Merge pull request #104 from heshamelmatary/disable_vm

bbl: boot payload in machine mode on --enable-boot-machine

bbl/bbl.ac

@@ -18,3 +18,8 @@ AC_ARG_WITH([payload], AS_HELP_STRING([--with-payload], [Set ELF payload for bbl
 AC_ARG_WITH([logo], AS_HELP_STRING([--with-logo], [Specify a better logo]),
   [AC_SUBST([BBL_LOGO_FILE], $with_logo, [Logo for bbl])],
   [AC_SUBST([BBL_LOGO_FILE], [riscv_logo.txt], [Logo for bbl])])
+
+AC_ARG_ENABLE([boot-machine], AS_HELP_STRING([--enable-boot-machine], [Run payload in machine mode]))
+AS_IF([test "x$enable_boot_machine" == "xyes"], [
+  AC_DEFINE([BBL_BOOT_MACHINE],,[Define to run payload in machine mode])
+])

bbl/bbl.c

@@ -58,7 +58,11 @@ void boot_other_hart(uintptr_t unused __attribute__((unused)))
     }
   }
 
+#ifdef BBL_BOOT_MACHINE
+  enter_machine_mode(entry, hartid, dtb_output());
+#else /* Run bbl in supervisor mode */
   enter_supervisor_mode(entry, hartid, dtb_output());
+#endif
 }
 
 void boot_loader(uintptr_t dtb)

config.h.in

@@ -1,5 +1,8 @@
 /* config.h.in.  Generated from configure.ac by autoheader.  */
 
+/* Define to run payload in machine mode */
+#undef BBL_BOOT_MACHINE
+
 /* Define if subproject MCPPBS_SPROJ_NORM is enabled */
 #undef BBL_ENABLED
 

configure

@@ -677,6 +677,7 @@ enable_vm
 enable_logo
 with_payload
 with_logo
+enable_boot_machine
 enable_fp_emulation
 '
       ac_precious_vars='build_alias
@@ -1325,6 +1326,7 @@ Optional Features:
                           Enable all optional subprojects
   --disable-vm            Disable virtual memory
   --enable-logo           Enable boot logo
+  --enable-boot-machine   Run payload in machine mode
   --disable-fp-emulation  Disable floating-point emulation
 
 Optional Packages:
@@ -4272,6 +4274,19 @@ else
 fi
 
 
+# Check whether --enable-boot-machine was given.
+if test "${enable_boot_machine+set}" = set; then :
+  enableval=$enable_boot_machine;
+fi
+
+if test "x$enable_boot_machine" == "xyes"; then :
+
+
+$as_echo "#define BBL_BOOT_MACHINE /**/" >>confdefs.h
+
+
+fi
+
 
 
 

machine/mentry.S

@@ -2,6 +2,7 @@
 
 #include "mtrap.h"
 #include "bits.h"
+#include "config.h"
 
   .data
   .align 6
@@ -18,7 +19,11 @@ trap_table:
   .word bad_trap
   .word mcall_trap
   .word bad_trap
+#ifdef BBL_BOOT_MACHINE
+  .word mcall_trap
+#else
   .word bad_trap
+#endif /* BBL_BOOT_MACHINE */
   .word bad_trap
 #define TRAP_FROM_MACHINE_MODE_VECTOR 13
   .word __trap_from_machine_mode

machine/minit.c

@@ -95,7 +95,9 @@ static void hart_init()
 {
   mstatus_init();
   fp_init();
+#ifndef BBL_BOOT_MACHINE
   delegate_traps();
+#endif /* BBL_BOOT_MACHINE */
 }
 
 static void plic_init()
@@ -184,7 +186,7 @@ void init_other_hart(uintptr_t hartid, uintptr_t dtb)
   boot_other_hart(dtb);
 }
 
-void enter_supervisor_mode(void (*fn)(uintptr_t), uintptr_t arg0, uintptr_t arg1)
+static inline void setup_pmp(void)
 {
   // Set up a PMP to permit access to all of memory.
   // Ignore the illegal-instruction trap if PMPs aren't supported.
@@ -196,6 +198,11 @@ void enter_supervisor_mode(void (*fn)(uintptr_t), uintptr_t arg0, uintptr_t arg1
                 ".align 2\n\t"
                 "1: csrw mtvec, t0"
                 : : "r" (pmpc), "r" (-1UL) : "t0");
+}
+
+void enter_supervisor_mode(void (*fn)(uintptr_t), uintptr_t arg0, uintptr_t arg1)
+{
+  setup_pmp();
 
   uintptr_t mstatus = read_csr(mstatus);
   mstatus = INSERT_FIELD(mstatus, MSTATUS_MPP, PRV_S);
@@ -213,3 +220,18 @@ void enter_supervisor_mode(void (*fn)(uintptr_t), uintptr_t arg0, uintptr_t arg1
   asm volatile ("mret" : : "r" (a0), "r" (a1));
   __builtin_unreachable();
 }
+
+void enter_machine_mode(void (*fn)(uintptr_t, uintptr_t), uintptr_t arg0, uintptr_t arg1)
+{
+  setup_pmp();
+
+  uintptr_t mstatus = read_csr(mstatus);
+  mstatus = INSERT_FIELD(mstatus, MSTATUS_MPIE, 0);
+  write_csr(mstatus, mstatus);
+  write_csr(mscratch, MACHINE_STACK_TOP() - MENTRY_FRAME_SIZE);
+
+  /* Jump to the payload's entry point */
+  fn(arg0, arg1);
+
+  __builtin_unreachable();
+}

machine/mtrap.h

@@ -67,6 +67,8 @@ void putstring(const char* s);
 
 void enter_supervisor_mode(void (*fn)(uintptr_t), uintptr_t arg0, uintptr_t arg1)
   __attribute__((noreturn));
+void enter_machine_mode(void (*fn)(uintptr_t, uintptr_t), uintptr_t arg0, uintptr_t arg1)
+  __attribute__((noreturn));
 void boot_loader(uintptr_t dtb);
 void boot_other_hart(uintptr_t dtb);