microblaze: Remove r0_ram pointer and PTO alignment

r0_ram pool was used for saving/restoring register
content if hw exception happen. This poll was replaced by
pt_pool_space with PT_SIZE size.
Based on this change SAVE_STATE_ARG_SPACE was removed which
caused that PTO offset is zero that's why is also removed.

r0_ram space was used as scratchpad by v850. In early
Microblaze Linux developing phase was this part of code
blindly copied.

Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/include/asm/entry.h

@@ -31,40 +31,4 @@ DECLARE_PER_CPU(unsigned int, R11_SAVE); /* Temp variable for entry */
 DECLARE_PER_CPU(unsigned int, CURRENT_SAVE); /* Saved current pointer */
 # endif /* __ASSEMBLY__ */
 
-#ifndef CONFIG_MMU
-
-/* noMMU hasn't any space for args */
-# define STATE_SAVE_ARG_SPACE	(0)
-
-#else /* CONFIG_MMU */
-
-/* If true, system calls save and restore all registers (except result
- * registers, of course).  If false, then `call clobbered' registers
- * will not be preserved, on the theory that system calls are basically
- * function calls anyway, and the caller should be able to deal with it.
- * This is a security risk, of course, as `internal' values may leak out
- * after a system call, but that certainly doesn't matter very much for
- * a processor with no MMU protection!  For a protected-mode kernel, it
- * would be faster to just zero those registers before returning.
- *
- * I can not rely on the glibc implementation. If you turn it off make
- * sure that r11/r12 is saved in user-space. --KAA
- *
- * These are special variables using by the kernel trap/interrupt code
- * to save registers in, at a time when there are no spare registers we
- * can use to do so, and we can't depend on the value of the stack
- * pointer.  This means that they must be within a signed 16-bit
- * displacement of 0x00000000.
- */
-
-/* A `state save frame' is a struct pt_regs preceded by some extra space
- * suitable for a function call stack frame. */
-
-/* Amount of room on the stack reserved for arguments and to satisfy the
- * C calling conventions, in addition to the space used by the struct
- * pt_regs that actually holds saved values. */
-#define STATE_SAVE_ARG_SPACE	(6*4) /* Up to six arguments */
-
-#endif /* CONFIG_MMU */
-
 #endif /* _ASM_MICROBLAZE_ENTRY_H */

arch/microblaze/include/asm/processor.h

@@ -155,7 +155,7 @@ unsigned long get_wchan(struct task_struct *p);
 #  define task_regs(task) ((struct pt_regs *)task_tos(task) - 1)
 
 #  define task_pt_regs_plus_args(tsk) \
-	(((void *)task_pt_regs(tsk)) - STATE_SAVE_ARG_SPACE)
+	((void *)task_pt_regs(tsk))
 
 #  define task_sp(task)	(task_regs(task)->r1)
 #  define task_pc(task)	(task_regs(task)->pc)