lkml.org 
[lkml]   [2021]   [Jun]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v8 17/19] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0
    Date
    Allow systems with mismatched 32-bit support at EL0 to run 32-bit
    applications based on a new kernel parameter.

    Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
    Signed-off-by: Will Deacon <will@kernel.org>
    ---
    Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++
    arch/arm64/kernel/cpufeature.c | 7 +++++++
    2 files changed, 15 insertions(+)

    diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
    index cb89dbdedc46..a2e453919bb6 100644
    --- a/Documentation/admin-guide/kernel-parameters.txt
    +++ b/Documentation/admin-guide/kernel-parameters.txt
    @@ -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:
    diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
    index 72efdc611b14..f2c97baa050f 100644
    --- a/arch/arm64/kernel/cpufeature.c
    +++ b/arch/arm64/kernel/cpufeature.c
    @@ -1298,6 +1298,13 @@ 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)
    {
    --
    2.32.0.rc0.204.g9fa02ecfa5-goog
    \
     
     \ /
      Last update: 2021-06-02 18:50    [W:4.031 / U:0.120 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site