[PATCH v12 for-next 0/4] riscv: ftrace: Miscellaneous ftrace improvements

Björn Töpel
2023-11-30T12:16:00Z

From: Björn Töpel <bjorn@rivosinc.com>

NB! Song told me that he would not have the time work on this series,
so I picked it up.

This series includes a three ftrace improvements for RISC-V:

1. Do not require to run recordmcount at build time (patch 1)
2. Simplification of the function graph functionality (patch 2)
3. Enable DYNAMIC_FTRACE_WITH_DIRECT_CALLS (patch 3 and 4)

The series has been tested on Qemu/rv64 virt/Debian sid with the
following test configs:
CONFIG_FTRACE_SELFTEST=y
CONFIG_FTRACE_STARTUP_TEST=y
CONFIG_SAMPLE_FTRACE_DIRECT=m
CONFIG_SAMPLE_FTRACE_DIRECT_MULTI=m
CONFIG_SAMPLE_FTRACE_OPS=m

All tests pass.

Cheers,
Björn

Changes in v12:
- Massaged the commit messages a bit.
- Squashed the samples patches, so that the rv32 support is included
from the start.
- Minor whitespace changes in the mcount-dyn.S.
- Minor style changes.

Changes in v11:
https://lore.kernel.org/linux-riscv/20230627111612.761164-1-suagrfillet@gmail.com/

- append a patch that makes the DIRECT_CALL samples support RV32I in
this series fixing the rv32 build failure reported by Palmer
- validated with ftrace boottime selftest and manual sample modules test
in qemu-system for RV32I and RV64I

Changes in v10:
https://lore.kernel.org/all/20230511093234.3123181-1-suagrfillet@gmail.com/

- add Acked-by from Björn Töpel in patch 2 and patch 4
- replace `move` with `mv` in patch3
- prettify patch 2/4 with proper tabs

Changes in v9:
https://lore.kernel.org/linux-riscv/20230510101857.2953955-1-suagrfillet@gmail.com/

1. add Acked-by from Björn Töpel in patch 1

2. rebase patch2/patch3 on Linux v6.4-rc1

- patch 2: to make the `SAVE_ABI_REGS` configurable, revert the
modification of mcount-dyn.S from commit (45b32b946a97 "riscv:
entry: Consolidate general regs saving/restoring")

- patch 3: to pass the trace_selftest, add the implement of
`ftrace_stub_direct_tramp` from commit (fee86a4ed536 "ftrace:
selftest: remove broken trace_direct_tramp") ; and fixup the context
conflict in Kconfig

Changes in v8:
https://lore.kernel.org/linux-riscv/20230324033342.3177979-1-suagrfillet@gmail.com/
- Fix incorrect address values in the 4nd patch
- Rebased on v6.3-rc2

Changes in v7:
https://lore.kernel.org/linux-riscv/20230112090603.1295340-1-guoren@kernel.org/
- Fixup RESTORE_ABI_REGS by remove PT_T0(sp) overwrite.
- Add FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY [1]
- Fixup kconfig with HAVE_SAMPLE_FTRACE_DIRECT &
HAVE_SAMPLE_FTRACE_DIRECT_MULTI

Changes in v6:
https://lore.kernel.org/linux-riscv/20230107133549.4192639-1-guoren@kernel.org/
- Replace 8 with MCOUNT_INSN_SIZE
- Replace "REG_L a1, PT_RA(sp)" with "mv a1, ra"
- Add Evgenii Shatokhin comment

Changes in v5:
https://lore.kernel.org/linux-riscv/20221208091244.203407-1-guoren@kernel.org/
- Sort Kconfig entries in alphabetical order.

Changes in v4:
https://lore.kernel.org/linux-riscv/20221129033230.255947-1-guoren@kernel.org/
- Include [3] for maintenance. [Song Shuai]

Changes in V3:
https://lore.kernel.org/linux-riscv/20221123153950.2911981-1-guoren@kernel.org/
- Include [2] for maintenance. [Song Shuai]

[1]: https://lore.kernel.org/linux-riscv/CAAYs2=j3Eak9vU6xbAw0zPuoh00rh8v5C2U3fePkokZFibWs2g@mail.gmail.com/T/#t
[2]: https://lore.kernel.org/lkml/20221120084230.910152-1-suagrfillet@gmail.com/
[3]: https://lore.kernel.org/linux-riscv/20221123142025.1504030-1-suagrfillet@gmail.com/

Song Shuai (4):
riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
riscv: ftrace: Make function graph use ftrace directly
riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support
samples: ftrace: Add RISC-V support for SAMPLE_FTRACE_DIRECT[_MULTI]

arch/riscv/Kconfig | 4 +
arch/riscv/include/asm/ftrace.h | 18 +-
arch/riscv/kernel/ftrace.c | 30 ++-
arch/riscv/kernel/mcount-dyn.S | 198 ++++++++++++++++----
samples/ftrace/ftrace-direct-modify.c | 35 ++++
samples/ftrace/ftrace-direct-multi-modify.c | 41 ++++
samples/ftrace/ftrace-direct-multi.c | 25 +++
samples/ftrace/ftrace-direct-too.c | 28 +++
samples/ftrace/ftrace-direct.c | 24 +++
9 files changed, 348 insertions(+), 55 deletions(-)

base-commit: 3ca112b71f35dd5d99fc4571a56b5fc6f0c15814