kernel/linux.git/samples/ftrace, branch v6.6.132

samples/ftrace: Adjust LoongArch register restore order in direct calls

2026-01-11T14:22:17+00:00

commit bb85d206be208bbf834883e948125a35ac59993a upstream. Ensure that in the ftrace direct call logic, the CPU register state (with ra = parent return address) is restored to the correct state after the execution of the custom trampoline function and before returning to the traced function. Additionally, guarantee the correctness of the jump logic for jr t0 (traced function address). Cc: stable@vger.kernel.org Fixes: 9cdc3b6a299c ("LoongArch: ftrace: Add direct call support") Reported-by: Youling Tang Acked-by: Steven Rostedt (Google) Signed-off-by: Chenghao Duan Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

ftrace/samples: Fix function size computation

2025-09-19T14:32:02+00:00

[ Upstream commit 80d03a40837a9b26750a25122b906c052cc846c9 ] In my_tramp1 function .size directive was placed above ASM_RET instruction, leading to a wrong function size. Link: https://lore.kernel.org/aK3d7vxNcO52kEmg@vova-pc Fixes: 9d907f1ae80b ("samples/ftrace: Fix asm function ELF annotations") Signed-off-by: Vladimir Riabchun Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin

tracing: samples: Initialize trace_array_printk() with the correct function

2025-05-22T12:12:21+00:00

commit 1b0c192c92ea1fe2dcb178f84adf15fe37c3e7c8 upstream. When using trace_array_printk() on a created instance, the correct function to use to initialize it is: trace_array_init_printk() Not trace_printk_init_buffer() The former is a proper function to use, the latter is for initializing trace_printk() and causes the NOTICE banner to be displayed. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Divya Indi Link: https://lore.kernel.org/20250509152657.0f6744d9@gandalf.local.home Fixes: 89ed42495ef4a ("tracing: Sample module to demonstrate kernel access to Ftrace instances.") Fixes: 38ce2a9e33db6 ("tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers") Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman

tracing: Allow creating instances with specified system events

2025-04-10T12:37:41+00:00

[ Upstream commit d23569979ca1cd139a42c410e0c7b9e6014c3b3a ] A trace instance may only need to enable specific events. As the eventfs directory of an instance currently creates all events which adds overhead, allow internal instances to be created with just the events in systems that they care about. This currently only deals with systems and not individual events, but this should bring down the overhead of creating instances for specific use cases quite bit. The trace_array_get_by_name() now has another parameter "systems". This parameter is a const string pointer of a comma/space separated list of event systems that should be created by the trace_array. (Note if the trace_array already exists, this parameter is ignored). The list of systems is saved and if a module is loaded, its events will not be added unless the system for those events also match the systems string. Link: https://lore.kernel.org/linux-trace-kernel/20231213093701.03fddec0@gandalf.local.home Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Sean Paul Cc: Arun Easi Cc: Daniel Wagner Tested-by: Dmytro Maluka Signed-off-by: Steven Rostedt (Google) Stable-dep-of: 0b4ffbe4888a ("tracing: Correct the refcount if the hist/hist_debug file fails to open") Signed-off-by: Sasha Levin

samples: ftrace: Replace bti assembly with hint for older compiler

2023-08-22T02:03:58+00:00

When cross-building the arm64 kernel with allmodconfig using GCC 9.4, the following error occurs on multiple files under samples/ftrace/: /tmp/ccPC1ODs.s: Assembler messages: /tmp/ccPC1ODs.s:8: Error: selected processor does not support `bti c' Fix this issue by replacing `bti c` with `hint 34`, which is compatible for the older compiler. Link: https://lore.kernel.org/linux-trace-kernel/20230820111509.1470826-1-gongruiqi@huaweicloud.com Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Florent Revest Fixes: 8c3526fb86060cb5 ("arm64: ftrace: Add direct call trampoline samples support") Acked-by: Mark Rutland Signed-off-by: GONG, Ruiqi Signed-off-by: Steven Rostedt (Google)

arm64: ftrace: Add direct call trampoline samples support

2023-07-10T21:51:54+00:00

The ftrace samples need per-architecture trampoline implementations to save and restore argument registers around the calls to my_direct_func* and to restore polluted registers (eg: x30). These samples also include which, on arm64, is not necessary and redefines previously defined macros (resulting in warnings) so these includes are guarded by !CONFIG_ARM64. Link: https://lkml.kernel.org/r/20230427140700.625241-3-revest@chromium.org Reviewed-by: Mark Rutland Tested-by: Mark Rutland Acked-by: Catalin Marinas Signed-off-by: Florent Revest Signed-off-by: Steven Rostedt (Google)

samples: ftrace: Save required argument registers in sample trampolines

2023-07-10T21:50:41+00:00

The ftrace-direct-too sample traces the handle_mm_fault function whose signature changed since the introduction of the sample. Since: commit bce617edecad ("mm: do page fault accounting in handle_mm_fault") handle_mm_fault now has 4 arguments. Therefore, the sample trampoline should save 4 argument registers. s390 saves all argument registers already so it does not need a change but x86_64 needs an extra push and pop. This also evolves the signature of the tracing function to make it mirror the signature of the traced function. Link: https://lkml.kernel.org/r/20230427140700.625241-2-revest@chromium.org Cc: stable@vger.kernel.org Fixes: bce617edecad ("mm: do page fault accounting in handle_mm_fault") Reviewed-by: Steven Rostedt (Google) Reviewed-by: Mark Rutland Acked-by: Catalin Marinas Signed-off-by: Florent Revest Signed-off-by: Steven Rostedt (Google)

Merge tag 'loongarch-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

2023-05-04T19:40:16+00:00

Pull LoongArch updates from Huacai Chen: - Better backtraces for humanization - Relay BCE exceptions to userland as SIGSEGV - Provide kernel fpu functions - Optimize memory ops (memset/memcpy/memmove) - Optimize checksum and crc32(c) calculation - Add ARCH_HAS_FORTIFY_SOURCE selection - Add function error injection support - Add ftrace with direct call support - Add basic perf tools support * tag 'loongarch-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (24 commits) tools/perf: Add basic support for LoongArch LoongArch: ftrace: Add direct call trampoline samples support LoongArch: ftrace: Add direct call support LoongArch: ftrace: Implement ftrace_find_callable_addr() to simplify code LoongArch: ftrace: Fix build error if DYNAMIC_FTRACE_WITH_REGS is not set LoongArch: ftrace: Abstract DYNAMIC_FTRACE_WITH_ARGS accesses LoongArch: Add support for function error injection LoongArch: Add ARCH_HAS_FORTIFY_SOURCE selection LoongArch: crypto: Add crc32 and crc32c hw acceleration LoongArch: Add checksum optimization for 64-bit system LoongArch: Optimize memory ops (memset/memcpy/memmove) LoongArch: Provide kernel fpu functions LoongArch: Relay BCE exceptions to userland as SIGSEGV with si_code=SEGV_BNDERR LoongArch: Tweak the BADV and CPUCFG.PRID lines in show_regs() LoongArch: Humanize the ESTAT line when showing registers LoongArch: Humanize the ECFG line when showing registers LoongArch: Humanize the EUEN line when showing registers LoongArch: Humanize the PRMD line when showing registers LoongArch: Humanize the CRMD line when showing registers LoongArch: Fix format of CSR lines during show_regs() ...

LoongArch: ftrace: Add direct call trampoline samples support

2023-05-01T09:19:53+00:00

ftrace: Rename _ftrace_direct_multi APIs to _ftrace_direct APIs

2023-03-21T17:43:32+00:00

Now that the original _ftrace_direct APIs are gone, the "_multi" suffixes only add confusion. Link: https://lkml.kernel.org/r/20230321140424.345218-5-revest@chromium.org Signed-off-by: Florent Revest Acked-by: Mark Rutland Tested-by: Mark Rutland Acked-by: Jiri Olsa Signed-off-by: Steven Rostedt (Google)