Reread the syscall number from pt_regs and stop returning the eventually
modified syscall number.
That moves the reread to the end of syscall_trace_enter() and prepares for
moving it to the call site.
No functional change.
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Michal Suchánek <[email protected]>
Reviewed-by: Jinjie Ruan <[email protected]>
Link: https://patch.msgid.link/[email protected]
Move it out of line and let it reread the syscall number on it's own. That
makes the low level entry code denser and allows to move the reread to the
call site of syscall_trace_enter() once the tracer is fixed up.
To prevent the compiler from putting audit_context() out of line and
thereby breaking dead code elimination, mark audit_context()
__always_inline.
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Michal Suchánek <[email protected]>
Reviewed-by: Jinjie Ruan <[email protected]>
Link: https://patch.msgid.link/[email protected]
After switching ARM64 to the generic entry code, a syscall_exit_work()
appeared as a profiling hotspot because it is not inlined.
Inlining both syscall_trace_enter() and syscall_exit_work() provides a
performance gain when any of the work items is enabled. With audit enabled
this results in a ~4% performance gain for perf bench basic syscall on
a kunpeng920 system:
| Metric | Baseline | Inlined | Change |
| ---------- | ----------- | ----------- | ------ |
| Total time | 2.353 [sec] | 2.264 [sec] | ↓3.8% |
| usecs/op | 0.235374 | 0.226472 | ↓3.8% |
| ops/sec | 4,248,588 | 4,415,554 | ↑3.9% |
Small gains can be observed on x86 as well, though the generated code
optimizes for the work case, which is counterproductive for high
performance scenarios where such entry/exit work is usually avoided.
Avoid this by marking the work check in syscall_enter_from_user_mode_work()
unlikely, which is what the corresponding check in the exit path does
already.
[ tglx: Massage changelog and add the unlikely() ]
Signed-off-by: Jinjie Ruan <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://patch.msgid.link/[email protected]
ARM64 requires a architecture specific ptrace wrapper as it needs to save
and restore scratch registers.
Provide arch_ptrace_report_syscall_entry/exit() wrappers which fall back to
ptrace_report_syscall_entry/exit() if the architecture does not provide
them.
No functional change intended.
[ tglx: Massaged changelog and comments ]
Suggested-by: Mark Rutland <[email protected]>
Suggested-by: Thomas Gleixner <[email protected]>
Signed-off-by: Jinjie Ruan <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Kevin Brodsky <[email protected]>
Link: https://patch.msgid.link/[email protected]
The 'syscall' argument of syscall_trace_enter() is immediately overwritten
before any real use and serves only as a local variable, so drop the
parameter.
No functional change intended.
Signed-off-by: Jinjie Ruan <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://patch.msgid.link/[email protected]
Currently CONFIG_GENERIC_ENTRY enables both the generic exception
entry logic and the generic syscall entry logic, which are otherwise
loosely coupled.
Introduce separate config options for these so that architectures can
select the two independently. This will make it easier for
architectures to migrate to generic entry code.
Suggested-by: Mark Rutland <[email protected]>
Signed-off-by: Jinjie Ruan <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Linus Walleij <[email protected]>
Link: https://lore.kernel.org/[email protected]
Link: https://lore.kernel.org/all/[email protected]
[Linus Walleij: rebase onto v6.16-rc1]
Thomas Gleixner