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| author | markj <markj@FreeBSD.org> | 2014-07-14 04:38:17 +0000 |
|---|---|---|
| committer | markj <markj@FreeBSD.org> | 2014-07-14 04:38:17 +0000 |
| commit | 880dd1a983b61825a671f8a16103eb480f6ce342 (patch) | |
| tree | f6f00a8ecef69c372df2dbabbd94de9a70811897 /sys/amd64/amd64/exception.S | |
| parent | 0b964c341a8548648d88f3097969b1e9b707da2e (diff) | |
| download | FreeBSD-src-880dd1a983b61825a671f8a16103eb480f6ce342.zip FreeBSD-src-880dd1a983b61825a671f8a16103eb480f6ce342.tar.gz | |
Invoke the DTrace trap handler before calling trap() on amd64. This matches
the upstream implementation and helps ensure that a trap induced by tracing
fbt::trap:entry is handled without recursively generating another trap.
This makes it possible to run most (but not all) of the DTrace tests under
common/safety/ without triggering a kernel panic.
Submitted by: Anton Rang <anton.rang@isilon.com> (original version)
Phabric: D95
Diffstat (limited to 'sys/amd64/amd64/exception.S')
| -rw-r--r-- | sys/amd64/amd64/exception.S | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/sys/amd64/amd64/exception.S b/sys/amd64/amd64/exception.S index d51078d..bb5fd56 100644 --- a/sys/amd64/amd64/exception.S +++ b/sys/amd64/amd64/exception.S @@ -228,7 +228,24 @@ alltraps_pushregs_no_rdi: .type calltrap,@function calltrap: movq %rsp,%rdi +#ifdef KDTRACE_HOOKS + /* + * Give DTrace a chance to vet this trap and skip the call to trap() if + * it turns out that it was caused by a DTrace probe. + */ + movq dtrace_trap_func,%rax + testq %rax,%rax + je skiphook + call *%rax + testq %rax,%rax + jne skiptrap + movq %rsp,%rdi +skiphook: +#endif call trap +#ifdef KDTRACE_HOOKS +skiptrap: +#endif MEXITCOUNT jmp doreti /* Handle any pending ASTs */ |
