Currently, we use the non-Xcode5 version of ExceptionHandlerAsm.nasm
only for the SEC and PEI phases, and this version was not compatible
with the XCODE or LLD linkers, which do not permit absolute relocations
in read-only sections.
Given that SEC and PEI code typically executes in place from flash and
does not use page alignment for sections, we can simply emit the code
carrying the absolute symbol references into the .data segment instead.
This works around the linker's objections, and the resulting image will
be mapped executable in its entirety anyway. Since this is only needed
for XCODE, let's make this change conditionally using a preprocessor
macro.
Let's rename the .nasm file to reflect the fact that is used for the
SecPei flavor of this library only, and while at it, remove some
unnecessary absolute references.
Also update the Xcode specific version of this library, and use this
source file instead. This is necesessary, as the Xcode specific version
modifies its own code at runtime, which is not permitted in SEC or PEI.
Note that this also removes CET support from the Xcode5 specific build
of the SEC/PEI version of this library, but this is not needed this
early in any case, and this aligns it with other toolchains, which use
this version of the library, which does not have CET support either.
1. Change for non-XCODE SecPeiCpuExceptionHandlerLib:
. Use SecPeiExceptionHandlerAsm.nasm (renamed from
ExceptionHandlerAsm.nasm)
. Removed some unnecessary absolute references
(32 IDT stubs are still in .text.)
2. Change for XCODE SecPeiCpuExceptionHandlerLib:
. Use SecPeiExceptionHandlerAsm.nasm instead of
Xcode5ExceptionHandlerAsm.nasm
. CET logic is not in SecPeiExceptionHandlerAsm.nasm (but aligns to
non-XCODE lib instance)
. Fixed a bug that does runtime fixup in TEXT section in SPI flash.
. Emitted the code carrying the absolute symbol references into the
.data which XCODE or LLD linkers allow.
. Then fixup can be done by other build tools such as GenFv if the code
runs in SPI flash, or by PE coff loader if the code is loaded to
memory.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Ray Ni <ray.ni@intel.com>
The API of InitializeSeparateExceptionStacks is just changed before, and
makes the struct CPU_EXCEPTION_INIT_DATA an internal definition.
Furthermore, we can even remove the struct to make core simpler.
Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>
If CET shadows stack feature enabled in SMM and stack switch is enabled.
When code execute from SMM handler to SMM exception, CPU will check SMM
exception shadow stack token busy bit if it is cleared or not.
If it is set, it will trigger #DF exception.
If it is not set, CPU will set the busy bit when enter SMM exception.
So, the busy bit should be cleared when return back form SMM exception to
SMM handler. Otherwise, keeping busy bit 1 will cause to trigger #DF
exception when enter SMM exception next time.
So, we use instruction SAVEPREVSSP, CLRSSBSY and RSTORSSP to clear the
shadow stack token busy bit before RETF instruction in SMM exception.
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3192
Signed-off-by: Sheng Wei <w.sheng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Roger Feng <roger.feng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198
Add base support to handle #VC exceptions. Update the common exception
handlers to invoke the VmgExitHandleVc () function of the VmgExitLib
library when a #VC is encountered. A non-zero return code will propagate
to the targeted exception handler.
Under SEV-ES, a DR7 read or write intercept generates a #VC exception.
To avoid exception recursion, a #VC exception will not try to read and
push the actual debug registers into the EFI_SYSTEM_CONTEXT_X64 struct
and instead push zeroes. The #VC exception handler does not make use of
the debug registers from the saved context and the exception processing
exit code does not attempt to restore the debug register values.
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
