sh: Merge legacy and dynamic PMB modes.

This implements a bit of rework for the PMB code, which permits us to
kill off the legacy PMB mode completely. Rather than trusting the boot
loader to do the right thing, we do a quick verification of the PMB
contents to determine whether to have the kernel setup the initial
mappings or whether it needs to mangle them later on instead.

If we're booting from legacy mappings, the kernel will now take control
of them and make them match the kernel's initial mapping configuration.
This is accomplished by breaking the initialization phase out in to
multiple steps: synchronization, merging, and resizing. With the recent
rework, the synchronization code establishes page links for compound
mappings already, so we build on top of this for promoting mappings and
reclaiming unused slots.

At the same time, the changes introduced for the uncached helpers also
permit us to dynamically resize the uncached mapping without any
particular headaches. The smallest page size is more than sufficient for
mapping all of kernel text, and as we're careful not to jump to any far
off locations in the setup code the mapping can safely be resized
regardless of whether we are executing from it or not.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

3 files changed, 22 insertions, 19 deletions

diff --git a/arch/sh/include/asm/mmu.h b/arch/sh/include/asm/mmu.h
index e42c4e2a41df..15a05b615ba7 100644
--- a/arch/sh/include/asm/mmu.h
+++ b/arch/sh/include/asm/mmu.h
@@ -58,7 +58,7 @@ typedef struct {
 long pmb_remap(unsigned long virt, unsigned long phys,
                unsigned long size, pgprot_t prot);
 void pmb_unmap(unsigned long addr);
-int pmb_init(void);
+void pmb_init(void);
 bool __in_29bit_mode(void);
 #else
 static inline long pmb_remap(unsigned long virt, unsigned long phys,
@@ -67,14 +67,8 @@ static inline long pmb_remap(unsigned long virt, unsigned long phys,
         return -EINVAL;
 }
 
-static inline void pmb_unmap(unsigned long addr)
-{
-}
-
-static inline int pmb_init(void)
-{
-        return -ENODEV;
-}
+#define pmb_unmap(addr)         do { } while (0)
+#define pmb_init(addr)          do { } while (0)
 
 #ifdef CONFIG_29BIT
 #define __in_29bit_mode()       (1)
diff --git a/arch/sh/include/asm/page.h b/arch/sh/include/asm/page.h
index 8237d9f53e56..d71feb359304 100644
--- a/arch/sh/include/asm/page.h
+++ b/arch/sh/include/asm/page.h
@@ -45,21 +45,12 @@
 #endif
 
 #ifndef __ASSEMBLY__
+#include <asm/uncached.h>
 
 extern unsigned long shm_align_mask;
 extern unsigned long max_low_pfn, min_low_pfn;
 extern unsigned long memory_start, memory_end;
 
-#ifdef CONFIG_UNCACHED_MAPPING
-extern unsigned long uncached_start, uncached_end;
-
-extern int virt_addr_uncached(unsigned long kaddr);
-extern void uncached_init(void);
-#else
-#define virt_addr_uncached(kaddr)       (0)
-#define uncached_init()                 do { } while (0)
-#endif
-
 static inline unsigned long
 pages_do_alias(unsigned long addr1, unsigned long addr2)
 {
diff --git a/arch/sh/include/asm/uncached.h b/arch/sh/include/asm/uncached.h
new file mode 100644
index 000000000000..e3419f96626a
--- /dev/null
+++ b/arch/sh/include/asm/uncached.h
@@ -0,0 +1,18 @@
+#ifndef __ASM_SH_UNCACHED_H
+#define __ASM_SH_UNCACHED_H
+
+#include <linux/bug.h>
+
+#ifdef CONFIG_UNCACHED_MAPPING
+extern unsigned long uncached_start, uncached_end;
+
+extern int virt_addr_uncached(unsigned long kaddr);
+extern void uncached_init(void);
+extern void uncached_resize(unsigned long size);
+#else
+#define virt_addr_uncached(kaddr)       (0)
+#define uncached_init()                 do { } while (0)
+#define uncached_resize(size)           BUG()
+#endif
+
+#endif /* __ASM_SH_UNCACHED_H */