Merge pull request #67 from riscv/dts2

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

11 files changed, 64 insertions, 28 deletions

diff --git a/bbl/bbl.c b/bbl/bbl.c
index d3d6d9f..1f91ea2 100644
--- a/bbl/bbl.c
+++ b/bbl/bbl.c
@@ -9,6 +9,7 @@
 #include <string.h>
 
 static const void* entry_point;
+long disabled_hart_mask;
 
 static uintptr_t dtb_output()
 {
@@ -24,7 +25,7 @@ static void filter_dtb(uintptr_t source)
   memcpy((void*)dest, (void*)source, size);
 
   // Remove information from the chained FDT
-  filter_harts(dest, platform__disabled_hart_mask);
+  filter_harts(dest, &disabled_hart_mask);
   filter_plic(dest);
   filter_compat(dest, "riscv,clint0");
   filter_compat(dest, "riscv,debug-013");
@@ -37,7 +38,18 @@ void boot_other_hart(uintptr_t unused __attribute__((unused)))
     entry = entry_point;
     mb();
   } while (!entry);
-  enter_supervisor_mode(entry, read_csr(mhartid), dtb_output());
+
+  long hartid = read_csr(mhartid);
+  if ((1 << hartid) & disabled_hart_mask) {
+    while (1) {
+      __asm__ volatile("wfi");
+#ifdef __riscv_div
+      __asm__ volatile("div x0, x0, x0");
+#endif
+    }
+  }
+
+  enter_supervisor_mode(entry, hartid, dtb_output());
 }
 
 void boot_loader(uintptr_t dtb)
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..5f98501 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>
 
@@ -18,22 +19,28 @@ size_t plic_ndevs;
 static void mstatus_init()
 {
   // Enable FPU
-  write_csr(mstatus, MSTATUS_FS);
+  if (supports_extension('D') || supports_extension('F'))
+    write_csr(mstatus, MSTATUS_FS);
 
   // Enable user/supervisor use of perf counters
-  write_csr(scounteren, -1);
+  if (supports_extension('S'))
+    write_csr(scounteren, -1);
   write_csr(mcounteren, -1);
 
   // Enable software interrupts
   write_csr(mie, MIP_MSIP);
 
   // Disable paging
-  write_csr(sptbr, 0);
+  if (supports_extension('S'))
+    write_csr(sptbr, 0);
 }
 
 // send S-mode interrupts and most exceptions straight to S-mode
 static void delegate_traps()
 {
+  if (!supports_extension('S'))
+    return;
+
   uintptr_t interrupts = MIP_SSIP | MIP_STIP | MIP_SEIP;
   uintptr_t exceptions =
     (1U << CAUSE_MISALIGNED_FETCH) |
@@ -52,11 +59,12 @@ static void delegate_traps()
 
 static void fp_init()
 {
+  if (!supports_extension('D') && !supports_extension('F'))
+    return;
+
   assert(read_csr(mstatus) & MSTATUS_FS);
 
 #ifdef __riscv_flen
-  if (!supports_extension('D'))
-    die("FPU not found; recompile pk with -msoft-float");
   for (int i = 0; i < 32; i++)
     init_fp_reg(i);
   write_csr(fcsr, 0);
@@ -125,18 +133,18 @@ 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
 }
 
 void init_first_hart(uintptr_t hartid, uintptr_t dtb)
 {
-  hart_init();
-  hls_init(0); // this might get called again from parse_config_string
-
   // Confirm console as early as possible
   query_uart(dtb);
 
+  hart_init();
+  hls_init(0); // this might get called again from parse_config_string
+
   // Find the power button early as well so die() works
   query_finisher(dtb);
 
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;
diff --git a/pk/pk.c b/pk/pk.c
index 11a2cdf..e7cfc3a 100644
--- a/pk/pk.c
+++ b/pk/pk.c
@@ -7,6 +7,7 @@
 #include <stdbool.h>
 
 elf_info current;
+long disabled_hart_mask;
 
 static void handle_option(const char* s)
 {
diff --git a/platform/platform_interface.h b/platform/platform_interface.h
index f083085..203457d 100644
--- a/platform/platform_interface.h
+++ b/platform/platform_interface.h
@@ -20,10 +20,6 @@ const char *platform__get_logo(void);
 /* Returns TRUE if it's valid to use the HTIF */
 int platform__use_htif(void);
 
-/* The harts that should be excluded from booting to the target program and
- * should intsead be held in a loop. */
-extern long platform__disabled_hart_mask;
-
 #endif
 
 #endif
diff --git a/platform/sifive-vc707-devkit.c b/platform/sifive-vc707-devkit.c
index cc0e0f1..bd27861 100644
--- a/platform/sifive-vc707-devkit.c
+++ b/platform/sifive-vc707-devkit.c
@@ -28,8 +28,6 @@ static const char logo[] =
 "\r\n"
 "           SiFive RISC-V Coreplex\r\n";
 
-long platform__disabled_hart_mask = 0x1;
-
 const char *platform__get_logo(void)
 {
   return logo;
diff --git a/platform/spike.c b/platform/spike.c
index 4d9d397..159255f 100644
--- a/platform/spike.c
+++ b/platform/spike.c
@@ -25,8 +25,6 @@ static const char logo[] =
 "\n"
 "       INSTRUCTION SETS WANT TO BE FREE\n";
 
-long platform__disabled_hart_mask = 0;
-
 const char *platform__get_logo(void)
 {
   return logo;