On Tue, Mar 05, 2024 at 11:56:05AM +0100, Andrea della Porta wrote: > On 11:58 Wed 07 Feb , Andrea della Porta wrote: > > Introducing the field 'el0' to the idreg-override for register > > ID_AA64PFR0_EL1. This field is also aliased to the new kernel > > command line option 'arm64.no32bit_el0' as a more recognizable > > and mnemonic name to disable the execution of 32 bit userspace > > applications (i.e. avoid Aarch32 execution state in EL0) from > > kernel command line. > > > > Changes in V2: > > - fixed the order of appearance of arm64.no32bit_el0 entry in > > kernel-parameters.txt documentation. > > > > Link: https://lore.kernel.org/r/ZVTleETzfFUchs77@apocalypse > > Signed-off-by: Andrea della Porta <andrea.porta@xxxxxxxx> > > --- > > Documentation/admin-guide/kernel-parameters.txt | 3 +++ > > arch/arm64/kernel/idreg-override.c | 2 ++ > > 2 files changed, 5 insertions(+) > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index 65731b060e3f..fa7cdf2f4f3a 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -415,6 +415,9 @@ > > arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards > > Format: <io>,<irq>,<nodeID> > > > > + arm64.no32bit_el0 [ARM64] Unconditionally disable the execution of > > + 32 bit applications > > + > > arm64.nobti [ARM64] Unconditionally disable Branch Target > > Identification support > > > > diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c > > index e30fd9e32ef3..642cda19e42d 100644 > > --- a/arch/arm64/kernel/idreg-override.c > > +++ b/arch/arm64/kernel/idreg-override.c > > @@ -86,6 +86,7 @@ static const struct ftr_set_desc pfr0 __prel64_initconst = { > > .override = &id_aa64pfr0_override, > > .fields = { > > FIELD("sve", ID_AA64PFR0_EL1_SVE_SHIFT, pfr0_sve_filter), > > + FIELD("el0", ID_AA64PFR0_EL1_EL0_SHIFT, NULL), > > {} > > }, > > }; > > @@ -197,6 +198,7 @@ static const struct { > > { "arm64.nomops", "id_aa64isar2.mops=0" }, > > { "arm64.nomte", "id_aa64pfr1.mte=0" }, > > { "nokaslr", "arm64_sw.nokaslr=1" }, > > + { "arm64.no32bit_el0", "id_aa64pfr0.el0=1" }, > > }; > > > > static int __init parse_hexdigit(const char *p, u64 *v) > > -- > > 2.41.0 > > > > A gentle ping about this patch... any thoughts about it? It looks reasonable to me, but arch/arm64/kernel/idreg-override.c no longer exists upstream, so you need to rebase. Thanks, Will
