[PATCH 2/2] arm64/mm: show TAINT_CPU_OUT_OF_SPEC warning if the cache size is over the spec.

Masayoshi Mizuma
2019-06-11T15:20:31Z

From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>

Show the warning and taints as TAINT_CPU_OUT_OF_SPEC if the cache line
size is greater than the maximum.

Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Tested-by: Zhang Lei <zhang.lei@jp.fujitsu.com>
---
arch/arm64/include/asm/cache.h | 2 ++
arch/arm64/mm/init.c | 5 +++++
2 files changed, 7 insertions(+)

diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
index 926434f413fa..636e277fefc9 100644
--- a/arch/arm64/include/asm/cache.h
+++ b/arch/arm64/include/asm/cache.h
@@ -91,6 +91,8 @@ static inline u32 cache_type_cwg(void)

#define __read_mostly __attribute__((__section__(".data..read_mostly")))

+#define ARM64_MAX_CACHE_LINE_SIZE 2048
+
static inline int cache_line_size(void)
{
u32 cwg = cache_type_cwg();
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index d2adffb81b5d..df621d90b19c 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -562,6 +562,11 @@ void __init mem_init(void)
*/
sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
}
+
+ WARN_TAINT(cache_line_size() > ARM64_MAX_CACHE_LINE_SIZE,
+ TAINT_CPU_OUT_OF_SPEC,
+ "CTR_EL0.CWG is greater than the spec (%d > %d)",
+ cache_line_size(), ARM64_MAX_CACHE_LINE_SIZE);
}

void free_initmem(void)
--
2.20.1