sh: Isolate uncached mapping support.

This splits out the uncached mapping support under its own config option,
presently only used by 29-bit mode and 32-bit + PMB. This will make it
possible to optionally add an uncached mapping on sh64 as well as booting
without an uncached mapping for 32-bit.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/ptrace.h

@@ -109,6 +109,8 @@ struct pt_dspregs {
 
 #ifdef __KERNEL__
 #include <asm/addrspace.h>
+#include <asm/page.h>
+#include <asm/system.h>
 
 #define user_mode(regs)			(((regs)->sr & 0x40000000)==0)
 #define instruction_pointer(regs)	((unsigned long)(regs)->pc)
@@ -137,9 +139,14 @@ static inline unsigned long profile_pc(struct pt_regs *regs)
 {
 	unsigned long pc = instruction_pointer(regs);
 
-#ifdef P2SEG
-	if (pc >= P2SEG && pc < P3SEG)
-		pc -= 0x20000000;
+#ifdef CONFIG_UNCACHED_MAPPING
+	/*
+	 * If PC points in to the uncached mapping, fix it up and hand
+	 * back the cached equivalent.
+	 */
+	if ((pc >= (memory_start + cached_to_uncached)) &&
+	    (pc <  (memory_start + cached_to_uncached + uncached_size)))
+		pc -= cached_to_uncached;
 #endif
 
 	return pc;

arch/sh/include/asm/system.h

@@ -10,7 +10,6 @@
 #include <linux/compiler.h>
 #include <linux/linkage.h>
 #include <asm/types.h>
-#include <asm/ptrace.h>
 
 #define AT_VECTOR_SIZE_ARCH 5 /* entries in ARCH_DLINFO */
 
@@ -114,6 +113,8 @@ static inline unsigned long __cmpxchg(volatile void * ptr, unsigned long old,
 				    (unsigned long)_n_, sizeof(*(ptr))); \
   })
 
+struct pt_regs;
+
 extern void die(const char *str, struct pt_regs *regs, long err) __attribute__ ((noreturn));
 void free_initmem(void);
 void free_initrd_mem(unsigned long start, unsigned long end);

arch/sh/include/asm/system_64.h

@@ -18,6 +18,7 @@
 /*
  *	switch_to() should switch tasks to task nr n, first
  */
+struct thread_struct;
 struct task_struct *sh64_switch_to(struct task_struct *prev,
 				   struct thread_struct *prev_thread,
 				   struct task_struct *next,

arch/sh/mm/Kconfig

@@ -75,6 +75,7 @@ config MEMORY_SIZE
 config 29BIT
 	def_bool !32BIT
 	depends on SUPERH32
+	select UNCACHED_MAPPING
 
 config 32BIT
 	bool
@@ -84,6 +85,7 @@ config PMB
 	bool "Support 32-bit physical addressing through PMB"
 	depends on MMU && EXPERIMENTAL && CPU_SH4A && !CPU_SH4AL_DSP
 	select 32BIT
+	select UNCACHED_MAPPING
 	help
 	  If you say Y here, physical addressing will be extended to
 	  32-bits through the SH-4A PMB. If this is not set, legacy
@@ -173,6 +175,9 @@ config IOREMAP_FIXED
        def_bool y
        depends on X2TLB || SUPERH64
 
+config UNCACHED_MAPPING
+	bool
+
 choice
 	prompt "Kernel page size"
 	default PAGE_SIZE_4KB

arch/sh/mm/init.c

@@ -21,11 +21,12 @@
 #include <asm/cacheflush.h>
 #include <asm/sections.h>
 #include <asm/cache.h>
+#include <asm/sizes.h>
 
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 pgd_t swapper_pg_dir[PTRS_PER_PGD];
 
-#ifdef CONFIG_SUPERH32
+#ifdef CONFIG_UNCACHED_MAPPING
 /*
  * This is the offset of the uncached section from its cached alias.
  *
@@ -36,8 +37,8 @@ pgd_t swapper_pg_dir[PTRS_PER_PGD];
  * Default value only valid in 29 bit mode, in 32bit mode this will be
  * updated by the early PMB initialization code.
  */
-unsigned long cached_to_uncached = P2SEG - P1SEG;
-unsigned long uncached_size = 0x20000000;
+unsigned long cached_to_uncached = 0x20000000;
+unsigned long uncached_size = SZ_512M;
 #endif
 
 #ifdef CONFIG_MMU
@@ -281,7 +282,9 @@ void __init mem_init(void)
 #endif
 		"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 		"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB) (cached)\n"
+#ifdef CONFIG_UNCACHED_MAPPING
 		"            : 0x%08lx - 0x%08lx   (%4ld MB) (uncached)\n"
+#endif
 		"      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 		"      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 		"      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
@@ -299,9 +302,11 @@ void __init mem_init(void)
 		(unsigned long)memory_start, (unsigned long)high_memory,
 		((unsigned long)high_memory - (unsigned long)memory_start) >> 20,
 
+#ifdef CONFIG_UNCACHED_MAPPING
 		(unsigned long)memory_start + cached_to_uncached,
 		(unsigned long)memory_start + cached_to_uncached + uncached_size,
 		uncached_size >> 20,
+#endif
 
 		(unsigned long)&__init_begin, (unsigned long)&__init_end,
 		((unsigned long)&__init_end -