Simplify boot code

8 files changed, 31 insertions, 53 deletions

diff --git a/pk/configstring.c b/pk/configstring.c
index b7d443f..288d211 100644
--- a/pk/configstring.c
+++ b/pk/configstring.c
@@ -179,7 +179,7 @@ static void query_harts(const char* config_string)
       query_result res = query_config_string(config_string, buf);
       if (!res.start)
         break;
-      uintptr_t* base = (uintptr_t*)get_uint(res);
+      csr_t* base = (csr_t*)get_uint(res);
       uintptr_t hart_id = base[CSR_MHARTID];
       hls_init(hart_id, base);
       debug_printk("at %p, found hart %ld\n", base, hart_id);
diff --git a/pk/encoding.h b/pk/encoding.h
index 9189fde..f2fab36 100644
--- a/pk/encoding.h
+++ b/pk/encoding.h
@@ -61,8 +61,11 @@
 #define IRQ_S_TIMER  5
 #define IRQ_H_TIMER  6
 #define IRQ_M_TIMER  7
-#define IRQ_COP      8
-#define IRQ_HOST     9
+#define IRQ_S_DEV    9
+#define IRQ_H_DEV    10
+#define IRQ_M_DEV    11
+#define IRQ_COP      12
+#define IRQ_HOST     13
 
 #define DEFAULT_RSTVEC 0x0
 #define DEFAULT_NMIVEC 0x4
diff --git a/pk/mentry.S b/pk/mentry.S
index b8e9136..ee3a146 100644
--- a/pk/mentry.S
+++ b/pk/mentry.S
@@ -222,37 +222,23 @@ do_reset:
   li x31, 0
   csrw mscratch, x0
 
-  csrr a0, mhartid
-  bnez a0, .LmultiHart
-
   # sp <- end of first full page after the end of the binary
   la sp, _end + 2*RISCV_PGSIZE - 1
   li t0, -RISCV_PGSIZE
   and sp, sp, t0
   addi sp, sp, -MENTRY_FRAME_SIZE
 
-  j init_first_hart
+  csrr a0, mhartid
+  slli a1, a0, RISCV_PGSHIFT
+  add sp, sp, a1
+
+  beqz a0, init_first_hart
 
 .LmultiHart:
 #if MAX_HARTS > 1
   # make sure our hart id is within a valid range
   li a1, MAX_HARTS
-  bgeu a0, a1, .LmultiHart
-
-  # signal we're ready to boot
-  li a1, 1
-  sll a1, a1, a0
-  la a2, booted_harts_mask
-  amoor.w x0, a1, (a2)
-
-  # wait for main hart to grant us a stack
-1:csrrw sp, mscratch, x0
-  beqz sp, 1b
-
-  j init_other_hart
-#else
-  j .LmultiHart
+  bltu a0, a1, init_other_hart
+  wfi
 #endif
-
-  # XXX depend on sbi_base to force its linkage
-  la x0, sbi_base
+  j .LmultiHart
diff --git a/pk/minit.c b/pk/minit.c
index 033e476..bf151e8 100644
--- a/pk/minit.c
+++ b/pk/minit.c
@@ -1,7 +1,6 @@
 #include "vm.h"
 #include "mtrap.h"
 
-volatile uint32_t booted_harts_mask;
 uintptr_t mem_size;
 uint32_t num_harts;
 
@@ -72,21 +71,12 @@ static void fp_init()
 #endif
 }
 
-void hls_init(uint32_t id, uintptr_t* csrs)
+void hls_init(uint32_t id, csr_t* csrs)
 {
   hls_t* hls = OTHER_HLS(id);
   memset(hls, 0, sizeof(*hls));
-  hls->hart_id = id;
   hls->csrs = csrs;
   hls->console_ibuf = -1;
-
-  if (id != 0) {
-    while (((booted_harts_mask >> id) & 1) == 0)
-      ;
-    mb();
-    // wake up the hart by granting it a stack
-    csrs[CSR_MSCRATCH] = (uintptr_t)(OTHER_STACK_TOP(id) - MENTRY_FRAME_SIZE);
-  }
 }
 
 static void hart_init()
@@ -123,6 +113,9 @@ void init_other_hart()
   mb();
   write_csr(sptbr, (uintptr_t)root_page_table >> RISCV_PGSHIFT);
 
+  // make sure hart 0 has discovered us
+  kassert(HLS()->csrs != NULL);
+
   boot_other_hart();
 }
 
diff --git a/pk/mtrap.c b/pk/mtrap.c
index f07a395..4e45b80 100644
--- a/pk/mtrap.c
+++ b/pk/mtrap.c
@@ -82,7 +82,7 @@ void __attribute__((noreturn)) bad_trap()
 
 static uintptr_t mcall_hart_id()
 {
-  return HLS()->hart_id;
+  return read_const_csr(mhartid);
 }
 
 void request_htif_keyboard_interrupt()
diff --git a/pk/mtrap.h b/pk/mtrap.h
index 705d09d..5d2154f 100644
--- a/pk/mtrap.h
+++ b/pk/mtrap.h
@@ -145,26 +145,24 @@ static insn_t __attribute__((always_inline)) get_insn(uintptr_t mepc, uintptr_t*
   return insn;
 }
 
-static inline long __attribute__((pure)) isa()
-{
-  long res;
-  asm ("csrr %0, misa" : "=r"(res)); // not volatile, so don't use read_csr()
-  return res;
-}
+#define read_const_csr(reg) ({ unsigned long __tmp; \
+  asm ("csrr %0, " #reg : "=r"(__tmp)); \
+  __tmp; })
 
 static inline int supports_extension(char ext)
 {
-  return isa() & (1 << (ext - 'A'));
+  return read_const_csr(misa) & (1 << (ext - 'A'));
 }
 
 static inline int xlen()
 {
-  return isa() < 0 ? 64 : 32;
+  return read_const_csr(misa) < 0 ? 64 : 32;
 }
 
+typedef uintptr_t csr_t; // TODO this might become uint128_t for RV128
+
 typedef struct {
-  volatile uintptr_t* csrs;
-  int hart_id;
+  volatile csr_t* csrs;
   volatile int mipi_pending;
   volatile int sipi_pending;
   int console_ibuf;
@@ -183,7 +181,7 @@ typedef struct {
 
 void request_htif_keyboard_interrupt();
 
-void hls_init(uint32_t hart_id, uintptr_t* csrs);
+void hls_init(uint32_t hart_id, csr_t* csrs);
 
 #define MACHINE_STACK_TOP() ({ \
   register uintptr_t sp asm ("sp"); \
@@ -191,8 +189,7 @@ void hls_init(uint32_t hart_id, uintptr_t* csrs);
 
 // hart-local storage, at top of stack
 #define HLS() ((hls_t*)(MACHINE_STACK_TOP() - HLS_SIZE))
-#define OTHER_STACK_TOP(id) (MACHINE_STACK_TOP() + RISCV_PGSIZE * ((id) - HLS()->hart_id))
-#define OTHER_HLS(id) ((hls_t*)((void*)HLS() + RISCV_PGSIZE * ((id) - HLS()->hart_id)))
+#define OTHER_HLS(id) ((hls_t*)((void*)HLS() + RISCV_PGSIZE * ((id) - read_const_csr(mhartid))))
 
 #define printk printm
 
diff --git a/pk/pk.h b/pk/pk.h
index 98738bf..7785ca9 100644
--- a/pk/pk.h
+++ b/pk/pk.h
@@ -4,7 +4,7 @@
 #define _PK_H
 
 #ifdef __riscv_atomic
-# define MAX_HARTS 32 // coupled to width of booted_harts_mask
+# define MAX_HARTS 8 // arbitrary
 #else
 # define MAX_HARTS 1
 #endif
@@ -54,7 +54,6 @@ extern "C" {
 extern uintptr_t mem_size;
 extern int have_vm;
 extern uint32_t num_harts;
-extern volatile uint32_t booted_harts_mask;
 
 struct mainvars* parse_args(struct mainvars*);
 void printk(const char* s, ...);
diff --git a/pk/pk.ld b/pk/pk.ld
index cf1d9de..77ba6cf 100644
--- a/pk/pk.ld
+++ b/pk/pk.ld
@@ -88,7 +88,7 @@ SECTIONS
 
   .sbi :
   {
-    *(.sbi)
+    sbi.o(.sbi)
   }
 
   _end = .;