nixpkgs/pkgs/development/compilers/llvm/aarch64.patch

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--- lib/Support/Unix/Memory.inc
+++ lib/Support/Unix/Memory.inc
@@ -126,8 +126,12 @@
Result.Address = Addr;
Result.Size = NumPages*PageSize;
- if (PFlags & MF_EXEC)
- Memory::InvalidateInstructionCache(Result.Address, Result.Size);
+ // Rely on protectMappedMemory to invalidate instruction cache.
+ if (PFlags & MF_EXEC) {
+ EC = Memory::protectMappedMemory (Result, PFlags);
+ if (EC != std::error_code())
+ return MemoryBlock();
+ }
return Result;
}
@@ -156,15 +160,31 @@
return std::error_code(EINVAL, std::generic_category());
int Protect = getPosixProtectionFlags(Flags);
-
uintptr_t Start = alignAddr((uint8_t *)M.Address - PageSize + 1, PageSize);
uintptr_t End = alignAddr((uint8_t *)M.Address + M.Size, PageSize);
+
+ bool InvalidateCache = (Flags & MF_EXEC);
+
+#if defined(__arm__) || defined(__aarch64__)
+ // Certain ARM implementations treat icache clear instruction as a memory read,
+ // and CPU segfaults on trying to clear cache on !PROT_READ page. Therefore we need
+ // to temporarily add PROT_READ for the sake of flushing the instruction caches.
+ if (InvalidateCache && !(Protect & PROT_READ)) {
+ int Result = ::mprotect((void *)Start, End - Start, Protect | PROT_READ);
+ if (Result != 0)
+ return std::error_code(errno, std::generic_category());
+
+ Memory::InvalidateInstructionCache(M.Address, M.Size);
+ InvalidateCache = false;
+ }
+#endif
+
int Result = ::mprotect((void *)Start, End - Start, Protect);
if (Result != 0)
return std::error_code(errno, std::generic_category());
- if (Flags & MF_EXEC)
+ if (InvalidateCache)
Memory::InvalidateInstructionCache(M.Address, M.Size);
return std::error_code();