sh: Expose physical addressing mode through cpuinfo.

CPUs can be in either the legacy 29-bit or 32-bit physical addressing
modes. This follows the x86 approach of tracking the phys bits in cpuinfo
and exposing it to userspace through procfs.

This change was requested to permit kexec-tools to detect the physical
addressing mode in order to determine the appropriate address mangling.

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

arch/sh/include/asm/processor.h

@@ -89,6 +89,7 @@ struct sh_cpuinfo {
 	struct task_struct *idle;
 #endif
 
+	unsigned int phys_bits;
 	unsigned long flags;
 } __attribute__ ((aligned(L1_CACHE_BYTES)));
 

arch/sh/kernel/cpu/init.c

@@ -340,6 +340,8 @@ asmlinkage void __cpuinit cpu_init(void)
 	 */
 	current_cpu_data.asid_cache = NO_CONTEXT;
 
+	current_cpu_data.phys_bits = __in_29bit_mode() ? 29 : 32;
+
 	speculative_execution_init();
 	expmask_init();
 

arch/sh/kernel/setup.c

@@ -52,6 +52,7 @@ struct sh_cpuinfo cpu_data[NR_CPUS] __read_mostly = {
 		.type			= CPU_SH_NONE,
 		.family			= CPU_FAMILY_UNKNOWN,
 		.loops_per_jiffy	= 10000000,
+		.phys_bits		= MAX_PHYSMEM_BITS,
 	},
 };
 EXPORT_SYMBOL(cpu_data);
@@ -432,6 +433,8 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 	if (c->flags & CPU_HAS_L2_CACHE)
 		show_cacheinfo(m, "scache", c->scache);
 
+	seq_printf(m, "address sizes\t: %u bits physical\n", c->phys_bits);
+
 	seq_printf(m, "bogomips\t: %lu.%02lu\n",
 		     c->loops_per_jiffy/(500000/HZ),
 		     (c->loops_per_jiffy/(5000/HZ)) % 100);