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From: "Ard Biesheuvel" <ard.biesheuvel@arm.com>
To: Leif Lindholm <leif@nuviainc.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 12:29:30 +0200	[thread overview]
Message-ID: <0e6a6c40-1a48-a5cb-563f-4f5b39c41fef@arm.com> (raw)
In-Reply-To: <20200402102804.GN7468@vanye>

On 4/2/20 12:28 PM, Leif Lindholm wrote:
> 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.
> 

But none of the other consumers of ArmMmuLib do an #include of 
ArmPkg/Drivers/CpuDxe/CpuDxe.h, right? So I am slightly puzzled by this 
result.


  reply	other threads:[~2020-04-02 10:29 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
2020-04-02 10:29         ` Ard Biesheuvel [this message]
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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