m68k: Fix assembler constraint to prevent overeager gcc optimisation

Passing the address of a variable as an operand to an asm statement
doesn't mark the value of this variable as used, so gcc may optimize its
initialisation away.  Fix this by using the "m" constraint instead.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org

diff --git a/arch/m68k/atari/config.c b/arch/m68k/atari/config.c
index 4203d101363cf23074e7ce0e22a6f19579bf92ba..c4ac15c4f065ce97d0f86aafeb148efd5734e7ba 100644 (file)
--- a/arch/m68k/atari/config.c
+++ b/arch/m68k/atari/config.c
@@ -414,9 +414,9 @@ void __init config_atari(void)
                                         * FDC val = 4 -> Supervisor only */
                asm volatile ("\n"
                        "       .chip   68030\n"
-                       "       pmove   %0@,%/tt1\n"
+                       "       pmove   %0,%/tt1\n"
                        "       .chip   68k"
-                       : : "a" (&tt1_val));
+                       : : "m" (tt1_val));
        } else {
                asm volatile ("\n"
                        "       .chip   68040\n"
@@ -569,10 +569,10 @@ static void atari_reset(void)
                        : "d0");
        } else
                asm volatile ("\n"
-                       "       pmove   %0@,%%tc\n"
+                       "       pmove   %0,%%tc\n"
                        "       jmp     %1@"
                        : /* no outputs */
-                       : "a" (&tc_val), "a" (reset_addr));
+                       : "m" (tc_val), "a" (reset_addr));
 }
 
 

diff --git a/arch/m68k/kernel/process_mm.c b/arch/m68k/kernel/process_mm.c
index 1bc223aa07ec297a6ed923bbc49168b89eedfec3..aa4ffb882366c01ca814ef109d4412d75ce9b777 100644 (file)
--- a/arch/m68k/kernel/process_mm.c
+++ b/arch/m68k/kernel/process_mm.c
@@ -189,8 +189,8 @@ void flush_thread(void)
        current->thread.fs = __USER_DS;
        if (!FPU_IS_EMU)
                asm volatile (".chip 68k/68881\n\t"
-                             "frestore %0@\n\t"
-                             ".chip 68k" : : "a" (&zero));
+                             "frestore %0\n\t"
+                             ".chip 68k" : : "m" (zero));
 }
 
 /*

diff --git a/arch/m68k/kernel/process_no.c b/arch/m68k/kernel/process_no.c
index 69c1803fcf1bed00b4a2ba6a60956992543ffac1..5e1078cabe0e54bf10d4537aa86eaa11c8b0e8a5 100644 (file)
--- a/arch/m68k/kernel/process_no.c
+++ b/arch/m68k/kernel/process_no.c
@@ -163,8 +163,8 @@ void flush_thread(void)
 #ifdef CONFIG_FPU
        if (!FPU_IS_EMU)
                asm volatile (".chip 68k/68881\n\t"
-                             "frestore %0@\n\t"
-                             ".chip 68k" : : "a" (&zero));
+                             "frestore %0\n\t"
+                             ".chip 68k" : : "m" (zero));
 #endif
 }
 

diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c
index 89362f2bb56a3e8bae88a364a1b06de7a68e8a61..eb67469780837661d34804c69c166829a362e8d3 100644 (file)
--- a/arch/m68k/kernel/traps.c
+++ b/arch/m68k/kernel/traps.c
@@ -552,13 +552,13 @@ static inline void bus_error030 (struct frame *fp)
 
 #ifdef DEBUG
                asm volatile ("ptestr %3,%2@,#7,%0\n\t"
-                             "pmove %%psr,%1@"
-                             : "=a&" (desc)
-                             : "a" (&temp), "a" (addr), "d" (ssw));
+                             "pmove %%psr,%1"
+                             : "=a&" (desc), "=m" (temp)
+                             : "a" (addr), "d" (ssw));
 #else
                asm volatile ("ptestr %2,%1@,#7\n\t"
-                             "pmove %%psr,%0@"
-                             : : "a" (&temp), "a" (addr), "d" (ssw));
+                             "pmove %%psr,%0"
+                             : "=m" (temp) : "a" (addr), "d" (ssw));
 #endif
                mmusr = temp;
 
@@ -605,20 +605,18 @@ static inline void bus_error030 (struct frame *fp)
                               !(ssw & RW) ? "write" : "read", addr,
                               fp->ptregs.pc, ssw);
                        asm volatile ("ptestr #1,%1@,#0\n\t"
-                                     "pmove %%psr,%0@"
-                                     : /* no outputs */
-                                     : "a" (&temp), "a" (addr));
+                                     "pmove %%psr,%0"
+                                     : "=m" (temp)
+                                     : "a" (addr));
                        mmusr = temp;
 
                        printk ("level 0 mmusr is %#x\n", mmusr);
 #if 0
-                       asm volatile ("pmove %%tt0,%0@"
-                                     : /* no outputs */
-                                     : "a" (&tlong));
+                       asm volatile ("pmove %%tt0,%0"
+                                     : "=m" (tlong));
                        printk("tt0 is %#lx, ", tlong);
-                       asm volatile ("pmove %%tt1,%0@"
-                                     : /* no outputs */
-                                     : "a" (&tlong));
+                       asm volatile ("pmove %%tt1,%0"
+                                     : "=m" (tlong));
                        printk("tt1 is %#lx\n", tlong);
 #endif
 #ifdef DEBUG
@@ -668,13 +666,13 @@ static inline void bus_error030 (struct frame *fp)
 
 #ifdef DEBUG
        asm volatile ("ptestr #1,%2@,#7,%0\n\t"
-                     "pmove %%psr,%1@"
-                     : "=a&" (desc)
-                     : "a" (&temp), "a" (addr));
+                     "pmove %%psr,%1"
+                     : "=a&" (desc), "=m" (temp)
+                     : "a" (addr));
 #else
        asm volatile ("ptestr #1,%1@,#7\n\t"
-                     "pmove %%psr,%0@"
-                     : : "a" (&temp), "a" (addr));
+                     "pmove %%psr,%0"
+                     : "=m" (temp) : "a" (addr));
 #endif
        mmusr = temp;
 

diff --git a/arch/m68k/mm/cache.c b/arch/m68k/mm/cache.c
index 5437fff5fe076958bf296d4b378b8da0bca97df1..5550aa4fd8119b3474db30c2a76aa9238f7206cd 100644 (file)
--- a/arch/m68k/mm/cache.c
+++ b/arch/m68k/mm/cache.c
@@ -52,9 +52,9 @@ static unsigned long virt_to_phys_slow(unsigned long vaddr)
                unsigned long *descaddr;
 
                asm volatile ("ptestr %3,%2@,#7,%0\n\t"
-                             "pmove %%psr,%1@"
-                             : "=a&" (descaddr)
-                             : "a" (&mmusr), "a" (vaddr), "d" (get_fs().seg));
+                             "pmove %%psr,%1"
+                             : "=a&" (descaddr), "=m" (mmusr)
+                             : "a" (vaddr), "d" (get_fs().seg));
                if (mmusr & (MMU_I|MMU_B|MMU_L))
                        return 0;
                descaddr = phys_to_virt((unsigned long)descaddr);