From bdd101c4d4aeab6c9e76250c310c16f5704b8b8c Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Tue, 4 Oct 2022 12:54:36 -0400 Subject: dtrace: Add a "regs" variable This allows invop-based providers (i.e., fbt and kinst) to expose the register file of the CPU at the point where the probe fired. It does not work for SDT providers because their probes are implemented as plain function calls and so don't save registers. It's not clear what semantics "regs" should have for them anyway. This is akin to "uregs", which nominally provides access to the userspace registers. In fact, DIF already had a DIF_VAR_REGS variable defined, it was simply unimplemented. Usage example: print the contents of %rdi upon each call to amd64_syscall(): fbt::amd64_syscall:entry {printf("%x", regs[R_RDI]);} Note that the R_* constants are defined in /usr/lib/dtrace/regs_x86.d. Currently there are no similar definitions for non-x86 platforms. Reviewed by: christos MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D36799 --- cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'cddl') diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c index f55d488f4d91..9621a0fcb391 100644 --- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c +++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c @@ -416,6 +416,8 @@ static const dt_ident_t _dtrace_globals[] = { &dt_idops_func, "void(int)" }, { "rand", DT_IDENT_FUNC, 0, DIF_SUBR_RAND, DT_ATTR_STABCMN, DT_VERS_1_0, &dt_idops_func, "int()" }, +{ "regs", DT_IDENT_ARRAY, 0, DIF_VAR_REGS, DT_ATTR_STABCMN, DT_VERS_1_13, + &dt_idops_regs, NULL }, { "rindex", DT_IDENT_FUNC, 0, DIF_SUBR_RINDEX, DT_ATTR_STABCMN, DT_VERS_1_1, &dt_idops_func, "int(const char *, const char *, [int])" }, #ifdef illumos -- cgit v1.2.3