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Pull powerpc updates from Ben Herrenschmidt: "Here is the bulk of the powerpc changes for this merge window. It got a bit delayed in part because I wasn't paying attention, and in part because I discovered I had a core PCI change without a PCI maintainer ack in it. Bjorn eventually agreed it was ok to merge it though we'll probably improve it later and I didn't want to rebase to add his ack. There is going to be a bit more next week, essentially fixes that I still want to sort through and test. The biggest item this time is the support to build the ppc64 LE kernel with our new v2 ABI. We previously supported v2 userspace but the kernel itself was a tougher nut to crack. This is now sorted mostly thanks to Anton and Rusty. We also have a fairly big series from Cedric that add support for 64-bit LE zImage boot wrapper. This was made harder by the fact that traditionally our zImage wrapper was always 32-bit, but our new LE toolchains don't really support 32-bit anymore (it's somewhat there but not really "supported") so we didn't want to rely on it. This meant more churn that just endian fixes. This brings some more LE bits as well, such as the ability to run in LE mode without a hypervisor (ie. under OPAL firmware) by doing the right OPAL call to reinitialize the CPU to take HV interrupts in the right mode and the usual pile of endian fixes. There's another series from Gavin adding EEH improvements (one day we *will* have a release with less than 20 EEH patches, I promise!). Another highlight is the support for the "Split core" functionality on P8 by Michael. This allows a P8 core to be split into "sub cores" of 4 threads which allows the subcores to run different guests under KVM (the HW still doesn't support a partition per thread). And then the usual misc bits and fixes ..." [ Further delayed by gmail deciding that BenH is a dirty spammer. Google knows. ] * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (155 commits) powerpc/powernv: Add missing include to LPC code selftests/powerpc: Test the THP bug we fixed in the previous commit powerpc/mm: Check paca psize is up to date for huge mappings powerpc/powernv: Pass buffer size to OPAL validate flash call powerpc/pseries: hcall functions are exported to modules, need _GLOBAL_TOC() powerpc: Exported functions __clear_user and copy_page use r2 so need _GLOBAL_TOC() powerpc/powernv: Set memory_block_size_bytes to 256MB powerpc: Allow ppc_md platform hook to override memory_block_size_bytes powerpc/powernv: Fix endian issues in memory error handling code powerpc/eeh: Skip eeh sysfs when eeh is disabled powerpc: 64bit sendfile is capped at 2GB powerpc/powernv: Provide debugfs access to the LPC bus via OPAL powerpc/serial: Use saner flags when creating legacy ports powerpc: Add cpu family documentation powerpc/xmon: Fix up xmon format strings powerpc/powernv: Add calls to support little endian host powerpc: Document sysfs DSCR interface powerpc: Fix regression of per-CPU DSCR setting powerpc: Split __SYSFS_SPRSETUP macro arch: powerpc/fadump: Cleaning up inconsistent NULL checks ... |
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This directory attempts to document the ABI between the Linux kernel and userspace, and the relative stability of these interfaces. Due to the everchanging nature of Linux, and the differing maturity levels, these interfaces should be used by userspace programs in different ways. We have four different levels of ABI stability, as shown by the four different subdirectories in this location. Interfaces may change levels of stability according to the rules described below. The different levels of stability are: stable/ This directory documents the interfaces that the developer has defined to be stable. Userspace programs are free to use these interfaces with no restrictions, and backward compatibility for them will be guaranteed for at least 2 years. Most interfaces (like syscalls) are expected to never change and always be available. testing/ This directory documents interfaces that are felt to be stable, as the main development of this interface has been completed. The interface can be changed to add new features, but the current interface will not break by doing this, unless grave errors or security problems are found in them. Userspace programs can start to rely on these interfaces, but they must be aware of changes that can occur before these interfaces move to be marked stable. Programs that use these interfaces are strongly encouraged to add their name to the description of these interfaces, so that the kernel developers can easily notify them if any changes occur (see the description of the layout of the files below for details on how to do this.) obsolete/ This directory documents interfaces that are still remaining in the kernel, but are marked to be removed at some later point in time. The description of the interface will document the reason why it is obsolete and when it can be expected to be removed. removed/ This directory contains a list of the old interfaces that have been removed from the kernel. Every file in these directories will contain the following information: What: Short description of the interface Date: Date created KernelVersion: Kernel version this feature first showed up in. Contact: Primary contact for this interface (may be a mailing list) Description: Long description of the interface and how to use it. Users: All users of this interface who wish to be notified when it changes. This is very important for interfaces in the "testing" stage, so that kernel developers can work with userspace developers to ensure that things do not break in ways that are unacceptable. It is also important to get feedback for these interfaces to make sure they are working in a proper way and do not need to be changed further. How things move between levels: Interfaces in stable may move to obsolete, as long as the proper notification is given. Interfaces may be removed from obsolete and the kernel as long as the documented amount of time has gone by. Interfaces in the testing state can move to the stable state when the developers feel they are finished. They cannot be removed from the kernel tree without going through the obsolete state first. It's up to the developer to place their interfaces in the category they wish for it to start out in. Notable bits of non-ABI, which should not under any circumstances be considered stable: - Kconfig. Userspace should not rely on the presence or absence of any particular Kconfig symbol, in /proc/config.gz, in the copy of .config commonly installed to /boot, or in any invocation of the kernel build process. - Kernel-internal symbols. Do not rely on the presence, absence, location, or type of any kernel symbol, either in System.map files or the kernel binary itself. See Documentation/stable_api_nonsense.txt.