[src/trunk]: src/lib/libkvm Fix _kvm_kvatop so that it now works.

[skrll <skrll%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/befbb7557909
branches:  trunk
changeset: 995366:befbb7557909
user:      skrll <skrll%NetBSD.org@localhost>
date:      Tue Dec 18 16:25:47 2018 +0000

description:
Fix _kvm_kvatop so that it now works.

diffstat:

 lib/libkvm/kvm_aarch64.c |  40 ++++++++++++++++++----------------------
 1 files changed, 18 insertions(+), 22 deletions(-)

diffs (107 lines):

diff -r 71a4fb345ca8 -r befbb7557909 lib/libkvm/kvm_aarch64.c
--- a/lib/libkvm/kvm_aarch64.c  Tue Dec 18 16:23:20 2018 +0000
+++ b/lib/libkvm/kvm_aarch64.c  Tue Dec 18 16:25:47 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: kvm_aarch64.c,v 1.5 2018/11/09 04:06:40 mrg Exp $ */
+/* $NetBSD: kvm_aarch64.c,v 1.6 2018/12/18 16:25:47 skrll Exp $ */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -48,7 +48,7 @@
 
 #include "kvm_private.h"
 
-__RCSID("$NetBSD: kvm_aarch64.c,v 1.5 2018/11/09 04:06:40 mrg Exp $");
+__RCSID("$NetBSD: kvm_aarch64.c,v 1.6 2018/12/18 16:25:47 skrll Exp $");
 
 /*ARGSUSED*/
 void
@@ -83,27 +83,24 @@
        }
 
        const cpu_kcore_hdr_t * const cpu_kh = kd->cpu_data;
-       const uint64_t tg1 = cpu_kh->kh_tcr1 & TCR_TG1; 
+       const uint64_t tg1 = cpu_kh->kh_tcr1 & TCR_TG1;
        const u_int t1siz = __SHIFTOUT(cpu_kh->kh_tcr1, TCR_T1SZ);
+       const u_int inputsz = 64 - t1siz;
 
        /*
         * Real kernel virtual address: do the translation.
         */
 
-       u_int va_bits;
        u_int page_shift;
 
        switch (tg1) {
        case TCR_TG1_4KB:
-               va_bits = t1siz + 36;
                page_shift = 12;
                break;
        case TCR_TG1_16KB:
-               va_bits = 48;
                page_shift = 14;
                break;
        case TCR_TG1_64KB:
-               va_bits = t1siz + 38;
                page_shift = 16;
                break;
        default:
@@ -111,28 +108,27 @@
        }
 
        const size_t page_size = 1 << page_shift;
-       const uint64_t page_mask = (page_size - 1);
-       const uint64_t page_addr = __BITS(47, 0) & ~page_mask;
-       const uint64_t pte_mask = page_mask >> 3;
+       const uint64_t page_mask = __BITS(page_shift - 1, 0);
+       const uint64_t page_addr = __BITS(47, page_shift);
        const u_int pte_shift = page_shift - 3;
 
-       /* how many level of page tables do we have? */
-       u_int level = (48 + page_shift - 1) / page_shift;
+       /* how many levels of page tables do we have? */
+       u_int levels = howmany(inputsz - page_shift, pte_shift);
 
        /* restrict va to the valid VA bits */
-       va &= (1LL << va_bits) - 1;
+       va &= __BITS(inputsz - 1, 0);
 
-       u_int addr_shift = page_shift + (level - 1) * pte_shift;
+       u_int addr_shift = page_shift + (levels - 1) * pte_shift;
 
        /* clear out the unused low bits of the table address */
-       paddr_t pte_addr = (cpu_kh->kh_ttbr1 & TTBR_BADDR);
-       pte_addr &= ~((8L << (va_bits - addr_shift)) - 1);
+       paddr_t pte_addr = cpu_kh->kh_ttbr1 & TTBR_BADDR;
 
        for (;;) {
                pt_entry_t pte;
 
                /* now index into the pte table */
-               pte_addr += 8 * ((va >> addr_shift) & pte_mask);
+               const u_int idx_mask =  __BITS(addr_shift + pte_shift - 1, addr_shift);
+               pte_addr += 8 * __SHIFTOUT(va, idx_mask);
 
                /* Find and read the PTE. */
                if (_kvm_pread(kd, kd->pmfd, &pte, sizeof(pte),
@@ -148,15 +144,15 @@
                }
 
                if ((pte & LX_TYPE) == LX_TYPE_BLK) {
-                       const paddr_t blk_mask = ((1L << addr_shift) - 1);
+                       const size_t blk_size = 1 << addr_shift;
+                       const paddr_t blk_mask = __BITS(addr_shift - 1, 0);
 
                        *pa = (pte & page_addr & ~blk_mask) | (va & blk_mask);
-                       return 0;
+                       return blk_size - (va & blk_mask);
                }
-
-               if (level == page_shift) {
+               if (--levels == 0) {
                        *pa = (pte & page_addr) | (va & page_mask);
-                       return 0;
+                       return page_size - (va & page_mask); 
                }
 
                /*