From 901711f79522cf851917443e777684550d285a64 Mon Sep 17 00:00:00 2001
From: Mark Johnston <mark.johnston@klarasystems.com>
Date: Thu, 17 Nov 2022 12:48:37 -0500
Subject: [PATCH 11/52] mips: Add a sysctl to dump the TLB

---
 sys/mips/mips/tlb.c | 74 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 73 insertions(+), 1 deletion(-)

diff --git a/sys/mips/mips/tlb.c b/sys/mips/mips/tlb.c
index cb246ad39447..2e39f06c7f31 100644
--- a/sys/mips/mips/tlb.c
+++ b/sys/mips/mips/tlb.c
@@ -35,6 +35,7 @@
 #include <sys/systm.h>
 #include <sys/pcpu.h>
 #include <sys/smp.h>
+#include <sys/sysctl.h>
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
@@ -280,7 +281,6 @@ tlb_invalidate_range(pmap_t pmap, vm_offset_t start, vm_offset_t end)
 	intr_restore(s);
 }
 
-/* XXX Only if DDB?  */
 void
 tlb_save(void)
 {
@@ -371,6 +371,78 @@ tlb_invalidate_one(unsigned i)
 	tlb_write_indexed();
 }
 
+static int
+tlb_sysctl(SYSCTL_HANDLER_ARGS)
+{
+	struct tlb_state *tlbs;
+	struct tlb_entry *tlbe;
+	register_t s;
+	int error, val;
+
+	val = 0;
+	error = sysctl_handle_int(oidp, &val, sizeof(val), req);
+	if (error != 0 || req->newptr == NULL || val == 0)
+		return (error);
+
+	if (num_tlbentries > MIPS_MAX_TLB_ENTRIES) {
+		printf("num entries %d is larger than max\n", num_tlbentries);
+		return (EINVAL);
+	}
+
+	s = intr_disable();
+	tlb_save();
+	tlbs = &tlb_state[curcpu];
+	for (int i = 0; i < num_tlbentries; i++) {
+		const char *pagesize, *region;
+		register_t asid;
+		vm_offset_t va;
+
+		tlbe = &tlbs->entry[i];
+
+#define	VAL2STR(var, val, name)	\
+	case val:		\
+		var = name;	\
+		break
+
+		switch (TLBHI_VA_R(tlbe->entryhi)) {
+		VAL2STR(region, TLBHI_R_USER, "user");
+		VAL2STR(region, TLBHI_R_KERNEL, "kern");
+		VAL2STR(region, TLBHI_R_SUPERVISOR, "supr");
+		default:
+			panic("unrecognized region for %#jx", tlbe->entryhi);
+		}
+		switch (tlbe->pagemask) {
+		VAL2STR(pagesize, TLBMASK_4K_PAGE, "4K");
+		VAL2STR(pagesize, TLBMASK_16K_PAGE, "16K");
+		VAL2STR(pagesize, TLBMASK_64K_PAGE, "64K");
+		VAL2STR(pagesize, TLBMASK_256K_PAGE, "256K");
+		VAL2STR(pagesize, TLBMASK_1M_PAGE, "1M");
+		VAL2STR(pagesize, TLBMASK_4M_PAGE, "4M");
+		VAL2STR(pagesize, TLBMASK_16M_PAGE, "16M");
+		VAL2STR(pagesize, TLBMASK_64M_PAGE, "64M");
+#if 0
+		VAL2STR(pagesize, TLBMASK_256M_PAGE, "256M");
+#endif
+		default:
+			panic("unrecognized pagemask %#jx", tlbe->pagemask);
+		}
+#undef VAL2STR
+
+		asid = tlbe->entryhi & TLBHI_ASID_MASK;
+		va = tlbe->entryhi & ~TLBHI_ASID_MASK;
+		printf("%d%s:\tregion %s va %#016jx asid %#lu pagesize %s lo0 %#jx lo1 %#jx\n",
+		    i, i == tlbs->wired ? "(w)" : "", region, va, asid, pagesize,
+		    TLBLO_PTE_TO_PA(tlbe->entrylo0),
+		    TLBLO_PTE_TO_PA(tlbe->entrylo1));
+	}
+	intr_restore(s);
+
+	return (0);
+}
+SYSCTL_PROC(_debug, OID_AUTO, dump_tlb,
+    CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW,
+    0, 0, tlb_sysctl, "I", "Dump current CPU's TLB entries");
+
 #ifdef DDB
 #include <ddb/ddb.h>
 
-- 
2.41.0