Files
system76-edk2/UefiCpuPkg/PiSmmCpuDxeSmm/X64/Semaphore.c
Laszlo Ersek 9686a4678d UefiCpuPkg/PiSmmCpuDxeSmm: remove DBs from SmmRelocationSemaphoreComplete32()
(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>
2018-04-04 16:44:25 +02:00

76 lines
2.3 KiB
C

/** @file
Semaphore mechanism to indicate to the BSP that an AP has exited SMM
after SMBASE relocation.
Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "PiSmmCpuDxeSmm.h"
X86_ASSEMBLY_PATCH_LABEL gPatchSmmRelocationOriginalAddressPtr32;
X86_ASSEMBLY_PATCH_LABEL gPatchRebasedFlagAddr32;
UINTN mSmmRelocationOriginalAddress;
volatile BOOLEAN *mRebasedFlag;
/**
AP Semaphore operation in 32-bit mode while BSP runs in 64-bit mode.
**/
VOID
SmmRelocationSemaphoreComplete32 (
VOID
);
/**
Hook return address of SMM Save State so that semaphore code
can be executed immediately after AP exits SMM to indicate to
the BSP that an AP has exited SMM after SMBASE relocation.
@param[in] CpuIndex The processor index.
@param[in] RebasedFlag A pointer to a flag that is set to TRUE
immediately after AP exits SMM.
**/
VOID
SemaphoreHook (
IN UINTN CpuIndex,
IN volatile BOOLEAN *RebasedFlag
)
{
SMRAM_SAVE_STATE_MAP *CpuState;
UINTN TempValue;
mRebasedFlag = RebasedFlag;
PatchInstructionX86 (
gPatchRebasedFlagAddr32,
(UINT32)(UINTN)mRebasedFlag,
4
);
CpuState = (SMRAM_SAVE_STATE_MAP *)(UINTN)(SMM_DEFAULT_SMBASE + SMRAM_SAVE_STATE_MAP_OFFSET);
mSmmRelocationOriginalAddress = HookReturnFromSmm (
CpuIndex,
CpuState,
(UINT64)(UINTN)&SmmRelocationSemaphoreComplete32,
(UINT64)(UINTN)&SmmRelocationSemaphoreComplete
);
//
// Use temp value to fix ICC complier warning
//
TempValue = (UINTN)&mSmmRelocationOriginalAddress;
PatchInstructionX86 (
gPatchSmmRelocationOriginalAddressPtr32,
(UINT32)TempValue,
4
);
}