On 16/04/2024 12:17, Suzuki K Poulose wrote:
> On 12/04/2024 09:42, Steven Price wrote:
>> If the host attempts to access granules that have been delegated for use
>> in a realm these accesses will be caught and will trigger a Granule
>> Protection Fault (GPF).
>>
>> A fault during a page walk signals a bug in the kernel and is handled by
>> oopsing the kernel. A non-page walk fault could be caused by user space
>> having access to a page which has been delegated to the kernel and will
>> trigger a SIGBUS to allow debugging why user space is trying to access a
>> delegated page.
>>
>> Signed-off-by: Steven Price <steven.price@xxxxxxx>
>> ---
>> arch/arm64/mm/fault.c | 29 ++++++++++++++++++++++++-----
>> 1 file changed, 24 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
>> index 8251e2fea9c7..91da0f446dd9 100644
>> --- a/arch/arm64/mm/fault.c
>> +++ b/arch/arm64/mm/fault.c
>> @@ -765,6 +765,25 @@ static int do_tag_check_fault(unsigned long far,
>> unsigned long esr,
>> return 0;
>> }
>> +static int do_gpf_ptw(unsigned long far, unsigned long esr, struct
>> pt_regs *regs)
>> +{
>> + const struct fault_info *inf = esr_to_fault_info(esr);
>> +
>> + die_kernel_fault(inf->name, far, esr, regs);
>> + return 0;
>> +}
>> +
>> +static int do_gpf(unsigned long far, unsigned long esr, struct
>> pt_regs *regs)
>> +{
>> + const struct fault_info *inf = esr_to_fault_info(esr);
>> +
>> + if (!is_el1_instruction_abort(esr) && fixup_exception(regs))
>> + return 0;
>> +
>> + arm64_notify_die(inf->name, regs, inf->sig, inf->code, far, esr);
>> + return 0;
>> +}
>> +
>> static const struct fault_info fault_info[] = {
>> { do_bad, SIGKILL, SI_KERNEL, "ttbr address size
>> fault" },
>> { do_bad, SIGKILL, SI_KERNEL, "level 1 address size
>> fault" },
>> @@ -802,11 +821,11 @@ static const struct fault_info fault_info[] = {
>> { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment
>> fault" },
>> { do_bad, SIGKILL, SI_KERNEL, "unknown 34" },
>> { do_bad, SIGKILL, SI_KERNEL, "unknown 35" },
>
> Should this also be converted to do_gpf_ptw, "GPF at level -1", given we
> support LPA2 ?
Ah, yes I somehow missed that. Although something has gone majorly wrong
if this triggers! ;)
Steve
>> - { do_bad, SIGKILL, SI_KERNEL, "unknown 36" },
>> - { do_bad, SIGKILL, SI_KERNEL, "unknown 37" },
>> - { do_bad, SIGKILL, SI_KERNEL, "unknown 38" },
>> - { do_bad, SIGKILL, SI_KERNEL, "unknown 39" },
>> - { do_bad, SIGKILL, SI_KERNEL, "unknown 40" },
>> + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection
>> Fault at level 0" },
>> + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection
>> Fault at level 1" },
>> + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection
>> Fault at level 2" },
>> + { do_gpf_ptw, SIGKILL, SI_KERNEL, "Granule Protection
>> Fault at level 3" },
>> + { do_gpf, SIGBUS, SI_KERNEL, "Granule Protection Fault
>> not on table walk" },
>> { do_bad, SIGKILL, SI_KERNEL, "level -1 address size
>> fault" },
>> { do_bad, SIGKILL, SI_KERNEL, "unknown 42" },
>> { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level -1
>> translation fault" },
>
>
> Rest looks fine to me.
>
> Suzuki
