Re: [PATCH 3/8] powerpc/64s: add a table of implicit soft-masked addresses

On 28-Jun-2021, at 1:19 PM, Nicholas Piggin [off-list ref] wrote:

Commit 9d1988ca87dd ("powerpc/64: treat low kernel text as irqs
soft-masked") ends up catching too much code, including ret_from_fork,
and parts of interrupt and syscall return that do not expect to be
interrupts to be soft-masked. If an interrupt gets marked pending,
and then the code proceeds out of the implicit soft-masked region it
will fail to deal with the pending interrupt.

Fix this by adding a new table of addresses which explicitly marks
the regions of code that are soft masked. This table is only checked
for interrupts that below __end_soft_masked, so most kernel interrupts
will not have the overhead of the table search.

Fixes: 9d1988ca87dd ("powerpc/64: treat low kernel text as irqs soft-masked")
Reported-by: Sachin Sant <redacted>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Thanks Nick for the fix.

I was able to verify this patch. 
Both kernel boot and test ran to completion without the reported warning.

Tested-by: Sachin Sant <redacted>

-Sachin