Detect harts that can't boot Linux instead of hard-coding them

This checks to see if a hart can't boot Linux by looking for a
compatible "mmu-type" field.  If the hart can't boot Linux, then bbl
masks it off.

6 files changed, 34 insertions, 10 deletions

diff --git a/machine/disabled_hart_mask.h b/machine/disabled_hart_mask.h
new file mode 100644
index 0000000..2a3a73c
--- /dev/null
+++ b/machine/disabled_hart_mask.h
@@ -0,0 +1,4 @@
+#ifndef DISABLED_HART_MASK_H
+#define DISABLED_HART_MASK_H
+extern long disabled_hart_mask;
+#endif
diff --git a/machine/fdt.c b/machine/fdt.c
index 35681f8..061b19e 100644
--- a/machine/fdt.c
+++ b/machine/fdt.c
@@ -1,3 +1,4 @@
+#include <stdbool.h>
 #include <stdint.h>
 #include <string.h>
 #include "config.h"
@@ -553,13 +554,15 @@ struct hart_filter {
   int compat;
   int hart;
   char *status;
-  unsigned long mask;
+  char *mmu_type;
+  long *disabled_hart_mask;
 };
 
 static void hart_filter_open(const struct fdt_scan_node *node, void *extra)
 {
   struct hart_filter *filter = (struct hart_filter *)extra;
-  filter->status = 0;
+  filter->status = NULL;
+  filter->mmu_type = NULL;
   filter->compat = 0;
   filter->hart = -1;
 }
@@ -575,9 +578,22 @@ static void hart_filter_prop(const struct fdt_scan_prop *prop, void *extra)
     filter->hart = reg;
   } else if (!strcmp(prop->name, "status")) {
     filter->status = (char*)prop->value;
+  } else if (!strcmp(prop->name, "mmu-type")) {
+    filter->mmu_type = (char*)prop->value;
   }
 }
 
+static bool hart_filter_mask(const struct hart_filter *filter)
+{
+  if (filter->mmu_type == NULL) return true;
+  if (strcmp(filter->status, "okay")) return true;
+  if (!strcmp(filter->mmu_type, "riscv,sv39")) return false;
+  if (!strcmp(filter->mmu_type, "riscv,sv48")) return false;
+  printm("hart_filter_mask saw unknown hart type: status=\"%s\", mmu_type=\"%s\"\n",
+         filter->status, filter->mmu_type);
+  return true;
+}
+
 static void hart_filter_done(const struct fdt_scan_node *node, void *extra)
 {
   struct hart_filter *filter = (struct hart_filter *)extra;
@@ -586,14 +602,15 @@ static void hart_filter_done(const struct fdt_scan_node *node, void *extra)
   assert (filter->status);
   assert (filter->hart >= 0);
 
-  if (((filter->mask >> filter->hart) & 1) && !strcmp(filter->status, "okay")) {
+  if (hart_filter_mask(filter)) {
     strcpy(filter->status, "masked");
     uint32_t *len = (uint32_t*)filter->status;
     len[-2] = bswap(strlen("masked")+1);
+    *filter->disabled_hart_mask |= (1 << filter->hart);
   }
 }
 
-void filter_harts(uintptr_t fdt, unsigned long hart_mask)
+void filter_harts(uintptr_t fdt, long *disabled_hart_mask)
 {
   struct fdt_cb cb;
   struct hart_filter filter;
@@ -604,7 +621,8 @@ void filter_harts(uintptr_t fdt, unsigned long hart_mask)
   cb.done = hart_filter_done;
   cb.extra = &filter;
 
-  filter.mask = hart_mask;
+  filter.disabled_hart_mask = disabled_hart_mask;
+  *disabled_hart_mask = 0;
   fdt_scan(fdt, &cb);
 }
 
diff --git a/machine/fdt.h b/machine/fdt.h
index 5932e17..d436778 100644
--- a/machine/fdt.h
+++ b/machine/fdt.h
@@ -61,7 +61,7 @@ void query_plic(uintptr_t fdt);
 void query_clint(uintptr_t fdt);
 
 // Remove information from FDT
-void filter_harts(uintptr_t fdt, unsigned long hart_mask);
+void filter_harts(uintptr_t fdt, long *disabled_hart_mask);
 void filter_plic(uintptr_t fdt);
 void filter_compat(uintptr_t fdt, const char *compat);
 
diff --git a/machine/mentry.S b/machine/mentry.S
index 33d7be4..11c053c 100644
--- a/machine/mentry.S
+++ b/machine/mentry.S
@@ -258,7 +258,7 @@ do_reset:
   add sp, sp, a2
 
   # Boot on the first unmasked hart
-  la a4, platform__disabled_hart_mask
+  la a4, disabled_hart_mask
   LOAD a4, 0(a4)
   addi a5, a4, 1
   not a4, a4
@@ -277,7 +277,7 @@ do_reset:
   wfi
 
   # masked harts never start
-  la a4, platform__disabled_hart_mask
+  la a4, disabled_hart_mask
   LOAD a4, 0(a4)
   srl a4, a4, a3
   andi a4, a4, 1
diff --git a/machine/minit.c b/machine/minit.c
index 187bef7..8ce96b1 100644
--- a/machine/minit.c
+++ b/machine/minit.c
@@ -6,6 +6,7 @@
 #include "uart.h"
 #include "finisher.h"
 #include "platform_interface.h"
+#include "disabled_hart_mask.h"
 #include <string.h>
 #include <limits.h>
 
@@ -125,7 +126,7 @@ static void hart_plic_init()
 static void wake_harts()
 {
   for (int hart = 0; hart < MAX_HARTS; ++hart)
-    if ((((~platform__disabled_hart_mask & hart_mask) >> hart) & 1))
+    if ((((~disabled_hart_mask & hart_mask) >> hart) & 1))
       *OTHER_HLS(hart)->ipi = 1; // wakeup the hart
 }
 
diff --git a/machine/mtrap.c b/machine/mtrap.c
index e5faae3..dba3613 100644
--- a/machine/mtrap.c
+++ b/machine/mtrap.c
@@ -9,6 +9,7 @@
 #include "fdt.h"
 #include "unprivileged_memory.h"
 #include "platform_interface.h"
+#include "disabled_hart_mask.h"
 #include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
@@ -63,7 +64,7 @@ void printm(const char* s, ...)
 
 static void send_ipi(uintptr_t recipient, int event)
 {
-  if (((platform__disabled_hart_mask >> recipient) & 1)) return;
+  if (((disabled_hart_mask >> recipient) & 1)) return;
   atomic_or(&OTHER_HLS(recipient)->mipi_pending, event);
   mb();
   *OTHER_HLS(recipient)->ipi = 1;