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go/src/runtime/defs_plan9_amd64.go
Ian Lance Taylor d03e8b226c runtime: record current PC for SIGPROF on non-Go thread
If we get a SIGPROF on a non-Go thread, and the program has not called
runtime.SetCgoTraceback so we have no way to collect a stack trace, then
record a profile that is just the PC where the signal occurred. That
will at least point the user to the right area.

Retrieving the PC from the sigctxt in a signal handler on a non-G thread
required marking a number of trivial sigctxt methods as nosplit, and,
for extra safety, nowritebarrierrec.

The test shows that the existing test CgoPprofThread test does not test
the stack trace, just the profile signal. Leaving that for later.

Change-Id: I8f8f3ff09ac099fc9d9df94b5a9d210ffc20c4ab
Reviewed-on: https://go-review.googlesource.com/30252
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2016-10-11 12:56:15 +00:00

78 lines
1.7 KiB
Go

package runtime
const _PAGESIZE = 0x1000
type ureg struct {
ax uint64
bx uint64
cx uint64
dx uint64
si uint64
di uint64
bp uint64
r8 uint64
r9 uint64
r10 uint64
r11 uint64
r12 uint64
r13 uint64
r14 uint64
r15 uint64
ds uint16
es uint16
fs uint16
gs uint16
_type uint64
error uint64 /* error code (or zero) */
ip uint64 /* pc */
cs uint64 /* old context */
flags uint64 /* old flags */
sp uint64 /* sp */
ss uint64 /* old stack segment */
}
type sigctxt struct {
u *ureg
}
//go:nosplit
//go:nowritebarrierrec
func (c *sigctxt) pc() uintptr { return uintptr(c.u.ip) }
func (c *sigctxt) sp() uintptr { return uintptr(c.u.sp) }
func (c *sigctxt) lr() uintptr { return uintptr(0) }
func (c *sigctxt) setpc(x uintptr) { c.u.ip = uint64(x) }
func (c *sigctxt) setsp(x uintptr) { c.u.sp = uint64(x) }
func (c *sigctxt) setlr(x uintptr) {}
func (c *sigctxt) savelr(x uintptr) {}
func dumpregs(u *ureg) {
print("ax ", hex(u.ax), "\n")
print("bx ", hex(u.bx), "\n")
print("cx ", hex(u.cx), "\n")
print("dx ", hex(u.dx), "\n")
print("di ", hex(u.di), "\n")
print("si ", hex(u.si), "\n")
print("bp ", hex(u.bp), "\n")
print("sp ", hex(u.sp), "\n")
print("r8 ", hex(u.r8), "\n")
print("r9 ", hex(u.r9), "\n")
print("r10 ", hex(u.r10), "\n")
print("r11 ", hex(u.r11), "\n")
print("r12 ", hex(u.r12), "\n")
print("r13 ", hex(u.r13), "\n")
print("r14 ", hex(u.r14), "\n")
print("r15 ", hex(u.r15), "\n")
print("ip ", hex(u.ip), "\n")
print("flags ", hex(u.flags), "\n")
print("cs ", hex(u.cs), "\n")
print("fs ", hex(u.fs), "\n")
print("gs ", hex(u.gs), "\n")
}
func sigpanictramp() {}