kselftest/arm64: Add tests for POR_EL0 save/reset/restore

POR_EL0 is expected to be:
- Saved in the poe_context record
- Reset to POR_EL0_INIT when invoking the signal handler
- Restored from poe_context when returning from the signal handler

Add a new test, poe_restore, to check that the save/reset/restore
mechanism is working as intended. See commit 2e8a1acea859 ("arm64:
signal: Improve POR_EL0 handling to avoid uaccess failures") for
more details.

This commit did not handle the case where poe_context is missing
correctly. This was recently fixed; add a new test,
poe_missing_poe_context, to check this case.

Note: td->pass is only set to true at the very end, as an unexpected
signal may occur in case of failure (especially in
poe_missing_poe_context if POR_EL0 is restored to an invalid value).
Failures are tracked with a global, failed_check.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>

0 files changed, 0 insertions, 0 deletions