[PATCH v6 6/6] drm: Add arch arm64 for drm_clflush_virt_range

[Michael Cheng]

Use flush_tlb_kernel_range when invoking drm_clflush_virt_range on
arm64 platforms. Using flush_tlb_kernel_range will:

1. Make sure prior page-table updates have been completed
2. Invalidate the TLB
3. Check if the TLB invalidation has been completed

Signed-off-by: Michael Cheng <michael.ch...@intel.com>
---
 drivers/gpu/drm/drm_cache.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index f19d9acbe959..d2506060a7c8 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -176,6 +176,10 @@ drm_clflush_virt_range(void *addr, unsigned long length)
 
        if (wbinvd_on_all_cpus())
                pr_err("Timed out waiting for cache flush\n");
+
+#elif defined(CONFIG_ARM64)
+       void *end = addr + length;
+       flush_tlb_kernel_range(*addr, *end);
 #else
        pr_err("Architecture has no drm_cache.c support\n");
        WARN_ON_ONCE(1);
-- 
2.25.1