1 files changed, 99 insertions, 0 deletions
diff --git a/pk/pk.c b/pk/pk.c
new file mode 100644
index 0000000..cc2a761
--- /dev/null
+++ b/pk/pk.c
@@ -0,0 +1,99 @@
+#include "pk.h"
+#include "vm.h"
+#include "elf.h"
+
+void run_loaded_program(struct mainvars* args)
+{
+  if (current.is_supervisor)
+    panic("pk can't run kernel binaries; try using bbl instead");
+
+  uintptr_t kernel_stack_top = pk_vm_init();
+
+  extern char trap_entry;
+  write_csr(stvec, &trap_entry);
+  write_csr(sscratch, 0);
+
+  // enter supervisor mode
+  asm volatile("la t0, 1f; csrw mepc, t0; eret; 1:" ::: "t0");
+
+  // copy phdrs to user stack
+  size_t stack_top = current.stack_top - current.phdr_size;
+  memcpy((void*)stack_top, (void*)current.phdr, current.phdr_size);
+  current.phdr = stack_top;
+
+  // copy argv to user stack
+  for (size_t i = 0; i < args->argc; i++) {
+    size_t len = strlen((char*)(uintptr_t)args->argv[i])+1;
+    stack_top -= len;
+    memcpy((void*)stack_top, (void*)(uintptr_t)args->argv[i], len);
+    args->argv[i] = stack_top;
+  }
+  stack_top &= -sizeof(void*);
+
+  struct {
+    long key;
+    long value;
+  } aux[] = {
+    {AT_ENTRY, current.entry},
+    {AT_PHNUM, current.phnum},
+    {AT_PHENT, current.phent},
+    {AT_PHDR, current.phdr},
+    {AT_PAGESZ, RISCV_PGSIZE},
+    {AT_SECURE, 0},
+    {AT_RANDOM, stack_top},
+    {AT_NULL, 0}
+  };
+
+  // place argc, argv, envp, auxp on stack
+  #define PUSH_ARG(type, value) do { \
+    *((type*)sp) = value; \
+    sp += sizeof(type); \
+  } while (0)
+
+  #define STACK_INIT(type) do { \
+    unsigned naux = sizeof(aux)/sizeof(aux[0]); \
+    stack_top -= (1 + args->argc + 1 + 1 + 2*naux) * sizeof(type); \
+    stack_top &= -16; \
+    long sp = stack_top; \
+    PUSH_ARG(type, args->argc); \
+    for (unsigned i = 0; i < args->argc; i++) \
+      PUSH_ARG(type, args->argv[i]); \
+    PUSH_ARG(type, 0); /* argv[argc] = NULL */ \
+    PUSH_ARG(type, 0); /* envp[0] = NULL */ \
+    for (unsigned i = 0; i < naux; i++) { \
+      PUSH_ARG(type, aux[i].key); \
+      PUSH_ARG(type, aux[i].value); \
+    } \
+  } while (0)
+
+  if (current.elf64)
+    STACK_INIT(uint64_t);
+  else
+    STACK_INIT(uint32_t);
+
+  if (current.t0) // start timer if so requested
+    current.t0 = rdcycle();
+
+  if (uarch_counters_enabled) { // start tracking the uarch counters if requested
+    size_t i = 0;
+    #define READ_CTR_INIT(name) do { \
+      while (i >= NUM_COUNTERS) ; \
+      long csr = read_csr(name); \
+      uarch_counters[i++] = csr; \
+    } while (0)
+    READ_CTR_INIT(cycle);   READ_CTR_INIT(instret);
+    READ_CTR_INIT(uarch0);  READ_CTR_INIT(uarch1);  READ_CTR_INIT(uarch2);
+    READ_CTR_INIT(uarch3);  READ_CTR_INIT(uarch4);  READ_CTR_INIT(uarch5);
+    READ_CTR_INIT(uarch6);  READ_CTR_INIT(uarch7);  READ_CTR_INIT(uarch8);
+    READ_CTR_INIT(uarch9);  READ_CTR_INIT(uarch10); READ_CTR_INIT(uarch11);
+    READ_CTR_INIT(uarch12); READ_CTR_INIT(uarch13); READ_CTR_INIT(uarch14);
+    READ_CTR_INIT(uarch15);
+    #undef READ_CTR_INIT
+  }
+
+  trapframe_t tf;
+  init_tf(&tf, current.entry, stack_top, current.elf64);
+  __clear_cache(0, 0);
+  write_csr(sscratch, kernel_stack_top);
+  start_user(&tf);
+}