powerpc/64s/interrupt: Check and fix srr_valid without crashing

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The PPC_RFI_SRR_DEBUG check added by patch "powerpc/64s: avoid reloading
(H)SRR registers if they are still valid" has a few deficiencies. It
does not fix the actual problem, it's not enabled by default, and it
causes a program check interrupt which can cause more difficulties.

However there are a lot of paths which may clobber SRRs or change return
regs, and difficult to have a high confidence that all paths are covered
without wider testing.

Add a relatively low overhead always-enabled check that catches most
such cases, reports once, and fixes it so the kernel can continue.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Rebase, use switch & INT names, squash in race fix from Nick]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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Nicholas Piggin 2021-06-22 22:16:28 +10:00 • committed by Michael Ellerman

parent ae58b1c645

commit 6eaaf9de35

1 changed files with 89 additions and 0 deletions

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arch/powerpc/kernel/interrupt.c

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