Messages in this thread | | | Date | Wed, 27 Aug 2014 13:08:51 +0200 | Subject | Re: [PATCH] of: Fix memory block alignment in early_init_dt_add_memory_arch() | From | Geert Uytterhoeven <> |
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Hi Grant,
On Wed, Aug 27, 2014 at 12:30 PM, Grant Likely <grant.likely@linaro.org> wrote: > On Wed, 20 Aug 2014 17:10:31 +0200, Geert Uytterhoeven <geert+renesas@glider.be> wrote: >> If a memory block is not aligned to PAGE_SIZE, its base address must be >> rounded up, not down, and its size must be reduced. >> >> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > > Looks reasonable. What is the situation that exposed this problem?
When ARM switched from arm_add_memory() to early_init_dt_add_memory_arch() for DT-based platforms, I just noticed this when comparing the two implementations.
I don't know if it triggers in the wild.
> Should size be checked for page alignment also?
Size is already rounded down if it's not page aligned, cfr. the context below.
>> --- >> drivers/of/fdt.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c >> index f46a24ffa3fe..95fa81b8ca19 100644 >> --- a/drivers/of/fdt.c >> +++ b/drivers/of/fdt.c >> @@ -928,7 +928,11 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, >> void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size) >> { >> const u64 phys_offset = __pa(PAGE_OFFSET); >> - base &= PAGE_MASK; >> + >> + if (!PAGE_ALIGNED(base)) { >> + size -= PAGE_SIZE - (base & ~PAGE_MASK); >> + base = PAGE_ALIGN(base); >> + } >> size &= PAGE_MASK; >> >> if (base > MAX_PHYS_ADDR) { >> -- >> 1.9.1
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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