The branch main has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=22cce201da76a1916be5c993201f0478f3048292
commit 22cce201da76a1916be5c993201f0478f3048292
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2025-09-16 03:41:55 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2025-09-16 16:05:24 +0000
vm/vm_fault.c: update and split comments for vm_fault() and vm_fault_trap()
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differrential revision: https://reviews.freebsd.org/D52567
---
sys/vm/vm_fault.c | 42 ++++++++++++++++++++++++++++++------------
1 file changed, 30 insertions(+), 12 deletions(-)
diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
index 524aed2be2ff..2e150b368d71 100644
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@@ -708,21 +708,18 @@ _Static_assert(UCODE_PAGEFLT == T_PAGEFLT, "T_PAGEFLT");
#endif
/*
- * vm_fault_trap:
+ * vm_fault_trap:
*
- * Handle a page fault occurring at the given address,
- * requiring the given permissions, in the map specified.
- * If successful, the page is inserted into the
- * associated physical map.
+ * Helper for the page fault trap handlers, wrapping vm_fault().
+ * Issues ktrace(2) tracepoints for the faults.
*
- * NOTE: the given address should be truncated to the
- * proper page address.
+ * If a fault cannot be handled successfully by satisfying the
+ * required mapping, and the faulted instruction cannot be restarted,
+ * the signal number and si_code values are returned for trapsignal()
+ * to deliver.
*
- * KERN_SUCCESS is returned if the page fault is handled; otherwise,
- * a standard error specifying why the fault is fatal is returned.
- *
- * The map in question must be referenced, and remains so.
- * Caller may hold no locks.
+ * Returns Mach error codes, but callers should only check for
+ * KERN_SUCCESS.
*/
int
vm_fault_trap(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
@@ -1626,6 +1623,27 @@ vm_fault_object(struct faultstate *fs, int *behindp, int
*aheadp)
return (res);
}
+/*
+ * vm_fault:
+ *
+ * Handle a page fault occurring at the given address, requiring the
+ * given permissions, in the map specified. If successful, the page
+ * is inserted into the associated physical map, and optionally
+ * referenced and returned in *m_hold.
+ *
+ * The given address should be truncated to the proper page address.
+ *
+ * KERN_SUCCESS is returned if the page fault is handled; otherwise, a
+ * Mach error specifying why the fault is fatal is returned.
+ *
+ * The map in question must be alive, either being the map for current
+ * process, or the owner process hold count incremented to prevent
+ * exit().
+ *
+ * If the thread private TDP_NOFAULTING flag is set, any fault results
+ * in immediate protection failure. Otherwise the fault is processed,
+ * and caller may hold no locks.
+ */
int
vm_fault(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
int fault_flags, vm_page_t *m_hold)
