Changeset 345 for soft/giet_vm/giet_common/vmem.c

Timestamp:

Jun 25, 2014, 2:19:37 PM (10 years ago)

Author:

cfuguet

Message:

giet_vm optimizations:

• Several modifications in GIET_VM in order to support compilation with GCC optimizations (-O2) activated.

• Adding missing volatile in some global variables.

• Using ioread and iowrite utility functions in peripheral drivers which prevent GCC to remove writes or reads in hardware memory mapped registers.

• Code refactoring of stdio printf functions. Now, shr_printf and tty_printf function reuse the same function body. The only difference is that shr_printf wraps printf function call with TTY get lock and release lock.

File:

• soft/giet_vm/giet_common/vmem.c (modified) (4 diffs)

soft/giet_vm/giet_common/vmem.c

@@ -95 +95 @@
     unsigned long long pte2_paddr;
 
-    register unsigned int pte2_msb;
-    register unsigned int pte2_lsb;
-    register unsigned int flags_value;
-    register unsigned int ppn_value;
+    volatile unsigned int pte2_msb;
+    volatile unsigned int pte2_lsb;
+    unsigned int flags_value;
+    unsigned int ppn_value;
 
     unsigned int ix1 = vpn >> 9;
     unsigned int ix2 = vpn & 0x1FF;
+
+    unsigned int save_sr;
 
     // get PTE1
@@ -110 +112 @@
 
     // get physical addresses of pte2 (two 32 bits words)
-    ptba       = (unsigned long long) (pt->pt1[ix1] & 0x0FFFFFFF) << 12;
+    ptba       = (unsigned long long) (pte1 & 0x0FFFFFFF) << 12;
     pte2_paddr = ptba + 8*ix2;
     pte2_lsb   = (unsigned int) pte2_paddr;
     pte2_msb   = (unsigned int) (pte2_paddr >> 32);
 
+    // disable interrupts and save status register
+    _it_disable( &save_sr );
+
     // gets ppn_value and flags_value, after temporary DTLB desactivation
     asm volatile (
-                "li      $2,     0xFFFFFFFE  \n"     /* Mask for IE bits     */
-                "mfc0    $4,     $12         \n"     /* $4 <= SR             */ 
-                "and     $2,     $2,    $4   \n"
-                "mtc0    $2,     $12         \n"     /* disable Interrupts   */
-
-                "li      $3,     0xB         \n"     
-                "mtc2    $3,     $1          \n"     /* DTLB unactivated     */ 
+                "mfc2    $2,     $1          \n"     /* $2 <= MMU_MODE       */
+                "andi    $3,     $2,    0xb  \n"
+                "mtc2    $3,     $1          \n"     /* DTLB off             */
 
                 "mtc2    %2,     $24         \n"     /* PADDR_EXT <= msb     */
@@ -130 +131 @@
                 "mtc2    $0,     $24         \n"     /* PADDR_EXT <= 0       */
 
-                "li      $3,     0xF         \n" 
-                "mtc2    $3,     $1          \n"     /* DTLB activated       */
+                "mtc2    $2,     $1          \n"     /* restore MMU_MODE     */
+                : "=r" (flags_value), "=r" (ppn_value)
+                : "r"  (pte2_msb)   , "r"  (pte2_lsb)
+                : "$2", "$3");
 
-                "mtc0    $4,     $12         \n"     /* restore SR           */
-                : "=r" (flags_value), "=r" (ppn_value)
-                : "r" (pte2_msb), "r" (pte2_lsb)
-                : "$2","$3","$4");
+    // restore saved status register
+    _it_restore( &save_sr );
 
     // check PTE2 mapping
@@ -142 +143 @@
 
     // set return values 
-    *ppn = ppn_value;
+    *ppn   = ppn_value;
     *flags = flags_value;
+
     return 0;
 } // end _v2p_translate()