010SecMain_InitializeDebugAgentPhase2

InitializeDebugAgentPhase2

进入到DEBUG Agent初始化第二阶段，这里做的事情主要处理以下事务

• 更新某些Mailbox信息，DebugPortHandle
• Trigger one software interrupt to inform HOST
• 开启Debug APCI timer中断
• 开启CPU中断

至此，Debug Agent初始化完成。

/**Caller provided function to be invoked at the end of DebugPortInitialize().Refer to the description for DebugPortInitialize() for more details.@param[in] Context           The first input argument of DebugPortInitialize().@param[in] DebugPortHandle   Debug port handle created by Debug Communication Library.**/
VOID
EFIAPI
InitializeDebugAgentPhase2 (IN VOID               *Context,IN DEBUG_PORT_HANDLE  DebugPortHandle)
{DEBUG_AGENT_PHASE2_CONTEXT  *Phase2Context;UINT64                      *MailboxLocation;DEBUG_AGENT_MAILBOX         *Mailbox;EFI_SEC_PEI_HAND_OFF        *SecCoreData;UINT16                      BufferSize;UINT64                      NewDebugPortHandle;Phase2Context   = (DEBUG_AGENT_PHASE2_CONTEXT *)Context;MailboxLocation = GetLocationSavedMailboxPointerInIdtEntry ();Mailbox         = (DEBUG_AGENT_MAILBOX *)(UINTN)(*MailboxLocation);BufferSize      = PcdGet16 (PcdDebugPortHandleBufferSize);if ((Phase2Context->InitFlag == DEBUG_AGENT_INIT_PEI) && (BufferSize != 0)) {NewDebugPortHandle = (UINT64)(UINTN)AllocateCopyPool (BufferSize, DebugPortHandle);} else {NewDebugPortHandle = (UINT64)(UINTN)DebugPortHandle;}UpdateMailboxContent (Mailbox, DEBUG_MAILBOX_DEBUG_PORT_HANDLE_INDEX, NewDebugPortHandle);//// Trigger one software interrupt to inform HOST//TriggerSoftInterrupt (SYSTEM_RESET_SIGNATURE);if (Phase2Context->InitFlag == DEBUG_AGENT_INIT_PREMEM_SEC) {//// If Temporary RAM region is below 128 MB, then send message to// host to disable low memory filtering.//SecCoreData = (EFI_SEC_PEI_HAND_OFF *)Phase2Context->Context;if (((UINTN)SecCoreData->TemporaryRamBase < BASE_128MB) && IsHostAttached ()) {SetDebugFlag (DEBUG_AGENT_FLAG_MEMORY_READY, 1);TriggerSoftInterrupt (MEMORY_READY_SIGNATURE);}//// Enable Debug Timer interrupt//SaveAndSetDebugTimerInterrupt (TRUE);//// Enable CPU interrupts so debug timer interrupts can be delivered//EnableInterrupts ();//// Call continuation function if it is not NULL.//Phase2Context->Function (Phase2Context->Context);}
}

TriggerSoftInterrupt

触发一次软件中断，看看是否可以正常触发中断。处理流程可以参考文章DebugAgent处理流程

/**Trigger one software interrupt to debug agent to handle it.@param[in] Signature       Software interrupt signature.**/
VOID
TriggerSoftInterrupt (IN UINT32  Signature)
{UINTN  Dr0;UINTN  Dr1;//// Save Debug Register State//Dr0 = AsmReadDr0 ();Dr1 = AsmReadDr1 ();//// DR0 = Signature//AsmWriteDr0 (SOFT_INTERRUPT_SIGNATURE);AsmWriteDr1 (Signature);//// Do INT3 to communicate with HOST side//CpuBreakpoint ();//// Restore Debug Register State only when Host didn't change it inside exception handler.//   Dr registers can only be changed by setting the HW breakpoint.//AsmWriteDr0 (Dr0);AsmWriteDr1 (Dr1);
}

SaveAndSetDebugTimerInterrupt

    //// Enable Debug Timer interrupt//SaveAndSetDebugTimerInterrupt (TRUE);

启动APIC timer中断

EnableInterrupts

启用CPU中断，自此我们可以使用Source Debug了

    //// Enable CPU interrupts so debug timer interrupts can be delivered//EnableInterrupts ();

/**Enables CPU interrupts.**/
VOID
EFIAPI
EnableInterrupts (VOID)
{_asm {sti}
}

Phase2Context->Function (Phase2Context->Context);

这是一个跳转函数，debug agent 初始化完成。该进入函数SecStartupPhase2，去初始化平台了。