src/sys/modules/dtrace/Makefile, branch main

sdt: Enable on 32-bit powerpc and powerpc64le

2026-02-04T14:48:34Z

Reviewed by: jhibbits, adrian MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D54814

dtrace: Build systrace_freebsd32 only if COMPAT_FREEBSD32 is configured

2025-01-22T21:26:07Z

MFC after: 1 week Sponsored by: Innovate UK

Remove residual blank line at start of Makefile

2024-07-15T22:43:39Z

This is a residual of the $FreeBSD$ removal. MFC After: 3 days (though I'll just run the command on the branches) Sponsored by: Netflix

sdt: Implement SDT probes using hot-patching

2024-06-19T20:57:41Z

The idea here is to avoid a memory access and conditional branch per probe site. Instead, the probe is represented by an "unreachable" unconditional function call. asm goto is used to store the address of the probe site (represented by a no-op sled) and the address of the function call into a tracepoint record. Each SDT probe carries a list of tracepoints. When the probe is enabled, the no-op sled corresponding to each tracepoint is overwritten with a jmp to the corresponding label. The implementation uses smp_rendezvous() to park all other CPUs while the instruction is being overwritten, as this can't be done atomically in general. The compiler moves argument marshalling code and the sdt_probe() function call out-of-line, i.e., to the end of the function. Per gallatin@ in D43504, this approach has less overhead when probes are disabled. To make the implementation a bit simpler, I removed support for probes with 7 arguments; nothing makes use of this except a regression test case. It could be re-added later if need be. The approach taken in this patch enables some more improvements: 1. We can now automatically fill out the "function" field of SDT probe names. The SDT macros let the programmer specify the function and module names, but this is really a bug and shouldn't have been allowed. The intent was to be able to have the same probe in multiple functions and to let the user restrict which probes actually get enabled by specifying a function name or glob. 2. We can avoid branching on SDT_PROBES_ENABLED() by adding the ability to include blocks of code in the out-of-line path. For example: if (SDT_PROBES_ENABLED()) { int reason = CLD_EXITED; if (WCOREDUMP(signo)) reason = CLD_DUMPED; else if (WIFSIGNALED(signo)) reason = CLD_KILLED; SDT_PROBE1(proc, , , exit, reason); } could be written SDT_PROBE1_EXT(proc, , , exit, reason, int reason; reason = CLD_EXITED; if (WCOREDUMP(signo)) reason = CLD_DUMPED; else if (WIFSIGNALED(signo)) reason = CLD_KILLED; ); In the future I would like to use this mechanism more generally, e.g., to remove branches and marshalling code used by hwpmc, and generally to make it easier to add new tracepoint consumers without having to add more conditional branches to hot code paths. Reviewed by: Domagoj Stolfa, avg MFC after: 2 months Differential Revision: https://reviews.freebsd.org/D44483

sys: Remove $FreeBSD$: one-line sh pattern

2023-08-16T17:54:58Z

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

kinst: port to arm64

2023-07-19T14:58:18Z

Reviewed by: markj Approved by: markj (mentor) Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D40337

kinst: port to riscv

2023-07-04T15:38:01Z

Reviewed by: markj Approved by: markj (mentor) Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D39884

dtrace: include fbt module unconditionally

2023-01-12T15:04:36Z

It is supported on all platforms. Reviewed by: markj Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D37658

dtrace: Add pid provider to the build for powerpc

2022-10-30T20:00:56Z

The fasttrap pid provider has been in place for a long time, but stopped getting built by efe88d92da in preparation for 64-bit atomics. 32-bit emulation of 64-bit atomics was added in 9aafc7c05. MFC after: 3 weeks

kinst: Initial revision

2022-10-11T22:19:08Z

This is a new DTrace provider which allows arbitrary kernel instructions to be traced. Currently it is implemented only for amd64. kinst probes are created on demand by libdtrace, and there is a probe for each kernel instruction. Probes are named kinst:::, where "offset" is the offset of the target instruction relative to the beginning of the function. Omitting "offset" causes all instructions in the function to be traced. kinst works similarly to FBT in that it places a breakpoint on the target instruction and hooks into the kernel breakpoint handler. Because kinst has to be able to trace arbitrary instructions, it does not emulate most of them in software but rather causes the traced thread to execute a copy of the instruction before returning to the original code. The provider is quite low-level and as-is will be useful mostly only to kernel developers. However, it provides a great deal of visibility into kernel code execution and could be used as a building block for higher-level tooling which can in some sense translate between C sources and generated machine code. In particular, the "regs" variable recently added to D allows the CPU's register file to be accessed from kinst probes. kinst is experimental and should not be used on production systems for now. In collaboration with: markj Sponsored by: Google, Inc. (GSoC 2022) MFC after: 3 months Differential Revision: https://reviews.freebsd.org/D36851