Currently, we initialize the "current" pointer in the PACA (which is used by the "current" macro in the kernel) before calling setup_system(). That means that early_setup() is called with current still "NULL" which is -not- a good idea. It happens to work so far but breaks with lockdep when early code calls printk. This changes it so that all PACAs are statically initialized with __current pointing to the init task. For non-0 CPUs, this is fixed up before use. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras

[POWERPC] iSeries: Make iseries_reg_save private to iSeries

2008-04-15T11:21:25Z

Now that we have the alpaca, the reg_save_ptr is no longer needed in the paca. Eradicate all global uses of it and make it static in the iSeries lpardata.c Signed-off-by: Stephen Rothwell Signed-off-by: Paul Mackerras

[POWERPC] Implement SLB shadow buffer

2006-08-08T07:08:56Z

This adds a shadow buffer for the SLBs and regsiters it with PHYP. Only the bolted SLB entries (top 3) are shadowed. The SLB shadow buffer tells the hypervisor what the kernel needs to have in the SLB for the kernel to be able to function. The hypervisor can use this information to speed up partition context switches. Signed-off-by: Michael Neuling Signed-off-by: Paul Mackerras

Remove obsolete #include

2006-06-30T17:25:36Z

Signed-off-by: Jörn Engel Signed-off-by: Adrian Bunk

[POWERPC] Clean up it_lp_queue.h

2006-06-28T05:18:55Z

No more StudlyCaps. Remove from a couple of places it is no longer needed. Use C style comments. Signed-off-by: Stephen Rothwell Signed-off-by: Paul Mackerras

[PATCH] powerpc: Allow non zero boot cpuids

2006-03-27T03:48:48Z

We currently have a hack to flip the boot cpu and its secondary thread to logical cpuid 0 and 1. This means the logical - physical mapping will differ depending on which cpu is boot cpu. This is most apparent on kexec, where we might kexec on any cpu and therefore change the mapping from boot to boot. The patch below does a first pass early on to work out the logical cpuid of the boot thread. We then fix up some paca structures to match. Ive also removed the boot_cpuid_phys variable for ppc64, to be consistent we use get_hard_smp_processor_id(boot_cpuid) everywhere. Signed-off-by: Anton Blanchard Signed-off-by: Paul Mackerras

[PATCH] powerpc: Remove lppaca structure from the PACA

2006-01-13T10:17:39Z

At present the lppaca - the structure shared with the iSeries hypervisor and phyp - is contained within the PACA, our own low-level per-cpu structure. This doesn't have to be so, the patch below removes it, making a separate array of lppaca structures. This saves approximately 500*NR_CPUS bytes of image size and kernel memory, because we don't need aligning gap between the Linux and hypervisor portions of every PACA. On the other hand it means an extra level of dereference in many accesses to the lppaca. The patch also gets rid of several places where we assign the paca address to a local variable for no particular reason. Signed-off-by: David Gibson Signed-off-by: Paul Mackerras