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go/src/runtime/signal_netbsd_386.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

46 lines
1.8 KiB
Go

// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runtime
import "unsafe"
type sigctxt struct {
info *siginfo
ctxt unsafe.Pointer
}
//go:nosplit
//go:nowritebarrierrec
func (c *sigctxt) regs() *mcontextt { return &(*ucontextt)(c.ctxt).uc_mcontext }
func (c *sigctxt) eax() uint32 { return c.regs().__gregs[_REG_EAX] }
func (c *sigctxt) ebx() uint32 { return c.regs().__gregs[_REG_EBX] }
func (c *sigctxt) ecx() uint32 { return c.regs().__gregs[_REG_ECX] }
func (c *sigctxt) edx() uint32 { return c.regs().__gregs[_REG_EDX] }
func (c *sigctxt) edi() uint32 { return c.regs().__gregs[_REG_EDI] }
func (c *sigctxt) esi() uint32 { return c.regs().__gregs[_REG_ESI] }
func (c *sigctxt) ebp() uint32 { return c.regs().__gregs[_REG_EBP] }
func (c *sigctxt) esp() uint32 { return c.regs().__gregs[_REG_UESP] }
//go:nosplit
//go:nowritebarrierrec
func (c *sigctxt) eip() uint32 { return c.regs().__gregs[_REG_EIP] }
func (c *sigctxt) eflags() uint32 { return c.regs().__gregs[_REG_EFL] }
func (c *sigctxt) cs() uint32 { return c.regs().__gregs[_REG_CS] }
func (c *sigctxt) fs() uint32 { return c.regs().__gregs[_REG_FS] }
func (c *sigctxt) gs() uint32 { return c.regs().__gregs[_REG_GS] }
func (c *sigctxt) sigcode() uint32 { return uint32(c.info._code) }
func (c *sigctxt) sigaddr() uint32 {
return *(*uint32)(unsafe.Pointer(&c.info._reason[0]))
}
func (c *sigctxt) set_eip(x uint32) { c.regs().__gregs[_REG_EIP] = x }
func (c *sigctxt) set_esp(x uint32) { c.regs().__gregs[_REG_UESP] = x }
func (c *sigctxt) set_sigcode(x uint32) { c.info._code = int32(x) }
func (c *sigctxt) set_sigaddr(x uint32) {
*(*uint32)(unsafe.Pointer(&c.info._reason[0])) = x
}