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author | Andreas Sandberg <Andreas.Sandberg@ARM.com> | 2015-03-02 04:00:27 -0500 |
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committer | Andreas Sandberg <Andreas.Sandberg@ARM.com> | 2015-03-02 04:00:27 -0500 |
commit | 34dcd90b61b6fcde7f4ff1cd717f71edca40f9b9 (patch) | |
tree | a94eaca5591e9f6027e6d279b2ee004d098d38e9 /src/arch/arm/vtophys.cc | |
parent | 670f44e05eb8eb1a56b36c4390cf83807a28d823 (diff) | |
download | gem5-34dcd90b61b6fcde7f4ff1cd717f71edca40f9b9.tar.xz |
arm: Fix broken page table permissions checks in remote GDB
The remote GDB interface currently doesn't check if translations are
valid before reading memory. This causes a panic when GDB tries to
access unmapped memory (e.g., when getting a stack trace). There are
two reasons for this: 1) The function used to check for valid
translations (virtvalid()) doesn't work and panics on invalid
translations. 2) The method in the GDB interface used to test if a
translation is valid (RemoteGDB::acc) always returns true regardless
of the return from virtvalid().
This changeset fixes both of these issues.
Diffstat (limited to 'src/arch/arm/vtophys.cc')
-rw-r--r-- | src/arch/arm/vtophys.cc | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/src/arch/arm/vtophys.cc b/src/arch/arm/vtophys.cc index bed76acbd..3aad35818 100644 --- a/src/arch/arm/vtophys.cc +++ b/src/arch/arm/vtophys.cc @@ -63,8 +63,8 @@ ArmISA::vtophys(Addr vaddr) fatal("VTOPHYS: Can't convert vaddr to paddr on ARM without a thread context"); } -Addr -ArmISA::vtophys(ThreadContext *tc, Addr addr) +static std::pair<bool, Addr> +try_translate(ThreadContext *tc, Addr addr) { Fault fault; // Set up a functional memory Request to pass to the TLB @@ -82,22 +82,33 @@ ArmISA::vtophys(ThreadContext *tc, Addr addr) tlb = static_cast<ArmISA::TLB*>(tc->getDTBPtr()); fault = tlb->translateFunctional(&req, tc, BaseTLB::Read, TLB::NormalTran); if (fault == NoFault) - return req.getPaddr(); + return std::make_pair(true, req.getPaddr()); tlb = static_cast<ArmISA::TLB*>(tc->getITBPtr()); fault = tlb->translateFunctional(&req, tc, BaseTLB::Read, TLB::NormalTran); if (fault == NoFault) - return req.getPaddr(); + return std::make_pair(true, req.getPaddr()); - panic("Table walkers support functional accesses. We should never get here\n"); + return std::make_pair(false, 0); +} + +Addr +ArmISA::vtophys(ThreadContext *tc, Addr addr) +{ + const std::pair<bool, Addr> translation(try_translate(tc, addr)); + + if (translation.first) + return translation.second; + else + panic("Table walkers support functional accesses. We should never get here\n"); } bool ArmISA::virtvalid(ThreadContext *tc, Addr vaddr) { - if (vtophys(tc, vaddr) != -1) - return true; - return false; + const std::pair<bool, Addr> translation(try_translate(tc, vaddr)); + + return translation.first; } |