kernel/linux.git/samples/ftrace, branch v6.4.15

samples: ftrace: Save required argument registers in sample trampolines

2023-07-23T11:54:09+00:00

commit 8564c315876ab86fcaf8e7f558d6a84cb2ce5590 upstream. 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) Signed-off-by: Greg Kroah-Hartman

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

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 (e.g: ra). Signed-off-by: Qing Zhang Signed-off-by: Youling Tang Signed-off-by: Huacai Chen

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)

ftrace: Replace uses of _ftrace_direct APIs with _ftrace_direct_multi

2023-03-21T17:42:12+00:00

The _multi API requires that users keep their own ops but can enforce that an op is only associated to one direct call. Link: https://lkml.kernel.org/r/20230321140424.345218-3-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)

ftrace: Let unregister_ftrace_direct_multi() call ftrace_free_filter()

2023-03-21T17:42:11+00:00

A common pattern when using the ftrace_direct_multi API is to unregister the ops and also immediately free its filter. We've noticed it's very easy for users to miss calling ftrace_free_filter(). This adds a "free_filters" argument to unregister_ftrace_direct_multi() to both remind the user they should free filters and also to make their life easier. Link: https://lkml.kernel.org/r/20230321140424.345218-2-revest@chromium.org Suggested-by: Steven Rostedt Signed-off-by: Florent Revest Acked-by: Mark Rutland Acked-by: Jiri Olsa Signed-off-by: Steven Rostedt (Google)

samples: ftrace: Make some global variables static

2023-02-07T17:48:00+00:00

smatch reports this representative issue samples/ftrace/ftrace-ops.c:15:14: warning: symbol 'nr_function_calls' was not declared. Should it be static? The nr_functions_calls and several other global variables are only used in ftrace-ops.c, so they should be static. Remove the instances of initializing static int to 0. Link: https://lore.kernel.org/linux-trace-kernel/20230130193708.1378108-1-trix@redhat.com Signed-off-by: Tom Rix Acked-by: Mark Rutland Signed-off-by: Steven Rostedt (Google)

ftrace: sample: avoid open-coded 64-bit division

2023-02-07T17:45:18+00:00

Calculating the average period requires a 64-bit division that leads to a link failure on 32-bit architectures: x86_64-linux-ld: samples/ftrace/ftrace-ops.o: in function `ftrace_ops_sample_init': ftrace-ops.c:(.init.text+0x23b): undefined reference to `__udivdi3' Use the div_u64() helper to do this instead. Since this is an init function that is not called frequently, the runtime overhead is going to be acceptable. Link: https://lore.kernel.org/linux-trace-kernel/20230130130246.247537-1-arnd@kernel.org Cc: Masami Hiramatsu Fixes: b56c68f705ca ("ftrace: Add sample with custom ops") Signed-off-by: Arnd Bergmann Acked-by: Mark Rutland Signed-off-by: Steven Rostedt (Google)

samples: ftrace: Include the nospec-branch.h only for x86

2023-02-07T17:44:39+00:00

When other architectures without the nospec functionality write their direct-call functions of samples/ftrace/*.c, the including of asm/nospec-branch.h must be taken care to fix the no header file found error in building process. This commit (ee3e2469b346 "x86/ftrace: Make it call depth tracking aware") file-globally includes asm/nospec-branch.h providing CALL_DEPTH_ACCOUNT for only x86 direct-call functions. It seems better to move the including to `#ifdef CONFIG_X86_64`. Link: https://lore.kernel.org/linux-trace-kernel/20230130085954.647845-1-suagrfillet@gmail.com Signed-off-by: Song Shuai Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google)

ftrace: Add sample with custom ops

2023-01-25T15:31:23+00:00

When reworking core ftrace code or architectural ftrace code, it's often necessary to test/analyse/benchmark a number of ftrace_ops configurations. This patch adds a module which can be used to explore some of those configurations. I'm using this to benchmark various options for changing the way trampolines and handling of ftrace_ops work on arm64, and ensuring other architectures aren't adversely affected. For example, in a QEMU+KVM VM running on a 2GHz Xeon E5-2660 workstation, loading the module in various configurations produces: | # insmod ftrace-ops.ko | ftrace_ops: registering: | relevant ops: 1 | tracee: tracee_relevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | irrelevant ops: 0 | tracee: tracee_irrelevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | saving registers: NO | assist recursion: NO | assist RCU: NO | ftrace_ops: Attempted 100000 calls to tracee_relevant [ftrace_ops] in 1681558ns (16ns / call) | # insmod ftrace-ops.ko nr_ops_irrelevant=5 | ftrace_ops: registering: | relevant ops: 1 | tracee: tracee_relevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | irrelevant ops: 5 | tracee: tracee_irrelevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | saving registers: NO | assist recursion: NO | assist RCU: NO | ftrace_ops: Attempted 100000 calls to tracee_relevant [ftrace_ops] in 1693042ns (16ns / call) | # insmod ftrace-ops.ko nr_ops_relevant=2 | ftrace_ops: registering: | relevant ops: 2 | tracee: tracee_relevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | irrelevant ops: 0 | tracee: tracee_irrelevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | saving registers: NO | assist recursion: NO | assist RCU: NO | ftrace_ops: Attempted 100000 calls to tracee_relevant [ftrace_ops] in 11965582ns (119ns / call) | # insmod ftrace-ops.ko save_regs=true | ftrace_ops: registering: | relevant ops: 1 | tracee: tracee_relevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | irrelevant ops: 0 | tracee: tracee_irrelevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | saving registers: YES | assist recursion: NO | assist RCU: NO | ftrace_ops: Attempted 100000 calls to tracee_relevant [ftrace_ops] in 4459624ns (44ns / call) Link: https://lkml.kernel.org/r/20230103124912.2948963-4-mark.rutland@arm.com Cc: Florent Revest Acked-by: Masami Hiramatsu (Google) Signed-off-by: Mark Rutland Signed-off-by: Steven Rostedt (Google)