fix(trp): preserve RMI SMC X4 when not used as return

This patch adds X2-X6 and 'smc_ret' parameters to trp_rmi_handler().
The last 'smc_ret' parameter passed in X7 contains address of
'trp_smc_result' structure on stack to return result of RMI SMC call.

This allows to preserve X4 if not used as a return argument as per
SMCCCv1.2. The patch also removes use of trp_args_t in RMI handling.

Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
Change-Id: I9e3387a7380b37863eeccc53d13e92e0ac5cffbd

diff --git a/include/services/trp/trp_helpers.h b/include/services/trp/trp_helpers.h
index 8e786e21b0de8c53a931d69446c7c0b486f71ac8..83ec74040f170d51894abb827d1097147e3cbdf1 100644 (file)
--- a/include/services/trp/trp_helpers.h
+++ b/include/services/trp/trp_helpers.h
@@ -39,5 +39,12 @@ trp_args_t *set_smc_args(uint64_t arg0,
 
 __dead2 void trp_boot_abort(uint64_t err);
 
+/* TRP SMC result registers X0-X4 */
+#define TRP_SMC_RESULT_REGS    5
+
+struct trp_smc_result {
+       unsigned long long x[TRP_SMC_RESULT_REGS];
+};
+
 #endif /* __ASSEMBLER __ */
 #endif /* TRP_HELPERS_H */

diff --git a/services/std_svc/rmmd/trp/trp_entry.S b/services/std_svc/rmmd/trp/trp_entry.S
index 47c1df14d0af61e4f17419d63ecd4251e3045470..ae9f9aa0dd22bdb4b7e5afc9ca9e07533b2cce01 100644 (file)
--- a/services/std_svc/rmmd/trp/trp_entry.S
+++ b/services/std_svc/rmmd/trp/trp_entry.S
@@ -115,7 +115,29 @@ endfunc trp_smc
         * ---------------------------------------------
         */
 func trp_handler
+       /*
+        * Save Link Register and X4, as per SMCCC v1.2 its value
+        * must be preserved unless it contains result, as specified
+        * in the function definition.
+        */
+       stp     x4, lr, [sp, #-16]!
+
+       /*
+        * Zero the space for X0-X3 in trp_smc_result structure
+        * and pass its address as the last argument.
+        */
+       stp     xzr, xzr, [sp, #-16]!
+       stp     xzr, xzr, [sp, #-16]!
+       mov     x7, sp
+
        bl      trp_rmi_handler
-       restore_args_call_smc
+
+       ldp     x1, x2, [sp], #16
+       ldp     x3, x4, [sp], #16
+       ldp     x5, lr, [sp], #16
+
+       ldr     x0, =RMM_RMI_REQ_COMPLETE
+       smc     #0
+
        b       trp_handler
 endfunc trp_handler

diff --git a/services/std_svc/rmmd/trp/trp_main.c b/services/std_svc/rmmd/trp/trp_main.c
index 5a56af04382d43bf226674246a6c521518f0177b..ce3260f84db11b245fee11463bc323f5344bfcb8 100644 (file)
--- a/services/std_svc/rmmd/trp/trp_main.c
+++ b/services/std_svc/rmmd/trp/trp_main.c
@@ -4,7 +4,6 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-
 #include <common/debug.h>
 #include <plat/common/platform.h>
 #include <services/rmm_core_manifest.h>
@@ -31,11 +30,11 @@ void trp_setup(uint64_t x0,
               uint64_t x3)
 {
        /*
-        * Validate boot parameters.
+        * Validate boot parameters
         *
-        * According to the Boot Interface ABI v.0.1, the
-        * parameters recived from EL3 are:
-        * x0: CPUID (verified earlier so not used)
+        * According to the Boot Interface ABI v.0.1,
+        * the parameters received from EL3 are:
+        * x0: CPUID (verified earlier, so not used)
         * x1: Boot Interface version
         * x2: PLATFORM_CORE_COUNT
         * x3: Pointer to the shared memory area.
@@ -73,14 +72,14 @@ void trp_main(void)
        NOTICE("TRP: %s\n", build_message);
        NOTICE("TRP: Supported RMM-EL3 Interface ABI: v.%u.%u\n",
                TRP_RMM_EL3_ABI_VERS_MAJOR, TRP_RMM_EL3_ABI_VERS_MINOR);
-       NOTICE("TRP: Boot Manifest Version : v.%u.%u\n",
+       NOTICE("TRP: Boot Manifest Version: v.%u.%u\n",
                RMMD_GET_MANIFEST_VERSION_MAJOR(trp_boot_manifest_version),
                RMMD_GET_MANIFEST_VERSION_MINOR(trp_boot_manifest_version));
-       INFO("TRP: Memory base : 0x%lx\n", (unsigned long)RMM_BASE);
-       INFO("TRP: Base address for the shared region : 0x%lx\n",
+       INFO("TRP: Memory base: 0x%lx\n", (unsigned long)RMM_BASE);
+       INFO("TRP: Shared region base address: 0x%lx\n",
                        (unsigned long)trp_shared_region_start);
-       INFO("TRP: Total size : 0x%lx bytes\n", (unsigned long)(RMM_END
-                                                               - RMM_BASE));
+       INFO("TRP: Total size: 0x%lx bytes\n",
+                       (unsigned long)(RMM_END - RMM_BASE));
        INFO("TRP: RMM-EL3 Interface ABI reported by EL3: v.%u.%u\n",
                TRP_RMM_EL3_VERSION_GET_MAJOR(trp_boot_abi_version),
                TRP_RMM_EL3_VERSION_GET_MINOR(trp_boot_abi_version));
@@ -89,62 +88,73 @@ void trp_main(void)
 /*******************************************************************************
  * Returning RMI version back to Normal World
  ******************************************************************************/
-static trp_args_t *trp_ret_rmi_version(void)
+static void trp_ret_rmi_version(struct trp_smc_result *smc_ret)
 {
        VERBOSE("RMM version is %u.%u\n", RMI_ABI_VERSION_MAJOR,
                                          RMI_ABI_VERSION_MINOR);
-       return set_smc_args(RMM_RMI_REQ_COMPLETE, RMI_ABI_VERSION,
-                           0, 0, 0, 0, 0, 0);
+       smc_ret->x[0] = RMI_ABI_VERSION;
 }
 
 /*******************************************************************************
  * Transitioning granule of NON-SECURE type to REALM type
  ******************************************************************************/
-static trp_args_t *trp_asc_mark_realm(unsigned long long x1)
+static void trp_asc_mark_realm(unsigned long long x1,
+                               struct trp_smc_result *smc_ret)
 {
-       unsigned long long ret;
-
        VERBOSE("Delegating granule 0x%llx\n", x1);
-       ret = trp_smc(set_smc_args(RMM_GTSI_DELEGATE, x1, 0, 0, 0, 0, 0, 0));
+       smc_ret->x[0] = trp_smc(set_smc_args(RMM_GTSI_DELEGATE, x1,
+                                               0UL, 0UL, 0UL, 0UL, 0UL, 0UL));
 
-       if (ret != 0ULL) {
+       if (smc_ret->x[0] != 0ULL) {
                ERROR("Granule transition from NON-SECURE type to REALM type "
-                       "failed 0x%llx\n", ret);
+                       "failed 0x%llx\n", smc_ret->x[0]);
        }
-       return set_smc_args(RMM_RMI_REQ_COMPLETE, ret, 0, 0, 0, 0, 0, 0);
 }
 
 /*******************************************************************************
  * Transitioning granule of REALM type to NON-SECURE type
  ******************************************************************************/
-static trp_args_t *trp_asc_mark_nonsecure(unsigned long long x1)
+static void trp_asc_mark_nonsecure(unsigned long long x1,
+                                  struct trp_smc_result *smc_ret)
 {
-       unsigned long long ret;
-
        VERBOSE("Undelegating granule 0x%llx\n", x1);
-       ret = trp_smc(set_smc_args(RMM_GTSI_UNDELEGATE, x1, 0, 0, 0, 0, 0, 0));
+       smc_ret->x[0] = trp_smc(set_smc_args(RMM_GTSI_UNDELEGATE, x1,
+                                               0UL, 0UL, 0UL, 0UL, 0UL, 0UL));
 
-       if (ret != 0ULL) {
+       if (smc_ret->x[0] != 0ULL) {
                ERROR("Granule transition from REALM type to NON-SECURE type "
-                       "failed 0x%llx\n", ret);
+                       "failed 0x%llx\n", smc_ret->x[0]);
        }
-       return set_smc_args(RMM_RMI_REQ_COMPLETE, ret, 0, 0, 0, 0, 0, 0);
 }
 
 /*******************************************************************************
  * Main RMI SMC handler function
  ******************************************************************************/
-trp_args_t *trp_rmi_handler(unsigned long fid, unsigned long long x1)
+void trp_rmi_handler(unsigned long fid,
+                    unsigned long long x1, unsigned long long x2,
+                    unsigned long long x3, unsigned long long x4,
+                    unsigned long long x5, unsigned long long x6,
+                    struct trp_smc_result *smc_ret)
 {
+       /* Not used in the current implementation */
+       (void)x2;
+       (void)x3;
+       (void)x4;
+       (void)x5;
+       (void)x6;
+
        switch (fid) {
        case RMI_RMM_REQ_VERSION:
-               return trp_ret_rmi_version();
+               trp_ret_rmi_version(smc_ret);
+               break;
        case RMI_RMM_GRANULE_DELEGATE:
-               return trp_asc_mark_realm(x1);
+               trp_asc_mark_realm(x1, smc_ret);
+               break;
        case RMI_RMM_GRANULE_UNDELEGATE:
-               return trp_asc_mark_nonsecure(x1);
+               trp_asc_mark_nonsecure(x1, smc_ret);
+               break;
        default:
-               ERROR("Invalid SMC code to %s, FID %lu\n", __func__, fid);
+               ERROR("Invalid SMC code to %s, FID %lx\n", __func__, fid);
+               smc_ret->x[0] = SMC_UNK;
        }
-       return set_smc_args(SMC_UNK, 0, 0, 0, 0, 0, 0, 0);
 }