sparc: Resolve conflict between sparc v9 and M7 on usage of bit 9 of TTE

sparc: Resolve conflict between sparc v9 and M7 on usage of bit 9 of TTE

Bit 9 of TTE is CV (Cacheable in V-cache) on sparc v9 processor while
the same bit 9 is MCDE (Memory Corruption Detection Enable) on M7
processor. This creates a conflicting usage of the same bit. Kernel
sets TTE.cv bit on all pages for sun4v architecture which works well
for sparc v9 but enables memory corruption detection on M7 processor
which is not the intent. This patch adds code to determine if kernel
is running on M7 processor and takes steps to not enable memory
corruption detection in TTE erroneously.

Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 28 insertions, 0 deletions

diff --git a/arch/sparc/kernel/entry.h b/arch/sparc/kernel/entry.h
index 07cc49e541f4..0f679421b468 100644
--- a/arch/sparc/kernel/entry.h
+++ b/arch/sparc/kernel/entry.h
@@ -69,6 +69,8 @@ void sun4v_patch_1insn_range(struct sun4v_1insn_patch_entry *,
                              struct sun4v_1insn_patch_entry *);
 void sun4v_patch_2insn_range(struct sun4v_2insn_patch_entry *,
                              struct sun4v_2insn_patch_entry *);
+void sun_m7_patch_2insn_range(struct sun4v_2insn_patch_entry *,
+                             struct sun4v_2insn_patch_entry *);
 extern unsigned int dcache_parity_tl1_occurred;
 extern unsigned int icache_parity_tl1_occurred;
 
diff --git a/arch/sparc/kernel/setup_64.c b/arch/sparc/kernel/setup_64.c
index c38d19fc27ba..f7b261749383 100644
--- a/arch/sparc/kernel/setup_64.c
+++ b/arch/sparc/kernel/setup_64.c
@@ -255,6 +255,24 @@ void sun4v_patch_2insn_range(struct sun4v_2insn_patch_entry *start,
         }
 }
 
+void sun_m7_patch_2insn_range(struct sun4v_2insn_patch_entry *start,
+                             struct sun4v_2insn_patch_entry *end)
+{
+        while (start < end) {
+                unsigned long addr = start->addr;
+
+                *(unsigned int *) (addr +  0) = start->insns[0];
+                wmb();
+                __asm__ __volatile__("flush     %0" : : "r" (addr +  0));
+
+                *(unsigned int *) (addr +  4) = start->insns[1];
+                wmb();
+                __asm__ __volatile__("flush     %0" : : "r" (addr +  4));
+
+                start++;
+        }
+}
+
 static void __init sun4v_patch(void)
 {
         extern void sun4v_hvapi_init(void);
@@ -267,6 +285,9 @@ static void __init sun4v_patch(void)
 
         sun4v_patch_2insn_range(&__sun4v_2insn_patch,
                                 &__sun4v_2insn_patch_end);
+        if (sun4v_chip_type == SUN4V_CHIP_SPARC_M7)
+                sun_m7_patch_2insn_range(&__sun_m7_2insn_patch,
+                                         &__sun_m7_2insn_patch_end);
 
         sun4v_hvapi_init();
 }
diff --git a/arch/sparc/kernel/vmlinux.lds.S b/arch/sparc/kernel/vmlinux.lds.S
index 09243057cb0b..f1a2f688b28a 100644
--- a/arch/sparc/kernel/vmlinux.lds.S
+++ b/arch/sparc/kernel/vmlinux.lds.S
@@ -138,6 +138,11 @@ SECTIONS
                 *(.pause_3insn_patch)
                 __pause_3insn_patch_end = .;
         }
+        .sun_m7_2insn_patch : {
+                __sun_m7_2insn_patch = .;
+                *(.sun_m7_2insn_patch)
+                __sun_m7_2insn_patch_end = .;
+        }
         PERCPU_SECTION(SMP_CACHE_BYTES)
 
         . = ALIGN(PAGE_SIZE);