diff options
| author | Florent Revest <revest@chromium.org> | 2023-04-05 21:02:46 +0300 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2023-04-11 20:06:39 +0300 |
| commit | 2aa6ac03516d078cf0c35aaa273b5cd11ea9734c (patch) | |
| tree | 9925d6da6b5feeffeb8ba2cd1e6f5edca50ce57e /arch/arm64/Kconfig | |
| parent | f89b30b8555a853d47fe1affd4da9e9405bcdc8c (diff) | |
| download | linux-2aa6ac03516d078cf0c35aaa273b5cd11ea9734c.tar.xz | |
arm64: ftrace: Add direct call support
This builds up on the CALL_OPS work which extends the ftrace patchsite
on arm64 with an ops pointer usable by the ftrace trampoline.
This ops pointer is valid at all time. Indeed, it is either pointing to
ftrace_list_ops or to the single ops which should be called from that
patchsite.
There are a few cases to distinguish:
- If a direct call ops is the only one tracing a function:
- If the direct called trampoline is within the reach of a BL
instruction
-> the ftrace patchsite jumps to the trampoline
- Else
-> the ftrace patchsite jumps to the ftrace_caller trampoline which
reads the ops pointer in the patchsite and jumps to the direct
call address stored in the ops
- Else
-> the ftrace patchsite jumps to the ftrace_caller trampoline and its
ops literal points to ftrace_list_ops so it iterates over all
registered ftrace ops, including the direct call ops and calls its
call_direct_funcs handler which stores the direct called
trampoline's address in the ftrace_regs and the ftrace_caller
trampoline will return to that address instead of returning to the
traced function
Signed-off-by: Florent Revest <revest@chromium.org>
Co-developed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230405180250.2046566-2-revest@chromium.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/Kconfig')
| -rw-r--r-- | arch/arm64/Kconfig | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 1023e896d46b..f3503d0cc1b8 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -185,6 +185,10 @@ config ARM64 select HAVE_DEBUG_KMEMLEAK select HAVE_DMA_CONTIGUOUS select HAVE_DYNAMIC_FTRACE + select HAVE_DYNAMIC_FTRACE_WITH_ARGS \ + if $(cc-option,-fpatchable-function-entry=2) + select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \ + if DYNAMIC_FTRACE_WITH_ARGS && DYNAMIC_FTRACE_WITH_CALL_OPS select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \ if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG && \ !CC_OPTIMIZE_FOR_SIZE) |