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>

3 files changed, 6 insertions, 0 deletions

diff --git a/arch/sh/include/asm/processor.h b/arch/sh/include/asm/processor.h
index 0a58cb25a658..c9e7cbc4768a 100644
--- a/arch/sh/include/asm/processor.h
+++ b/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)));
 
diff --git a/arch/sh/kernel/cpu/init.c b/arch/sh/kernel/cpu/init.c
index 97661061ff20..fac742e514ee 100644
--- a/arch/sh/kernel/cpu/init.c
+++ b/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();
 
diff --git a/arch/sh/kernel/setup.c b/arch/sh/kernel/setup.c
index 4e278467f76c..82c0a0c1df0d 100644
--- a/arch/sh/kernel/setup.c
+++ b/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);