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>

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)