Remove kbind(2)'s restriction that a target buffer not cross page

boundaries: hppa has 8-byte PLT entries that sometimes do that.

ok kettenis@

diff --git a/sys/uvm/uvm_mmap.c b/sys/uvm/uvm_mmap.c
index 0a31c62..d721562 100644 (file)
--- a/sys/uvm/uvm_mmap.c
+++ b/sys/uvm/uvm_mmap.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uvm_mmap.c,v 1.167 2021/12/23 18:50:32 guenther Exp $ */
+/*     $OpenBSD: uvm_mmap.c,v 1.168 2022/01/05 17:53:44 guenther Exp $ */
 /*     $NetBSD: uvm_mmap.c,v 1.49 2001/02/18 21:19:08 chs Exp $        */
 
 /*
@@ -1124,7 +1124,7 @@ sys_kbind(struct proc *p, void *v, register_t *retval)
        vaddr_t baseva, last_baseva, endva, pageoffset, kva;
        size_t psize, s;
        u_long pc;
-       int count, i;
+       int count, i, extra;
        int error;
 
        /*
@@ -1175,7 +1175,6 @@ sys_kbind(struct proc *p, void *v, register_t *retval)
                    paramp[count].kb_size > KBIND_DATA_MAX ||
                    baseva >= VM_MAXUSER_ADDRESS ||
                    endva >= VM_MAXUSER_ADDRESS ||
-                   trunc_page(baseva) != trunc_page(endva) ||
                    s < paramp[count].kb_size)
                        return EINVAL;
 
@@ -1191,9 +1190,17 @@ sys_kbind(struct proc *p, void *v, register_t *retval)
        TAILQ_INIT(&dead_entries);
        for (i = 0; i < count; i++) {
                baseva = (vaddr_t)paramp[i].kb_addr;
+               s = paramp[i].kb_size;
                pageoffset = baseva & PAGE_MASK;
                baseva = trunc_page(baseva);
 
+               /* hppa at least runs PLT entries over page edge */
+               extra = (pageoffset + s) & PAGE_MASK;
+               if (extra > pageoffset)
+                       extra = 0;
+               else
+                       s -= extra;
+redo:
                /* make sure sure the desired page is mapped into kernel_map */
                if (baseva != last_baseva) {
                        if (kva != 0) {
@@ -1210,10 +1217,17 @@ sys_kbind(struct proc *p, void *v, register_t *retval)
                }
 
                /* do the update */
-               if ((error = kcopy(data, (char *)kva + pageoffset,
-                   paramp[i].kb_size)))
+               if ((error = kcopy(data, (char *)kva + pageoffset, s)))
                        break;
-               data += paramp[i].kb_size;
+               data += s;
+
+               if (extra > 0) {
+                       baseva += PAGE_SIZE;
+                       s = extra;
+                       pageoffset = 0;
+                       extra = 0;
+                       goto redo;
+               }
        }
 
        if (kva != 0) {