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From: "Leif Lindholm" <leif@nuviainc.com>
To: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: devel@edk2.groups.io, Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: Re: [edk2-devel] [PATCH 1/5] ArmPkg/CpuDxe: use private copy of GetRootTranslationTableInfo()
Date: Thu, 2 Apr 2020 11:28:04 +0100	[thread overview]
Message-ID: <20200402102804.GN7468@vanye> (raw)
In-Reply-To: <e23fe3a9-78e8-aab2-fe81-2078ad651eb2@arm.com>

On Thu, Apr 02, 2020 at 12:20:54 +0200, Ard Biesheuvel wrote:
> On 4/2/20 12:16 PM, Leif Lindholm via groups.io wrote:
> > On Sat, Mar 28, 2020 at 11:43:17 +0100, Ard Biesheuvel wrote:
> > > Before getting rid of GetRootTranslationTableInfo() and the related
> > > LookupAddresstoRootTable() in AARCH64's version of ArmMmuLib, add a
> > > version of the former to CpuDxe, which will be its only remaining
> > > user. While at it, simplify it a bit, since in the CpuDxe cases,
> > > both OUT arguments are always provided.
> > > 
> > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > > ---
> > >   ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c | 15 +++++++++++++++
> > >   ArmPkg/Drivers/CpuDxe/CpuDxe.h      |  7 -------
> > >   2 files changed, 15 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c b/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
> > > index 3b6c5e733709..24eb1c4221e3 100644
> > > --- a/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
> > > +++ b/ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
> > > @@ -15,6 +15,21 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> > >   #define TT_ATTR_INDX_INVALID    ((UINT32)~0)
> > > +#define MIN_T0SZ        16
> > > +#define BITS_PER_LEVEL  9
> > > +
> > > +STATIC
> > > +VOID
> > > +GetRootTranslationTableInfo (
> > > +  IN  UINTN     T0SZ,
> > > +  OUT UINTN     *RootTableLevel,
> > > +  OUT UINTN     *RootTableEntryCount
> > > +  )
> > > +{
> > > +  *RootTableLevel       = (T0SZ - MIN_T0SZ) / BITS_PER_LEVEL;
> > > +  *RootTableEntryCount  = TT_ENTRY_COUNT >> (T0SZ - MIN_T0SZ) % BITS_PER_LEVEL;
> > > +}
> > > +
> > >   STATIC
> > >   UINT64
> > >   GetFirstPageAttribute (
> > > diff --git a/ArmPkg/Drivers/CpuDxe/CpuDxe.h b/ArmPkg/Drivers/CpuDxe/CpuDxe.h
> > > index b627c3c50ff8..3fe5c24d5e5b 100644
> > > --- a/ArmPkg/Drivers/CpuDxe/CpuDxe.h
> > > +++ b/ArmPkg/Drivers/CpuDxe/CpuDxe.h
> > > @@ -134,13 +134,6 @@ GetMemoryRegion (
> > >     OUT    UINTN                   *RegionAttributes
> > >     );
> > > -VOID
> > > -GetRootTranslationTableInfo (
> > 
> > So, this may be super picky, but:
> > Deleting the prototype without making the definition also STATIC would
> > cause build errors with -Wmissing-prototypes (which someone might be
> > enabling explicitly or implicitly if say doing some code hardening on
> > the side).
> > 
> > Now, it's a valid point to say that -Wmissing-prototypes isn't in our
> > current CFLAGS, but I think it would be a good habit to get into.
> > So you get a:
> > 
> > Reviewed-by: Leif Lindholm <leif@nuviainc.com>
> > 
> > regardless, but I'd appreciate if you could sling a STATIC into
> > ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c as well before
> > pushing.
> > 
> 
> Well, while I see your point, please note that the prototype only exists in
> a local header file that only gets included by CpuDxe, and not by any of the
> other consumers of ArmMmuLib.

What I'm saying is that with -Wmissing-prototypes added, building
after applying this patch (but before applying the one that deletes
the function) gives:

"aarch64-linux-gnu-gcc"   -g -fshort-wchar -fno-builtin -fno-strict-aliasing -Wall -Werror -Wno-array-bounds -ffunction-sections -fdata-sections -include AutoGen.h -fno-common -DSTRING_ARRAY_NAME=ArmMmuBaseLibStrings -g -Os -fshort-wchar -fno-builtin -fno-strict-aliasing -Wall -Werror -Wno-array-bounds -include AutoGen.h -fno-common -mlittle-endian -fno-short-enums -fverbose-asm -funsigned-char -ffunction-sections -fdata-sections -Wno-address -fno-asynchronous-unwind-tables -fno-unwind-tables -fno-pic -fno-pie -ffixed-x18 -mcmodel=small -flto -Wno-unused-but-set-variable -Wno-unused-const-variable -DMDEPKG_NDEBUG -DDISABLE_NEW_DEPRECATED_INTERFACES -mstrict-align -mgeneral-regs-only -c -o /work/git/tianocore/Build/ArmVirtQemu-AARCH64/RELEASE_GCC5/AARCH64/ArmPkg/Library/ArmMmuLib/ArmMmuBaseLib/OUTPUT/AArch64/ArmMmuLibCore.obj -I/work/git/edk2/ArmPkg/Library/ArmMmuLib/AArch64 -I/work/git/edk2/ArmPkg/Library/ArmMmuLib -I/work/git/tianocore/Build/ArmVirtQemu-AARCH64/RELEASE_GCC5/AARCH64/ArmPkg/Library/ArmMmuLib/ArmMmuBaseLib/DEBUG -I/work/git/edk2/ArmPkg -I/work/git/edk2/ArmPkg/Include -I/work/git/edk2/EmbeddedPkg -I/work/git/edk2/EmbeddedPkg/Include -I/work/git/edk2/MdePkg -I/work/git/edk2/MdePkg/Include -I/work/git/edk2/MdePkg/Include/AArch64 /work/git/edk2/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
leif@vanye:/work/git/tianocore$ "aarch64-linux-gnu-gcc"   -g -fshort-wchar -fno-builtin -fno-strict-aliasing -Wall -Werror -Wno-array-bounds -ffunction-sections -fdata-sections -include AutoGen.h -fno-common -DSTRING_ARRAY_NAME=ArmMmuBaseLibStrings -g -Os -fshort-wchar -fno-builtin -fno-strict-aliasing -Wall -Werror -Wno-array-bounds -include AutoGen.h -fno-common -mlittle-endian -fno-short-enums -fverbose-asm -funsigned-char -ffunction-sections -fdata-sections -Wno-address -fno-asynchronous-unwind-tables -fno-unwind-tables -fno-pic -fno-pie -ffixed-x18 -mcmodel=small -flto -Wno-unused-but-set-variable -Wno-unused-const-variable -DMDEPKG_NDEBUG -DDISABLE_NEW_DEPRECATED_INTERFACES -mstrict-align -mgeneral-regs-only -c -o /work/git/tianocore/Build/ArmVirtQemu-AARCH64/RELEASE_GCC5/AARCH64/ArmPkg/Library/ArmMmuLib/ArmMmuBaseLib/OUTPUT/AArch64/ArmMmuLibCore.obj -I/work/git/edk2/ArmPkg/Library/ArmMmuLib/AArch64 -I/work/git/edk2/ArmPkg/Library/ArmMmuLib -I/work/git/tianocore/Build/ArmVirtQemu-AARCH64/RELEASE_GCC5/AARCH64/ArmPkg/Library/ArmMmuLib/ArmMmuBaseLib/DEBUG -I/work/git/edk2/ArmPkg -I/work/git/edk2/ArmPkg/Include -I/work/git/edk2/EmbeddedPkg -I/work/git/edk2/EmbeddedPkg/Include -I/work/git/edk2/MdePkg -I/work/git/edk2/MdePkg/Include -I/work/git/edk2/MdePkg/Include/AArch64 /work/git/edk2/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c -Wmissing-prototypes
/work/git/edk2/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c:109:1: error: no previous prototype for ‘GetRootTranslationTableInfo’ [-Werror=missing-prototypes]
 GetRootTranslationTableInfo (
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

So it breaks bisect if you're experimenting with hardening.

As I said, I don't insist, but I want to be sure you realise that bit
before you decide.

/
    Leif

> 
> 
> > > -  IN  UINTN    T0SZ,
> > > -  OUT UINTN   *TableLevel,
> > > -  OUT UINTN   *TableEntryCount
> > > -  );
> > > -
> > >   EFI_STATUS
> > >   SetGcdMemorySpaceAttributes (
> > >     IN EFI_GCD_MEMORY_SPACE_DESCRIPTOR    *MemorySpaceMap,
> > > -- 
> > > 2.17.1
> > > 
> > 
> > 
> > 
> 

  reply	other threads:[~2020-04-02 10:28 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-28 10:43 [PATCH 0/5] ArmPkg: cosmetic cleanups for ArmMmuLib Ard Biesheuvel
2020-03-28 10:43 ` [PATCH 1/5] ArmPkg/CpuDxe: use private copy of GetRootTranslationTableInfo() Ard Biesheuvel
2020-04-02 10:16   ` Leif Lindholm
2020-04-02 10:20     ` [edk2-devel] " Ard Biesheuvel
2020-04-02 10:28       ` Leif Lindholm [this message]
2020-04-02 10:29         ` Ard Biesheuvel
2020-04-02 11:03           ` Leif Lindholm
2020-04-02 12:44             ` Ard Biesheuvel
2020-03-28 10:43 ` [PATCH 2/5] ArmPkg/CpuDxe: move PageAttributeToGcdAttribute() out of ArmMmuLib Ard Biesheuvel
2020-03-28 10:43 ` [PATCH 3/5] ArmPkg/ArmMmuLib: drop pointless LookupAddresstoRootTable() routine Ard Biesheuvel
2020-03-28 10:43 ` [PATCH 4/5] ArmPkg/ArmMmuLib: get rid of GetRootTranslationTableInfo() Ard Biesheuvel
2020-03-28 10:43 ` [PATCH 5/5] ArmPkg/ArmMmuLib: drop unused TT_ATTR_INDX_INVALID CPP symbol Ard Biesheuvel
2020-04-02 10:23   ` Leif Lindholm
2020-04-02 10:29     ` [edk2-devel] " Ard Biesheuvel
2020-04-02 10:57       ` Leif Lindholm
2020-04-02 11:05         ` Ard Biesheuvel

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