Hi Nithin,

While we always appreciate extra eyes on code quality in TF-A, could I ask you to collect the MISRA C issues that you find and open a GitHub issue? It’s a bit difficult to keep track of these reports on the mailing list so it would help to have a central discussion area, especially as some of these issues overlap.

You can file issues on GitHub here: https://github.com/TrustedFirmware-A/trusted-firmware-a/issues

Regards,

Chris

From: Nithin G via TF-A <tf-a@lists.trustedfirmware.org>
Date: Tuesday, 30 January 2024 at 12:41
To: tf-a@lists.trustedfirmware.org <tf-a@lists.trustedfirmware.org>
Subject: [TF-A] All if...else if constructs shall be terminated with an else statement.

Hello,

In the file /lib/el3_runtime/aarch64/context_mgmt.c. getting misra_c_2012_rule_15_7_violation:  No non-empty terminating "else" statement. during the Coverity MISRA-C analysis.

void cm_prepare_el3_exit(uint32_t security_state)
{
    u_register_t sctlr_elx, scr_el3, mdcr_el2;


if (security_state == NON_SECURE) {
         scr_el3 = read_ctx_reg(get_el3state_ctx(ctx),
                                          CTX_SCR_EL3);
misra_c_2012_rule_15_7_violation:       No non-empty terminating "else" statement.
         if ((scr_el3 & SCR_HCE_BIT) != 0U) {
                 ...
                 ...
                 ...
                 write_sctlr_el2(sctlr_elx);
         } else if (el_implemented(2) != EL_IMPL_NONE) {
                 el2_unused = true;
                 ...
                 ...
                 ...
                 write_cnthp_ctl_el2(CNTHP_CTL_RESET_VAL &
                                         ~(CNTHP_CTL_ENABLE_BIT));
         }
         manage_extensions_nonsecure(el2_unused, ctx);
    }
cm_el1_sysregs_context_restore(security_state);
    cm_set_next_eret_context(security_state);
}

Resolution: added empty else statement to resolve the issue.

diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 8e6bfc5..8996746 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -789,6 +789,8 @@ void cm_prepare_el3_exit(uint32_t security_state)
                  */
                 write_cnthp_ctl_el2(CNTHP_CTL_RESET_VAL &
                                         ~(CNTHP_CTL_ENABLE_BIT));
+               } else {
+                       /* To fix the MISRA 15.7 warning - Added an empty else statement */
         }
         manage_extensions_nonsecure(el2_unused, ctx);
    }
--
Is it possible to add an empty else statement in this code? Please suggest.

Regards,
Nithin G
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