[PATCH RFC 1/6] xen/arm: mm: Remove special case for CPU0 in dump_hyp_walk()

[Julien Grall <julien@xxxxxxx>]

From: Stefano Stabellini <sstabellini@xxxxxxxxxx>

There is no need to have a special case for CPU0 when converting the
page-table virtual address into a physical address. The helper
virt_to_maddr() is able to translate any address as long as the root
page-tables is mapped in the virtual address. This is the case for all
the CPUs at the moment.

So use the same BUG_ON() regardless the CPU.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
[julien: Rework the commit message]
Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>

---

I went back through the conversation in [1] regarding the issue when
loading Xen below 2MB on Arm32. The example provided is wrong because to
find the physical address, we need to add 'phys_offset', not substract.

So I removed the comment regarding the code was buggy.

[1] https://marc.info/?l=xen-devel&m=157081398022401
---
 xen/arch/arm/mm.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 9c4b26bf079b..4dd886f7c80d 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -284,10 +284,7 @@ void dump_hyp_walk(vaddr_t addr)
            "on CPU%d via TTBR 0x%016"PRIx64"\n",
            addr, smp_processor_id(), ttbr);
 
-    if ( smp_processor_id() == 0 )
-        BUG_ON( (lpae_t *)(unsigned long)(ttbr - phys_offset) != pgtable );
-    else
-        BUG_ON( virt_to_maddr(pgtable) != ttbr );
+    BUG_ON( virt_to_maddr(pgtable) != ttbr );
     dump_pt_walk(ttbr, addr, HYP_PT_ROOT_LEVEL, 1);
 }
 
-- 
2.17.1