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From: "Leif Lindholm" <leif@nuviainc.com>
To: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Laszlo Ersek <lersek@redhat.com>,
	Rebecca Cran <rebecca@nuviainc.com>,
	devel@edk2.groups.io
Subject: Re: [PATCH v4 04/10] ArmPkg: Add helper to read the Memory Model Features Register 2
Date: Thu, 17 Dec 2020 18:04:29 +0000	[thread overview]
Message-ID: <20201217180429.GS1664@vanye> (raw)
In-Reply-To: <3e9ab014-ef61-435b-e2a3-cb0c9950b7f9@arm.com>

On Thu, Dec 17, 2020 at 14:47:48 +0100, Ard Biesheuvel wrote:
> >> ArmPkg/Library/ArmGicArchLib/AArch64/ArmGicArchLib.c:  if (ArmReadIdPfr0 () & AARCH64_PFR0_GIC) {
> >> ArmPkg/Library/ArmGicArchLib/Arm/ArmGicArchLib.c:  if (ArmReadIdPfr1 () & ARM_PFR1_GIC) {
> >>
> >> I would propose that since the high-level abstraction serve only to
> >> confuse things, we change existing (and new) accessors to ID registers
> >> to be explicit:
> >>
> >> - ArmReadIdAArch64Mmfr0
> >> - ArmReadIdAArch64Pfr0
> >> - ArmReadIdAArch64Pfr1
> > 
> > I can follow until here... (and yes, using the concrete register names
> > in the function names makes sense)
> > 
> >>
> >> The question is whether we should make the AArch32 aspect explicit or
> >> implicit? My instinctive reaction is the latter. This matches the
> >> native naming scheme used in the ARM ARM, and we don't support mixing
> >> instruction set widths in UEFI.
> > 
> > I lost you here, sorry.
> > 
> 
> So did I :-)
> 
> But I think that we should raise the level of abstraction here:
> something like
> 
> if (ArmReadIdPfr0 () & AARCH64_PFR0_GIC) {
> 
> should not exist in code that is shared between AArch64 and AArch32, I'd
> much rather have a helper
> 
> ArmHasGicSre()
> 
> that encapsulates whatever is needed on each respective architecture,
> and which may or may not end up using the same ID register or mask value.

Yeah, agreed. In the end, that's what Rebecca's set does in patch 6/10
- so I'll whip something together to replicate this for the GIC case.

I like the ArmHas* format though - Rebecca, could you use that for
your v5?

> 
> >>
> >> The AArch64 prototypes should then only be made available to AARCH64
> >> code, and the AArch32 ones only to ARM.
> > 
> > But this again makes sense to me.
> > 
> > I guess what confuses me is your interpretation of "implicit" vs.
> > "explicit". I'm missing what the "AArch32 aspect" means, probably.
> > 
> > Thanks
> > laszlo
> > 
> 

  reply	other threads:[~2020-12-17 18:04 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-07 17:54 [PATCH v4 00/10] ArmPkg,MdePkg: Add Universal/Smbios, and related changes Rebecca Cran
2020-12-07 17:54 ` [PATCH v4 01/10] ArmPkg: Add ARM SMC Architecture functions to ArmStdSmc.h Rebecca Cran
2020-12-15 18:06   ` Leif Lindholm
2020-12-16 11:23   ` [edk2-devel] " Sami Mujawar
2020-12-07 17:54 ` [PATCH v4 02/10] MdePkg: Update IndustryStandard/SmBios.h with processor status data Rebecca Cran
2020-12-08  4:50   ` 回复: " gaoliming
2020-12-07 17:54 ` [PATCH v4 03/10] ArmPkg: Add register encoding definition for MMFR2 Rebecca Cran
2020-12-15 18:42   ` Leif Lindholm
2020-12-16 11:31   ` [edk2-devel] " Sami Mujawar
2020-12-07 17:54 ` [PATCH v4 04/10] ArmPkg: Add helper to read the Memory Model Features Register 2 Rebecca Cran
2020-12-15 19:11   ` Leif Lindholm
2020-12-16 11:06     ` [edk2-devel] " Sami Mujawar
2020-12-17 13:38     ` Laszlo Ersek
2020-12-17 13:47       ` Ard Biesheuvel
2020-12-17 18:04         ` Leif Lindholm [this message]
2020-12-17 18:19           ` Rebecca Cran
2020-12-17 17:57       ` Leif Lindholm
2020-12-07 17:54 ` [PATCH v4 05/10] ArmPkg: Add helper function to read the Memory Model Feature Register 4 Rebecca Cran
2020-12-16 11:23   ` [edk2-devel] " Sami Mujawar
2020-12-07 17:54 ` [PATCH v4 06/10] ArmPkg: Add helper to read CCIDX status Rebecca Cran
2020-12-16 11:23   ` [edk2-devel] " Sami Mujawar
2020-12-07 17:54 ` [PATCH v4 07/10] ArmPkg: Fix the return type of the ReadCCSIDR function Rebecca Cran
2020-12-15 19:24   ` Leif Lindholm
2020-12-16 11:31   ` [edk2-devel] " Sami Mujawar
2020-12-07 17:54 ` [PATCH v4 08/10] ArmPkg: Update ArmLibPrivate.h with cache register definitions Rebecca Cran
2020-12-15 19:27   ` Leif Lindholm
2020-12-07 17:54 ` [PATCH v4 09/10] ArmPkg: Add definition of the maximum cache level in ARMv8-A Rebecca Cran
2020-12-15 19:27   ` Leif Lindholm
2020-12-16 11:31   ` [edk2-devel] " Sami Mujawar
2020-12-07 17:54 ` [PATCH v4 10/10] ArmPkg: Add Universal/Smbios, a generic SMBIOS library for ARM Rebecca Cran
2020-12-15 19:29   ` Leif Lindholm
2020-12-15 21:14     ` Rebecca Cran
2020-12-16 15:13   ` [edk2-devel] " Sami Mujawar
2020-12-16 15:21     ` Rebecca Cran
2020-12-19  3:14     ` Rebecca Cran
     [not found]   ` <16513B32D4BA613C.12945@groups.io>
2020-12-29 15:10     ` Sami Mujawar
2021-01-03 23:52       ` Rebecca Cran
2021-01-04 10:21         ` Sami Mujawar
2020-12-14 15:45 ` [PATCH v4 00/10] ArmPkg,MdePkg: Add Universal/Smbios, and related changes Rebecca Cran
2020-12-15 18:36 ` Leif Lindholm

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