Date: Tue, 16 Sep 2025 16:05:34 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 22cce201da76 - main - vm/vm_fault.c: update and split comments for vm_fault() and vm_fault_trap() Message-ID: <202509161605.58GG5Y8I009511@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=22cce201da76a1916be5c993201f0478f3048292 commit 22cce201da76a1916be5c993201f0478f3048292 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2025-09-16 03:41:55 +0000 Commit: Konstantin Belousov <kib@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)
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