On 10/20/17 15:00, Leif Lindholm wrote:
> On Fri, Oct 20, 2017 at 12:23:25PM +0100, Ard Biesheuvel wrote:
>> DEBUG builds of PEI code will print a diagnostic message regarding
>> the utilization of temporary RAM before switching to permanent RAM.
>> For example,
>>
>> Total temporary memory: 16352 bytes.
>> temporary memory stack ever used: 4820 bytes.
>> temporary memory heap used for HobList: 4720 bytes.
>>
>> Tracking stack utilization like this requires the stack to be seeded
>> with a known magic value, and this needs to occur before entering C
>> code, given that it uses the stack. Currently, only Nt32Pkg appears
>> to implement this feature, but it is useful nonetheless, so let's
>> wire it up for PrePeiCore.
>>
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Ard Biesheuvel <[email protected]>
>> ---
>> ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S | 7 +++++++
>> ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S | 10 ++++++++++
>> ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm | 10 ++++++++++
>> 3 files changed, 27 insertions(+)
>>
>> diff --git a/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
>> b/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
>> index aab5edab0c42..7a33e2754869 100644
>> --- a/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
>> +++ b/ArmPlatformPkg/PrePeiCore/AArch64/PrePeiCoreEntryPoint.S
>> @@ -13,6 +13,8 @@
>>
>> #include <AsmMacroIoLibV8.h>
>>
>> +#define INIT_CAR_VALUE 0x5AA55AA55AA55AA5
>> +
>> ASM_FUNC(_ModuleEntryPoint)
>> // Do early platform specific actions
>> bl ASM_PFX(ArmPlatformPeiBootAction)
>> @@ -84,4 +86,9 @@ _PrepareArguments:
>>
>> _SetupPrimaryCoreStack:
>> mov sp, x1
>> + MOV64 (x8, FixedPcdGet64(PcdCPUCoresStackBase))
>> + MOV64 (x9, INIT_CAR_VALUE)
>> +0:stp x9, x9, [x8], #16
>> + cmp x8, x1
>> + b.lt 0b
>> b _PrepareArguments
>> diff --git a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
>> b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
>> index 14344425ad4c..7342e49bea59 100644
>> --- a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
>> +++ b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.S
>> @@ -13,6 +13,8 @@
>>
>> #include <AsmMacroIoLib.h>
>>
>> +#define INIT_CAR_VALUE 0x5AA55AA5
>> +
>
> Worth moving to a common header somewhere?
>
> Also defined/used in MdeModulePkg/Core/Pei/Dispatcher/Dispatcher.c.
Furthermore, open-coded in:
EmulatorPkg/Unix/Host/Host.c: *StackPointer = 0x5AA55AA5;
Nt32Pkg/Sec/SecMain.c: *StackPointer = 0x5AA55AA5;
Honestly I think it should be a Fixed-At-Build PCD, in MdeModulePkg.dec,
similarly to
gEfiMdePkgTokenSpaceGuid.PcdDebugClearMemoryValue
in MdePkg.dec.
I'm unhappy that we have to annoy Ard with a request to "upstream" this
constant to MdeModulePkg in some form, but we'll need it yet again in
OVMF...
>
> That file has an explicit comment saying "temporary memory is filled
> with this initial value during SEC phase". Should this end have a
> corresponding comment saying "checked for during PEI phase"?
Thanks
Laszlo
>
> /
> Leif
>
>> ASM_FUNC(_ModuleEntryPoint)
>> // Do early platform specific actions
>> bl ASM_PFX(ArmPlatformPeiBootAction)
>> @@ -65,6 +67,14 @@ _PrepareArguments:
>>
>> _SetupPrimaryCoreStack:
>> mov sp, r1
>> + MOV32 (r8, FixedPcdGet64(PcdCPUCoresStackBase))
>> + MOV32 (r9, INIT_CAR_VALUE)
>> + mov r10, r9
>> + mov r11, r9
>> + mov r12, r9
>> +0:stm r8!, {r9-r12}
>> + cmp r8, r1
>> + blt 0b
>> b _PrepareArguments
>>
>> _NeverReturn:
>> diff --git a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
>> b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
>> index abea675828df..7455de8aa66e 100644
>> --- a/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
>> +++ b/ArmPlatformPkg/PrePeiCore/Arm/PrePeiCoreEntryPoint.asm
>> @@ -13,6 +13,8 @@
>>
>> #include <AutoGen.h>
>>
>> +#define INIT_CAR_VALUE 0x5AA55AA5
>> +
>> INCLUDE AsmMacroIoLib.inc
>>
>> IMPORT CEntryPoint
>> @@ -79,6 +81,14 @@ _PrepareArguments
>>
>> _SetupPrimaryCoreStack
>> mov sp, r1
>> + mov32 r8, FixedPcdGet64(PcdCPUCoresStackBase)
>> + mov32 r9, INIT_CAR_VALUE
>> + mov r10, r9
>> + mov r11, r9
>> + mov r12, r9
>> +0:stm r8!, {r9-r12}
>> + cmp r8, r1
>> + blt 0b
>> b _PrepareArguments
>>
>> _NeverReturn
>> --
>> 2.11.0
>>
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