On Wed, 2015-10-07 at 14:16 +0530, Aneesh Kumar K.V wrote: > Michael Ellerman <m...@ellerman.id.au> writes: > > > On Fri, 2015-02-10 at 14:33:48 UTC, "Aneesh Kumar K.V" wrote: > >> This avoid errors like > >> > >> unsigned int usize = 1 << 30; > >> int size = 1 << 30; > >> unsigned long addr = 64UL << 30 ; > >> > >> value = _ALIGN_DOWN(addr, usize); -> 0 > >> value = _ALIGN_DOWN(addr, size); -> 0x1000000000 > > > > Are you actually seeing that anywhere? I assume not. > > I hit that in new development. So not in the current kernel.
OK. > >> diff --git a/arch/powerpc/boot/page.h b/arch/powerpc/boot/page.h > >> index 14eca30fef64..87c42d7d283d 100644 > >> --- a/arch/powerpc/boot/page.h > >> +++ b/arch/powerpc/boot/page.h > >> @@ -22,8 +22,8 @@ > >> #define PAGE_MASK (~(PAGE_SIZE-1)) > >> > >> /* align addr on a size boundary - adjust address up/down if needed */ > >> -#define _ALIGN_UP(addr,size) (((addr)+((size)-1))&(~((size)-1))) > >> -#define _ALIGN_DOWN(addr,size) ((addr)&(~((size)-1))) > >> +#define _ALIGN_UP(addr, size) > >> (((addr)+((size)-1))&(~((typeof(addr))(size)-1))) > >> +#define _ALIGN_DOWN(addr, size) ((addr)&(~((typeof(addr))(size)-1))) > >> > >> /* align addr on a size boundary - adjust address up if needed */ > >> #define _ALIGN(addr,size) _ALIGN_UP(addr,size) > >> diff --git a/arch/powerpc/include/asm/page.h > >> b/arch/powerpc/include/asm/page.h > >> index 71294a6e976e..1dd69774a31c 100644 > >> --- a/arch/powerpc/include/asm/page.h > >> +++ b/arch/powerpc/include/asm/page.h > >> @@ -240,8 +240,8 @@ extern long long virt_phys_offset; > >> #endif > >> > >> /* align addr on a size boundary - adjust address up/down if needed */ > >> -#define _ALIGN_UP(addr,size) (((addr)+((size)-1))&(~((size)-1))) > >> -#define _ALIGN_DOWN(addr,size) ((addr)&(~((size)-1))) > >> +#define _ALIGN_UP(addr, size) > >> (((addr)+((size)-1))&(~((typeof(addr))(size)-1))) > >> +#define _ALIGN_DOWN(addr, size) ((addr)&(~((typeof(addr))(size)-1))) > > > > > > It looks like ALIGN() in kernel.h already does this right, so can we just > > use > > that instead for _ALIGN_UP() at least. > > > > But we still can't get rid of _ALIGN_UP, because that is used in other > parts of the kernel and if you are suggesting use > > #define _ALIGN_UP __ALIGN_KERNEL, IMHO that is unnecessary indirection > for no real benefit. Huh? The benefit is not having to define the same macro twice, that seems like a pretty clear win. _ALIGN_UP is ALIGN, just with this bug unfixed. In other words if _ALIGN_UP was already an alias for ALIGN then you would have not seen the bug (except in _ALIGN_DOWN()). cheers _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
