arg0 should be an offset of the return point within the function, arg1
should be the return value. Previously the return probe had arguments as
if for the entry probe.
Tested on armv7.
andrew noted that the same problem seems to be present on arm64, mips,
and riscv.
I am not sure if I will get around to fixing those. So, platform users
or anyone looking to make a contribution please be aware of this
opportunity.
Reviewed by: markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D25685
When emulating a load pair or store pair in dtrace on arm64 we need to
copy the data between the stack and trap frame. When the registers are
either the link register or the zero register we will access memory
past the end of the trap frame as these are encoded as registers 30 and
31 respectively while the array they access only has 30 entries.
Fix this by creating 2 helper functions to perform the operation with
special cases for these registers.
Sponsored by: Innovate UK
If DTRACE is enabled at compile time, all kernel breakpoint traps are
first given to dtrace to see if they are triggered by a FBT probe.
Previously if dtrace didn't recognize the trap, it was silently
ignored breaking the handling of other kernel breakpoint traps such as
the debug.kdb.enter sysctl. This only returns early from the trap
handler if dtrace recognizes the trap and handles it.
Submitted by: Nicolò Mazzucato <nicomazz97@gmail.com>
Reviewed by: markj
Obtained from: CheriBSD
Differential Revision: https://reviews.freebsd.org/D24478
r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.
This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.
Mark all obvious cases as MPSAFE. All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT
Approved by: kib (mentor, blanket)
Commented by: kib, gallatin, melifaro
Differential Revision: https://reviews.freebsd.org/D23718
The registers in ilumos and FreeBSD have a different number.
In the illumos, last 32-bits register defined is SS an in FreeBSD is GS.
While translating register we should comper it to the highest one.
PR: 240358
Reported by: lwhsu@
MFC after: 2 weeks
There is no reason for these routines to be written in assembly. In
the ports of DTrace to other platforms, they are already written in C.
No functional change intended.
MFC after: 1 week
Sponsored by: Netflix
The registers in ilumos and FreeBSD have a different number.
In the illumos, last 32-bits register defined is SS an in FreeBSD is GS.
This off-by-one caused the uregs array to returns the wrong 64-bits register
on amd64.
Reviewed by: markj
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20363
'.' function names exist only in ELFv1. ELFv2 does away with function
descriptors, and look more like they do on powerpc(32) and most other
platforms, as direct function pointers. Stop blacklisting regular function
names in ELFv2.
Submitted by: Brandon Bergren
Differential Revision: https://reviews.freebsd.org/D20346
Fix stack unwinding such that requesting N stack frames in lockstat will
actually give you N frames, not anywhere from 0-3 as had been before.
lockstat prints the mutex function instead of the caller as the reported
locker, but the stack frame is detailed enough to find the real caller.
MFC after: 2 weeks
In all practical situations, the resolver visibility is static.
Requested by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Approved by: so (emaste)
Differential revision: https://reviews.freebsd.org/D20281
Fix some execution bugs in the dtrace powerpc asm. addme pulls in the carry
flag which we don't want, and the result wasn't recorded anyways, so the
following beq to check for exit condition wasn't checking the right
condition.
Simplify the stack walking in dtrace_isa.c, so there's only a single walker
that handles both pc and sp. This should make it easier to follow, and any
bugfix that may be needed for walking only needs to be made in one place
instead of two now.
MFC after: 2 weeks
It simply doesn't work in general since VCPUs may migrate between
physical cores. The approach used to measure skew also doesn't
make much sense in a VM.
PR: 218452
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
fasttrap hooks the userspace breakpoint handler; the hook looks up the
breakpoint address in a hash table of tracepoints. It is possible for
the tracepoint to be removed by a different thread in between the
breakpoint trap and the hash table lookup, in which case SIGTRAP gets
delivered to the target process. Fix the problem by adding a
per-process generation counter that gets incremented when a tracepoint
belonging to that process is removed. Then, when a lookup fails, the
trapping instruction is restarted if the thread's counter doesn't match
that of the process.
Reviewed by: cem
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19273
dtrace has its own routines which were not updated after SMAP support got
implemented. Use ifunc just like for other routines.
This in particular fixes ustack().
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18542
The FBT fuction boundary prober was setting one return probe marker value,
but the dtrace handler was expecting another. This causes a hang when
tracing return probes.
There seems to be a race in CI, such that dtrace_asm.S might be assembled
before the genassym is completed. This causes a build failure when PSL_EE
doesn't exist, and is read as 0. Get around this by explicitly specifying
the bits in the mask instead.
- Remove the arm64-specific cpu_*cache* and cpu_tlb_flush* functions.
Instead, add RISC-V specific inline functions in cpufunc.h for the
fence.i and sfence.vma instructions.
- Catch up to changes in the arm64 pmap and remove all the cpu_dcache_*
calls, pmap_is_current, pmap_l3_valid_cacheable, and PTE_NEXT bits from
pmap.
- Remove references to the unimplemented riscv_setttb().
- Remove unused cpu_nullop.
- Add a link to the SBI doc to sbi.h.
- Add support for a 4th argument in SBI calls. It's not documented but
it seems implied for the asid argument to SBI_REMOVE_SFENCE_VMA_ASID.
- Pass the arguments from sbi_remote_sfence*() to the SEE. BBL ignores
them so this is just cosmetic.
- Flush icaches on other CPUs when they resume from kdb in case the
debugger wrote any breakpoints while the CPUs were paused in the IPI_STOP
handler.
- Add SMP vs UP versions of pmap_invalidate_* similar to amd64. The
UP versions just use simple fences. The SMP versions use the
sbi_remove_sfence*() functions to perform TLB shootdowns. Since we
don't have a valid pm_active field in the riscv pmap, just IPI all
CPUs for all invalidations for now.
- Remove an extraneous TLB flush from the end of pmap_bootstrap().
- Don't do a TLB flush when writing new mappings in pmap_enter(), only if
modifying an existing mapping. Note that for COW faults a TLB flush is
only performed after explicitly clearing the old mapping as is done in
other pmaps.
- Sync the i-cache on all harts before updating the PTE for executable
mappings in pmap_enter and pmap_enter_quick. Previously the i-cache was
only sync'd after updating the PTE in pmap_enter.
- Use sbi_remote_fence() instead of smp_rendezvous in pmap_sync_icache().
Reviewed by: markj
Approved by: re (gjb, kib)
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D17414
With GNU ifuncs, multiple FBT probes may correspond to the same
instruction. fbt_invop() assumed that this could not happen and
would return after the first probe found in the global FBT hash
table, which might not be the one that's enabled. Fix the problem
on x86 by linking probes that share a tracepoint and having each
linked probe fire when the tracepoint is hit.
PR: 230846
Approved by: re (gjb)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D16921
Even though there do appear to be more artificial frames, with 12, stack
traces no longer list at all. Revert until a better, more stable value can
be determined.
unwind_frame() may be instrumented by FBT, leading to recursion into
dtrace_probe(). Manually inline unwind_frame() as we do with stack
unwinding code for other architectures.
Submitted by: Domagoj Stolfa
Reviewed by: manu
MFC after: 1 week
Sponsored by: DARPA / AFRL
Differential Revision: https://reviews.freebsd.org/D15359
While here predict false.
Note the code is wrong (regardless of this change). Dereference of the
pointer can race with module unload. A fix would set the probe to a
nop stub instead of NULL.
Each malloc/free was testing dtrace_malloc_enabled and forcing
extra reads from the malloc type struct to see if perhaps a
dtmalloc probe was on.
Treat it like lockstat and sdt: have a global bolean.
This helps catch cases where an instrumented function is called while
in probe context.
Submitted by: Domagoj Stolfa <domagoj.stolfa@gmail.com>
MFC after: 2 weeks
Sponsored by: DARPA/AFRL
Differential Revision: https://reviews.freebsd.org/D14863
These have been supplanted by the MI signal information codes in
<sys/signal.h> since 7.0. The FPE_*_TRAP ones were deprecated even
earlier in 1999.
PR: 226579 (exp-run)
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D14637
assym is only to be included by other .s files, and should never
actually be assembled by itself.
Reviewed by: imp, bdrewery (earlier)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D14180
dtrace_gethrtime() may be called outside of probe context, and in
particular, from the DTRACEIOC_BUFSNAP handler.
Disable interrupts rather than using sched_pin() to help ensure that
we don't call any external functions when in probe context.
PR: 218452
MFC after: 1 week
Turn on the required options in the ERL config file, and ensure
that the fbt module is listed as a dependency for mips in
the modules/dtrace/dtraceall/dtraceall.c file.
PR: 220346
Reviewed by: gnn, markj
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D12227
o Replace __riscv64 with (__riscv && __riscv_xlen == 64)
This is required to support new GCC 7.1 compiler.
This is compatible with current GCC 6.1 compiler.
RISC-V is extensible ISA and the idea here is to have built-in define
per each extension, so together with __riscv we will have some subset
of these as well (depending on -march string passed to compiler):
__riscv_compressed
__riscv_atomic
__riscv_mul
__riscv_div
__riscv_muldiv
__riscv_fdiv
__riscv_fsqrt
__riscv_float_abi_soft
__riscv_float_abi_single
__riscv_float_abi_double
__riscv_cmodel_medlow
__riscv_cmodel_medany
__riscv_cmodel_pic
__riscv_xlen
Reviewed by: ngie
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D11901
Close a potential race in reading the CPU dtrace flags, where a thread can
start on one CPU, and partway through retrieving the flags be swapped out,
while another thread traps and sets the CPU_DTRACE_NOFAULT. This could
cause the first thread to return without handling the fault.
Discussed with: markj@
The idle thread may process callouts while reloading the timer in
cpu_activeclock(). In this case, provide a representative value, &cpu_idle,
instead of 0 for args[0] so that the active thread can be more easily
identified from the probe.
This addresses intermittent failures of the profile-n/tst.argtest.d test.
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D10651
The current method only sort of works, and usually doesn't work reliably.
Also, on Book-E the return address from DEBUG exceptions is not the sentinel
addresses, so it won't exit the loop correctly.
Fix this by better handling trap frames during unwinding, and using the
common trap handler for debug traps, as the code in that segment is
identical between the two.
MFC after: 1 week
r314370 changed EXC_DTRACE to a different instruction, but neglected to
make the same change to fbt, so dtrace didn't actually pick it up,
resulting in entering KDB instead of trapping for dtrace.
MFC after: 1 week
