Re: [PATCH] ArmPkg/ArmSmcPsciResetSystemLib: add support for warm reboot

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 9 October 2017 at 19:22, Leif Lindholm <leif.lindholm@linaro.org> wrote:
> On Fri, Oct 06, 2017 at 09:41:52PM +0100, Ard Biesheuvel wrote:
>> PSCI SYSTEM_RESET is specified as a cold reboot, which does not
>> preserve the contents of DRAM. In version 1.1, a new reset method
>> was introduced that allows a warm reboot to be requested.
>>
>> This is especially relevant for capsule update, given that it will
>> invoke a warm reboot before processing the capsule, under the
>> assumption that the capsule will still be in memory when the PEI
>> phase is reentered.
>>
>> So wire up the [rather inaccurately named] EnterS3WithImmediateWake()
>> entry point that the capsule update runtime uses to the new PSCI 1.1
>> warm reboot. Note that many PSCI implementations will not support this
>> yet, so fall back to a cold reboot if warm reboot fails.
>>
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>>
>> I don't actually need this code for Synquacer, but given that I had
>> already wrote it, we may just as well merge it.
>>
>>  ArmPkg/Include/IndustryStandard/ArmStdSmc.h                        | 10 +++++++---
>>  ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c | 14 ++++++++++++--
>>  2 files changed, 19 insertions(+), 5 deletions(-)
>>
>> diff --git a/ArmPkg/Include/IndustryStandard/ArmStdSmc.h b/ArmPkg/Include/IndustryStandard/ArmStdSmc.h
>> index 593a3ce729ce..41b086947eaa 100644
>> --- a/ArmPkg/Include/IndustryStandard/ArmStdSmc.h
>> +++ b/ArmPkg/Include/IndustryStandard/ArmStdSmc.h
>> @@ -57,10 +57,12 @@
>>  #define ARM_SMC_ID_PSCI_MIGRATE_AARCH32        0x84000005
>>  #define ARM_SMC_ID_PSCI_SYSTEM_OFF             0x84000008
>>  #define ARM_SMC_ID_PSCI_SYSTEM_RESET           0x84000009
>> +#define ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH64  0xc4000012
>> +#define ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH32  0x84000012
>
> If we're starting to add more of these, could we do some macro rather
> than duplication?
>
> (see below)
>
>> -/* The current PSCI version is:  0.2 */
>> -#define ARM_SMC_PSCI_VERSION_MAJOR  0
>> -#define ARM_SMC_PSCI_VERSION_MINOR  2
>> +/* The current PSCI version is:  1.1 */
>> +#define ARM_SMC_PSCI_VERSION_MAJOR  1
>> +#define ARM_SMC_PSCI_VERSION_MINOR  1
>>  #define ARM_SMC_PSCI_VERSION  \
>>    ((ARM_SMC_PSCI_VERSION_MAJOR << 16) | ARM_SMC_PSCI_VERSION_MINOR)
>>
>> @@ -93,4 +95,6 @@
>>  #define ARM_SMC_ID_PSCI_AFFINITY_INFO_OFF         1
>>  #define ARM_SMC_ID_PSCI_AFFINITY_INFO_ON_PENDING  2
>>
>> +#define ARM_SMC_ID_PSCI_SYSTEM_RESET2_WARM  0
>> +
>>  #endif
>> diff --git a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
>> index d6d26bce5009..ffd726554c0f 100644
>> --- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
>> +++ b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
>> @@ -55,7 +55,17 @@ ResetWarm (
>>    VOID
>>    )
>>  {
>> -  // Map a warm reset into a cold reset
>> +  ARM_SMC_ARGS ArmSmcArgs;
>> +
>> +#if defined(MDE_CPU_AARCH64)
>> +  ArmSmcArgs.Arg0 = ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH64;
>> +#else
>> +  ArmSmcArgs.Arg0 = ARM_SMC_ID_PSCI_SYSTEM_RESET2_AARCH32;
>> +#endif
>
> #define ARM_SMC64_VALUE 0x40000000UL
> #define ARM_SMC64(x) ((x) | ARM_SMC64_VALUE)
> #define ARM_SMC32(x) ((x) & ~ARM_SMC64_VALUE)
>
> #if defined(MDE_CPU_AARCH64)
> #define ARM_SMC(x) ARM_SMC64(x)
> #else
> #define ARM_SMC(x) ARM_SMC32(x)
> #endif
>
> Want me to whip up a mini-set that does that and changes existing
> definitiions/invokations?
>

Yes please