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> --- Changes since v2: * Include missing "Granule Protection Fault at level -1" --- arch/arm64/mm/fault.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 451ba7cbd5ad..8adc0d0b41a2 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -751,6 +751,25 @@ 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" }, @@ -787,12 +806,12 @@ static const struct fault_info fault_info[] = { { do_bad, SIGKILL, SI_KERNEL, "unknown 32" }, { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" }, { do_bad, SIGKILL, SI_KERNEL, "unknown 34" }, - { do_bad, SIGKILL, SI_KERNEL, "unknown 35" }, - { 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 -1" }, + { 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" }, -- 2.34.1