Changeset e3c762cd in mainline for arch/amd64/src/asm_utils.S

Timestamp:

2006-05-05T11:59:19Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

de07bcf

Parents:

22cf454d

Message:

Complete implementation of copy_from_uspace() and copy_to_uspace()
for amd64 and ia32. Other architectures still compile and run,
but need to implement their own assembly-only memcpy(), memcpy_from_uspace(),
memcpy_to_uspace() and their failover parts. For these architectures
only dummy implementations are provided.

File:

• arch/amd64/src/asm_utils.S (modified) (2 diffs)

arch/amd64/src/asm_utils.S

@@ -61 +61 @@
         jmp printf
 
-.global memcpy
-memcpy:
-        jmp _memcpy
-        
 .global cpuid
 .global has_cpuid
@@ -70 +66 @@
 .global read_efer_flag
 .global set_efer_flag
-        
+.global memcpy
+.global memcpy_from_uspace
+.global memcpy_to_uspace
+.global memcpy_from_uspace_failover_address
+.global memcpy_to_uspace_failover_address
+
+#define MEMCPY_DST      %rdi
+#define MEMCPY_SRC      %rsi
+#define MEMCPY_SIZE     %rdx
+
+/**
+ * Copy memory from/to userspace.
+ *
+ * This is almost conventional memcpy().
+ * The difference is that there is a failover part
+ * to where control is returned from a page fault if
+ * the page fault occurs during copy_from_uspace()
+ * or copy_to_uspace().
+ *
+ * @param MEMCPY_DST    Destination address.
+ * @param MEMCPY_SRC    Source address.
+ * @param MEMCPY_SIZE   Number of bytes to copy.
+ *
+ * @retrun MEMCPY_SRC on success, 0 on failure.
+ */
+memcpy:
+memcpy_from_uspace:
+memcpy_to_uspace:
+        movq MEMCPY_SRC, %rax
+
+        movq MEMCPY_SIZE, %rcx
+        shrq $3, %rcx                   /* size / 8 */
+        
+        rep movsq                       /* copy as much as possible word by word */
+
+        movq MEMCPY_SIZE, %rcx
+        andq $7, %rcx                   /* size % 8 */
+        jz 0f
+        
+        rep movsb                       /* copy the rest byte by byte */
+        
+0:
+        ret                             /* return MEMCPY_SRC, success */
+
+memcpy_from_uspace_failover_address:
+memcpy_to_uspace_failover_address:
+        xorq %rax, %rax                 /* return 0, failure */
+        ret
+
 ## Determine CPUID support
 #