MIPS: Probe for presence of KScratch registers.

Probe c0_config4 for KScratch registers and report them in /proc/cpuinfo.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1877/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 4 insertions, 0 deletions

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 68dae7b6b5db..f65d4c8c65a6 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -739,6 +739,8 @@ static inline unsigned int decode_config4(struct cpuinfo_mips *c)
             && cpu_has_tlb)
                 c->tlbsize += (config4 & MIPS_CONF4_MMUSIZEEXT) * 0x40;
 
+        c->kscratch_mask = (config4 >> 16) & 0xff;
+
         return config4 & MIPS_CONF_M;
 }
 
diff --git a/arch/mips/kernel/proc.c b/arch/mips/kernel/proc.c
index 4195abb55e59..e309665b6c81 100644
--- a/arch/mips/kernel/proc.c
+++ b/arch/mips/kernel/proc.c
@@ -74,6 +74,8 @@ static int show_cpuinfo(struct seq_file *m, void *v)
                 );
         seq_printf(m, "shadow register sets\t: %d\n",
                        cpu_data[n].srsets);
+        seq_printf(m, "kscratch registers\t: %d\n",
+                   hweight8(cpu_data[n].kscratch_mask));
         seq_printf(m, "core\t\t\t: %d\n", cpu_data[n].core);
 
         sprintf(fmt, "VCE%%c exceptions\t\t: %s\n",