From 88fdce5be696c7ef992cffce9da9ec6895a1abfc Mon Sep 17 00:00:00 2001 From: David Spickett Date: Wed, 3 Nov 2021 12:10:40 +0000 Subject: [lldb] Remove non address bits from memory read arguments Addresses on AArch64 can have top byte tags, memory tags and pointer authentication signatures in the upper bits. While testing memory tagging I found that memory read couldn't read a range if the two addresses had different tags. The same could apply to signed pointers given the right circumstance. (lldb) memory read mte_buf_alt_tag mte_buf+16 error: end address (0x900fffff7ff8010) must be greater than the start address (0xa00fffff7ff8000). Or it would try to read a lot more memory than expected. (lldb) memory read mte_buf mte_buf_alt_tag+16 error: Normally, 'memory read' will not read over 1024 bytes of data. error: Please use --force to override this restriction just once. error: or set target.max-memory-read-size if you will often need a larger limit. Fix this by removing non address bits before we calculate the read range. A test is added for AArch64 Linux that confirms this by using the top byte ignore feature. This means that if you do read with a tagged pointer the output does not include those tags. This is potentially confusing but I think overall it's better that we don't pretend that we're reading memory from a range that the process is unable to map. (lldb) p ptr1 (char *) $4 = 0x3400fffffffff140 "\x80\xf1\xff\xff\xff\xff" (lldb) p ptr2 (char *) $5 = 0x5600fffffffff140 "\x80\xf1\xff\xff\xff\xff" (lldb) memory read ptr1 ptr2+16 0xfffffffff140: 80 f1 ff ff ff ff 00 00 38 70 bc f7 ff ff 00 00 ........8p...... Reviewed By: omjavaid, danielkiss Differential Revision: https://reviews.llvm.org/D103626 --- lldb/source/Commands/CommandObjectMemory.cpp | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'lldb/source/Commands/CommandObjectMemory.cpp') diff --git a/lldb/source/Commands/CommandObjectMemory.cpp b/lldb/source/Commands/CommandObjectMemory.cpp index 9df42f36fafd..e59cd8028998 100644 --- a/lldb/source/Commands/CommandObjectMemory.cpp +++ b/lldb/source/Commands/CommandObjectMemory.cpp @@ -23,6 +23,7 @@ #include "lldb/Interpreter/Options.h" #include "lldb/Symbol/SymbolFile.h" #include "lldb/Symbol/TypeList.h" +#include "lldb/Target/ABI.h" #include "lldb/Target/Language.h" #include "lldb/Target/MemoryHistory.h" #include "lldb/Target/MemoryRegionInfo.h" @@ -590,9 +591,16 @@ protected: return false; } + ABISP abi = m_exe_ctx.GetProcessPtr()->GetABI(); + if (abi) + addr = abi->FixDataAddress(addr); + if (argc == 2) { lldb::addr_t end_addr = OptionArgParser::ToAddress( &m_exe_ctx, command[1].ref(), LLDB_INVALID_ADDRESS, nullptr); + if (end_addr != LLDB_INVALID_ADDRESS && abi) + end_addr = abi->FixDataAddress(end_addr); + if (end_addr == LLDB_INVALID_ADDRESS) { result.AppendError("invalid end address expression."); result.AppendError(error.AsCString()); -- cgit v1.2.3