Pull button into test branch

[linux-drm-fsl-dcu.git] / arch / s390 / kernel / cpcmd.c

diff --git a/arch/s390/kernel/cpcmd.c b/arch/s390/kernel/cpcmd.c
index 4ef44e536b2c6495a7ff5e05c4f7e5d444d40042..a5972f1541fea7525afc6c12f868cb7aa5d0efbd 100644 (file)
--- a/arch/s390/kernel/cpcmd.c
+++ b/arch/s390/kernel/cpcmd.c
@@ -21,83 +21,60 @@ static DEFINE_SPINLOCK(cpcmd_lock);
 static char cpcmd_buf[241];
 
 /*
- * the caller of __cpcmd has to ensure that the response buffer is below 2 GB
+ * __cpcmd has some restrictions over cpcmd
+ *  - the response buffer must reside below 2GB (if any)
+ *  - __cpcmd is unlocked and therefore not SMP-safe
  */
 int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
 {
-       const int mask = 0x40000000L;
-       unsigned long flags;
-       int return_code;
-       int return_len;
-       int cmdlen;
+       unsigned cmdlen;
+       int return_code, return_len;
 
-       spin_lock_irqsave(&cpcmd_lock, flags);
        cmdlen = strlen(cmd);
        BUG_ON(cmdlen > 240);
        memcpy(cpcmd_buf, cmd, cmdlen);
        ASCEBC(cpcmd_buf, cmdlen);
 
        if (response != NULL && rlen > 0) {
+               register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
+               register unsigned long reg3 asm ("3") = (addr_t) response;
+               register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L;
+               register unsigned long reg5 asm ("5") = rlen;
+
                memset(response, 0, rlen);
+               asm volatile(
 #ifndef CONFIG_64BIT
-               asm volatile (  "lra    2,0(%2)\n"
-                               "lr     4,%3\n"
-                               "o      4,%6\n"
-                               "lra    3,0(%4)\n"
-                               "lr     5,%5\n"
-                               "diag   2,4,0x8\n"
-                               "brc    8, 1f\n"
-                               "ar     5, %5\n"
-                               "1: \n"
-                               "lr     %0,4\n"
-                               "lr     %1,5\n"
-                               : "=d" (return_code), "=d" (return_len)
-                               : "a" (cpcmd_buf), "d" (cmdlen),
-                               "a" (response), "d" (rlen), "m" (mask)
-                               : "cc", "2", "3", "4", "5" );
+                       "       diag    %2,%0,0x8\n"
+                       "       brc     8,1f\n"
+                       "       ar      %1,%4\n"
 #else /* CONFIG_64BIT */
-                asm volatile ( "lrag   2,0(%2)\n"
-                               "lgr    4,%3\n"
-                               "o      4,%6\n"
-                               "lrag   3,0(%4)\n"
-                               "lgr    5,%5\n"
-                               "sam31\n"
-                               "diag   2,4,0x8\n"
-                               "sam64\n"
-                               "brc    8, 1f\n"
-                               "agr    5, %5\n"
-                               "1: \n"
-                               "lgr    %0,4\n"
-                               "lgr    %1,5\n"
-                               : "=d" (return_code), "=d" (return_len)
-                               : "a" (cpcmd_buf), "d" (cmdlen),
-                               "a" (response), "d" (rlen), "m" (mask)
-                               : "cc", "2", "3", "4", "5" );
+                       "       sam31\n"
+                       "       diag    %2,%0,0x8\n"
+                       "       sam64\n"
+                       "       brc     8,1f\n"
+                       "       agr     %1,%4\n"
 #endif /* CONFIG_64BIT */
+                       "1:\n"
+                       : "+d" (reg4), "+d" (reg5)
+                       : "d" (reg2), "d" (reg3), "d" (rlen) : "cc");
+               return_code = (int) reg4;
+               return_len = (int) reg5;
                 EBCASC(response, rlen);
         } else {
+               register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf;
+               register unsigned long reg3 asm ("3") = cmdlen;
                return_len = 0;
+               asm volatile(
 #ifndef CONFIG_64BIT
-                asm volatile ( "lra    2,0(%1)\n"
-                               "lr     3,%2\n"
-                               "diag   2,3,0x8\n"
-                               "lr     %0,3\n"
-                               : "=d" (return_code)
-                               : "a" (cpcmd_buf), "d" (cmdlen)
-                               : "2", "3"  );
+                       "       diag    %1,%0,0x8\n"
 #else /* CONFIG_64BIT */
-                asm volatile ( "lrag   2,0(%1)\n"
-                               "lgr    3,%2\n"
-                               "sam31\n"
-                               "diag   2,3,0x8\n"
-                               "sam64\n"
-                               "lgr    %0,3\n"
-                               : "=d" (return_code)
-                               : "a" (cpcmd_buf), "d" (cmdlen)
-                               : "2", "3" );
+                       "       sam31\n"
+                       "       diag    %1,%0,0x8\n"
+                       "       sam64\n"
 #endif /* CONFIG_64BIT */
+                       : "+d" (reg3) : "d" (reg2) : "cc");
+               return_code = (int) reg3;
         }
-       spin_unlock_irqrestore(&cpcmd_lock, flags);
        if (response_code != NULL)
                *response_code = return_code;
        return return_len;
@@ -105,15 +82,18 @@ int  __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
 
 EXPORT_SYMBOL(__cpcmd);
 
-#ifdef CONFIG_64BIT
 int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
 {
        char *lowbuf;
        int len;
+       unsigned long flags;
 
        if ((rlen == 0) || (response == NULL)
-           || !((unsigned long)response >> 31))
+           || !((unsigned long)response >> 31)) {
+               spin_lock_irqsave(&cpcmd_lock, flags);
                len = __cpcmd(cmd, response, rlen, response_code);
+               spin_unlock_irqrestore(&cpcmd_lock, flags);
+       }
        else {
                lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
                if (!lowbuf) {
@@ -121,7 +101,9 @@ int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
                                "cpcmd: could not allocate response buffer\n");
                        return -ENOMEM;
                }
+               spin_lock_irqsave(&cpcmd_lock, flags);
                len = __cpcmd(cmd, lowbuf, rlen, response_code);
+               spin_unlock_irqrestore(&cpcmd_lock, flags);
                memcpy(response, lowbuf, rlen);
                kfree(lowbuf);
        }
@@ -129,4 +111,3 @@ int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
 }
 
 EXPORT_SYMBOL(cpcmd);
-#endif         /* CONFIG_64BIT */