The EBC driver emits thunks for native to EBC calls, which are short
instructions sequences that bridge the gap between the native execution
environment and the EBC virtual machine.
Since these thunks are allocated using MemoryAllocationLib::AllocatePool(),
they are emitted into EfiBootServicesData regions, which does not reflect
the nature of these thunks accurately, and interferes with strict memory
protection policies that map data regions non-executable.
So instead, create a new helper EbcAllocatePoolForThunk() that invokes the
AllocatePool() boot service directly to allocate EfiBootServicesCode pool
memory explicitly, and wire up this helper for the various architecture
specific thunk generation routines.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
* This patch introduces EbcDebuggerHook.c/h and inserts the required
EBCDebugger references into the existing EBC source files.
* With all the hooks defined to their empty version in EbcDebuggerHook.c
the existing EBC VM behaviour is left unaffected.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
The prototypes of EbcInterpret() and ExecuteEbcImageEntryPoint() are
private to the AARCH64 implementation of EbcDxe, so we can shuffle
the arguments around a bit and make the assembler thunking glue a lot
simpler.
For ExecuteEbcImageEntryPoint(), this involves passing the EntryPoint
argument as the third parameter, rather than the first, which allows
us to do a tail call. For EbcInterpret(), instead of copying each
argument beyond #8 from one native stack frame to the next (before
another copy is made into the VM stack), pass a pointer to the
argument stack.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Feng Tian <feng.tian@intel.com>
The thunk generation is needlessly complex, given that it attempts to
deal with variable length instructions, which don't exist on AArch64.
So replace it with a simple template coded in assembler, with a matching
struct definition in C. That way, we can create and manipulate the thunks
easily without looping over the instructions looking for 'magic' numbers.
Also, use x16 rather than x9, since it is the architectural register to
use for thunks/veneers.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Michael D Kinney
Ard Biesheuvel
Pete Batard
Jeff Brasen