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Enable the generic IRQ entry/exit infrastructure on PowerPC by selecting GENERIC_ENTRY and integrating the architecture-specific interrupt and syscall handlers with the generic entry/exit APIs. This change replaces PowerPC’s local interrupt entry/exit handling with calls to the generic irqentry_* helpers, aligning the architecture with the common kernel entry model. The macros that define interrupt, async, and NMI handlers are updated to use irqentry_enter()/irqentry_exit() and irqentry_nmi_enter()/irqentry_nmi_exit() where applicable also convert the PowerPC syscall entry and exit paths to use the generic entry/exit framework and integrating with the common syscall handling routines. Key updates include: - The architecture now selects GENERIC_ENTRY in Kconfig. - Replace interrupt_enter/exit_prepare() with arch_interrupt_* helpers. - Integrate irqentry_enter()/exit() in standard and async interrupt paths. - Integrate irqentry_nmi_enter()/exit() in NMI handlers. - Remove redundant irq_enter()/irq_exit() calls now handled generically. - Use irqentry_exit_cond_resched() for preemption checks. - interrupt.c and syscall.c are simplified to delegate context management and user exit handling to the generic entry path. - The new pt_regs field `exit_flags` introduced earlier is now used to carry per-syscall exit state flags (e.g. _TIF_RESTOREALL). - Remove unused code. This change establishes the necessary wiring for PowerPC to use the generic IRQ entry/exit framework while maintaining existing semantics. This aligns PowerPC with the common entry code used by other architectures and reduces duplicated logic around syscall tracing, context tracking, and signal handling. The performance benchmarks from perf bench basic syscall are below: perf bench syscall usec/op (-ve is improvement) | Syscall | Base | test | change % | | ------- | ----------- | ----------- | -------- | | basic | 0.093543 | 0.093023 | -0.56 | | execve | 446.557781 | 450.107172 | +0.79 | | fork | 1142.204391 | 1156.377214 | +1.24 | | getpgid | 0.097666 | 0.092677 | -5.11 | perf bench syscall ops/sec (+ve is improvement) | Syscall | Base | New | change % | | ------- | -------- | -------- | -------- | | basic | 10690548 | 10750140 | +0.56 | | execve | 2239 | 2221 | -0.80 | | fork | 875 | 864 | -1.26 | | getpgid | 10239026 | 10790324 | +5.38 | IPI latency benchmark (-ve is improvement) | Metric | Base (ns) | New (ns) | % Change | | -------------- | ------------- | ------------- | -------- | | Dry run | 583136.56 | 584136.35 | 0.17% | | Self IPI | 4167393.42 | 4149093.90 | -0.44% | | Normal IPI | 61769347.82 | 61753728.39 | -0.03% | | Broadcast IPI | 2235584825.02 | 2227521401.45 | -0.36% | | Broadcast lock | 2164964433.31 | 2125658641.76 | -1.82% | Thats very close to performance earlier with arch specific handling. Signed-off-by: Mukesh Kumar Chaurasiya <mkchauras@linux.ibm.com> Tested-by: Samir M <samir@linux.ibm.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com> Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/20260427122742.210074-8-mkchauras@gmail.com
Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst