linux-arm.git - Russell King's ARM Linux kernel tree

Age	Commit message (Collapse)	Author
2024-05-06	powerpc/dexcr: Add DEXCR prctl interface	Benjamin Gray
	Now that we track a DEXCR on a per-task basis, individual tasks are free to configure it as they like. The interface is a pair of getter/setter prctl's that work on a single aspect at a time (multiple aspects at once is more difficult if there are different rules applied for each aspect, now or in future). The getter shows the current state of the process config, and the setter allows setting/clearing the aspect. Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> [mpe: Account for PR_RISCV_SET_ICACHE_FLUSH_CTX, shrink some longs lines] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240417112325.728010-5-bgray@linux.ibm.com
2024-05-03	powerpc/dexcr: Reset DEXCR value across exec	Benjamin Gray
	Inheriting the DEXCR across exec can have security and usability concerns. If a program is compiled with hash instructions it generally expects to run with NPHIE enabled. But if the parent process disables NPHIE then if it's not careful it will be disabled for any children too and the protection offered by hash checks is basically worthless. This patch introduces a per-process reset value that new execs in a particular process tree are initialized with. This enables fine grained control over what DEXCR value child processes run with by default. For example, containers running legacy binaries that expect hash instructions to act as NOPs could configure the reset value of the container root to control the default reset value for all members of the container. Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> [mpe: Add missing SPDX tag on dexcr.c] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240417112325.728010-4-bgray@linux.ibm.com