I'm doing some tests on tf-rmm while found something interesting. Why this code can execute without error?This code is part of a driver. __attribute__((aligned(4096))) static int realm_start(void) { return 11; } int create_realm(void) { struct smc_result result; int ret = 10;
flush_cache_all(); flush_tlb_all(); isb();
host_rmi_granule_delegate(virt_to_phys(realm_start), &result); CHECK_RMI_RESULT(); pr_info("host_rmi_granule_delegate %lx\n", (uintptr_t)virt_to_phys(realm_start));
flush_cache_all(); flush_tlb_all(); isb();
ret = realm_start(); pr_info("run realm start %d\n", ret); char dst[9] = {0}; memcpy(dst, realm_start, 8); pr_info("memcpy done %x\n", *(uint64_t *)dst); host_rmi_granule_undelegate(virt_to_phys(realm_start), &result); CHECK_RMI_RESULT(); pr_info("host_rmi_granule_undelegate done\n"); return 0; }
Here is the output of linux and tf-rmm[ 743.248076] realm: loading out-of-tree module taints kernel.[ 743.260986] realm_create: Module loaded[ 743.261778] SMC_GRANULE_DELEGATE: addr = 0xeda70000 eda70000[ 743.265428] host_rmi_granule_delegate eda70000[ 743.266110] run realm start 11[ 743.266581] memcpy done 52800160[ 743.268005] host_rmi_granule_undelegate doneSMC_RMI_GRANULE_DELEGATE eda70000 > RMI_SUCCESS SMC_RMI_GRANULE_UNDELEGATE eda70000 > RMI_SUCCESS