From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Laszlo Ersek <lersek@redhat.com>
Cc: edk2-devel-01 <edk2-devel@lists.01.org>,
Jordan Justen <jordan.l.justen@intel.com>
Subject: Re: [PATCH v2 2/4] OvmfPkg/Sec/Ia32: seed the temporary RAM with PcdInitValueInTempStack
Date: Thu, 16 Nov 2017 09:32:45 +0000 [thread overview]
Message-ID: <CAKv+Gu81u3b1bY6wRsia--LUyZ8e70voRiRePq2jwvLQ_oCG7g@mail.gmail.com> (raw)
In-Reply-To: <20171115215703.16491-3-lersek@redhat.com>
On 15 November 2017 at 21:57, Laszlo Ersek <lersek@redhat.com> wrote:
> This allows the PEI core to report the maximum temporary SEC/PEI stack
> usage on the DEBUG_INFO level, in the PeiCheckAndSwitchStack() function
> [MdeModulePkg/Core/Pei/Dispatcher/Dispatcher.c]:
>
> * Normal boot:
>
>> Temp Stack : BaseAddress=0x814000 Length=0x4000
>> Temp Heap : BaseAddress=0x810000 Length=0x4000
>> Total temporary memory: 32768 bytes.
>> temporary memory stack ever used: 3664 bytes. <----
>> temporary memory heap used for HobList: 5904 bytes.
>> temporary memory heap occupied by memory pages: 0 bytes.
>
> * S3 resume (with PEI decompression / SMM):
>
>> Temp Stack : BaseAddress=0x814000 Length=0x4000
>> Temp Heap : BaseAddress=0x810000 Length=0x4000
>> Total temporary memory: 32768 bytes.
>> temporary memory stack ever used: 3428 bytes. <----
>> temporary memory heap used for HobList: 4816 bytes.
>> temporary memory heap occupied by memory pages: 0 bytes.
>
> I unit-tested this change by transitorily adding an infinite loop right
> after the "rep stosd", and dumping the guest's temp SEC/PEI RAM (32KB
> currently) while the guest was stuck in the loop. The dump includes one
> dword from before and after the temp SEC/PEI RAM:
>
>> $ virsh qemu-monitor-command GUEST_NAME --hmp 'xp /8194wx 0x80FFFC'
>>
>> 000000000080fffc: 0x00000000 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5
>> 000000000081000c: 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5
>> ...
>> 0000000000817fec: 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5 0x5aa55aa5
>> 0000000000817ffc: 0x5aa55aa5 0x00000000
>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=747
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>
> Notes:
> v2:
> - update comment on ES [Jordan]
> - document the other segment registers too [Jordan]
> - move seeding to top of routine [Jordan]
> - hence, drop earlier EAX -> EBX renaming [Jordan]
> - replace runtime right shift with compile-time division [Jordan]
> - drop Ard's Reviewed-by
>
> OvmfPkg/Sec/SecMain.inf | 1 +
> OvmfPkg/Sec/Ia32/SecEntry.nasm | 18 ++++++++++++++++++
> 2 files changed, 19 insertions(+)
>
> diff --git a/OvmfPkg/Sec/SecMain.inf b/OvmfPkg/Sec/SecMain.inf
> index 711b59530907..6051cb3c6c4c 100644
> --- a/OvmfPkg/Sec/SecMain.inf
> +++ b/OvmfPkg/Sec/SecMain.inf
> @@ -71,6 +71,7 @@ [Pcd]
> gEfiMdePkgTokenSpaceGuid.PcdGuidedExtractHandlerTableAddress
> gUefiOvmfPkgTokenSpaceGuid.PcdGuidedExtractHandlerTableSize
> gUefiOvmfPkgTokenSpaceGuid.PcdOvmfDecompressionScratchEnd
> + gEfiMdeModulePkgTokenSpaceGuid.PcdInitValueInTempStack
>
> [FeaturePcd]
> gUefiOvmfPkgTokenSpaceGuid.PcdSmmSmramRequire
> diff --git a/OvmfPkg/Sec/Ia32/SecEntry.nasm b/OvmfPkg/Sec/Ia32/SecEntry.nasm
> index 7fee1c2b2e4f..03501969ebce 100644
> --- a/OvmfPkg/Sec/Ia32/SecEntry.nasm
> +++ b/OvmfPkg/Sec/Ia32/SecEntry.nasm
> @@ -29,12 +29,30 @@ extern ASM_PFX(SecCoreStartupWithStack)
> ; @param[in] EAX Initial value of the EAX register (BIST: Built-in Self Test)
> ; @param[in] DI 'BP': boot-strap processor, or 'AP': application processor
> ; @param[in] EBP Pointer to the start of the Boot Firmware Volume
> +; @param[in] DS Selector allowing flat access to all addresses
> +; @param[in] ES Selector allowing flat access to all addresses
> +; @param[in] FS Selector allowing flat access to all addresses
> +; @param[in] GS Selector allowing flat access to all addresses
> +; @param[in] SS Selector allowing flat access to all addresses
> ;
> ; @return None This routine does not return
> ;
> global ASM_PFX(_ModuleEntryPoint)
> ASM_PFX(_ModuleEntryPoint):
>
> + ;
> + ; Fill the temporary RAM with the initial stack value.
> + ; The loop below will seed the heap as well, but that's harmless.
> + ;
> + mov eax, FixedPcdGet32 (PcdInitValueInTempStack) ; dword to store
> + mov edi, FixedPcdGet32 (PcdOvmfSecPeiTempRamBase) ; base address,
> + ; relative to
> + ; ES
> + mov ecx, FixedPcdGet32 (PcdOvmfSecPeiTempRamSize) / 4 ; dword count
> + cld ; store from base
> + ; up
> + rep stosd
> +
> ;
> ; Load temporary RAM stack based on PCDs
> ;
> --
> 2.14.1.3.gb7cf6e02401b
>
>
next prev parent reply other threads:[~2017-11-16 9:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-15 21:56 [PATCH v2 0/4] UefiCpuPkg, OvmfPkg: add reset vector docs, tweak temp stack / RAM Laszlo Ersek
2017-11-15 21:57 ` [PATCH v2 1/4] UefiCpuPkg/ResetVector/Vtf0: document segment register setup Laszlo Ersek
2017-11-16 9:31 ` Ard Biesheuvel
2017-11-15 21:57 ` [PATCH v2 2/4] OvmfPkg/Sec/Ia32: seed the temporary RAM with PcdInitValueInTempStack Laszlo Ersek
2017-11-16 9:32 ` Ard Biesheuvel [this message]
2017-11-15 21:57 ` [PATCH v2 3/4] OvmfPkg/Sec/X64: " Laszlo Ersek
2017-11-16 9:33 ` Ard Biesheuvel
2017-11-15 21:57 ` [PATCH v2 4/4] OvmfPkg: restore temporary SEC/PEI RAM size to 64KB Laszlo Ersek
2017-11-16 0:57 ` [PATCH v2 0/4] UefiCpuPkg, OvmfPkg: add reset vector docs, tweak temp stack / RAM Jordan Justen
2017-11-17 17:15 ` Laszlo Ersek
2017-11-20 15:22 ` Dong, Eric
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