Re: [PATCH v4 1/6] x86-64: Clean up vdso/kernel shared variables

From: Andrew Lutomirski
Date: Mon May 16 2011 - 13:34:34 EST

On Mon, May 16, 2011 at 1:23 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Mon, May 16, 2011 at 12:00:58PM -0400, Andy Lutomirski wrote:
>> Variables that are shared between the vdso and the kernel are
>> currently a bit of a mess.  They are each defined with their own
>> magic, they are accessed differently in the kernel, the vsyscall page,
>> and the vdso, and one of them (vsyscall_clock) doesn't even really
>> exist.
>> This changes them all to use a common mechanism.  All of them are
>> delcared in vvar.h with a fixed address (validated by the linker
>> script).  In the kernel (as before), they look like ordinary
>> read-write variables.  In the vsyscall page and the vdso, they are
>> accessed through a new macro VVAR, which gives read-only access.
>> The vdso is now loaded verbatim into memory without any fixups.  As a
>> side bonus, access from the vdso is faster because a level of
>> indirection is removed.
>> While we're at it, pack jiffies and vgetcpu_mode into the same
>> cacheline.
> How about
> Signed-off-by:...

Signed-off-by: Andy Lutomirski <luto@xxxxxxx>

If whoever wants to pick up these patches wants it (or if there's a
v5), I'll send a new patch.

> or you don't wanna? :)

Nope. I probably just hit the delete button too hard or something.

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