Fix various typos in comments and documentation.
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Antoine Coeur <coeur@gmx.fr>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Signed-off-by: Philippe Mathieu-Daude <philmd@redhat.com>
Message-Id: <20200207010831.9046-78-philmd@redhat.com>
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1091
Previously, when compiling NASM source files, BaseTools did not support
including files outside of the NASM source file directory. As a result, we
duplicated multiple copies of "StuffRsb.inc" files in UefiCpuPkg. Those
INC files contain the common logic to stuff the Return Stack Buffer and
are identical.
After the fix of BZ 1085:
https://bugzilla.tianocore.org/show_bug.cgi?id=1085
The above support was introduced.
Thus, this commit will merge all the StuffRsb.inc files in UefiCpuPkg into
one file. The merged file will be named 'StuffRsbNasm.inc' and be placed
under folder UefiCpuPkg/Include/.
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1093
Return Stack Buffer (RSB) is used to predict the target of RET
instructions. When the RSB underflows, some processors may fall back to
using branch predictors. This might impact software using the retpoline
mitigation strategy on those processors.
This commit will add RSB stuffing logic before returning from SMM (the RSM
instruction) to avoid interfering with non-SMM usage of the retpoline
technique.
After the stuffing, RSB entries will contain a trap like:
@SpecTrap:
pause
lfence
jmp @SpecTrap
A more detailed explanation of the purpose of commit is under the
'Branch target injection mitigation' section of the below link:
https://software.intel.com/security-software-guidance/insights/host-firmware-speculative-execution-side-channel-mitigation
Please note that this commit requires further actions (BZ 1091) to remove
the duplicated 'StuffRsb.inc' files and merge them into one under a
UefiCpuPkg package-level directory (such as UefiCpuPkg/Include/).
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1091
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
(1) SmmRelocationSemaphoreComplete32() runs in 32-bit mode, so wrap it in
a (BITS 32 ... BITS 64) bracket.
(2) SmmRelocationSemaphoreComplete32() currently compiles to:
> 000002AE C6050000000001 mov byte [dword 0x0],0x1
> 000002B5 FF2500000000 jmp dword [dword 0x0]
where the first instruction is patched with the contents of
"mRebasedFlag" (so that (*mRebasedFlag) is set to 1), and the second
instruction is patched with the address of
"mSmmRelocationOriginalAddress" (so that we jump to
"mSmmRelocationOriginalAddress").
In its current form the first instruction could not be patched with
PatchInstructionX86(), given that the operand to patch is not encoded
in the trailing bytes of the instruction. Therefore, adopt an
EAX-based version, inspired by both the IA32 and X64 variants of
SmmRelocationSemaphoreComplete():
> 000002AE 50 push eax
> 000002AF B800000000 mov eax,0x0
> 000002B4 C60001 mov byte [eax],0x1
> 000002B7 58 pop eax
> 000002B8 FF2500000000 jmp dword [dword 0x0]
Here both instructions can be patched with PatchInstructionX86(), and
the DBs can be replaced with native NASM syntax.
(3) Turn the "mRebasedFlagAddr32" and "mSmmRelocationOriginalAddressPtr32"
variables into markers that suit PatchInstructionX86().
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Rename the variable to "gPatchSmmInitStack" so that its association with
PatchInstructionX86() is clear from the declaration, change its type to
X86_ASSEMBLY_PATCH_LABEL, and patch it with PatchInstructionX86(). This
lets us remove the binary (DB) encoding of some instructions in
"SmmInit.nasm".
The size of the patched source operand is (sizeof (UINTN)).
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
The IA32 version of "SmmInit.nasm" does not need "gSmmJmpAddr" at all (its
PiSmmCpuSmmInitFixupAddress() variant doesn't do anything either). We can
simply use the NASM syntax for the following Mixed-Size Jump:
> jmp PROTECT_MODE_CS : dword @32bit
The generated object code for the instruction is unchanged:
> 00000182 66EA5A0000000800 jmp dword 0x8:0x5a
(The NASM manual explains that putting the DWORD prefix after the colon
":" reflects the intent better, since it is the offset that is a DWORD.
Thus, that's what I used. However, both syntaxes are interchangeable,
hence the ndisasm output.)
The X64 version of "SmmInit.nasm" appears to require "gSmmJmpAddr";
however that's accidental, not inherent:
- Bring LONG_MODE_CODE_SEGMENT from
"UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h" to "SmmInit.nasm" as
LONG_MODE_CS, same as PROTECT_MODE_CODE_SEGMENT was brought to the IA32
version as PROTECT_MODE_CS earlier.
- Apply the NASM-native Mixed-Size Jump syntax again, but jump to the
fixed zero offset in LONG_MODE_CS. This will produce no relocation
record at all. Add a label after the instruction.
- Modify PiSmmCpuSmmInitFixupAddress() to patch the jump target backwards
from the label. Because we modify the DWORD offset with a DWORD access,
the segment selector is unharmed in the instruction, and we need not set
it from PiCpuSmmEntry().
According to "objdump --reloc", the X64 version undergoes only the
following relocations, after this patch:
> RELOCATION RECORDS FOR [.text]:
> OFFSET TYPE VALUE
> 0000000000000095 R_X86_64_PC32 SmmInitHandler-0x0000000000000004
> 00000000000000e0 R_X86_64_PC32 mRebasedFlag-0x0000000000000004
> 00000000000000ea R_X86_64_PC32 mSmmRelocationOriginalAddress-0x0000000000000004
Therefore the patch does not regress
<https://bugzilla.tianocore.org/show_bug.cgi?id=849> ("Enable XCODE5 tool
chain for UefiCpuPkg with nasm source code").
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Like "gSmmCr4" in the previous patch, "gSmmCr0" is not only used for
machine code patching, but also as a means to communicate the initial CR0
value from SmmRelocateBases() to InitSmmS3ResumeState(). In other words,
the last four bytes of the "mov eax, Cr0Value" instruction's binary
representation are utilized as normal data too.
In order to get rid of the DB for "mov eax, Cr0Value", we have to split
both roles, patching and data flow. Introduce the "mSmmCr0" global (SMRAM)
variable for the data flow purpose. Rename the "gSmmCr0" variable to
"gPatchSmmCr0" so that its association with PatchInstructionX86() is clear
from the declaration, change its type to X86_ASSEMBLY_PATCH_LABEL, and
patch it with PatchInstructionX86(), to the value now contained in
"mSmmCr0".
This lets us remove the binary (DB) encoding of "mov eax, Cr0Value" in
"SmmInit.nasm".
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Unlike "gSmmCr3" in the previous patch, "gSmmCr4" is not only used for
machine code patching, but also as a means to communicate the initial CR4
value from SmmRelocateBases() to InitSmmS3ResumeState(). In other words,
the last four bytes of the "mov eax, Cr4Value" instruction's binary
representation are utilized as normal data too.
In order to get rid of the DB for "mov eax, Cr4Value", we have to split
both roles, patching and data flow. Introduce the "mSmmCr4" global (SMRAM)
variable for the data flow purpose. Rename the "gSmmCr4" variable to
"gPatchSmmCr4" so that its association with PatchInstructionX86() is clear
from the declaration, change its type to X86_ASSEMBLY_PATCH_LABEL, and
patch it with PatchInstructionX86(), to the value now contained in
"mSmmCr4".
This lets us remove the binary (DB) encoding of "mov eax, Cr4Value" in
"SmmInit.nasm".
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Rename the variable to "gPatchSmmCr3" so that its association with
PatchInstructionX86() is clear from the declaration, change its type to
X86_ASSEMBLY_PATCH_LABEL, and patch it with PatchInstructionX86(). This
lets us remove the binary (DB) encoding of some instructions in
"SmmInit.nasm".
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
(This patch is the 64-bit variant of commit e75ee97224,
"UefiCpuPkg/PiSmmCpuDxeSmm: remove unneeded DBs from IA32 SmmStartup()",
2018-01-31.)
The SmmStartup() function executes in SMM, which is very similar to real
mode. Add "BITS 16" before it and "BITS 64" after it (just before the
@LongMode label).
Remove the manual 0x66 operand-size override prefixes, for selecting
32-bit operands -- the sizes of our operands trigger NASM to insert the
prefixes automatically in almost every spot. The one place where we have
to add it back manually is the LGDT instruction. In the LGDT instruction
we also replace the binary 0x2E prefix with the normal NASM syntax for CS
segment override.
The stores to the Control Registers were always 32-bit wide; the source
code only used RAX as source operand because it generated the expected
object code (with NASM compiling the source as if in BITS 64). With BITS
16 added, we can use the actual register width in the source operands
(EAX).
This patch causes NASM to generate byte-identical object code (determined
by disassembling both the pre-patch and post-patch versions, and comparing
the listings), except:
> @@ -231,7 +231,7 @@
> 000001D2 6689D3 mov ebx,edx
> 000001D5 66B800000000 mov eax,0x0
> 000001DB 0F22D8 mov cr3,eax
> -000001DE 662E670F0155F6 o32 lgdt [cs:ebp-0xa]
> +000001DE 2E66670F0155F6 o32 lgdt [cs:ebp-0xa]
> 000001E5 66B800000000 mov eax,0x0
> 000001EB 80CC02 or ah,0x2
> 000001EE 0F22E0 mov cr4,eax
The only difference is the prefix list order, it changes from:
- 0x66, 0x2E, 0x67
to
- 0x2E, 0x66, 0x67
Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
If PcdDxeNxMemoryProtectionPolicy is set to enable protection for memory
of EfiBootServicesCode, EfiConventionalMemory, the BIOS will hang at a page
fault exception triggered by PiSmmCpuDxeSmm.
The root cause is that PiSmmCpuDxeSmm will access default SMM RAM starting
at 0x30000 which is marked as non-executable, but NX feature was not
enabled during SMM initialization. Accessing memory which has invalid
attributes set will cause page fault exception. This patch fixes it by
checking NX capability in cpuid and enable NXE in EFER MSR if it's
available.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
https://bugzilla.tianocore.org/show_bug.cgi?id=849
In V2, use "mov rax, strict qword 0" to replace the hard code db.
1. Use lea instruction to get the address instead of mov instruction.
2. Use the dummy address as jmp destination, and add the logic to fix up
the address to the absolute address at boot time.
3. On MpFuncs.nasm, use ExchangeInfo to record InitializeFloatingPointUnits.
This way is same to MpInitLib.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Liming Gao <liming.gao@intel.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>