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" },
- { 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" },
--
2.34.1
