kern: vm: Introduce initial mmap() impldev

- Adds kernel mmap() function
- Adds SYS_mmap syscall

Signed-off-by: Ian Moffett <ian@osmora.org>

5 files changed, 72 insertions, 1 deletions

diff --git a/src/sys/include/compat/unix/syscall.h b/src/sys/include/compat/unix/syscall.h
index 9b76139..5df3c51 100644
--- a/src/sys/include/compat/unix/syscall.h
+++ b/src/sys/include/compat/unix/syscall.h
@@ -39,6 +39,7 @@
 #include <os/iotap.h>
 #include <os/reboot.h>
 #include <dms/dms.h>
+#include <vm/map.h>
 
 /*
  * Exit the current process - exit(2) syscall
@@ -100,7 +101,8 @@ scret_t(*g_unix_sctab[])(struct syscall_args *) = {
     [SYS_lseek] = sys_lseek,
     [SYS_socket] = sys_socket,
     [SYS_listen] = sys_listen,
-    [SYS_seteuid] = sys_seteuid
+    [SYS_seteuid] = sys_seteuid,
+    [SYS_mmap] = sys_mmap
 };
 
 #endif  /* !_NEED_UNIX_SCTAB */
diff --git a/src/sys/include/sys/mman.h b/src/sys/include/sys/mman.h
index 7ae1ed2..b688fdd 100644
--- a/src/sys/include/sys/mman.h
+++ b/src/sys/include/sys/mman.h
@@ -39,4 +39,9 @@
 #define PROT_USER   BIT(3)
 #endif  /* _KERNEL */
 
+/*
+ * Map memory pages
+ */
+void *mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off);
+
 #endif  /* !_SYS_MMAN_H_ */
diff --git a/src/sys/include/sys/syscall.h b/src/sys/include/sys/syscall.h
index d148405..ee6ef48 100644
--- a/src/sys/include/sys/syscall.h
+++ b/src/sys/include/sys/syscall.h
@@ -62,6 +62,7 @@
 #define SYS_socket      0x11    /* get a socket fd */
 #define SYS_listen      0x12    /* listen on a socket */
 #define SYS_seteuid     0x13    /* set effective UID */
+#define SYS_mmap        0x14    /* map a virtual address */
 
 typedef __ssize_t scret_t;
 typedef __ssize_t scarg_t;
diff --git a/src/sys/include/vm/map.h b/src/sys/include/vm/map.h
index 69d7d73..8183b62 100644
--- a/src/sys/include/vm/map.h
+++ b/src/sys/include/vm/map.h
@@ -31,6 +31,7 @@
 #define _VM_MAP_H_  1
 
 #include <sys/types.h>
+#include <sys/syscall.h>
 #include <sys/mman.h>
 #include <machine/vas.h>    /* standard */
 #include <vm/mmu.h>
@@ -52,4 +53,9 @@
  */
 int vm_map(struct vm_vas *vas, struct mmu_map *spec, size_t len, int prot);
 
+/*
+ * POSIX mmap syscall
+ */
+scret_t sys_mmap(struct syscall_args *scargs);
+
 #endif  /* !_VM_MAP_H_ */
diff --git a/src/sys/vm/vm_map.c b/src/sys/vm/vm_map.c
index f299b34..1d801af 100644
--- a/src/sys/vm/vm_map.c
+++ b/src/sys/vm/vm_map.c
@@ -30,12 +30,16 @@
 #include <sys/types.h>
 #include <sys/param.h>
 #include <sys/errno.h>
+#include <sys/param.h>
 #include <sys/syslog.h>
 #include <vm/physseg.h>
 #include <vm/mmu.h>
 #include <vm/map.h>
 #include <vm/vm.h>
 
+#define MMAP_START 0x6F3C8E0C0000
+#define MMAP_END   0x6F3C90000000
+
 /*
  * Create a virtual to physical memory
  * mapping
@@ -137,3 +141,56 @@ vm_map(struct vm_vas *vas, struct mmu_map *spec, size_t len, int prot)
     __vm_map(vas, &spec_cpy, DEFAULT_PAGESIZE, 0);
     return 0;
 }
+
+void *
+mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off)
+{
+    struct mmu_map spec;
+    struct vm_vas vas;
+    paddr_t pa;
+    int error;
+
+    /* TODO: Support address allocation  */
+    if (len == 0 || addr == NULL) {
+        return NULL;
+    }
+
+    spec.va = (uintptr_t)addr;
+    spec.pa = 0;
+    error = mmu_this_vas(&vas);
+    if (error < 0) {
+        return NULL;
+    }
+
+    /* Create the mapping */
+    error = vm_map(&vas, &spec, len, prot);
+    if (error < 0) {
+        return NULL;
+    }
+
+    return (void *)spec.va;
+}
+
+/*
+ * ARG0: Address
+ * ARG1: Length
+ * ARG2: Protection flags
+ * ARG3: Flags
+ * ARG4: Fildes
+ * ARG5: Offset
+ */
+scret_t
+sys_mmap(struct syscall_args *scargs)
+{
+    void *address = SCARG(scargs, void *, 0);
+    size_t length = SCARG(scargs, size_t, 1);
+    int prot = SCARG(scargs, int, 2);
+
+    prot |= PROT_USER;
+    if (address != NULL) {
+        address = PTR_OFFSET(address, MMAP_START);
+    }
+
+    /* XXX: Should use rest of the args */
+    return (uintptr_t)mmap(address, length, prot, 0, 0, 0);
+}