Rework smc_unknown return code path in smc_handler

[project/bcm63xx/atf.git] / bl31 / aarch64 / runtime_exceptions.S

diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S
index 1734d7ec60de87cd0cea20be9b056e698379224c..6ffd9955555e91ed20c7817f10b878df57cd2d5c 100644 (file)
--- a/bl31/aarch64/runtime_exceptions.S
+++ b/bl31/aarch64/runtime_exceptions.S
@@ -352,28 +352,6 @@ smc_handler64:
        mov     x5, xzr
        mov     x6, sp
 
-       /* Get the unique owning entity number */
-       ubfx    x16, x0, #FUNCID_OEN_SHIFT, #FUNCID_OEN_WIDTH
-       ubfx    x15, x0, #FUNCID_TYPE_SHIFT, #FUNCID_TYPE_WIDTH
-       orr     x16, x16, x15, lsl #FUNCID_OEN_WIDTH
-
-       /* Load descriptor index from array of indices */
-       adr     x14, rt_svc_descs_indices
-       ldrb    w15, [x14, x16]
-
-       /* Any index greater than 127 is invalid. Check bit 7. */
-       tbnz    w15, 7, smc_unknown
-
-       /*
-        * Get the descriptor using the index
-        * x11 = (base + off), w15 = index
-        *
-        * handler = (base + off) + (index << log2(size))
-        */
-       adr     x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE)
-       lsl     w10, w15, #RT_SVC_SIZE_LOG2
-       ldr     x15, [x11, w10, uxtw]
-
        /*
         * Restore the saved C runtime stack value which will become the new
         * SP_EL0 i.e. EL3 runtime stack. It was saved in the 'cpu_context'
@@ -400,6 +378,28 @@ smc_handler64:
 
        mov     sp, x12
 
+       /* Get the unique owning entity number */
+       ubfx    x16, x0, #FUNCID_OEN_SHIFT, #FUNCID_OEN_WIDTH
+       ubfx    x15, x0, #FUNCID_TYPE_SHIFT, #FUNCID_TYPE_WIDTH
+       orr     x16, x16, x15, lsl #FUNCID_OEN_WIDTH
+
+       /* Load descriptor index from array of indices */
+       adr     x14, rt_svc_descs_indices
+       ldrb    w15, [x14, x16]
+
+       /* Any index greater than 127 is invalid. Check bit 7. */
+       tbnz    w15, 7, smc_unknown
+
+       /*
+        * Get the descriptor using the index
+        * x11 = (base + off), w15 = index
+        *
+        * handler = (base + off) + (index << log2(size))
+        */
+       adr     x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE)
+       lsl     w10, w15, #RT_SVC_SIZE_LOG2
+       ldr     x15, [x11, w10, uxtw]
+
        /*
         * Call the Secure Monitor Call handler and then drop directly into
         * el3_exit() which will program any remaining architectural state
@@ -414,15 +414,14 @@ smc_handler64:
 
 smc_unknown:
        /*
-        * Unknown SMC call. Populate return value with SMC_UNK, restore
-        * GP registers, and return to caller.
+        * Unknown SMC call. Populate return value with SMC_UNK and call
+        * el3_exit() which will restore the remaining architectural state
+        * i.e., SYS, GP and PAuth registers(if any) prior to issuing the ERET
+         * to the desired lower EL.
         */
        mov     x0, #SMC_UNK
-       str     x0, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
-#if CTX_INCLUDE_PAUTH_REGS
-       bl      pauth_context_restore
-#endif
-       b       restore_gp_registers_eret
+       str     x0, [x6, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+       b       el3_exit
 
 smc_prohibited:
        ldr     x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]