Thread (18 messages) 18 messages, 3 authors, 2016-11-23

[PATCHv3 5/6] arm64: Use __pa_symbol for kernel symbols

From: mark.rutland@arm.com (Mark Rutland)
Date: 2016-11-18 16:46:53
Also in: linux-mm, lkml

On Fri, Nov 18, 2016 at 02:35:44PM +0000, Mark Rutland wrote:
Hi Laura,

On Thu, Nov 17, 2016 at 05:16:55PM -0800, Laura Abbott wrote:
quoted
__pa_symbol is technically the marco that should be used for kernel
symbols. Switch to this as a pre-requisite for DEBUG_VIRTUAL which
will do bounds checking.

Signed-off-by: Laura Abbott <redacted>
---
v3: Conversion of more sites besides just _end. Addition of __lm_sym_addr
macro to take care of the _va(__pa_symbol(..)) idiom.

Note that a copy of __pa_symbol was added to avoid a mess of headers
since the #ifndef __pa_symbol case is defined in linux/mm.h
I think we also need to fix up virt_to_phys(__cpu_soft_restart) in
arch/arm64/kernel/cpu-reset.h. Otherwise, this looks complete for uses
falling under arch/arm64/.
I think I spoke too soon. :(

In the kasan code, use of tmp_pg_dir, kasan_zero_{page,pte,pmd,pud} all
need to be vetted, as those are in the image, but get passed directly to
functions which will end up doing a virt_to_phys behind the scenes (e.g.
cpu_replace_ttbr1(), pmd_populate_kernel()).

There's also some virt_to_pfn(<symbol>) usage that needs to be fixed up
in arch/arm64/kernel/hibernate.c.

... there's also more of that in common kernel code. :(

Thanks,
Mark.
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