[PATCH] ARM: Remove global nwfpe register variable

Recent changes to nwfpe broke the build with some gcc versions:

In file included from arch/arm/nwfpe/softfloat.c:33:
arch/arm/nwfpe/fpa11.h:32: global register variable follows a function definition
make[1]: *** [arch/arm/nwfpe/softfloat.o] Error 1

Since we now ensure that the kernel stack is empty when returning
to user space, we can now access the userspace registers with
reference to the kernel stack using current_thread_info(), rather
than remembering the stack pointer at the time nwfpe was called.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 9 insertions, 11 deletions

diff --git a/arch/arm/nwfpe/fpa11.h b/arch/arm/nwfpe/fpa11.h
index 45cc65426a22..e4a61aea534b 100644
--- a/arch/arm/nwfpe/fpa11.h
+++ b/arch/arm/nwfpe/fpa11.h
@@ -29,9 +29,7 @@
  * stack+task struct.  Use the same method as 'current' uses to
  * reach them.
  */
-register unsigned long *user_registers asm("sl");
-
-#define GET_USERREG() (user_registers)
+#define GET_USERREG() ((struct pt_regs *)(THREAD_START_SP + (unsigned long)current_thread_info()) - 1)
 
 #include <linux/config.h>
 #include <linux/thread_info.h>
diff --git a/arch/arm/nwfpe/fpmodule.c b/arch/arm/nwfpe/fpmodule.c
index a8efcf34888e..12885f31d347 100644
--- a/arch/arm/nwfpe/fpmodule.c
+++ b/arch/arm/nwfpe/fpmodule.c
@@ -132,7 +132,7 @@ void float_raise(signed char flags)
         printk(KERN_DEBUG
                "NWFPE: %s[%d] takes exception %08x at %p from %08lx\n",
                current->comm, current->pid, flags,
-               __builtin_return_address(0), GET_USERREG()[15]);
+               __builtin_return_address(0), GET_USERREG()->ARM_pc);
 #endif
 
         /* Keep SoftFloat exception flags up to date.  */
diff --git a/arch/arm/nwfpe/fpmodule.inl b/arch/arm/nwfpe/fpmodule.inl
index e5f59e9a3022..2c39ad408f22 100644
--- a/arch/arm/nwfpe/fpmodule.inl
+++ b/arch/arm/nwfpe/fpmodule.inl
@@ -28,8 +28,8 @@ static inline unsigned long readRegister(const unsigned int nReg)
            for this in this routine.  LDF/STF instructions with Rn = PC
            depend on the PC being correct, as they use PC+8 in their
            address calculations. */
-        unsigned long *userRegisters = GET_USERREG();
-        unsigned int val = userRegisters[nReg];
+        struct pt_regs *regs = GET_USERREG();
+        unsigned int val = regs->uregs[nReg];
         if (REG_PC == nReg)
                 val -= 4;
         return val;
@@ -38,8 +38,8 @@ static inline unsigned long readRegister(const unsigned int nReg)
 static inline void
 writeRegister(const unsigned int nReg, const unsigned long val)
 {
-        unsigned long *userRegisters = GET_USERREG();
-        userRegisters[nReg] = val;
+        struct pt_regs *regs = GET_USERREG();
+        regs->uregs[nReg] = val;
 }
 
 static inline unsigned long readCPSR(void)
@@ -63,12 +63,12 @@ static inline unsigned long readConditionCodes(void)
 
 static inline void writeConditionCodes(const unsigned long val)
 {
-        unsigned long *userRegisters = GET_USERREG();
+        struct pt_regs *regs = GET_USERREG();
         unsigned long rval;
         /*
          * Operate directly on userRegisters since
          * the CPSR may be the PC register itself.
          */
-        rval = userRegisters[REG_CPSR] & ~CC_MASK;
-        userRegisters[REG_CPSR] = rval | (val & CC_MASK);
+        rval = regs->ARM_cpsr & ~CC_MASK;
+        regs->ARM_cpsr = rval | (val & CC_MASK);
 }