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# fix: ACPI code now safely handles concurrent memory accesses

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This was SVN commit r5273.
This commit is contained in:
janwas 2007-07-25 19:16:00 +00:00
parent 2bc83d9e5c
commit 4ac699d021
1 changed files with 201 additions and 136 deletions
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337
source/lib/sysdep/acpi.cpp
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@ -7,54 +7,197 @@
#pragma pack(1) #pragma pack(1)
typedef const volatile u8* PCV_u8;
//----------------------------------------------------------------------------- typedef const volatile AcpiTable* PCV_AcpiTable;
// table utility functions
//-----------------------------------------------------------------------------
// return 8-bit checksum of a buffer (should be 0) // return 8-bit checksum of a buffer (should be 0)
static u8 ComputeChecksum(const void* buf, size_t numBytes) static u8 ComputeChecksum(PCV_u8 buf, size_t numBytes)
{ {
// (can't use std::accumulate - we need 8-bit wraparound)
u8 sum = 0; u8 sum = 0;
const u8* end = (const u8*)buf+numBytes; for(PCV_u8 p = buf; p < buf+numBytes; p++)
for(const u8* p = (const u8*)buf; p < end; p++)
sum += *p; sum += *p;
return sum; return sum;
} }
// caller is responsible for verifying the table is valid and must //-----------------------------------------------------------------------------
// free() the returned pointer. // exception-safe transactional map/use/unmap
//-----------------------------------------------------------------------------
// note: if the OS happens to unmap our physical memory, the Unsafe*
// functions may crash. we catch this via SEH; on Unix, we'd need handlers
// for SIGBUS and/or SIGSEGV. the code is safe in that it releases the
// mapped memory and returns an error code.
static void* SUCCEEDED = (void*)(intptr_t)1;
static void* FAILED = (void*)(intptr_t)-1;
typedef void* (*UnsafeFunction)(PCV_u8 mem, size_t numBytes, void* arg);
static inline void* CallWithSafetyBlanket(UnsafeFunction func, PCV_u8 mem, size_t numBytes, void* arg)
{
#if MSC_VERSION
__try
{
return func(mem, numBytes, arg);
}
__except(1)
{
return FAILED;
}
#else
return func(mem, numBytes, arg);
#endif
}
static void* TransactPhysicalMemory(u64 physicalAddress, size_t numBytes, UnsafeFunction func, void* arg = 0)
{
PCV_u8 mem = (PCV_u8)mahaf_MapPhysicalMemory(physicalAddress, numBytes);
if(!mem)
return FAILED;
void* ret = CallWithSafetyBlanket(func, mem, numBytes, arg);
mahaf_UnmapPhysicalMemory((volatile void*)mem);
return ret;
}
//-----------------------------------------------------------------------------
// Root System Descriptor Pointer
//-----------------------------------------------------------------------------
struct BiosDataArea
{
u16 serialBase[4];
u16 parallelBase[3];
u16 ebdaSegment;
};
typedef const volatile BiosDataArea* PCV_BiosDataArea;
static void* UnsafeReadEbdaPhysicalAddress(PCV_u8 mem, size_t numBytes, void* UNUSED(arg))
{
debug_assert(numBytes >= sizeof(BiosDataArea));
PCV_BiosDataArea bda = (PCV_BiosDataArea)mem;
const uintptr_t ebdaPhysicalAddress = ((uintptr_t)bda->ebdaSegment) * 16;
return (void*)ebdaPhysicalAddress;
}
struct RSDP
{
char signature[8]; // "RSD PTR "
u8 checksum; // sum of this struct = 0
char oemId[6];
u8 revision; // 0 for 1.0, 2 for 2.0
u32 rsdtPhysicalAddress;
};
typedef const volatile RSDP* PCV_RSDP;
static const size_t RSDP_ALIGNMENT = 16;
static void* UnsafeLocateAndRetrieveRsdp(PCV_u8 buf, size_t numBytes, void* arg)
{
debug_assert(numBytes >= sizeof(RSDP));
for(PCV_u8 p = buf; p < buf+numBytes; p += RSDP_ALIGNMENT)
{
RSDP* prsdp = (RSDP*)p;
if(memcmp(prsdp->signature, "RSD PTR ", 8) != 0)
continue;
if(ComputeChecksum(p, sizeof(RSDP)) != 0)
continue;
*(RSDP*)arg = *prsdp;
return SUCCEEDED;
}
return FAILED;
}
static bool RetrieveRsdp(RSDP& rsdp)
{
// See ACPIspec30b, section 5.2.5.1:
// RSDP is either in the first KIB of the extended BIOS data area,
void* ret = TransactPhysicalMemory(0x400, 0x100, UnsafeReadEbdaPhysicalAddress);
if(ret != FAILED)
{
const uintptr_t ebdaPhysicalAddress = (uintptr_t)ret;
ret = TransactPhysicalMemory(ebdaPhysicalAddress, 0x400, UnsafeLocateAndRetrieveRsdp, &rsdp);
if(ret == SUCCEEDED)
return true;
}
// or in read-only BIOS memory.
ret = TransactPhysicalMemory(0xE0000, 0x20000, UnsafeLocateAndRetrieveRsdp, &rsdp);
if(ret == SUCCEEDED)
return true;
return false; // not found
}
//-----------------------------------------------------------------------------
// table retrieval
//-----------------------------------------------------------------------------
static inline void* UnsafeAllocateCopyOfTable(PCV_u8 mem, size_t numBytes, void* arg)
{
debug_assert(numBytes >= sizeof(AcpiTable));
PCV_AcpiTable table = (PCV_AcpiTable)mem;
const size_t tableSize = table->size;
// physical memory window is smaller than the table
// (caller will map a larger window and call us again)
if(numBytes < tableSize)
{
*(size_t*)arg = tableSize;
return 0;
}
PCV_u8 copy = (PCV_u8)malloc(tableSize);
if(!copy)
return FAILED;
cpu_memcpy((void*)copy, (const void*)mem, tableSize);
return (void*)copy;
}
// caller is responsible for verifying the table is valid and using
// DeallocateTable to free it.
static const AcpiTable* AllocateCopyOfTable(u64 physicalAddress) static const AcpiTable* AllocateCopyOfTable(u64 physicalAddress)
{ {
// ACPI table sizes are not known until they've been mapped. since that // ACPI table sizes are not known until they've been mapped. since that
// is slow, we don't want to do it twice; solution is map enough to // is slow, we don't always want to do it twice. the solution is to map
// hold a typical table. if it should be too small, we do so again. // enough for a typical table; if that is too small, realloc and map again.
static const size_t initialSize = 4*KiB; static const size_t initialSize = 4*KiB;
const volatile AcpiTable* mappedTable = (const volatile AcpiTable*)mahaf_MapPhysicalMemory(physicalAddress, initialSize); size_t actualSize = 0;
if(!mappedTable) void* ret = TransactPhysicalMemory(physicalAddress, initialSize, UnsafeAllocateCopyOfTable, &actualSize);
// initialSize was too small; actualSize has been set
if(ret == 0)
ret = TransactPhysicalMemory(physicalAddress, actualSize, UnsafeAllocateCopyOfTable);
// *either* of the above calls failed to allocate memory
if(ret == FAILED)
return 0; return 0;
const size_t size = mappedTable->size; return (const AcpiTable*)ret;
if(initialSize < size) }
{
mappedTable = (const volatile AcpiTable*)mahaf_MapPhysicalMemory(physicalAddress, size);
if(!mappedTable)
return 0;
}
const AcpiTable* table = (const AcpiTable*)malloc(size);
if(table)
cpu_memcpy((void*)table, (const void*)mappedTable, size);
mahaf_UnmapPhysicalMemory((volatile void*)mappedTable); template<typename T>
static void DeallocateTable(const T* table)
return table; {
free((void*)table);
} }
static bool VerifyTable(const AcpiTable* table, const char* signature = 0) static bool VerifyTable(const AcpiTable* table, const char* signature = 0)
{ {
if(!table)
return false;
// caller knowns the signature; make sure it matches // caller knowns the signature; make sure it matches
if(signature) if(signature)
{ {
@ -79,100 +222,28 @@ static bool VerifyTable(const AcpiTable* table, const char* signature = 0)
// .. AMIBIOS OEMB table has an incorrect checksum (off-by-one), // .. AMIBIOS OEMB table has an incorrect checksum (off-by-one),
// so don't complain about any OEM tables (ignored anyway). // so don't complain about any OEM tables (ignored anyway).
const bool isOemTable = (memcmp(table->signature, "OEM", 3) == 0); const bool isOemTable = (memcmp(table->signature, "OEM", 3) == 0);
if(ComputeChecksum(table, table->size) != 0 && !isOemTable) if(ComputeChecksum((PCV_u8)table, table->size) != 0 && !isOemTable)
return false; return false;
return true; return true;
} }
//----------------------------------------------------------------------------- static const AcpiTable* GetTable(u64 physicalAddress, const char* signature = 0)
// Root System Descriptor Pointer
//-----------------------------------------------------------------------------
struct RSDP
{ {
char signature[8]; // "RSD PTR " const AcpiTable* table = AllocateCopyOfTable(physicalAddress);
u8 checksum; // sum of this struct = 0 if(VerifyTable(table, signature))
char oemId[6]; return table;
u8 revision; // 0 for 1.0, 2 for 2.0 else
u32 rsdtPhysicalAddress;
};
static const size_t RSDP_ALIGNMENT = 16;
static const RSDP* LocateRsdp(const u8* buf, size_t numBytes)
{
const u8* const end = buf+numBytes;
for(const u8* p = buf; p < end; p += RSDP_ALIGNMENT)
{ {
const RSDP* rsdp = (const RSDP*)p; DeallocateTable(table);
if(memcmp(rsdp->signature, "RSD PTR ", 8) != 0)
continue;
if(ComputeChecksum(p, sizeof(RSDP)) != 0)
continue;
return rsdp;
}
return 0;
}
static bool LocateAndRetrieveRsdp(uintptr_t physicalAddress, size_t numBytes, RSDP& rsdp)
{
const volatile u8* buffer = (const volatile u8*)mahaf_MapPhysicalMemory(physicalAddress, numBytes);
if(!buffer)
return false;
const RSDP* prsdp = LocateRsdp((const u8*)buffer, numBytes);
if(prsdp)
rsdp = *prsdp; // stash in output parameter before unmapping
mahaf_UnmapPhysicalMemory((volatile void*)buffer);
return (prsdp != 0);
}
static uintptr_t LocateEbdaPhysicalAddress()
{
#pragma pack(push, 1)
struct BiosDataArea
{
u16 serialBase[4];
u16 parallelBase[3];
u16 ebdaSegment;
};
#pragma pack(pop)
const volatile BiosDataArea* bda = (const volatile BiosDataArea*)mahaf_MapPhysicalMemory(0x400, 0x100);
if(!bda)
return 0; return 0;
}
const uintptr_t ebdaPhysicalAddress = ((uintptr_t)bda->ebdaSegment) * 16;
mahaf_UnmapPhysicalMemory((void*)bda);
return ebdaPhysicalAddress;
}
static bool RetrieveRsdp(RSDP& rsdp)
{
// See ACPIspec30b, section 5.2.5.1:
// RSDP is either in the first KIB of the extended BIOS data area,
const uintptr_t ebdaPhysicalAddress = LocateEbdaPhysicalAddress();
if(LocateAndRetrieveRsdp(ebdaPhysicalAddress, 1*KiB, rsdp))
return true;
// or in read-only BIOS memory.
if(LocateAndRetrieveRsdp(0xE0000, 0x20000, rsdp))
return true;
return false; // not found
} }
//-----------------------------------------------------------------------------
// table storage
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
// Root System Descriptor Table // Root System Descriptor Table
@ -184,56 +255,47 @@ struct RSDT
// avoid std::map et al. because we may be called before _cinit // avoid std::map et al. because we may be called before _cinit
static const AcpiTable** tables; static const AcpiTable** tables;
static size_t numTables; static int numTables;
static bool LatchAllTables() static bool LatchAllTables()
{ {
RSDP rsdp; RSDP rsdp;
if(!RetrieveRsdp(rsdp)) if(!RetrieveRsdp(rsdp))
return false; return false;
const RSDT* rsdt = (const RSDT*)AllocateCopyOfTable(rsdp.rsdtPhysicalAddress); const RSDT* rsdt = (const RSDT*)GetTable(rsdp.rsdtPhysicalAddress, "RSDT");
if(!rsdt) if(!rsdt)
return false; return false;
if(!VerifyTable((const AcpiTable*)rsdt, "RSDT"))
{
free((void*)rsdt);
return false;
}
numTables = (rsdt->header.size - sizeof(AcpiTable)) / sizeof(rsdt->tables[0]); numTables = (rsdt->header.size - sizeof(AcpiTable)) / sizeof(rsdt->tables[0]);
debug_assert(numTables > 0);
tables = new const AcpiTable*[numTables]; tables = new const AcpiTable*[numTables];
for(int i = 0; i < numTables; i++)
tables[i] = GetTable(rsdt->tables[i]);
for(size_t i = 0; i < numTables; i++) DeallocateTable(rsdt);
{
const AcpiTable* table = AllocateCopyOfTable(rsdt->tables[i]);
if(!table)
continue;
if(!VerifyTable(table))
debug_warn("invalid ACPI table");
tables[i] = table; // transfers ownership
}
free((void*)rsdt);
return true; return true;
} }
static void FreeAllTables() static void FreeAllTables()
{ {
for(size_t i = 0; i < numTables; i++) if(tables)
{ {
SAFE_FREE(tables[i]); for(int i = 0; i < numTables; i++)
DeallocateTable(tables[i]);
delete[] tables;
} }
delete[] tables;
} }
const AcpiTable* acpi_GetTable(const char* signature) const AcpiTable* acpi_GetTable(const char* signature)
{ {
// (typically only a few tables, linear search is OK) // (typically only a few tables, linear search is OK)
for(size_t i = 0; i < numTables; i++) for(int i = 0; i < numTables; i++)
{ {
const AcpiTable* table = tables[i]; const AcpiTable* table = tables[i];
if(!table)
continue; // skip invalid tables, e.g. OEM (see above)
if(strncmp(table->signature, signature, 4) == 0) if(strncmp(table->signature, signature, 4) == 0)
return table; return table;
} }
@ -252,13 +314,16 @@ bool acpi_Init()
return true; return true;
if(!mahaf_Init()) if(!mahaf_Init())
{ goto fail;
ModuleSetError(&initState);
return false; if(!LatchAllTables())
} goto fail;
LatchAllTables();
return true; return true;
fail:
ModuleSetError(&initState);
return false;
} }
void acpi_Shutdown() void acpi_Shutdown()