signal_amd64.go

Documentation: runtime

     1  // Copyright 2013 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build amd64
     6  // +build darwin dragonfly freebsd linux netbsd openbsd solaris
     7  
     8  package runtime
     9  
    10  import (
    11  	"runtime/internal/sys"
    12  	"unsafe"
    13  )
    14  
    15  func dumpregs(c *sigctxt) {
    16  	print("rax    ", hex(c.rax()), "\n")
    17  	print("rbx    ", hex(c.rbx()), "\n")
    18  	print("rcx    ", hex(c.rcx()), "\n")
    19  	print("rdx    ", hex(c.rdx()), "\n")
    20  	print("rdi    ", hex(c.rdi()), "\n")
    21  	print("rsi    ", hex(c.rsi()), "\n")
    22  	print("rbp    ", hex(c.rbp()), "\n")
    23  	print("rsp    ", hex(c.rsp()), "\n")
    24  	print("r8     ", hex(c.r8()), "\n")
    25  	print("r9     ", hex(c.r9()), "\n")
    26  	print("r10    ", hex(c.r10()), "\n")
    27  	print("r11    ", hex(c.r11()), "\n")
    28  	print("r12    ", hex(c.r12()), "\n")
    29  	print("r13    ", hex(c.r13()), "\n")
    30  	print("r14    ", hex(c.r14()), "\n")
    31  	print("r15    ", hex(c.r15()), "\n")
    32  	print("rip    ", hex(c.rip()), "\n")
    33  	print("rflags ", hex(c.rflags()), "\n")
    34  	print("cs     ", hex(c.cs()), "\n")
    35  	print("fs     ", hex(c.fs()), "\n")
    36  	print("gs     ", hex(c.gs()), "\n")
    37  }
    38  
    39  //go:nosplit
    40  //go:nowritebarrierrec
    41  func (c *sigctxt) sigpc() uintptr { return uintptr(c.rip()) }
    42  
    43  func (c *sigctxt) sigsp() uintptr { return uintptr(c.rsp()) }
    44  func (c *sigctxt) siglr() uintptr { return 0 }
    45  func (c *sigctxt) fault() uintptr { return uintptr(c.sigaddr()) }
    46  
    47  // preparePanic sets up the stack to look like a call to sigpanic.
    48  func (c *sigctxt) preparePanic(sig uint32, gp *g) {
    49  	// Work around Leopard bug that doesn't set FPE_INTDIV.
    50  	// Look at instruction to see if it is a divide.
    51  	// Not necessary in Snow Leopard (si_code will be != 0).
    52  	if GOOS == "darwin" && sig == _SIGFPE && gp.sigcode0 == 0 {
    53  		pc := (*[4]byte)(unsafe.Pointer(gp.sigpc))
    54  		i := 0
    55  		if pc[i]&0xF0 == 0x40 { // 64-bit REX prefix
    56  			i++
    57  		} else if pc[i] == 0x66 { // 16-bit instruction prefix
    58  			i++
    59  		}
    60  		if pc[i] == 0xF6 || pc[i] == 0xF7 {
    61  			gp.sigcode0 = _FPE_INTDIV
    62  		}
    63  	}
    64  
    65  	pc := uintptr(c.rip())
    66  	sp := uintptr(c.rsp())
    67  
    68  	if shouldPushSigpanic(gp, pc, *(*uintptr)(unsafe.Pointer(sp))) {
    69  		c.pushCall(funcPC(sigpanic), pc)
    70  	} else {
    71  		// Not safe to push the call. Just clobber the frame.
    72  		c.set_rip(uint64(funcPC(sigpanic)))
    73  	}
    74  }
    75  
    76  func (c *sigctxt) pushCall(targetPC, resumePC uintptr) {
    77  	// Make it look like we called target at resumePC.
    78  	sp := uintptr(c.rsp())
    79  	sp -= sys.PtrSize
    80  	*(*uintptr)(unsafe.Pointer(sp)) = resumePC
    81  	c.set_rsp(uint64(sp))
    82  	c.set_rip(uint64(targetPC))
    83  }
    84
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