kernel/linux.git/arch/powerpc/include/asm/processor.h, branch v6.19.11

powerpc: Replace ASSEMBLY with ASSEMBLER in non-uapi headers

2025-09-01T07:53:29+00:00

While the GCC and Clang compilers already define __ASSEMBLER__ automatically when compiling assembler code, __ASSEMBLY__ is a macro that only gets defined by the Makefiles in the kernel. This is bad since macros starting with two underscores are names that are reserved by the C language. It can also be very confusing for the developers when switching between userspace and kernelspace coding, or when dealing with uapi headers that rather should use __ASSEMBLER__ instead. So let's standardize now on the __ASSEMBLER__ macro that is provided by the compilers. This is almost a completely mechanical patch (done with a simple "sed -i" statement), apart from tweaking two comments manually in arch/powerpc/include/asm/bug.h and arch/powerpc/include/asm/kasan.h (which did not have proper underscores at the end) and fixing a checkpatch error about spaces in arch/powerpc/include/asm/spu_csa.h. Signed-off-by: Thomas Huth Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20250801082007.32904-3-thuth@redhat.com

powerpc/4xx: Remove CONFIG_BOOKE_OR_40x

2024-06-28T12:28:48+00:00

Now that 40x is gone, replace CONFIG_BOOKE_OR_40x by CONFIG_BOOKE. Signed-off-by: Michael Ellerman Link: https://msgid.link/20240628121201.130802-5-mpe@ellerman.id.au

powerpc/dexcr: Add DEXCR prctl interface

2024-05-06T12:04:31+00:00

Now that we track a DEXCR on a per-task basis, individual tasks are free to configure it as they like. The interface is a pair of getter/setter prctl's that work on a single aspect at a time (multiple aspects at once is more difficult if there are different rules applied for each aspect, now or in future). The getter shows the current state of the process config, and the setter allows setting/clearing the aspect. Signed-off-by: Benjamin Gray [mpe: Account for PR_RISCV_SET_ICACHE_FLUSH_CTX, shrink some longs lines] Signed-off-by: Michael Ellerman Link: https://msgid.link/20240417112325.728010-5-bgray@linux.ibm.com

powerpc/dexcr: Reset DEXCR value across exec

2024-05-03T10:46:51+00:00

Inheriting the DEXCR across exec can have security and usability concerns. If a program is compiled with hash instructions it generally expects to run with NPHIE enabled. But if the parent process disables NPHIE then if it's not careful it will be disabled for any children too and the protection offered by hash checks is basically worthless. This patch introduces a per-process reset value that new execs in a particular process tree are initialized with. This enables fine grained control over what DEXCR value child processes run with by default. For example, containers running legacy binaries that expect hash instructions to act as NOPs could configure the reset value of the container root to control the default reset value for all members of the container. Signed-off-by: Benjamin Gray [mpe: Add missing SPDX tag on dexcr.c] Signed-off-by: Michael Ellerman Link: https://msgid.link/20240417112325.728010-4-bgray@linux.ibm.com

powerpc/dexcr: Track the DEXCR per-process

2024-05-03T10:46:51+00:00

Add capability to make the DEXCR act as a per-process SPR. We do not yet have an interface for changing the values per task. We also expect the kernel to use a single DEXCR value across all tasks while in privileged state, so there is no need to synchronize after changing it (the userspace aspects will synchronize upon returning to userspace). Signed-off-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://msgid.link/20240417112325.728010-3-bgray@linux.ibm.com

Merge tag 'powerpc-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2023-08-31T19:43:10+00:00

Pull powerpc updates from Michael Ellerman: - Add HOTPLUG_SMT support (/sys/devices/system/cpu/smt) and honour the configured SMT state when hotplugging CPUs into the system - Combine final TLB flush and lazy TLB mm shootdown IPIs when using the Radix MMU to avoid a broadcast TLBIE flush on exit - Drop the exclusion between ptrace/perf watchpoints, and drop the now unused associated arch hooks - Add support for the "nohlt" command line option to disable CPU idle - Add support for -fpatchable-function-entry for ftrace, with GCC >= 13.1 - Rework memory block size determination, and support 256MB size on systems with GPUs that have hotpluggable memory - Various other small features and fixes Thanks to Andrew Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Athira Rajeev, Benjamin Gray, Christophe Leroy, Frederic Barrat, Gautam Menghani, Geoff Levand, Hari Bathini, Immad Mir, Jialin Zhang, Joel Stanley, Jordan Niethe, Justin Stitt, Kajol Jain, Kees Cook, Krzysztof Kozlowski, Laurent Dufour, Liang He, Linus Walleij, Mahesh Salgaonkar, Masahiro Yamada, Michal Suchanek, Nageswara R Sastry, Nathan Chancellor, Nathan Lynch, Naveen N Rao, Nicholas Piggin, Nick Desaulniers, Omar Sandoval, Randy Dunlap, Reza Arbab, Rob Herring, Russell Currey, Sourabh Jain, Thomas Gleixner, Trevor Woerner, Uwe Kleine-König, Vaibhav Jain, Xiongfeng Wang, Yuan Tan, Zhang Rui, and Zheng Zengkai. * tag 'powerpc-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (135 commits) macintosh/ams: linux/platform_device.h is needed powerpc/xmon: Reapply "Relax frame size for clang" powerpc/mm/book3s64: Use 256M as the upper limit with coherent device memory attached powerpc/mm/book3s64: Fix build error with SPARSEMEM disabled powerpc/iommu: Fix notifiers being shared by PCI and VIO buses powerpc/mpc5xxx: Add missing fwnode_handle_put() powerpc/config: Disable SLAB_DEBUG_ON in skiroot powerpc/pseries: Remove unused hcall tracing instruction powerpc/pseries: Fix hcall tracepoints with JUMP_LABEL=n powerpc: dts: add missing space before { powerpc/eeh: Use pci_dev_id() to simplify the code powerpc/64s: Move CPU -mtune options into Kconfig powerpc/powermac: Fix unused function warning powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT powerpc: Don't include lppaca.h in paca.h powerpc/pseries: Move hcall_vphn() prototype into vphn.h powerpc/pseries: Move VPHN constants into vphn.h cxl: Drop unused detach_spa() powerpc: Drop zalloc_maybe_bootmem() powerpc/powernv: Use struct opal_prd_msg in more places ...

powerpc/watchpoints: Track perf single step directly on the breakpoint

2023-08-16T13:54:50+00:00

There is a bug in the current watchpoint tracking logic, where the teardown in arch_unregister_hw_breakpoint() uses bp->ctx->task, which it does not have a reference of and parallel threads may be in the process of destroying. This was partially addressed in commit fb822e6076d9 ("powerpc/hw_breakpoint: Fix oops when destroying hw_breakpoint event"), but the underlying issue of accessing a struct member in an unknown state still remained. Syzkaller managed to trigger a null pointer derefernce due to the race between the task destructor and checking the pointer and dereferencing it in the loop. While this null pointer dereference could be fixed by using READ_ONCE to access the task up front, that just changes the error to manipulating possbily freed memory. Instead, the breakpoint logic needs to be reworked to remove any dependency on a context or task struct during breakpoint removal. The reason we have this currently is to clear thread.last_hit_ubp. This member is used to differentiate the perf DAWR single-step sequence from other causes of single-step, such as userspace just calling ptrace(PTRACE_SINGLESTEP, ...). We need to differentiate them because, when the single step interrupt is received, we need to know whether to re-insert the DAWR breakpoint (perf) or not (ptrace / other). arch_unregister_hw_breakpoint() needs to clear this information to prevent dangling pointers to possibly freed memory. These pointers are dereferenced in single_step_dabr_instruction() without a way to check their validity. This patch moves the tracking of this information to the breakpoint itself. This means we no longer have to do anything special to clean up. Signed-off-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://msgid.link/20230801011744.153973-4-bgray@linux.ibm.com

locking: remove spin_lock_prefetch

2023-08-12T16:18:47+00:00

The only remaining consumer is new_inode, where it showed up in 2001 as commit c37fa164f793 ("v2.4.9.9 -> v2.4.9.10") in a historical repo [1] with a changelog which does not mention it. Since then the line got only touched up to keep compiling. While it may have been of benefit back in the day, it is guaranteed to at best not get in the way in the multicore setting -- as the code performs *a lot* of work between the prefetch and actual lock acquire, any contention means the cacheline is already invalid by the time the routine calls spin_lock(). It adds spurious traffic, for short. On top of it prefetch is notoriously tricky to use for single-threaded purposes, making it questionable from the get go. As such, remove it. I admit upfront I did not see value in benchmarking this change, but I can do it if that is deemed appropriate. Removal from new_inode and of the entire thing are in the same patch as requested by Linus, so whatever weird looks can be directed at that guy. Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/fs/inode.c?id=c37fa164f793735b32aa3f53154ff1a7659e6442 [1] Signed-off-by: Mateusz Guzik Signed-off-by: Linus Torvalds

powerpc/dexcr: Support userspace ROP protection

2023-06-19T07:36:26+00:00

The ISA 3.1B hashst and hashchk instructions use a per-cpu SPR HASHKEYR to hold a key used in the hash calculation. This key should be different for each process to make it harder for a malicious process to recreate valid hash values for a victim process. Add support for storing a per-thread hash key, and setting/clearing HASHKEYR appropriately. Signed-off-by: Benjamin Gray Reviewed-by: Russell Currey Signed-off-by: Michael Ellerman Link: https://msgid.link/20230616034846.311705-6-bgray@linux.ibm.com

powerpc: split validate_sp into two functions

2022-12-02T06:54:09+00:00

Most callers just want to validate an arbitrary kernel stack pointer, some need a particular size. Make the size case the exceptional one with an extra function. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221127124942.1665522-15-npiggin@gmail.com