Adds a utility to exercise the prctl DEXCR inheritance in the shell.
Supports setting and clearing each aspect.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
[mpe: Use correct SPDX license, use execvp() for usability, print errors]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240417112325.728010-9-bgray@linux.ibm.com
Some basic tests of the prctl interface of the DEXCR.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
[mpe: Add missing SPDX tag]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240417112325.728010-6-bgray@linux.ibm.com
Add a utility 'lsdexcr' to print the current DEXCR status. Useful for
quickly checking the status such as when debugging test failures or
verifying the new default DEXCR does what you want (for userspace at
least). Example output:
# ./lsdexcr
uDEXCR: 04000000 (NPHIE)
HDEXCR: 00000000
Effective: 04000000 (NPHIE)
SBHE (0): clear (Speculative branch hint enable)
IBRTPD (3): clear (Indirect branch recurrent target ...)
SRAPD (4): clear (Subroutine return address ...)
NPHIE * (5): set (Non-privileged hash instruction enable)
PHIE (6): clear (Privileged hash instruction enable)
DEXCR[NPHIE] enabled: hashst/hashchk working
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230616034846.311705-12-bgray@linux.ibm.com
Test the kernel DEXCR[NPHIE] interface and hashchk exception handling.
Introduces with it a DEXCR utils library for common DEXCR operations.
Volatile is used to prevent the compiler optimising away the signal
tests.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230616034846.311705-11-bgray@linux.ibm.com