Commit ead7de46 authored by Will Deacon's avatar Will Deacon Committed by Peter Zijlstra
Browse files

arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 



Allow systems with mismatched 32-bit support at EL0 to run 32-bit
applications based on a new kernel parameter.

Signed-off-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210730112443.23245-15-will@kernel.org
parent 7af33504

Documentation/admin-guide/kernel-parameters.txt

+8 −0
Original line number Diff line number Diff line
@@ -287,6 +287,14 @@ 
			do not want to use tracing_snapshot_alloc() as it needs

			to be done where GFP_KERNEL allocations are allowed.



	allow_mismatched_32bit_el0 [ARM64]

			Allow execve() of 32-bit applications and setting of the

			PER_LINUX32 personality on systems where only a strict

			subset of the CPUs support 32-bit EL0. When this

			parameter is present, the set of CPUs supporting 32-bit

			EL0 is indicated by /sys/devices/system/cpu/aarch32_el0

			and hot-unplug operations may be restricted.



	amd_iommu=	[HW,X86-64]

			Pass parameters to the AMD IOMMU driver in the system.

			Possible values are:

arch/arm64/kernel/cpufeature.c

+7 −0
Original line number Diff line number Diff line
@@ -1322,6 +1322,13 @@ const struct cpumask *system_32bit_el0_cpumask(void) 
	return cpu_possible_mask;

}



static int __init parse_32bit_el0_param(char *str)

{

	allow_mismatched_32bit_el0 = true;

	return 0;

}

early_param("allow_mismatched_32bit_el0", parse_32bit_el0_param);



static ssize_t aarch32_el0_show(struct device *dev,

				struct device_attribute *attr, char *buf)

{