Remove all non-configurable dead loops

Added a new platform porting function plat_panic_handler, to allow
platforms to handle unexpected error situations. It must be
implemented in assembly as it may be called before the C environment
is initialized. A default implementation is provided, which simply
spins.

Corrected all dead loops in generic code to call this function
instead. This includes the dead loop that occurs at the end of the
call to panic().

All unnecesary wfis from bl32/tsp/aarch64/tsp_exceptions.S have
been removed.

Change-Id: I67cb85f6112fa8e77bd62f5718efcef4173d8134

diff --git a/bl2/aarch64/bl2_entrypoint.S b/bl2/aarch64/bl2_entrypoint.S
index 75eb02a9da9cf68f76dbc9b9ac7658082c7d4f12..476efe8520b9360ad8223de95b0c3e37b70592a3 100644 (file)
--- a/bl2/aarch64/bl2_entrypoint.S
+++ b/bl2/aarch64/bl2_entrypoint.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -43,8 +43,8 @@ func bl2_entrypoint
         * available to BL2 for future use.
         * x0 is not currently used.
         * ---------------------------------------------
-        */
-       mov     x20, x1
+        */
+       mov     x20, x1
 
        /* ---------------------------------------------
         * Set the exception vector to something sane.
@@ -126,6 +126,11 @@ func bl2_entrypoint
         * ---------------------------------------------
         */
        bl      bl2_main
-_panic:
-       b       _panic
+
+       /* ---------------------------------------------
+        * Should never reach this point.
+        * ---------------------------------------------
+        */
+       bl      plat_panic_handler
+
 endfunc bl2_entrypoint

diff --git a/bl2u/aarch64/bl2u_entrypoint.S b/bl2u/aarch64/bl2u_entrypoint.S
index c9aad81f6e15f6b6318014297f0e6bd429950a15..ef3db926310c768e1ab4ea8350da8be7f260514c 100644 (file)
--- a/bl2u/aarch64/bl2u_entrypoint.S
+++ b/bl2u/aarch64/bl2u_entrypoint.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -122,6 +122,10 @@ func bl2u_entrypoint
         */
        bl      bl2u_main
 
-_panic:
-       b       _panic
+       /* ---------------------------------------------
+        * Should never reach this point.
+        * ---------------------------------------------
+        */
+       bl      plat_panic_handler
+
 endfunc bl2u_entrypoint

diff --git a/bl31/aarch64/crash_reporting.S b/bl31/aarch64/crash_reporting.S
index 1d1e60d8072b287ce0192bac5e040170674a8653..ff915728a16236d00cad5b99d51226a21a153862 100644 (file)
--- a/bl31/aarch64/crash_reporting.S
+++ b/bl31/aarch64/crash_reporting.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -351,17 +351,17 @@ func do_crash_reporting
        plat_print_interconnect_regs
 
        /* Done reporting */
-       b       crash_panic
+       bl      plat_panic_handler
 endfunc do_crash_reporting
 
 #else  /* CRASH_REPORTING */
 func report_unhandled_exception
 report_unhandled_interrupt:
-       b       crash_panic
+       bl      plat_panic_handler
 endfunc report_unhandled_exception
 #endif /* CRASH_REPORTING */
 
 
 func crash_panic
-       b       crash_panic
-endfunc crash_panic
\ No newline at end of file
+       bl      plat_panic_handler
+endfunc crash_panic

diff --git a/bl32/tsp/aarch64/tsp_entrypoint.S b/bl32/tsp/aarch64/tsp_entrypoint.S
index 531ab9bfadeb476e14ed2cfae751bfed7a5f33f1..453d2c14dd4c84697057b485fceea2aea4631ef7 100644 (file)
--- a/bl32/tsp/aarch64/tsp_entrypoint.S
+++ b/bl32/tsp/aarch64/tsp_entrypoint.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -391,7 +391,7 @@ tsp_sel1_intr_return:
 
        /* Should never reach here */
 tsp_sel1_int_entry_panic:
-       b       tsp_sel1_int_entry_panic
+       bl      plat_panic_handler
 endfunc tsp_sel1_intr_entry
 
        /*---------------------------------------------
@@ -407,8 +407,9 @@ endfunc tsp_sel1_intr_entry
 func tsp_cpu_resume_entry
        bl      tsp_cpu_resume_main
        restore_args_call_smc
-tsp_cpu_resume_panic:
-       b       tsp_cpu_resume_panic
+
+       /* Should never reach here */
+       bl      plat_panic_handler
 endfunc tsp_cpu_resume_entry
 
        /*---------------------------------------------
@@ -419,8 +420,9 @@ endfunc tsp_cpu_resume_entry
 func tsp_fast_smc_entry
        bl      tsp_smc_handler
        restore_args_call_smc
-tsp_fast_smc_entry_panic:
-       b       tsp_fast_smc_entry_panic
+
+       /* Should never reach here */
+       bl      plat_panic_handler
 endfunc tsp_fast_smc_entry
 
        /*---------------------------------------------
@@ -435,6 +437,7 @@ func tsp_std_smc_entry
        bl      tsp_smc_handler
        msr     daifset, #DAIF_FIQ_BIT | DAIF_IRQ_BIT
        restore_args_call_smc
-tsp_std_smc_entry_panic:
-       b       tsp_std_smc_entry_panic
+
+       /* Should never reach here */
+       bl      plat_panic_handler
 endfunc tsp_std_smc_entry

diff --git a/bl32/tsp/aarch64/tsp_exceptions.S b/bl32/tsp/aarch64/tsp_exceptions.S
index d5e089f6e8a8a00803ff6c68665e645de82a8d5c..edcfb718dd6ac84ecce8d38b89f4e481bd343a53 100644 (file)
--- a/bl32/tsp/aarch64/tsp_exceptions.S
+++ b/bl32/tsp/aarch64/tsp_exceptions.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -108,24 +108,23 @@ tsp_exceptions:
         * -----------------------------------------------------
         */
 sync_exception_sp_el0:
-       wfi
-       b       sync_exception_sp_el0
+       bl      plat_panic_handler
        check_vector_size sync_exception_sp_el0
 
        .align  7
 
 irq_sp_el0:
-       b       irq_sp_el0
+       bl      plat_panic_handler
        check_vector_size irq_sp_el0
 
        .align  7
 fiq_sp_el0:
-       b       fiq_sp_el0
+       bl      plat_panic_handler
        check_vector_size fiq_sp_el0
 
        .align  7
 serror_sp_el0:
-       b       serror_sp_el0
+       bl      plat_panic_handler
        check_vector_size serror_sp_el0
 
 
@@ -136,8 +135,7 @@ serror_sp_el0:
         */
        .align  7
 sync_exception_sp_elx:
-       wfi
-       b       sync_exception_sp_elx
+       bl      plat_panic_handler
        check_vector_size sync_exception_sp_elx
 
        .align  7
@@ -152,7 +150,7 @@ fiq_sp_elx:
 
        .align  7
 serror_sp_elx:
-       b       serror_sp_elx
+       bl      plat_panic_handler
        check_vector_size serror_sp_elx
 
 
@@ -163,23 +161,22 @@ serror_sp_elx:
         */
        .align  7
 sync_exception_aarch64:
-       wfi
-       b       sync_exception_aarch64
+       bl      plat_panic_handler
        check_vector_size sync_exception_aarch64
 
        .align  7
 irq_aarch64:
-       b       irq_aarch64
+       bl      plat_panic_handler
        check_vector_size irq_aarch64
 
        .align  7
 fiq_aarch64:
-       b       fiq_aarch64
+       bl      plat_panic_handler
        check_vector_size fiq_aarch64
 
        .align  7
 serror_aarch64:
-       b       serror_aarch64
+       bl      plat_panic_handler
        check_vector_size serror_aarch64
 
 
@@ -190,22 +187,21 @@ serror_aarch64:
         */
        .align  7
 sync_exception_aarch32:
-       wfi
-       b       sync_exception_aarch32
+       bl      plat_panic_handler
        check_vector_size sync_exception_aarch32
 
        .align  7
 irq_aarch32:
-       b       irq_aarch32
+       bl      plat_panic_handler
        check_vector_size irq_aarch32
 
        .align  7
 fiq_aarch32:
-       b       fiq_aarch32
+       bl      plat_panic_handler
        check_vector_size fiq_aarch32
 
        .align  7
 serror_aarch32:
-       b       serror_aarch32
+       bl      plat_panic_handler
        check_vector_size serror_aarch32
        .align  7

diff --git a/common/aarch64/debug.S b/common/aarch64/debug.S
index b3caafb97f8cf36ab39f74247802b6e62d4a80e9..d3538792d390128d97651c8077e40421ee70bb01 100644 (file)
--- a/common/aarch64/debug.S
+++ b/common/aarch64/debug.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -120,7 +120,7 @@ endfunc asm_print_str
 /*
  * This function prints a hexadecimal number in x4.
  * In: x4 = the hexadecimal to print.
- * Clobber: x30, x0, x5, x1, x2, x3
+ * Clobber: x30, x0 - x3, x5
  */
 func asm_print_hex
        mov     x3, x30
@@ -178,7 +178,7 @@ el3_panic:
        mov     x6, x30
        bl      plat_crash_console_init
        /* Check if the console is initialized */
-       cbz     x0, _panic_loop
+       cbz     x0, _panic_handler
        /* The console is initialized */
        adr     x4, panic_msg
        bl      asm_print_str
@@ -186,7 +186,10 @@ el3_panic:
        /* The panic location is lr -4 */
        sub     x4, x4, #4
        bl      asm_print_hex
-_panic_loop:
-       b       _panic_loop
-endfunc do_panic
 
+_panic_handler:
+       /* Pass to plat_panic_handler the address from where el3_panic was
+        * called, not the address of the call from el3_panic. */
+       mov     x30,x6
+       b       plat_panic_handler
+endfunc do_panic

diff --git a/docs/porting-guide.md b/docs/porting-guide.md
index 741ee20775113035f80aad286bacace2c5ae5740..bd1b4489cbda0fe99848627f382349cdce74e914 100644 (file)
--- a/docs/porting-guide.md
+++ b/docs/porting-guide.md
@@ -783,6 +783,20 @@ Possible errors reported by the generic code are:
 
 The default implementation simply spins.
 
+### Function : plat_panic_handler()
+
+    Argument : void
+    Return   : void
+
+This API is called when the generic code encounters an unexpected error
+situation from which it cannot recover. This function must not return,
+and must be implemented in assembly because it may be called before the C
+environment is initialized.
+
+Note: The address from where it was called is stored in x30 (Link Register).
+
+The default implementation simply spins.
+
 
 3.  Modifications specific to a Boot Loader stage
 -------------------------------------------------

diff --git a/include/common/el3_common_macros.S b/include/common/el3_common_macros.S
index 32df7d76346af0dffa9f68530ba3840c583ef460..0cd85c342608ab6c4ca7d59886103fec006d55f6 100644 (file)
--- a/include/common/el3_common_macros.S
+++ b/include/common/el3_common_macros.S
@@ -196,8 +196,7 @@
                /* This is a cold boot on a secondary CPU */
                bl      plat_secondary_cold_boot_setup
                /* plat_secondary_cold_boot_setup() is not supposed to return */
-       secondary_panic:
-               b       secondary_panic
+               bl      el3_panic
 
        do_primary_cold_boot:
        .endif /* _secondary_cold_boot */

diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h
index f37a80f3e0054137a190afb7c4f447a5ec3aa3a8..5c61f381281b30caa2d17ad7c2baaa55af186225 100644 (file)
--- a/include/plat/common/platform.h
+++ b/include/plat/common/platform.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -83,6 +83,7 @@ void plat_report_exception(unsigned long);
 int plat_crash_console_init(void);
 int plat_crash_console_putc(int c);
 void plat_error_handler(int err) __dead2;
+void plat_panic_handler(void) __dead2;
 
 /*******************************************************************************
  * Mandatory BL1 functions

diff --git a/plat/arm/board/fvp/aarch64/fvp_helpers.S b/plat/arm/board/fvp/aarch64/fvp_helpers.S
index fe7358f6a2adeb6f18c25d8830ecc3ec74200688..884fee82ad3f68e2145c5d76546ed03aea5e6dab 100644 (file)
--- a/plat/arm/board/fvp/aarch64/fvp_helpers.S
+++ b/plat/arm/board/fvp/aarch64/fvp_helpers.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -111,8 +111,7 @@ secondary_cold_boot_wait:
         */
        dsb     sy
        wfi
-cb_panic:
-       b       cb_panic
+       bl      plat_panic_handler
 #else
        mov_imm x0, PLAT_ARM_TRUSTED_MAILBOX_BASE
 
@@ -174,7 +173,7 @@ warm_reset:
         */
        mov_imm x0, PLAT_ARM_TRUSTED_MAILBOX_BASE
        ldr     x0, [x0]
-       cbz     x0, _panic
+       cbz     x0, _panic_handler
        ret
 
        /* ---------------------------------------------------------------------
@@ -182,8 +181,8 @@ warm_reset:
         * is empty. This should never happen!
         * ---------------------------------------------------------------------
         */
-_panic:
-       b       _panic
+_panic_handler:
+       bl      plat_panic_handler
 endfunc plat_get_my_entrypoint
 
        /* -----------------------------------------------------

diff --git a/plat/arm/board/juno/aarch64/juno_helpers.S b/plat/arm/board/juno/aarch64/juno_helpers.S
index 1931535e74b466a8d977922a00c897b6f61a101c..377b0cb3bcf2125175bfee7822b805169fd15fab 100644 (file)
--- a/plat/arm/board/juno/aarch64/juno_helpers.S
+++ b/plat/arm/board/juno/aarch64/juno_helpers.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -201,8 +201,7 @@ func plat_reset_handler
        JUMP_TO_HANDLER_IF_JUNO_R(2)
 
        /* Board revision is not supported */
-not_supported:
-       b       not_supported
+       bl      plat_panic_handler
 
 endfunc plat_reset_handler
 

diff --git a/plat/common/aarch64/platform_helpers.S b/plat/common/aarch64/platform_helpers.S
index 29f01ce9e0a72c0a76fc17c13f777af81de5ae93..08638303a5a6f98684a8b25fe00c2e9f46d3864c 100644 (file)
--- a/plat/common/aarch64/platform_helpers.S
+++ b/plat/common/aarch64/platform_helpers.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -39,6 +39,7 @@
        .weak   plat_disable_acp
        .weak   bl1_plat_prepare_exit
        .weak   plat_error_handler
+       .weak   plat_panic_handler
 
 #if !ENABLE_PLAT_COMPAT
        .globl  platform_get_core_pos
@@ -131,3 +132,12 @@ endfunc bl1_plat_prepare_exit
 func plat_error_handler
        b       plat_error_handler
 endfunc plat_error_handler
+
+       /* -----------------------------------------------------
+        * void plat_panic_handler(void) __dead2;
+        * Endless loop by default.
+        * -----------------------------------------------------
+        */
+func plat_panic_handler
+       b       plat_panic_handler
+endfunc plat_panic_handler