On Mon, Apr 01, 2019 at 12:30:14PM +0100, Vincenzo Frascino wrote: > Currently, compat tasks running on arm64 can allocate memory up to > TASK_SIZE_32 (UL(0x100000000)). > > This means that mmap() allocations, if we treat them as returning an > array, are not compliant with the sections 6.5.8 of the C standard > (C99) which states that: "If the expression P points to an element of > an array object and the expression Q points to the last element of the > same array object, the pointer expression Q+1 compares greater than P". > > Redefine TASK_SIZE_32 to address the issue. > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Will Deacon <will.deacon@xxxxxxx> > Cc: Jann Horn <jannh@xxxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> > Reported-by: Jann Horn <jannh@xxxxxxxxxx> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> > --- > arch/arm64/include/asm/processor.h | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h > index 5d9ce62bdebd..9c831d9d3cd2 100644 > --- a/arch/arm64/include/asm/processor.h > +++ b/arch/arm64/include/asm/processor.h > @@ -57,7 +57,15 @@ > #define TASK_SIZE_64 (UL(1) << vabits_user) > > #ifdef CONFIG_COMPAT > +#ifdef CONFIG_ARM64_64K_PAGES > +/* > + * With CONFIG_ARM64_64K_PAGES enabled, the last page is occupied > + * by the compact vectors page. s/compact/compat/ Will
