riscv/pmap.c: Add a ddb command for inspecting PTEs

This change implements the equivalent of the amd64-specific
'show pte' ddb command used to dump the page table entries
associated with a specific virtual address.

Differential Revision:	https://reviews.freebsd.org/D56924
Reviewed by:	mhorne

1 files changed, 61 insertions, 0 deletions

diff --git a/sys/riscv/riscv/pmap.c b/sys/riscv/riscv/pmap.c
index 0461400f2a7c..35194ebd7c28 100644
--- a/sys/riscv/riscv/pmap.c
+++ b/sys/riscv/riscv/pmap.c
@@ -112,6 +112,7 @@
  *	and to when physical maps must be made correct.
  */
 
+#include "opt_ddb.h"
 #include "opt_pmap.h"
 
 #include <sys/param.h>
@@ -136,6 +137,10 @@
 #include <sys/sched.h>
 #include <sys/sysctl.h>
 #include <sys/smp.h>
+#ifdef DDB
+#include <sys/kdb.h>
+#include <ddb/ddb.h>
+#endif
 
 #include <vm/vm.h>
 #include <vm/vm_param.h>
@@ -5596,3 +5601,59 @@ SYSCTL_OID(_vm_pmap, OID_AUTO, kernel_maps,
     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_SKIP,
     NULL, 0, sysctl_kmaps, "A",
     "Dump kernel address layout");
+
+#ifdef DDB
+DB_SHOW_COMMAND(pte, pmap_print_pte)
+{
+	pd_entry_t *l0, l0e, *l1, l1e;
+	pt_entry_t *l2, l2e, *l3, l3e;
+	vm_offset_t va;
+	pmap_t pmap;
+
+	if (!have_addr) {
+		db_printf("show pte addr\n");
+		return;
+	}
+
+	va = (vm_offset_t)addr;
+	if (!VIRT_IS_VALID(va)) {
+		db_printf("malformed virtual address %#lx\n", va);
+		return;
+	}
+
+	if (kdb_thread != NULL)
+		pmap = vmspace_pmap(kdb_thread->td_proc->p_vmspace);
+	else
+		pmap = PCPU_GET(curpmap);
+
+	db_printf("VA 0x%016lx", va);
+	if (pmap_mode == PMAP_MODE_SV48) {
+		l0 = pmap_l0(pmap, va);
+		l0e = pmap_load(l0);
+		db_printf(" l0e@0x%016lx 0x%016lx", (uint64_t)l0, l0e);
+	}
+	l1 = pmap_l1(pmap, va);
+	if (l1 == NULL) {
+		db_printf("\n");
+		return;
+	}
+	l1e = pmap_load(l1);
+	db_printf(" l1e@0x%016lx 0x%016lx", (uint64_t)l1, l1e);
+
+	l2 = pmap_l2(pmap, va);
+	if (l2 == NULL) {
+		db_printf("\n");
+		return;
+	}
+	l2e = pmap_load(l2);
+	db_printf(" l2e@0x%016lx 0x%016lx", (uint64_t)l2, l2e);
+
+	l3 = pmap_l3(pmap, va);
+	if (l3 == NULL) {
+		db_printf("\n");
+		return;
+	}
+	l3e = pmap_load(l3);
+	db_printf(" l3e@0x%016lx 0x%016lx\n", (uint64_t)l3, l3e);
+}
+#endif