From: Matthias Kaehlcke <mka@chromium.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: zijun_hu <zijun_hu@htc.com>,
Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Laura Abbott <labbott@redhat.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Doug Anderson <dianders@chromium.org>,
Greg Hackmann <ghackmann@google.com>
Subject: Re: [PATCH 2/2] arm64: Define PAGE_OFFSET using GENMASK_ULL
Date: Wed, 2 Aug 2017 16:44:31 -0700 [thread overview]
Message-ID: <20170802234431.GH84665@google.com> (raw)
In-Reply-To: <CAKwvOdn3sBibVa=ai2ZPeBdHb=v=0qJ9+HYAFr-umhEzQtwY7w@mail.gmail.com>
El Wed, Aug 02, 2017 at 04:19:11PM -0700 Nick Desaulniers ha dit:
> hmm, seems including the definition of GENMASK_ULL causes tons of issues
> see definition of UL() macro
> defines _AC
> token pastes UL on literal when not assembly
> so looks like GENMASK_ULL is not ready to be used from assembly
sorry, it seems I only did a partial build when testing this :/
> On Wed, Aug 2, 2017 at 4:13 PM, Nick Desaulniers
> <ndesaulniers@google.com> wrote:
> > don't forget to include linux/bitops.h now in memory.h
> >
> > /usr/local/google/home/ndesaulniers/android/kernel-wahoo/private/msm-google/arch/arm64/kernel/head.S:47:8:
> > error:
> > function-like macro 'GENMASK_ULL' is not defined
> > #elif (PAGE_OFFSET & 0x1fffff) != 0
> > ^
> > /usr/local/google/home/ndesaulniers/android/kernel-wahoo/private/msm-google/arch/arm64/include/asm/memory.h:52:22:
> > note:
> >
> > expanded from macro 'PAGE_OFFSET'
> > #define PAGE_OFFSET GENMASK_ULL(BITS_PER_LONG_LONG - 1, VA_BITS - 1)
> > ^
> > 1 error generated.
> >
> > On Wed, Aug 2, 2017 at 3:51 PM, Matthias Kaehlcke <mka@chromium.org> wrote:
> >> As is the definition causes an integer overflow, which is expected,
> >> however clang raises the following warning:
> >>
> >> arch/arm64/kernel/head.S:47:8: warning:
> >> integer overflow in preprocessor expression
> >> #elif (PAGE_OFFSET & 0x1fffff) != 0
> >> ^~~~~~~~~~~
> >> arch/arm64/include/asm/memory.h:52:46: note:
> >> expanded from macro 'PAGE_OFFSET'
> >> #define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1))
> >> ~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
> >>
> >> Use GENMASK_ULL() instead of shifting explicitly, the macro takes care
> >> of avoiding the overflow.
> >>
> >> Reported-by: Nick Desaulniers <ndesaulniers@google.com>
> >> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> >> ---
> >> arch/arm64/include/asm/memory.h | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> >> index 32f82723338a..732d4eed8edd 100644
> >> --- a/arch/arm64/include/asm/memory.h
> >> +++ b/arch/arm64/include/asm/memory.h
> >> @@ -65,7 +65,7 @@
> >> */
> >> #define VA_BITS (CONFIG_ARM64_VA_BITS)
> >> #define VA_START (UL(0xffffffffffffffff) << VA_BITS)
> >> -#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1))
> >> +#define PAGE_OFFSET GENMASK_ULL(BITS_PER_LONG_LONG - 1, VA_BITS - 1)
> >> #define KIMAGE_VADDR (MODULES_END)
> >> #define MODULES_END (MODULES_VADDR + MODULES_VSIZE)
> >> #define MODULES_VADDR (VA_START + KASAN_SHADOW_SIZE)
> >>
> >
> >
> >
>
>
>
next prev parent reply other threads:[~2017-08-02 23:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-02 22:51 [PATCH 1/2] bitops: Avoid integer overflow warning in GENMASK_ULL Matthias Kaehlcke
2017-08-02 22:51 ` [PATCH 2/2] arm64: Define PAGE_OFFSET using GENMASK_ULL Matthias Kaehlcke
2017-08-02 23:13 ` Nick Desaulniers
2017-08-02 23:19 ` Nick Desaulniers
2017-08-02 23:44 ` Matthias Kaehlcke [this message]
2017-08-03 13:20 ` Yury Norov
2017-08-03 17:11 ` [PATCH] arm64: avoid overflow in VA_START and PAGE_OFFSET Nick Desaulniers
2017-08-03 17:20 ` Ard Biesheuvel
2017-08-03 17:53 ` Nick Desaulniers
2017-08-03 18:03 ` [PATCH v2] " Nick Desaulniers
2017-08-04 2:26 ` [PATCH 2/2] arm64: Define PAGE_OFFSET using GENMASK_ULL kbuild test robot
2017-08-03 13:24 ` [PATCH 1/2] bitops: Avoid integer overflow warning in GENMASK_ULL Yury Norov
2017-08-03 17:03 ` Matthias Kaehlcke
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