Revert "optee: Clear stale cache entries during initialization"

This reverts commit b5c10dd which
breaks OP-TEE virtualization support [1]. The bug is in fact in the
Xen mediator [2] so the proper fix is to upgrade Xen when a new
maintenance release is available, at which point this revert should
be discarded.

Link: [1] OP-TEE/build#523
Link: [2] https://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=1c3ed9c908732d19660fbe83580674d585464d4c
Signed-off-by: Jerome Forissier <jerome@forissier.org>
[jf: rebase onto v5.16]
Signed-off-by: Jerome Forissier <jerome@forissier.org>

Author: jforissier

drivers/tee/optee/optee_private.h

@@ -224,7 +224,6 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool_mgr *poolm,
 						   size_t num_pages,
 						   unsigned long start));
 
-
 void optee_remove_common(struct optee *optee);
 int optee_open(struct tee_context *ctx, bool cap_memref_null);
 void optee_release(struct tee_context *ctx);

drivers/tee/optee/smc_abi.c

@@ -275,13 +275,11 @@ static void optee_enable_shm_cache(struct optee *optee)
 }
 
 /**
- * __optee_disable_shm_cache() - Disables caching of some shared memory
- *				 allocation in OP-TEE
+ * optee_disable_shm_cache() - Disables caching of some shared memory allocation
+ *			      in OP-TEE
  * @optee:	main service struct
- * @is_mapped:	true if the cached shared memory addresses were mapped by this
- *		kernel, are safe to dereference, and should be freed
  */
-static void __optee_disable_shm_cache(struct optee *optee, bool is_mapped)
+void optee_disable_shm_cache(struct optee *optee)
 {
 	struct optee_call_waiter w;
 
@@ -300,13 +298,6 @@ static void __optee_disable_shm_cache(struct optee *optee, bool is_mapped)
 		if (res.result.status == OPTEE_SMC_RETURN_OK) {
 			struct tee_shm *shm;
 
-			/*
-			 * Shared memory references that were not mapped by
-			 * this kernel must be ignored to prevent a crash.
-			 */
-			if (!is_mapped)
-				continue;
-
 			shm = reg_pair_to_ptr(res.result.shm_upper32,
 					      res.result.shm_lower32);
 			tee_shm_free(shm);
@@ -317,27 +308,6 @@ static void __optee_disable_shm_cache(struct optee *optee, bool is_mapped)
 	optee_cq_wait_final(&optee->call_queue, &w);
 }
 
-/**
- * optee_disable_shm_cache() - Disables caching of mapped shared memory
- *			       allocations in OP-TEE
- * @optee:	main service struct
- */
-static void optee_disable_shm_cache(struct optee *optee)
-{
-	return __optee_disable_shm_cache(optee, true);
-}
-
-/**
- * optee_disable_unmapped_shm_cache() - Disables caching of shared memory
- *					allocations in OP-TEE which are not
- *					currently mapped
- * @optee:	main service struct
- */
-static void optee_disable_unmapped_shm_cache(struct optee *optee)
-{
-	return __optee_disable_shm_cache(optee, false);
-}
-
 #define PAGELIST_ENTRIES_PER_PAGE				\
 	((OPTEE_MSG_NONCONTIG_PAGE_SIZE / sizeof(u64)) - 1)
 
@@ -1295,15 +1265,6 @@ static int optee_probe(struct platform_device *pdev)
 	optee->smc.memremaped_shm = memremaped_shm;
 	optee->pool = pool;
 
-	/*
-	 * Ensure that there are no pre-existing shm objects before enabling
-	 * the shm cache so that there's no chance of receiving an invalid
-	 * address during shutdown. This could occur, for example, if we're
-	 * kexec booting from an older kernel that did not properly cleanup the
-	 * shm cache.
-	 */
-	optee_disable_unmapped_shm_cache(optee);
-
 	optee_enable_shm_cache(optee);
 
 	if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_DYNAMIC_SHM)