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// Copyright 2023 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.
//go:build ppc64le && linux
package runtime
import (
"internal/abi"
"internal/goarch"
"math"
"unsafe"
)
type sigContext struct {
savedRegs sigcontext
}
func sigctxtSetContextRegister(ctxt *sigctxt, x uint64) {
ctxt.regs().gpr[11] = x
}
func sigctxtAtTrapInstruction(ctxt *sigctxt) bool {
return *(*uint32)(unsafe.Pointer(ctxt.sigpc())) == 0x7fe00008 // Trap
}
func sigctxtStatus(ctxt *sigctxt) uint64 {
return ctxt.r20()
}
func (h *debugCallHandler) saveSigContext(ctxt *sigctxt) {
sp := ctxt.sp()
sp -= 4 * goarch.PtrSize
ctxt.set_sp(sp)
*(*uint64)(unsafe.Pointer(uintptr(sp))) = ctxt.link() // save the current lr
ctxt.set_link(ctxt.pc()) // set new lr to the current pc
// Write the argument frame size.
*(*uintptr)(unsafe.Pointer(uintptr(sp - 32))) = h.argSize
// Save current registers.
h.sigCtxt.savedRegs = *ctxt.cregs()
}
// case 0
func (h *debugCallHandler) debugCallRun(ctxt *sigctxt) {
sp := ctxt.sp()
memmove(unsafe.Pointer(uintptr(sp)+32), h.argp, h.argSize)
if h.regArgs != nil {
storeRegArgs(ctxt.cregs(), h.regArgs)
}
// Push return PC, which should be the signal PC+4, because
// the signal PC is the PC of the trap instruction itself.
ctxt.set_link(ctxt.pc() + 4)
// Set PC to call and context register.
ctxt.set_pc(uint64(h.fv.fn))
sigctxtSetContextRegister(ctxt, uint64(uintptr(unsafe.Pointer(h.fv))))
}
// case 1
func (h *debugCallHandler) debugCallReturn(ctxt *sigctxt) {
sp := ctxt.sp()
memmove(h.argp, unsafe.Pointer(uintptr(sp)+32), h.argSize)
if h.regArgs != nil {
loadRegArgs(h.regArgs, ctxt.cregs())
}
// Restore the old lr from *sp
olr := *(*uint64)(unsafe.Pointer(uintptr(sp)))
ctxt.set_link(olr)
pc := ctxt.pc()
ctxt.set_pc(pc + 4) // step to next instruction
}
// case 2
func (h *debugCallHandler) debugCallPanicOut(ctxt *sigctxt) {
sp := ctxt.sp()
memmove(unsafe.Pointer(&h.panic), unsafe.Pointer(uintptr(sp)+32), 2*goarch.PtrSize)
ctxt.set_pc(ctxt.pc() + 4)
}
// case 8
func (h *debugCallHandler) debugCallUnsafe(ctxt *sigctxt) {
sp := ctxt.sp()
reason := *(*string)(unsafe.Pointer(uintptr(sp) + 40))
h.err = plainError(reason)
ctxt.set_pc(ctxt.pc() + 4)
}
// case 16
func (h *debugCallHandler) restoreSigContext(ctxt *sigctxt) {
// Restore all registers except for pc and sp
pc, sp := ctxt.pc(), ctxt.sp()
*ctxt.cregs() = h.sigCtxt.savedRegs
ctxt.set_pc(pc + 4)
ctxt.set_sp(sp)
}
// storeRegArgs sets up argument registers in the signal
// context state from an abi.RegArgs.
//
// Both src and dst must be non-nil.
func storeRegArgs(dst *sigcontext, src *abi.RegArgs) {
// Gprs R3..R10, R14..R17 are used to pass int arguments in registers on PPC64
for i := 0; i < 12; i++ {
if i > 7 {
dst.gp_regs[i+6] = uint64(src.Ints[i])
} else {
dst.gp_regs[i+3] = uint64(src.Ints[i])
}
}
// Fprs F1..F13 are used to pass float arguments in registers on PPC64
for i := 0; i < 12; i++ {
dst.fp_regs[i+1] = math.Float64frombits(src.Floats[i])
}
}
func loadRegArgs(dst *abi.RegArgs, src *sigcontext) {
// Gprs R3..R10, R14..R17 are used to pass int arguments in registers on PPC64
for i := range [12]int{} {
if i > 7 {
dst.Ints[i] = uintptr(src.gp_regs[i+6])
} else {
dst.Ints[i] = uintptr(src.gp_regs[i+3])
}
}
// Fprs F1..F13 are used to pass float arguments in registers on PPC64
for i := range [12]int{} {
dst.Floats[i] = math.Float64bits(src.fp_regs[i+1])
}
}
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