en Copyright 2015 Java http://kernelsources.org:8080/source/history/linux/arch/alpha/kernel/perf_regs.c#742f62b63904cdc20a364a49d2861e32464a0af7 Merge tag 'alpha-for-v7.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/lindholm/alphaPull alpha updates from Magnus Lindholm: "This completes Alpha's conversion to GENERIC_ENTRY and enables a range of kernel features through Kconfig updates, including UBSAN, gcov, kmemleak, page-table checking, fast GUP and sparse IRQs. It includes TLB and MMU context fixes prompted by glibc test-suite failures, HugeTLB support for 64KB, 512KB and 4MB pages, and fixes for poisoned-page faults and page-table checking. Machine-check handling is improved on Tsunami platforms, with bounded EV6 logout decoding, Clipper environmental event reporting and safer firmware console-log scanning. Other changes add self-extracting compressed kernels with support for all kernel compression formats, Alpha-specific XZ tuning, perf register and user-stack sampling, and Alpha support in the seccomp selftests. The series also fixes user stack-pointer reporting and IRQ entry ordering, adds 128-bit shift helpers, cleans up linker sections, and updates Kconfig help"* tag 'alpha-for-v7.4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/lindholm/alpha: (57 commits) alpha: add bounded Clipper console-log scanning alpha: decode Clipper environmental events alpha: decode and acknowledge Tsunami system machine checks alpha: bound EV6 logout decoding by the processor area alpha: describe the Tsunami system machine check frame alpha: move Tsunami machine check handling to err_tsunami.c alpha: fill in pc for software event samples alpha: add HAVE_PERF_REGS and HAVE_PERF_USER_STACK_DUMP support alpha: use user_stack_pointer() in KSTK_ESP() and dump_elf_thread() alpha: stop storing the user stack pointer in pt_regs alpha: fix stale user_stack_pointer() selftests/seccomp: add Alpha support to seccomp_bpf alpha: do not skip TLB shootdown IPIs for kthread-borrowed mms alpha: do not clear remote MMU contexts in migrate_flush_tlb_page() alpha: invalidate the local context in flush_icache_user_page() alpha: invalidate the local context in flush_tlb_mm() alpha: fix the local TLB invalidate in the UP flush_tlb_page() alpha: fix the local TLB invalidate in flush_tlb_page() alpha: invalidate the local context in flush_tlb_page() alpha: only use a targeted tbi() when the target mm is really current ... List of files: /linux/arch/alpha/kernel/perf_regs.c Wed, 21 Oct 2026 02:31:24 +0200 Linus Torvalds <torvalds@linux-foundation.org> http://kernelsources.org:8080/source/history/linux/arch/alpha/kernel/perf_regs.c#9280e99d87ddd8c6c7fd83f9ea1585967b3dcd60 alpha: add HAVE_PERF_REGS and HAVE_PERF_USER_STACK_DUMP supportLet perf sample registers and dump the user stack, which is what theperf tool needs for --call-graph dwarf.The register indices follow the hardware numbering, so r0-r30 mapdirectly to DWARF register numbers, with pc after them. r9-r15are callee-saved and live in switch_stack rather than pt_regs, so theycannot be sampled. Without r15 an unwinder cannot recover the CFA of afirst frame that uses $15 as its frame pointer.sp is not in pt_regs either: for user frames it comes fromuser_stack_pointer(), and for kernel frames (PERF_SAMPLE_REGS_INTR) itis the end of the trap frame, as in stacktrace.c.Software events such as context switches and tracepoints hand perf aper-CPU pt_regs filled in by perf_fetch_caller_regs() instead of atrap frame. It is not on the stack and has no room for sp, so reportsp as 0 there rather than the address of the per-CPU buffer.Assisted-by: Claude:claude-opus-5-5Acked-by: Ian Rogers <irogers@google.com>Tested-by: Magnus Lindholm <linmag7@gmail.com>Reviewed-by: Magnus Lindholm <linmag7@gmail.com>Signed-off-by: Matt Turner <mattst88@gmail.com>Link: https://lore.kernel.org/r/20261018-alpha-perf-regs-v3-v3-4-52be85332c57@gmail.comSigned-off-by: Magnus Lindholm <linmag7@gmail.com> List of files: /linux/arch/alpha/kernel/perf_regs.c Sun, 18 Oct 2026 16:22:04 +0200 Matt Turner <mattst88@gmail.com>