Re: [PATCH 1/2] ARM: copypage-fa: add kto and kfrom to input operands list
From: Linus Walleij
Date: Tue Oct 16 2018 - 04:00:34 EST
On Tue, Oct 16, 2018 at 12:16 AM Stefan Agner <stefan@xxxxxxxx> wrote:
> When functions incoming parameters are not in input operands list gcc
> 4.5 does not load the parameters into registers before calling this
> function but the inline assembly assumes valid addresses inside this
> function. This breaks the code because r0 and r1 are invalid when
> execution enters v4wb_copy_user_page ()
> Also the constant needs to be used as third input operand so account
> for that as well.
> This fixes copypage-fa.c what has previously done before for the other
> copypage implementations in commit 9a40ac86152c ("ARM: 6164/1: Add kto
> and kfrom to input operands list.").
> Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
I am on deep waters with ARM assembly, admittedly. So I wanted to
ask: OpenWRT has this cache patch:
I do not know why (sorry).
Do you think that patch is actually a hack to hide the problem
fixed with this patch? (OK maybe stupid question but...)
it appeared anonymously in OpenWRT with the commit message
"add v3.18 support" at one point.