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llvm-project/llvm/lib/Support/Unix/Memory.inc

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//===- Unix/Memory.cpp - Generic UNIX System Configuration ------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines some functions for various memory management utilities.
//
//===----------------------------------------------------------------------===//
#include "Unix.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Process.h"
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#ifdef __APPLE__
#include <mach/mach.h>
#endif
#if defined(__mips__)
# if defined(__OpenBSD__)
# include <mips64/sysarch.h>
# else
# include <sys/cachectl.h>
# endif
#endif
#ifdef __APPLE__
extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
#else
extern "C" void __clear_cache(void *, void*);
#endif
namespace {
int getPosixProtectionFlags(unsigned Flags) {
switch (Flags) {
case llvm::sys::Memory::MF_READ:
return PROT_READ;
case llvm::sys::Memory::MF_WRITE:
return PROT_WRITE;
case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_WRITE:
return PROT_READ | PROT_WRITE;
case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_EXEC:
return PROT_READ | PROT_EXEC;
case llvm::sys::Memory::MF_READ | llvm::sys::Memory::MF_WRITE |
llvm::sys::Memory::MF_EXEC:
return PROT_READ | PROT_WRITE | PROT_EXEC;
case llvm::sys::Memory::MF_EXEC:
#if defined(__FreeBSD__)
// On PowerPC, having an executable page that has no read permission
// can have unintended consequences. The function InvalidateInstruction-
// Cache uses instructions dcbf and icbi, both of which are treated by
// the processor as loads. If the page has no read permissions,
// executing these instructions will result in a segmentation fault.
// Somehow, this problem is not present on Linux, but it does happen
// on FreeBSD.
return PROT_READ | PROT_EXEC;
#else
return PROT_EXEC;
#endif
default:
llvm_unreachable("Illegal memory protection flag specified!");
}
// Provide a default return value as required by some compilers.
return PROT_NONE;
}
} // anonymous namespace
namespace llvm {
namespace sys {
MemoryBlock
Memory::allocateMappedMemory(size_t NumBytes,
const MemoryBlock *const NearBlock,
unsigned PFlags,
std::error_code &EC) {
EC = std::error_code();
if (NumBytes == 0)
return MemoryBlock();
static const size_t PageSize = Process::getPageSize();
const size_t NumPages = (NumBytes+PageSize-1)/PageSize;
int fd = -1;
int MMFlags = MAP_PRIVATE |
#ifdef MAP_ANONYMOUS
MAP_ANONYMOUS
#else
MAP_ANON
#endif
; // Ends statement above
int Protect = getPosixProtectionFlags(PFlags);
// Use any near hint and the page size to set a page-aligned starting address
uintptr_t Start = NearBlock ? reinterpret_cast<uintptr_t>(NearBlock->base()) +
NearBlock->size() : 0;
if (Start && Start % PageSize)
Start += PageSize - Start % PageSize;
void *Addr = ::mmap(reinterpret_cast<void*>(Start), PageSize*NumPages,
Protect, MMFlags, fd, 0);
if (Addr == MAP_FAILED) {
if (NearBlock) //Try again without a near hint
return allocateMappedMemory(NumBytes, nullptr, PFlags, EC);
EC = std::error_code(errno, std::generic_category());
return MemoryBlock();
}
MemoryBlock Result;
Result.Address = Addr;
Result.Size = NumPages*PageSize;
if (PFlags & MF_EXEC)
Memory::InvalidateInstructionCache(Result.Address, Result.Size);
return Result;
}
std::error_code
Memory::releaseMappedMemory(MemoryBlock &M) {
if (M.Address == nullptr || M.Size == 0)
return std::error_code();
if (0 != ::munmap(M.Address, M.Size))
return std::error_code(errno, std::generic_category());
M.Address = nullptr;
M.Size = 0;
return std::error_code();
}
std::error_code
Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
static const size_t PageSize = Process::getPageSize();
if (M.Address == nullptr || M.Size == 0)
return std::error_code();
if (!Flags)
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);
int Result = ::mprotect((void *)Start, End - Start, Protect);
if (Result != 0)
return std::error_code(errno, std::generic_category());
if (Flags & MF_EXEC)
Memory::InvalidateInstructionCache(M.Address, M.Size);
return std::error_code();
}
/// AllocateRWX - Allocate a slab of memory with read/write/execute
/// permissions. This is typically used for JIT applications where we want
/// to emit code to the memory then jump to it. Getting this type of memory
/// is very OS specific.
///
MemoryBlock
Memory::AllocateRWX(size_t NumBytes, const MemoryBlock* NearBlock,
std::string *ErrMsg) {
if (NumBytes == 0) return MemoryBlock();
static const size_t PageSize = Process::getPageSize();
size_t NumPages = (NumBytes+PageSize-1)/PageSize;
int fd = -1;
int flags = MAP_PRIVATE |
#ifdef MAP_ANONYMOUS
MAP_ANONYMOUS
#else
MAP_ANON
#endif
;
void* start = NearBlock ? (unsigned char*)NearBlock->base() +
NearBlock->size() : nullptr;
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_EXEC,
flags, fd, 0);
#elif defined(__NetBSD__) && defined(PROT_MPROTECT)
void *pa =
::mmap(start, PageSize * NumPages,
PROT_READ | PROT_WRITE | PROT_MPROTECT(PROT_EXEC), flags, fd, 0);
#else
void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
flags, fd, 0);
#endif
if (pa == MAP_FAILED) {
if (NearBlock) //Try again without a near hint
return AllocateRWX(NumBytes, nullptr);
MakeErrMsg(ErrMsg, "Can't allocate RWX Memory");
return MemoryBlock();
}
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)pa,
(vm_size_t)(PageSize*NumPages), 0,
VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
if (KERN_SUCCESS != kr) {
MakeErrMsg(ErrMsg, "vm_protect max RX failed");
return MemoryBlock();
}
kr = vm_protect(mach_task_self(), (vm_address_t)pa,
(vm_size_t)(PageSize*NumPages), 0,
VM_PROT_READ | VM_PROT_WRITE);
if (KERN_SUCCESS != kr) {
MakeErrMsg(ErrMsg, "vm_protect RW failed");
return MemoryBlock();
}
#endif
MemoryBlock result;
result.Address = pa;
result.Size = NumPages*PageSize;
return result;
}
bool Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) {
if (M.Address == nullptr || M.Size == 0) return false;
if (0 != ::munmap(M.Address, M.Size))
return MakeErrMsg(ErrMsg, "Can't release RWX Memory");
return false;
}
bool Memory::setWritable (MemoryBlock &M, std::string *ErrMsg) {
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
if (M.Address == 0 || M.Size == 0) return false;
Memory::InvalidateInstructionCache(M.Address, M.Size);
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address,
(vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_WRITE);
return KERN_SUCCESS == kr;
#else
return true;
#endif
}
bool Memory::setExecutable (MemoryBlock &M, std::string *ErrMsg) {
if (M.Address == nullptr || M.Size == 0) return false;
Memory::InvalidateInstructionCache(M.Address, M.Size);
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address,
(vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
return KERN_SUCCESS == kr;
#else
return true;
#endif
}
bool Memory::setRangeWritable(const void *Addr, size_t Size) {
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)Addr,
(vm_size_t)Size, 0,
VM_PROT_READ | VM_PROT_WRITE);
return KERN_SUCCESS == kr;
#else
return true;
#endif
}
bool Memory::setRangeExecutable(const void *Addr, size_t Size) {
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)Addr,
(vm_size_t)Size, 0,
VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
return KERN_SUCCESS == kr;
#else
return true;
#endif
}
/// InvalidateInstructionCache - Before the JIT can run a block of code
/// that has been emitted it must invalidate the instruction cache on some
/// platforms.
void Memory::InvalidateInstructionCache(const void *Addr,
size_t Len) {
// icache invalidation for PPC and ARM.
#if defined(__APPLE__)
# if (defined(__POWERPC__) || defined (__ppc__) || \
defined(_POWER) || defined(_ARCH_PPC) || defined(__arm__) || \
defined(__arm64__))
sys_icache_invalidate(const_cast<void *>(Addr), Len);
# endif
#else
# if (defined(__POWERPC__) || defined (__ppc__) || \
defined(_POWER) || defined(_ARCH_PPC)) && defined(__GNUC__)
const size_t LineSize = 32;
const intptr_t Mask = ~(LineSize - 1);
const intptr_t StartLine = ((intptr_t) Addr) & Mask;
const intptr_t EndLine = ((intptr_t) Addr + Len + LineSize - 1) & Mask;
for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
asm volatile("dcbf 0, %0" : : "r"(Line));
asm volatile("sync");
for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
asm volatile("icbi 0, %0" : : "r"(Line));
asm volatile("isync");
# elif (defined(__arm__) || defined(__aarch64__) || defined(__mips__)) && \
defined(__GNUC__)
// FIXME: Can we safely always call this for __GNUC__ everywhere?
const char *Start = static_cast<const char *>(Addr);
const char *End = Start + Len;
__clear_cache(const_cast<char *>(Start), const_cast<char *>(End));
# endif
#endif // end apple
ValgrindDiscardTranslations(Addr, Len);
}
} // namespace sys
} // namespace llvm
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