Allow mmap to map new segments larger than 1 page on top of existing mappings and add mprotect syscall

4 files changed, 44 insertions, 6 deletions

diff --git a/pk/syscall.c b/pk/syscall.c
index e25b883..0c73a83 100644
--- a/pk/syscall.c
+++ b/pk/syscall.c
@@ -75,7 +75,6 @@ ssize_t sys_write(int fd, const char* buf, size_t n)
 
 int sys_open(const char* name, int flags, int mode)
 {
-  printk("OPEN(%s)\n",name);
   file_t* file = file_open(name, flags, mode);
   if (IS_ERR_VALUE(file))
     return PTR_ERR(file);
@@ -110,7 +109,6 @@ int sys_openat(int dirfd, const char* name, int flags, int mode)
 
 int sys_close(int fd)
 {
-  //printk("CLOSE(%ld)\n",fd);
   int ret = fd_close(fd);
   if (ret < 0)
     return -EBADF;
@@ -119,7 +117,6 @@ int sys_close(int fd)
 
 int sys_fstat(int fd, void* st)
 {
-  printk("FSTAT(%ld)\n",fd);
   int r = -EBADF;
   file_t* f = file_get(fd);
 
@@ -275,9 +272,7 @@ int sys_getuid()
 
 uintptr_t sys_mmap(uintptr_t addr, size_t length, int prot, int flags, int fd, off_t offset)
 {
-  printk("MMAP(ad:%ld,len:%ld,prot:%ld,flags:%ld,fd:%ld,off:%ld\n",addr,length,prot,flags,fd,offset);
   uintptr_t ret =  do_mmap(addr, length, prot, flags, fd, offset);
-  //printk("MMAP DONE\n");
   return ret;
 }
 
@@ -291,6 +286,11 @@ uintptr_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);
 }
 
+uintptr_t sys_mprotect(uintptr_t addr, size_t length, int prot)
+{
+  return do_mprotect(addr, length, prot);
+}
+
 int sys_rt_sigaction(int sig, const void* act, void* oact, size_t sssz)
 {
   if (oact)
@@ -390,6 +390,7 @@ long syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n)
     [SYS_mmap] = sys_mmap,
     [SYS_munmap] = sys_munmap,
     [SYS_mremap] = sys_mremap,
+    [SYS_mprotect] = sys_mprotect,
     [SYS_rt_sigaction] = sys_rt_sigaction,
     [SYS_time] = sys_time,
     [SYS_gettimeofday] = sys_gettimeofday,
diff --git a/pk/syscall.h b/pk/syscall.h
index e3a88ce..5d6bbf0 100644
--- a/pk/syscall.h
+++ b/pk/syscall.h
@@ -35,6 +35,7 @@
 #define SYS_mmap 222
 #define SYS_munmap 215
 #define SYS_mremap 216
+#define SYS_mprotect 226
 #define SYS_time 1062
 #define SYS_getmainvars 2011
 #define SYS_rt_sigaction 134
diff --git a/pk/vm.c b/pk/vm.c
index 8ab466e..783153c 100644
--- a/pk/vm.c
+++ b/pk/vm.c
@@ -242,7 +242,7 @@ uintptr_t __do_mmap(uintptr_t addr, size_t length, int prot, int flags, file_t*
     kassert(pte);
 
     if (*pte)
-      __do_munmap(addr, RISCV_PGSIZE);
+      __do_munmap(a, RISCV_PGSIZE);
 
     *pte = (pte_t)v;
   }
@@ -346,6 +346,41 @@ uintptr_t do_mremap(uintptr_t addr, size_t old_size, size_t new_size, int flags)
   return res;
 }
 
+uintptr_t do_mprotect(uintptr_t addr, size_t length, int prot)
+{
+  uintptr_t res = 0;
+  if ((addr) & (RISCV_PGSIZE-1))
+    return -EINVAL;
+
+  spinlock_lock(&vm_lock);
+    for (uintptr_t a = addr; a < addr + length; a += RISCV_PGSIZE)
+    {
+      pte_t* pte = __walk(a);
+      if (pte == 0 || *pte == 0)
+        return -ENOMEM;
+  
+      if(!(*pte & PTE_V)){
+        vmr_t* v = (vmr_t*)*pte;
+        if((v->prot ^ prot) & ~v->prot){
+          //TODO:look at file to find perms
+          return -EACCES;
+        }
+        v->prot = prot;
+      }else{
+        pte_t perms = pte_create(0, 0, prot);
+        if ((*pte & perms) != perms){
+          //TODO:look at file to find perms
+          return -EACCES;
+        }
+        pte_t permset = (*pte & ~(PTE_UR | PTE_UW | PTE_UX)) | perms;
+        *pte = permset;
+      }
+    }
+  spinlock_unlock(&vm_lock);
+ 
+  return res;
+}
+
 static void __map_kernel_range(uintptr_t paddr, size_t len, int prot)
 {
   pte_t perms = pte_create(0, prot, 0);
diff --git a/pk/vm.h b/pk/vm.h
index cdd4f77..d46abec 100644
--- a/pk/vm.h
+++ b/pk/vm.h
@@ -24,6 +24,7 @@ uintptr_t __do_mmap(uintptr_t addr, size_t length, int prot, int flags, file_t*
 uintptr_t do_mmap(uintptr_t addr, size_t length, int prot, int flags, int fd, off_t offset);
 int do_munmap(uintptr_t addr, size_t length);
 uintptr_t do_mremap(uintptr_t addr, size_t old_size, size_t new_size, int flags);
+uintptr_t do_mprotect(uintptr_t addr, size_t length, int prot);
 uintptr_t do_brk(uintptr_t addr);
 
 #endif