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.
15 //go:nowritebarrierrec
16 func (c *sigctxt) regs() *regs64 { return &(*ucontext)(c.ctxt).uc_mcontext.ss }
18 func (c *sigctxt) rax() uint64 { return c.regs().rax }
19 func (c *sigctxt) rbx() uint64 { return c.regs().rbx }
20 func (c *sigctxt) rcx() uint64 { return c.regs().rcx }
21 func (c *sigctxt) rdx() uint64 { return c.regs().rdx }
22 func (c *sigctxt) rdi() uint64 { return c.regs().rdi }
23 func (c *sigctxt) rsi() uint64 { return c.regs().rsi }
24 func (c *sigctxt) rbp() uint64 { return c.regs().rbp }
25 func (c *sigctxt) rsp() uint64 { return c.regs().rsp }
26 func (c *sigctxt) r8() uint64 { return c.regs().r8 }
27 func (c *sigctxt) r9() uint64 { return c.regs().r9 }
28 func (c *sigctxt) r10() uint64 { return c.regs().r10 }
29 func (c *sigctxt) r11() uint64 { return c.regs().r11 }
30 func (c *sigctxt) r12() uint64 { return c.regs().r12 }
31 func (c *sigctxt) r13() uint64 { return c.regs().r13 }
32 func (c *sigctxt) r14() uint64 { return c.regs().r14 }
33 func (c *sigctxt) r15() uint64 { return c.regs().r15 }
36 //go:nowritebarrierrec
37 func (c *sigctxt) rip() uint64 { return c.regs().rip }
39 func (c *sigctxt) rflags() uint64 { return c.regs().rflags }
40 func (c *sigctxt) cs() uint64 { return c.regs().cs }
41 func (c *sigctxt) fs() uint64 { return c.regs().fs }
42 func (c *sigctxt) gs() uint64 { return c.regs().gs }
43 func (c *sigctxt) sigcode() uint64 { return uint64(c.info.si_code) }
44 func (c *sigctxt) sigaddr() uint64 { return c.info.si_addr }
46 func (c *sigctxt) set_rip(x uint64) { c.regs().rip = x }
47 func (c *sigctxt) set_rsp(x uint64) { c.regs().rsp = x }
48 func (c *sigctxt) set_sigcode(x uint64) { c.info.si_code = int32(x) }
49 func (c *sigctxt) set_sigaddr(x uint64) { c.info.si_addr = x }
52 func (c *sigctxt) fixsigcode(sig uint32) {
55 // OS X sets c.sigcode() == TRAP_BRKPT unconditionally for all SIGTRAPs,
56 // leaving no way to distinguish a breakpoint-induced SIGTRAP
57 // from an asynchronous signal SIGTRAP.
58 // They all look breakpoint-induced by default.
59 // Try looking at the code to see if it's a breakpoint.
60 // The assumption is that we're very unlikely to get an
61 // asynchronous SIGTRAP at just the moment that the
62 // PC started to point at unmapped memory.
63 pc := uintptr(c.rip())
64 // OS X will leave the pc just after the INT 3 instruction.
65 // INT 3 is usually 1 byte, but there is a 2-byte form.
66 code := (*[2]byte)(unsafe.Pointer(pc - 2))
67 if code[1] != 0xCC && (code[0] != 0xCD || code[1] != 3) {
68 // SIGTRAP on something other than INT 3.
69 c.set_sigcode(_SI_USER)
73 // x86-64 has 48-bit virtual addresses. The top 16 bits must echo bit 47.
74 // The hardware delivers a different kind of fault for a malformed address
75 // than it does for an attempt to access a valid but unmapped address.
76 // OS X 10.9.2 mishandles the malformed address case, making it look like
77 // a user-generated signal (like someone ran kill -SEGV ourpid).
78 // We pass user-generated signals to os/signal, or else ignore them.
79 // Doing that here - and returning to the faulting code - results in an
80 // infinite loop. It appears the best we can do is rewrite what the kernel
81 // delivers into something more like the truth. The address used below
82 // has very little chance of being the one that caused the fault, but it is
83 // malformed, it is clearly not a real pointer, and if it does get printed
84 // in real life, people will probably search for it and find this code.
85 // There are no Google hits for b01dfacedebac1e or 0xb01dfacedebac1e
86 // as I type this comment.
88 // Note: if this code is removed, please consider
89 // enabling TestSignalForwardingGo for darwin-amd64 in
90 // misc/cgo/testcarchive/carchive_test.go.
91 if c.sigcode() == _SI_USER {
92 c.set_sigcode(_SI_USER + 1)
93 c.set_sigaddr(0xb01dfacedebac1e)