[ARM] 3759/2: Remove uses of %?

Patch from Daniel Jacobowitz

The ARM kernel has several uses of asm("foo%?").  %? is a GCC internal
modifier used to output conditional execution predicates.  However, no
version of GCC supports conditionalizing asm statements.  GCC 4.2 will
correctly expand %? to the empty string in user asms.  Earlier versions may
reuse the condition from the previous instruction.  In 'if (foo) asm
("bar%?");' this is somewhat likely to be right... but not reliable.

So, the only safe thing to do is to remove the uses of %?.  I believe
the tlbflush.h occurances were supposed to be removed before, based
on the comment about %? not working at the top of that file.

Old versions of GCC could omit branches around user asms if the asm didn't
mark the condition codes as clobbered.  This problem hasn't been seen on any
recent (3.x or 4.x) GCC, but it could theoretically happen.  So, where
%? was removed a cc clobber was added.

Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 15 insertions, 12 deletions

diff --git a/arch/arm/mach-footbridge/dc21285.c b/arch/arm/mach-footbridge/dc21285.c
index 823e25d4547e..a1ae49df5c3b 100644
--- a/arch/arm/mach-footbridge/dc21285.c
+++ b/arch/arm/mach-footbridge/dc21285.c
@@ -69,16 +69,16 @@ dc21285_read_config(struct pci_bus *bus, unsigned int devfn, int where,
         if (addr)
                 switch (size) {
                 case 1:
-                        asm("ldr%?b     %0, [%1, %2]"
-                                : "=r" (v) : "r" (addr), "r" (where));
+                        asm("ldrb       %0, [%1, %2]"
+                                : "=r" (v) : "r" (addr), "r" (where) : "cc");
                         break;
                 case 2:
-                        asm("ldr%?h     %0, [%1, %2]"
-                                : "=r" (v) : "r" (addr), "r" (where));
+                        asm("ldrh       %0, [%1, %2]"
+                                : "=r" (v) : "r" (addr), "r" (where) : "cc");
                         break;
                 case 4:
-                        asm("ldr%?      %0, [%1, %2]"
-                                : "=r" (v) : "r" (addr), "r" (where));
+                        asm("ldr        %0, [%1, %2]"
+                                : "=r" (v) : "r" (addr), "r" (where) : "cc");
                         break;
                 }
 
@@ -103,16 +103,19 @@ dc21285_write_config(struct pci_bus *bus, unsigned int devfn, int where,
         if (addr)
                 switch (size) {
                 case 1:
-                        asm("str%?b     %0, [%1, %2]"
-                                : : "r" (value), "r" (addr), "r" (where));
+                        asm("strb       %0, [%1, %2]"
+                                : : "r" (value), "r" (addr), "r" (where)
+                                : "cc");
                         break;
                 case 2:
-                        asm("str%?h     %0, [%1, %2]"
-                                : : "r" (value), "r" (addr), "r" (where));
+                        asm("strh       %0, [%1, %2]"
+                                : : "r" (value), "r" (addr), "r" (where)
+                                : "cc");
                         break;
                 case 4:
-                        asm("str%?      %0, [%1, %2]"
-                                : : "r" (value), "r" (addr), "r" (where));
+                        asm("str        %0, [%1, %2]"
+                                : : "r" (value), "r" (addr), "r" (where)
+                                : "cc");
                         break;
                 }