[PATCH] bus: fsl-mc: Annotate fsl_mc_io.portal_virt_addr with __counted_by_ptr

[Bill Wendling <morbo@google.com>]

The GCC and Clang compilers provide the __counted_by_ptr attribute,
which is used by KASAN and compiler bounds-checking to detect
out-of-bounds accesses to pointer fields.

In "struct fsl_mc_io", the "portal_virt_addr" pointer points to the MC
command portal virtual address. The size of this allocated portal in
bytes is tracked by the "portal_size" field within the same structure.

Annotate the "portal_virt_addr" pointer field with
"__counted_by_ptr(portal_size)" to enable compiler bounds-checking and
harden against potential out-of-bounds accesses.

Cc: codemender-patching+linux@google.com
Assisted-by: LLM
Signed-off-by: Bill Wendling <morbo@google.com>
---
 include/linux/fsl/mc.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/fsl/mc.h b/include/linux/fsl/mc.h
index c25f0f7e6dd4..0b2c0eb9b605 100644
--- a/include/linux/fsl/mc.h
+++ b/include/linux/fsl/mc.h
@@ -336,7 +336,7 @@ struct fsl_mc_io {
 	u16 flags;
 	u32 portal_size;
 	phys_addr_t portal_phys_addr;
-	void __iomem *portal_virt_addr;
+	void __iomem *portal_virt_addr __counted_by_ptr(portal_size);
 	struct fsl_mc_device *dpmcp_dev;
 	union {
 		/*
-- 
2.55.0.1082.g2b9226bbc0-goog