Support C++ exceptions for rtld-c18n using otypes.

contrib/subrepo-cheri-libunwind/include/__libunwind_config.h

@@ -11,6 +11,14 @@
 
 #define _LIBUNWIND_VERSION 15000
 
+#if defined(_LIBUNWIND_SANDBOX_HARDENED) && !defined(_LIBUNWIND_SANDBOX_OTYPES)
+#error "_LIBUNWIND_SANDBOX_HARDENED is invalid without a sandboxing mechanism"
+#endif
+
+#if defined(_LIBUNWIND_SANDBOX_OTYPES) && defined(_LIBUNWIND_NO_HEAP)
+#error "_LIBUNWIND_NO_HEAP cannot be used with _LIBUNWIND_SANDBOX_OTYPES"
+#endif
+
 #if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && \
     !defined(__ARM_DWARF_EH__) && !defined(__SEH__)
 #define _LIBUNWIND_ARM_EHABI
@@ -20,7 +28,7 @@
 #define _LIBUNWIND_HIGHEST_DWARF_REGISTER_X86_64    32
 #define _LIBUNWIND_HIGHEST_DWARF_REGISTER_PPC       112
 #define _LIBUNWIND_HIGHEST_DWARF_REGISTER_PPC64     116
-#define _LIBUNWIND_HIGHEST_DWARF_REGISTER_MORELLO   229
+#define _LIBUNWIND_HIGHEST_DWARF_REGISTER_MORELLO   230
 #define _LIBUNWIND_HIGHEST_DWARF_REGISTER_ARM64     95
 #define _LIBUNWIND_HIGHEST_DWARF_REGISTER_ARM       287
 #define _LIBUNWIND_HIGHEST_DWARF_REGISTER_OR1K      32
@@ -76,11 +84,11 @@
 # elif defined(__aarch64__)
 #  define _LIBUNWIND_TARGET_AARCH64 1
 #  if defined(__CHERI_PURE_CAPABILITY__)
-#    define _LIBUNWIND_CONTEXT_SIZE 100
+#    define _LIBUNWIND_CONTEXT_SIZE 102
 #    if defined(__SEH__)
 #      error "Pure-capability aarch64 SEH not supported"
 #    else
-#      define _LIBUNWIND_CURSOR_SIZE 124
+#      define _LIBUNWIND_CURSOR_SIZE 126
 #    endif
 #    define _LIBUNWIND_HIGHEST_DWARF_REGISTER _LIBUNWIND_HIGHEST_DWARF_REGISTER_MORELLO
 #  else

contrib/subrepo-cheri-libunwind/include/libunwind.h

@@ -678,7 +678,8 @@ enum {
   UNW_ARM64_C30 = 228,
   UNW_ARM64_CLR = 228,
   UNW_ARM64_C31 = 229,
-  UNW_ARM64_CSP = 229
+  UNW_ARM64_CSP = 229,
+  UNW_ARM64_ECSP = 230,
 };
 
 // 32-bit ARM registers. Numbers match DWARF for ARM spec #3.1 Table 1.

contrib/subrepo-cheri-libunwind/src/AddressSpace.hpp

@@ -22,6 +22,7 @@
 #include "dwarf2.h"
 #include "EHHeaderParser.hpp"
 #include "Registers.hpp"
+#include "unwind_cheri.h"
 
 // We can no longer include C++ headers so duplicate std::min() here
 template<typename T> T uw_min(T a, T b) { return a < b ? a : b; }
@@ -320,6 +321,12 @@ class _LIBUNWIND_HIDDEN LocalAddressSpace {
     return get<v128>(addr);
   }
   capability_t     getCapability(pint_t addr) { return get<capability_t>(addr); }
+#if defined(__CHERI_PURE_CAPABILITY__) && defined(_LIBUNWIND_SANDBOX_OTYPES)
+  static uintcap_t getUnwindSealer();
+  static bool isValidSealer(uintcap_t sealer) {
+    return __builtin_cheri_tag_get(sealer);
+  }
+#endif // __CHERI_PURE_CAPABILITY__ && _LIBUNWIND_SANDBOX_OTYPES
   __attribute__((always_inline))
   uintptr_t       getP(pint_t addr);
   uint64_t        getRegister(pint_t addr);
@@ -408,6 +415,25 @@ inline uint64_t LocalAddressSpace::getRegister(pint_t addr) {
 #endif
 }
 
+#if defined(__CHERI_PURE_CAPABILITY__) && defined(_LIBUNWIND_SANDBOX_OTYPES)
+extern "C" {
+/// Call into the RTLD to get a sealer capability. This sealer will be used to
+/// seal information in the unwinding context if _LIBUNWIND_SANDBOX_HARDENED is
+/// specified.
+uintptr_t _rtld_unw_getsealer(void);
+uintptr_t __rtld_unw_getsealer();
+_LIBUNWIND_HIDDEN uintptr_t __rtld_unw_getsealer() {
+  return (uintptr_t)0;
+}
+_LIBUNWIND_WEAK_ALIAS(__rtld_unw_getsealer, _rtld_unw_getsealer)
+}
+
+/// C++ wrapper for calling into RTLD.
+inline uintcap_t LocalAddressSpace::getUnwindSealer() {
+  return _rtld_unw_getsealer();
+}
+#endif // __CHERI_PURE_CAPABILITY__ && _LIBUNWIND_SANDBOX_OTYPES
+
 /// Read a ULEB128 into a 64-bit word.
 inline uint64_t LocalAddressSpace::getULEB128(pint_t &addr, pint_t end) {
   const uint8_t *p = (uint8_t *)addr;
@@ -932,7 +958,8 @@ inline bool LocalAddressSpace::findUnwindSections(pc_t targetAddr,
     return true;
 #elif defined(_LIBUNWIND_USE_DL_ITERATE_PHDR)
   dl_iterate_cb_data cb_data = {this, &info, targetAddr};
-  CHERI_DBG("Calling dl_iterate_phdr()\n");
+  CHERI_DBG("Calling dl_iterate_phdr(0x%jx)\n",
+            (uintmax_t)targetAddr.address());
   int found = dl_iterate_phdr(findUnwindSectionsByPhdr, &cb_data);
   return static_cast<bool>(found);
 #endif

contrib/subrepo-cheri-libunwind/src/CompartmentInfo.hpp

@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//
+// Abstracts unwind information when used with a compartmentalizing runtime
+// linker.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __COMPARTMENT_INFO_HPP__
+#define __COMPARTMENT_INFO_HPP__
+
+namespace libunwind {
+class _LIBUNWIND_HIDDEN CompartmentInfo {
+public:
+  static CompartmentInfo sThisCompartmentInfo;
+#if defined(__CHERI_PURE_CAPABILITY__)
+  static const uintcap_t kInvalidRCSP = (uintcap_t)0;
+  // Per-architecture trusted stack frame layout.
+#if defined(_LIBUNWIND_TARGET_AARCH64)
+  static const uint32_t kNewSPOffset = 48;
+  static const uint32_t kNextOffset = 32;
+  static const uint32_t kFPOffset = 0;
+  static const uint32_t kCalleeSavedOffset = 80;
+  static const uint32_t kCalleeSavedCount = 10;
+  static const uint32_t kCalleeSavedSize = 16;
+  static const uint32_t kReturnAddressOffset = 40;
+  static const uint32_t kPCOffset = 16;
+  // kCalleeSavedCount - 1 because kCalleeSavedOffset is the first one.
+  static const uint32_t kTrustedFrameSize =
+      kCalleeSavedOffset + (kCalleeSavedCount - 1) * kCalleeSavedSize;
+#endif // _LIBUNWIND_TARGET_AARCH64
+#endif // __CHERI_PURE_CAPABILITY__
+};
+} // namespace libunwind
+#endif // __COMPARTMENT_INFO_HPP__