[src/trunk]: src/sys/arch/amd64/include Use large pages for the kASan shadow, ...

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

details:   https://anonhg.NetBSD.org/src/rev/2df4627083a6
branches:  trunk
changeset: 930863:2df4627083a6
user:      maxv <maxv%NetBSD.org@localhost>
date:      Wed Apr 15 17:00:07 2020 +0000

description:
Use large pages for the kASan shadow, same as kMSan.

diffstat:

 sys/arch/amd64/include/asan.h |  41 ++++++++++++++++++++++++++++++++++++-----
 1 files changed, 36 insertions(+), 5 deletions(-)

diffs (74 lines):

diff -r 567d0b22c2f3 -r 2df4627083a6 sys/arch/amd64/include/asan.h
--- a/sys/arch/amd64/include/asan.h     Wed Apr 15 16:39:06 2020 +0000
+++ b/sys/arch/amd64/include/asan.h     Wed Apr 15 17:00:07 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: asan.h,v 1.3 2019/03/09 08:42:25 maxv Exp $    */
+/*     $NetBSD: asan.h,v 1.4 2020/04/15 17:00:07 maxv Exp $    */
 
 /*
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -92,29 +92,60 @@
        else
                pa = pmap_get_physpage();
 
+       /* The page is zeroed. */
        return pa;
 }
 
+static inline paddr_t
+__md_palloc_large(void)
+{
+       struct pglist pglist;
+       int ret;
+
+       if (__predict_false(__md_early))
+               return 0;
+       if (!uvm.page_init_done)
+               return 0;
+
+       ret = uvm_pglistalloc(NBPD_L2, 0, ~0UL, NBPD_L2, 0,
+           &pglist, 1, 0);
+       if (ret != 0)
+               return 0;
+
+       /* The page may not be zeroed. */
+       return VM_PAGE_TO_PHYS(TAILQ_FIRST(&pglist));
+}
+
 static void
 kasan_md_shadow_map_page(vaddr_t va)
 {
+       const pt_entry_t pteflags = PTE_W | pmap_pg_nx | PTE_P;
        paddr_t pa;
 
        if (!pmap_valid_entry(L4_BASE[pl4_i(va)])) {
                pa = __md_palloc();
-               L4_BASE[pl4_i(va)] = pa | PTE_W | pmap_pg_nx | PTE_P;
+               L4_BASE[pl4_i(va)] = pa | pteflags;
        }
        if (!pmap_valid_entry(L3_BASE[pl3_i(va)])) {
                pa = __md_palloc();
-               L3_BASE[pl3_i(va)] = pa | PTE_W | pmap_pg_nx | PTE_P;
+               L3_BASE[pl3_i(va)] = pa | pteflags;
        }
        if (!pmap_valid_entry(L2_BASE[pl2_i(va)])) {
+               if ((pa = __md_palloc_large()) != 0) {
+                       L2_BASE[pl2_i(va)] = pa | pteflags | PTE_PS |
+                           pmap_pg_g;
+                       __insn_barrier();
+                       __builtin_memset((void *)va, 0, NBPD_L2);
+                       return;
+               }
                pa = __md_palloc();
-               L2_BASE[pl2_i(va)] = pa | PTE_W | pmap_pg_nx | PTE_P;
+               L2_BASE[pl2_i(va)] = pa | pteflags;
+       } else if (L2_BASE[pl2_i(va)] & PTE_PS) {
+               return;
        }
        if (!pmap_valid_entry(L1_BASE[pl1_i(va)])) {
                pa = __md_palloc();
-               L1_BASE[pl1_i(va)] = pa | PTE_W | pmap_pg_g | pmap_pg_nx | PTE_P;
+               L1_BASE[pl1_i(va)] = pa | pteflags | pmap_pg_g;
        }
 }