linux-toradex.git/samples/ftrace/ftrace-direct-multi-modify.c, branch v6.9-rc4

samples: ftrace: Add RISC-V support for SAMPLE_FTRACE_DIRECT[_MULTI]

2024-01-18T02:17:10+00:00

Add RISC-V variants of the ftrace-direct* samples.

Tested-by: Evgenii Shatokhin 
Signed-off-by: Song Shuai 
Tested-by: Guo Ren 
Signed-off-by: Guo Ren 
Acked-by: Björn Töpel 
Link: https://lore.kernel.org/r/20231130121531.1178502-5-bjorn@kernel.org
Signed-off-by: Palmer Dabbelt

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)

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: 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: 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: Export ftrace_free_filter() to modules

2023-01-24T16:20:58+00:00

Setting filters on an ftrace ops results in some memory being allocated
for the filter hashes, which must be freed before the ops can be freed.
This can be done by removing every individual element of the hash by
calling ftrace_set_filter_ip() or ftrace_set_filter_ips() with `remove`
set, but this is somewhat error prone as it's easy to forget to remove
an element.

Make it easier to clean this up by exporting ftrace_free_filter(), which
can be used to clean up all of the filter hashes after an ftrace_ops has
been unregistered.

Using this, fix the ftrace-direct* samples to free hashes prior to being
unloaded. All other code either removes individual filters explicitly or
is built-in and already calls ftrace_free_filter().

Link: https://lkml.kernel.org/r/20230103124912.2948963-3-mark.rutland@arm.com

Cc: stable@vger.kernel.org
Cc: Florent Revest 
Cc: Masami Hiramatsu 
Fixes: e1067a07cfbc ("ftrace/samples: Add module to test multi direct modify interface")
Fixes: 5fae941b9a6f ("ftrace/samples: Add multi direct interface test module")
Reviewed-by: Masami Hiramatsu (Google) 
Reviewed-by: Steven Rostedt (Google) 
Signed-off-by: Mark Rutland 
Signed-off-by: Steven Rostedt (Google)

x86/ftrace: Make it call depth tracking aware

2022-10-17T14:41:19+00:00

Since ftrace has trampolines, don't use thunks for the __fentry__ site
but instead require that every function called from there includes
accounting. This very much includes all the direct-call functions.

Additionally, ftrace uses ROP tricks in two places:

 - return_to_handler(), and
 - ftrace_regs_caller() when pt_regs->orig_ax is set by a direct-call.

return_to_handler() already uses a retpoline to replace an
indirect-jump to defeat IBT, since this is a jump-type retpoline, make
sure there is no accounting done and ALTERNATIVE the RET into a ret.

ftrace_regs_caller() does much the same and gets the same treatment.

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20220915111148.927545073@infradead.org