Add some syscalls

pk/pk.h

@@ -66,6 +66,7 @@ typedef struct {
   size_t phdr;
   size_t phdr_top;
   size_t stack_top;
+  size_t t0;
 } elf_info;
 
 extern elf_info current;

pk/syscall.c

@@ -13,6 +13,9 @@ typedef sysret_t (*syscall_t)(long, long, long, long, long, long, long);
 
 void sys_exit(int code)
 {
+  if (current.t0)
+    printk("%ld cycles\n", rdcycle() - current.t0);
+
   frontend_syscall(SYS_exit, code, 0, 0, 0);
   while (1);
 }
@@ -146,6 +149,55 @@ sysret_t sys_mmap(uintptr_t addr, size_t length, int prot, int flags, int fd, of
   return do_mmap(addr, length, prot, flags, fd, offset);
 }
 
+sysret_t sys_munmap(uintptr_t addr, size_t length)
+{
+  return do_munmap(addr, length);
+}
+
+sysret_t sys_mremap(uintptr_t addr, size_t old_size, size_t new_size, int flags)
+{
+  return do_mremap(addr, old_size, new_size, flags);
+}
+
+sysret_t sys_rt_sigaction(int sig, const void* act, void* oact, size_t sssz)
+{
+  if (oact)
+  {
+    size_t sz = current.elf64 ? 6*sizeof(uint64_t) : 8*sizeof(uint32_t);
+    populate_mapping(oact, sz, PROT_WRITE);
+    memset(oact, 0, sz);
+  }
+
+  return (sysret_t){0, 0};
+}
+
+sysret_t sys_time(long* loc)
+{
+  uintptr_t t = rdcycle(), hz = 1000000000;
+  if (loc)
+  {
+    populate_mapping(loc, sizeof(long), PROT_WRITE);
+    loc[0] = t/hz;
+  }
+  return (sysret_t){t, 0};
+}
+
+sysret_t sys_writev(int fd, const void* iov, int cnt)
+{
+  long get(int i) { return current.elf64 ? ((long*)iov)[i] : ((int*)iov)[i]; }
+  populate_mapping(iov, cnt*2*(current.elf64 ? 8 : 4), PROT_READ);
+
+  ssize_t ret = 0;
+  for (int i = 0; i < cnt; i++)
+  {
+    sysret_t r = sys_write(fd, (void*)get(2*i), get(2*i+1));
+    if (r.result < 0)
+      return r;
+    ret += r.result;
+  }
+  return (sysret_t){ret, 0};
+}
+
 sysret_t syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n)
 {
   const static void* syscall_table[] = {
@@ -168,6 +220,11 @@ sysret_t syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n)
     [SYS_getgid] = sys_getuid,
     [SYS_getegid] = sys_getuid,
     [SYS_mmap] = sys_mmap,
+    [SYS_munmap] = sys_munmap,
+    [SYS_mremap] = sys_mremap,
+    [SYS_rt_sigaction] = sys_rt_sigaction,
+    [SYS_time] = sys_time,
+    [SYS_writev] = sys_writev,
   };
 
   if(n >= ARRAY_SIZE(syscall_table) || !syscall_table[n])

pk/vm.c

@@ -175,6 +175,7 @@ static int __handle_page_fault(uintptr_t vaddr, int prot)
 
     vmr_t* v = (vmr_t*)*pte;
     *pte = pte_create(ppn, PROT_READ|PROT_WRITE, 0);
+    flush_tlb();
     if (v->file)
     {
       size_t flen = MIN(RISCV_PGSIZE, v->length - (vaddr - v->addr));
@@ -203,6 +204,22 @@ int handle_page_fault(uintptr_t vaddr, int prot)
   return ret;
 }
 
+static void __do_munmap(uintptr_t addr, size_t len)
+{
+  for (uintptr_t a = addr; a < addr + len; a += RISCV_PGSIZE)
+  {
+    pte_t* pte = __walk(a);
+    if (pte == 0 || *pte == 0)
+      continue;
+
+    if (!(*pte & PTE_V))
+      __vmr_decref((vmr_t*)*pte, 1);
+
+    *pte = 0;
+  }
+  flush_tlb(); // TODO: shootdown
+}
+
 uintptr_t __do_mmap(uintptr_t addr, size_t length, int prot, int flags, file_t* f, off_t offset)
 {
   size_t npage = (length-1)/RISCV_PGSIZE+1;
@@ -225,7 +242,7 @@ uintptr_t __do_mmap(uintptr_t addr, size_t length, int prot, int flags, file_t*
     kassert(pte);
 
     if (*pte)
-      kassert(*pte == 0); // TODO __do_munmap
+      __do_munmap(addr, RISCV_PGSIZE);
 
     *pte = (pte_t)v;
   }
@@ -244,6 +261,19 @@ fail_vmr:
   return (uintptr_t)-1;
 }
 
+sysret_t do_munmap(uintptr_t addr, size_t length)
+{
+  if ((addr & (RISCV_PGSIZE-1)) || addr < current.user_min ||
+      addr + length > current.stack_top || addr + length < addr)
+    return (sysret_t){-1, EINVAL};
+
+  spinlock_lock(&vm_lock);
+    __do_munmap(addr, length);
+  spinlock_unlock(&vm_lock);
+
+  return (sysret_t){0, 0};
+}
+
 sysret_t do_mmap(uintptr_t addr, size_t length, int prot, int flags, int fd, off_t offset)
 {
   if (!(flags & MAP_PRIVATE) || length == 0 || (offset & (RISCV_PGSIZE-1)))
@@ -276,7 +306,7 @@ size_t __do_brk(size_t addr)
 
   size_t newbrk_page = ROUNDUP(newbrk, RISCV_PGSIZE);
   if (current.brk > newbrk_page)
-    kassert(0); // TODO __do_munmap
+    __do_munmap(newbrk_page, current.brk - newbrk_page);
   else if (current.brk < newbrk_page)
     kassert(__do_mmap(current.brk, newbrk_page - current.brk, -1, MAP_FIXED|MAP_PRIVATE|MAP_ANONYMOUS, 0, 0) == current.brk);
   current.brk = newbrk_page;
@@ -293,6 +323,34 @@ sysret_t do_brk(size_t addr)
   return (sysret_t){addr, 0};
 }
 
+sysret_t do_mremap(uintptr_t addr, size_t old_size, size_t new_size, int flags)
+{
+  uintptr_t res = -1;
+  if (((addr | old_size | new_size) & (RISCV_PGSIZE-1)) ||
+      (flags & MREMAP_FIXED))
+    return (sysret_t){-1, EINVAL};
+
+  spinlock_lock(&vm_lock);
+    for (size_t i = 0; i < MAX_VMR; i++)
+    {
+      if (vmrs[i].refcnt && addr == vmrs[i].addr && old_size == vmrs[i].length)
+      {
+        size_t old_npage = (vmrs[i].length-1)/RISCV_PGSIZE+1;
+        size_t new_npage = (new_size-1)/RISCV_PGSIZE+1;
+        if (new_size < old_size)
+          __do_munmap(addr + new_size, old_size - new_size);
+        else if (new_size > old_size)
+          __do_mmap(addr + old_size, new_size - old_size, vmrs[i].prot, 0,
+                    vmrs[i].file, vmrs[i].offset + new_size - old_size);
+        __vmr_decref(&vmrs[i], old_npage - new_npage);
+        res = addr;
+      }
+    }
+  spinlock_unlock(&vm_lock);
+ 
+  return (sysret_t){res, 0};
+}
+
 static void __map_kernel_range(uintptr_t paddr, size_t len, int prot)
 {
   pte_t perms = pte_create(0, prot, 0);

pk/vm.h

@@ -15,12 +15,15 @@
 #define MAP_FIXED 0x10
 #define MAP_ANONYMOUS 0x20
 #define MAP_POPULATE 0x8000
+#define MREMAP_FIXED 0x2
 
 void vm_init();
 int handle_page_fault(uintptr_t vaddr, int prot);
 void populate_mapping(const void* start, size_t size, int prot);
 uintptr_t __do_mmap(uintptr_t addr, size_t length, int prot, int flags, file_t* file, off_t offset);
 sysret_t do_mmap(uintptr_t addr, size_t length, int prot, int flags, int fd, off_t offset);
+sysret_t do_munmap(uintptr_t addr, size_t length);
+sysret_t do_mremap(uintptr_t addr, size_t old_size, size_t new_size, int flags);
 sysret_t do_brk(uintptr_t addr);
 
 #endif