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authorOlivier Houchard <cognet@FreeBSD.org>2026-07-23 23:47:21 +0000
committerOlivier Houchard <cognet@FreeBSD.org>2026-08-04 10:28:40 +0000
commit35d56f200e94336d5f3baac7f124fbe93f82a98e (patch)
treec2a3de61ceb62954362f6c7e4333b2b6d1d725fb
parentaa8ffe6fbac70cccb7bb7519b4f98b7e13af25ee (diff)
arm64: Use the fault handler when one is provided
In align_abort() and tag_check_abort(), if we got a fault while in kernel, do not panic if a fault handler has been provided. We may get such a fault when trying to read or write userland data, it can at least happen with _umtx_op() if an unaligned pointer is provided. Instead, just let the fault handler deal with it. MFC After: 1 week Approved by: andrew Differential Revision: https://reviews.freebsd.org/D58426 (cherry picked from commit c6f5d8fb269fd67a8206420b4e7d67a93bc80733) Signed-off-by: Olivier Houchard <cognet@FreeBSD.org> (cherry picked from commit 60dd46db19f473af7aa505c0d8dcf9bb69847019) Signed-off-by: Olivier Houchard <cognet@FreeBSD.org>
-rw-r--r--sys/arm64/arm64/trap.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/sys/arm64/arm64/trap.c b/sys/arm64/arm64/trap.c
index 9f792332a931..6292522ae67b 100644
--- a/sys/arm64/arm64/trap.c
+++ b/sys/arm64/arm64/trap.c
@@ -212,6 +212,17 @@ align_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
uint64_t far, int lower)
{
if (!lower) {
+ /*
+ * Accessing unaligned memory may fault when using atomics.
+ * Make sure we don't panic if we're doing an unaligned
+ * access to userland memory, as can happen with _umtx_op()
+ */
+ if (td->td_intr_nesting_level == 0 &&
+ td->td_pcb->pcb_onfault != 0) {
+ frame->tf_elr = td->td_pcb->pcb_onfault;
+ return;
+ }
+
print_registers(frame);
print_gp_register("far", far);
printf(" esr: 0x%.16lx\n", esr);