drm/i915/cmdparser: Fix jump whitelist clearing
authorBen Hutchings <ben@decadent.org.uk>
Mon, 11 Nov 2019 16:13:24 +0000 (08:13 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 12 Nov 2019 18:18:57 +0000 (19:18 +0100)
commit ea0b163b13ffc52818c079adb00d55e227a6da6f upstream.

When a jump_whitelist bitmap is reused, it needs to be cleared.
Currently this is done with memset() and the size calculation assumes
bitmaps are made of 32-bit words, not longs.  So on 64-bit
architectures, only the first half of the bitmap is cleared.

If some whitelist bits are carried over between successive batches
submitted on the same context, this will presumably allow embedding
the rogue instructions that we're trying to reject.

Use bitmap_zero() instead, which gets the calculation right.

Fixes: f8c08d8faee5 ("drm/i915/cmdparser: Add support for backward jumps")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Jon Bloomfield <jon.bloomfield@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/gpu/drm/i915/i915_cmd_parser.c

index 5c2ae816ac3217ee0936825c7a52b9cefde727c3..e4b9eb1f6b6021b0563341aff68ae4eab3c75f98 100644 (file)
@@ -1374,7 +1374,7 @@ static void init_whitelist(struct i915_gem_context *ctx, u32 batch_len)
                return;
 
        if (batch_cmds <= ctx->jump_whitelist_cmds) {
-               memset(ctx->jump_whitelist, 0, exact_size * sizeof(u32));
+               bitmap_zero(ctx->jump_whitelist, batch_cmds);
                return;
        }
 
@@ -1394,8 +1394,7 @@ again:
        }
 
        DRM_DEBUG("CMD: Failed to extend whitelist. BB_START may be disallowed\n");
-       memset(ctx->jump_whitelist, 0,
-              BITS_TO_LONGS(ctx->jump_whitelist_cmds) * sizeof(u32));
+       bitmap_zero(ctx->jump_whitelist, ctx->jump_whitelist_cmds);
 
        return;
 }