git: dc39b2dc64d2 - main - Allow changing arm64 table attributes when bootstrapping pmap

[Andrew Turner]

The branch main has been updated by andrew:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=dc39b2dc64d2396083c916b1f688cbd22548f991

commit dc39b2dc64d2396083c916b1f688cbd22548f991
Author:     Andrew Turner <and...@freebsd.org>
AuthorDate: 2022-09-26 14:16:32 +0000
Commit:     Andrew Turner <and...@freebsd.org>
CommitDate: 2022-09-27 12:26:29 +0000

    Allow changing arm64 table attributes when bootstrapping pmap
    
    Only the DMAP region can be mapped with PXN. Allow the table attributes
    to be changed for other mappings.
    
    Sponsored by:   The FreeBSD Foundation
---
 sys/arm64/arm64/pmap.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
index 66046779802d..a31e95ba6f32 100644
--- a/sys/arm64/arm64/pmap.c
+++ b/sys/arm64/arm64/pmap.c
@@ -823,6 +823,7 @@ struct pmap_bootstrap_state {
        pt_entry_t      *l1;
        pt_entry_t      *l2;
        pt_entry_t      *l3;
+       pt_entry_t      table_attrs;
        u_int           l0_slot;
        u_int           l1_slot;
        u_int           l2_slot;
@@ -936,7 +937,7 @@ pmap_bootstrap_l1_table(struct pmap_bootstrap_state *state)
                l2_pa = pmap_early_vtophys((vm_offset_t)state->l2);
                MPASS((l2_pa & Ln_TABLE_MASK) == 0);
                MPASS(state->l1[l1_slot] == 0);
-               pmap_store(&state->l1[l1_slot], l2_pa | TATTR_PXN_TABLE |
+               pmap_store(&state->l1[l1_slot], l2_pa | state->table_attrs |
                    L1_TABLE);
        }
        KASSERT(state->l2 != NULL, ("%s: NULL l2", __func__));
@@ -980,7 +981,7 @@ pmap_bootstrap_l2_table(struct pmap_bootstrap_state *state)
                l3_pa = pmap_early_vtophys((vm_offset_t)state->l3);
                MPASS((l3_pa & Ln_TABLE_MASK) == 0);
                MPASS(state->l2[l2_slot] == 0);
-               pmap_store(&state->l2[l2_slot], l3_pa | TATTR_PXN_TABLE |
+               pmap_store(&state->l2[l2_slot], l3_pa | state->table_attrs |
                    L2_TABLE);
        }
        KASSERT(state->l3 != NULL, ("%s: NULL l3", __func__));
@@ -1238,6 +1239,11 @@ pmap_bootstrap(vm_offset_t l0pt, vm_offset_t l1pt, 
vm_paddr_t kernstart,
        /* Create a direct map region early so we can use it for pa -> va */
        freemempos = pmap_bootstrap_dmap(l1pt, min_pa, freemempos);
        bs_state.dmap_valid = true;
+       /*
+        * We only use PXN when we know nothing will be executed from it, e.g.
+        * the DMAP region.
+        */
+       bs_state.table_attrs &= ~TATTR_PXN_TABLE;
 
        start_pa = pa = KERNBASE - kern_delta;