message: Implement XMM register reading on Linux.
diff: @@ -300,10 +300,14 @@ pub struct FaultInfo {
  #[cfg(all(target_os = "linux", target_arch = "x86_64"))]
  pub unsafe fn get_fault_info(siginfo: *const c_void, ucontext: *const c_void) -> FaultInfo {
  use libc::{
  - ucontext_t, REG_R10, REG_R11, REG_R12, REG_R13, REG_R14, REG_R15, REG_R8, REG_R9, REG_RAX,
  - REG_RBP, REG_RBX, REG_RCX, REG_RDI, REG_RDX, REG_RIP, REG_RSI, REG_RSP,
  + _libc_xmmreg, ucontext_t, REG_R10, REG_R11, REG_R12, REG_R13, REG_R14, REG_R15, REG_R8,
  + REG_R9, REG_RAX, REG_RBP, REG_RBX, REG_RCX, REG_RDI, REG_RDX, REG_RIP, REG_RSI, REG_RSP,
  };
  + fn read_xmm(reg: &_libc_xmmreg) -> u64 {
  + (reg.element[0] as u64) | ((reg.element[1] as u64) << 32)
  + }
  +
  #[allow(dead_code)]
  #[repr(C)]
  struct siginfo_t {
  @@ -319,6 +323,7 @@ pub unsafe fn get_fault_info(siginfo: *const c_void, ucontext: *const c_void) ->
  let ucontext = ucontext as *const ucontext_t;
  let gregs = &(*ucontext).uc_mcontext.gregs;
  + let fpregs = &*(*ucontext).uc_mcontext.fpregs;
  let mut known_registers: [Option<u64>; 24] = [None; 24];
  known_registers[X64Register::GPR(GPR::R15).to_index().0] = Some(gregs[REG_R15 as usize] as _);
  @@ -339,7 +344,14 @@ pub unsafe fn get_fault_info(siginfo: *const c_void, ucontext: *const c_void) ->
  known_registers[X64Register::GPR(GPR::RBP).to_index().0] = Some(gregs[REG_RBP as usize] as _);
  known_registers[X64Register::GPR(GPR::RSP).to_index().0] = Some(gregs[REG_RSP as usize] as _);
  - // TODO: XMM registers
  + known_registers[X64Register::XMM(XMM::XMM0).to_index().0] = Some(read_xmm(&fpregs._xmm[0]));
  + known_registers[X64Register::XMM(XMM::XMM1).to_index().0] = Some(read_xmm(&fpregs._xmm[1]));
  + known_registers[X64Register::XMM(XMM::XMM2).to_index().0] = Some(read_xmm(&fpregs._xmm[2]));
  + known_registers[X64Register::XMM(XMM::XMM3).to_index().0] = Some(read_xmm(&fpregs._xmm[3]));
  + known_registers[X64Register::XMM(XMM::XMM4).to_index().0] = Some(read_xmm(&fpregs._xmm[4]));
  + known_registers[X64Register::XMM(XMM::XMM5).to_index().0] = Some(read_xmm(&fpregs._xmm[5]));
  + known_registers[X64Register::XMM(XMM::XMM6).to_index().0] = Some(read_xmm(&fpregs._xmm[6]));
  + known_registers[X64Register::XMM(XMM::XMM7).to_index().0] = Some(read_xmm(&fpregs._xmm[7]));
  FaultInfo {
  faulting_addr: si_addr as usize as _,
  