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

[Sachin Sant]

> On 28-Jun-2021, at 1:19 PM, Nicholas Piggin <npiggin at gmail.com> 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 <sachinp at linux.vnet.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin at 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 <sachinp at linux.vnet.ibm.com>

-Sachin