Re: [STABLE BACKPORT 4.4.y, 4.9.y and 4.14.y] compiler.h: Raise minimum version of GCC to 5.1 for arm64
On Wed, Jan 20, 2021 at 12:29 AM Nathan Chancellor wrote: > On Tue, Jan 19, 2021 at 02:15:43PM -0800, Nick Desaulniers wrote: > > > > Merging this from stable into "Android Common Kernel" trees that were > > built with AOSP GCC 4.9, I expect this to break some builds. Arnd, > > IIRC did you mention that AOSP GCC had picked up a fix? If so, did > > you verify that via disassembly, or gerrit patch file? The only information I had was the fact that the gcc bug tracker mentioned it being picked up into the Android gcc and gcc-linaro. I verified that it was present in gcc-linaro, but did not also check the Android sources. > If so, it looks like that patch was picked up in this commit. > > https://android.googlesource.com/toolchain/gcc/+/5ae0308a147ec3f6502fd321860524e634a647a6 Right. Arnd
Re: [STABLE BACKPORT 4.4.y, 4.9.y and 4.14.y] compiler.h: Raise minimum version of GCC to 5.1 for arm64
On Tue, Jan 19, 2021 at 02:15:43PM -0800, Nick Desaulniers wrote: > On Mon, Jan 18, 2021 at 5:54 AM Will Deacon wrote: > > > > commit dca5244d2f5b94f1809f0c02a549edf41ccd5493 upstream. > > > > GCC versions >= 4.9 and < 5.1 have been shown to emit memory references > > beyond the stack pointer, resulting in memory corruption if an interrupt > > is taken after the stack pointer has been adjusted but before the > > reference has been executed. This leads to subtle, infrequent data > > corruption such as the EXT4 problems reported by Russell King at the > > link below. > > > > Life is too short for buggy compilers, so raise the minimum GCC version > > required by arm64 to 5.1. > > > > Reported-by: Russell King > > Suggested-by: Arnd Bergmann > > Signed-off-by: Will Deacon > > Tested-by: Nathan Chancellor > > Reviewed-by: Nick Desaulniers > > Reviewed-by: Nathan Chancellor > > Acked-by: Linus Torvalds > > Cc: # 4.4.y, 4.9.y and 4.14.y only > > Cc: Theodore Ts'o > > Cc: Florian Weimer > > Cc: Peter Zijlstra > > Cc: Nick Desaulniers > > Link: https://lore.kernel.org/r/20210105154726.gd1...@shell.armlinux.org.uk > > Link: https://lore.kernel.org/r/20210112224832.10980-1-w...@kernel.org > > Signed-off-by: Catalin Marinas > > [will: backport to 4.4.y/4.9.y/4.14.y] > > Merging this from stable into "Android Common Kernel" trees that were > built with AOSP GCC 4.9, I expect this to break some builds. Arnd, > IIRC did you mention that AOSP GCC had picked up a fix? If so, did > you verify that via disassembly, or gerrit patch file? > > (AOSP GCC 4.9: > https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/ > master branch, roll back a few commits). > It looks like AOSP GCC `#defines __android__ 1`. It seems like this is the source for that toolchain? https://android.googlesource.com/toolchain/gcc If so, it looks like that patch was picked up in this commit. https://android.googlesource.com/toolchain/gcc/+/5ae0308a147ec3f6502fd321860524e634a647a6 Cheers, Nathan
Re: [STABLE BACKPORT 4.4.y, 4.9.y and 4.14.y] compiler.h: Raise minimum version of GCC to 5.1 for arm64
On Mon, Jan 18, 2021 at 5:54 AM Will Deacon wrote: > > commit dca5244d2f5b94f1809f0c02a549edf41ccd5493 upstream. > > GCC versions >= 4.9 and < 5.1 have been shown to emit memory references > beyond the stack pointer, resulting in memory corruption if an interrupt > is taken after the stack pointer has been adjusted but before the > reference has been executed. This leads to subtle, infrequent data > corruption such as the EXT4 problems reported by Russell King at the > link below. > > Life is too short for buggy compilers, so raise the minimum GCC version > required by arm64 to 5.1. > > Reported-by: Russell King > Suggested-by: Arnd Bergmann > Signed-off-by: Will Deacon > Tested-by: Nathan Chancellor > Reviewed-by: Nick Desaulniers > Reviewed-by: Nathan Chancellor > Acked-by: Linus Torvalds > Cc: # 4.4.y, 4.9.y and 4.14.y only > Cc: Theodore Ts'o > Cc: Florian Weimer > Cc: Peter Zijlstra > Cc: Nick Desaulniers > Link: https://lore.kernel.org/r/20210105154726.gd1...@shell.armlinux.org.uk > Link: https://lore.kernel.org/r/20210112224832.10980-1-w...@kernel.org > Signed-off-by: Catalin Marinas > [will: backport to 4.4.y/4.9.y/4.14.y] Merging this from stable into "Android Common Kernel" trees that were built with AOSP GCC 4.9, I expect this to break some builds. Arnd, IIRC did you mention that AOSP GCC had picked up a fix? If so, did you verify that via disassembly, or gerrit patch file? (AOSP GCC 4.9: https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/ master branch, roll back a few commits). It looks like AOSP GCC `#defines __android__ 1`. I'm not arguing against a backport, just trying to think through how we'll need to sort this out downstream. (Revert or patch on top that checks for __android__, if AOSP GCC does in fact have a fix.) > Signed-off-by: Will Deacon > --- > include/linux/compiler-gcc.h | 6 ++ > 1 file changed, 6 insertions(+) > > diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h > index af8b4a879934..3cc8adede67b 100644 > --- a/include/linux/compiler-gcc.h > +++ b/include/linux/compiler-gcc.h > @@ -145,6 +145,12 @@ > > #if GCC_VERSION < 30200 > # error Sorry, your compiler is too old - please upgrade it. > +#elif defined(CONFIG_ARM64) && GCC_VERSION < 50100 > +/* > + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293 > + * https://lore.kernel.org/r/20210107111841.gn1...@shell.armlinux.org.uk > + */ > +# error Sorry, your version of GCC is too old - please use 5.1 or newer. > #endif > > #if GCC_VERSION < 30300 > -- > 2.30.0.284.gd98b1dd5eaa7-goog > -- Thanks, ~Nick Desaulniers
