BL31: Enable pointer authentication support

The size increase after enabling options related to ARMv8.3-PAuth is:

+----------------------------+-------+-------+-------+--------+
|                            |  text |  bss  |  data | rodata |
+----------------------------+-------+-------+-------+--------+
| CTX_INCLUDE_PAUTH_REGS = 1 |  +192 | +1536 |   +0  |   +0   |
|                            |  0.3% |  3.1% |       |        |
+----------------------------+-------+-------+-------+--------+
| ENABLE_PAUTH = 1           | +1848 | +1536 |  +16  |   +0   |
|                            |  3.3% |  3.1% |  3.1% |        |
+----------------------------+-------+-------+-------+--------+

Results calculated with the following build configuration:

    make PLAT=fvp SPD=tspd DEBUG=1 \
    SDEI_SUPPORT=1                 \
    EL3_EXCEPTION_HANDLING=1       \
    TSP_NS_INTR_ASYNC_PREEMPT=1    \
    CTX_INCLUDE_PAUTH_REGS=1       \
    ENABLE_PAUTH=1

Change-Id: I43db7e509a4f39da6599ec2faa690d197573ec1b
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

diff --git a/bl31/aarch64/bl31_entrypoint.S b/bl31/aarch64/bl31_entrypoint.S
index c41773b886eb02af643542cd672cf73ab8300f37..8e9528b47488ebca41281d8236d9c802a96a1e25 100644 (file)
--- a/bl31/aarch64/bl31_entrypoint.S
+++ b/bl31/aarch64/bl31_entrypoint.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -87,29 +87,39 @@ func bl31_entrypoint
        bl      fixup_gdt_reloc
 #endif /* ENABLE_PIE */
 
-       /* ---------------------------------------------
-        * Perform platform specific early arch. setup
-        * ---------------------------------------------
+       /* --------------------------------------------------------------------
+        * Perform BL31 setup
+        * --------------------------------------------------------------------
         */
        mov     x0, x20
        mov     x1, x21
        mov     x2, x22
        mov     x3, x23
-       bl      bl31_early_platform_setup2
-       bl      bl31_plat_arch_setup
+       bl      bl31_setup
+
+       /* --------------------------------------------------------------------
+        * Enable pointer authentication
+        * --------------------------------------------------------------------
+        */
+#if ENABLE_PAUTH
+       mrs     x0, sctlr_el3
+       orr     x0, x0, #SCTLR_EnIA_BIT
+       msr     sctlr_el3, x0
+       isb
+#endif /* ENABLE_PAUTH */
 
-       /* ---------------------------------------------
+       /* --------------------------------------------------------------------
         * Jump to main function.
-        * ---------------------------------------------
+        * --------------------------------------------------------------------
         */
        bl      bl31_main
 
-       /* -------------------------------------------------------------
+       /* --------------------------------------------------------------------
         * Clean the .data & .bss sections to main memory. This ensures
         * that any global data which was initialised by the primary CPU
         * is visible to secondary CPUs before they enable their data
         * caches and participate in coherency.
-        * -------------------------------------------------------------
+        * --------------------------------------------------------------------
         */
        adr     x0, __DATA_START__
        adr     x1, __DATA_END__

diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index c9ba926c591f2ae2645eaf9da6445827a4cf54f6..10feae161f06ea30701c01cd71ec80732144d490 100644 (file)
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -75,6 +75,10 @@ ifeq (${ENABLE_MPAM_FOR_LOWER_ELS},1)
 BL31_SOURCES           +=      lib/extensions/mpam/mpam.c
 endif
 
+ifeq (${ENABLE_PAUTH},1)
+BL31_CFLAGS            +=      -msign-return-address=non-leaf
+endif
+
 ifeq (${WORKAROUND_CVE_2017_5715},1)
 BL31_SOURCES           +=      lib/cpus/aarch64/wa_cve_2017_5715_bpiall.S      \
                                lib/cpus/aarch64/wa_cve_2017_5715_mmu.S

diff --git a/bl31/bl31_main.c b/bl31/bl31_main.c
index da35f75edab72e0a84fd8ac23cfa90e81c82c161..aca16d6779b1c5862fbc1ede89e53b6266128982 100644 (file)
--- a/bl31/bl31_main.c
+++ b/bl31/bl31_main.c
@@ -63,6 +63,27 @@ void __init bl31_lib_init(void)
        cm_init();
 }
 
+/*******************************************************************************
+ * Setup function for BL31.
+ ******************************************************************************/
+void bl31_setup(u_register_t arg0, u_register_t arg1, u_register_t arg2,
+               u_register_t arg3)
+{
+       /* Perform early platform-specific setup */
+       bl31_early_platform_setup2(arg0, arg1, arg2, arg3);
+
+       /*
+        * Update pointer authentication key before the MMU is enabled. It is
+        * saved in the rodata section, that can be writen before enabling the
+        * MMU. This function must be called after the console is initialized
+        * in the early platform setup.
+        */
+       bl_handle_pauth();
+
+       /* Perform late platform-specific setup */
+       bl31_plat_arch_setup();
+}
+
 /*******************************************************************************
  * BL31 is responsible for setting up the runtime services for the primary cpu
  * before passing control to the bootloader or an Operating System. This

diff --git a/include/bl31/bl31.h b/include/bl31/bl31.h
index 08c555d902711d7fb9f2f550e53619de38cfb9d2..3deb0a51d22590cdd1b9cf6f256d47c671fd13a6 100644 (file)
--- a/include/bl31/bl31.h
+++ b/include/bl31/bl31.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -12,6 +12,8 @@
 /*******************************************************************************
  * Function prototypes
  ******************************************************************************/
+void bl31_setup(u_register_t arg0, u_register_t arg1, u_register_t arg2,
+               u_register_t arg3);
 void bl31_next_el_arch_setup(uint32_t security_state);
 void bl31_set_next_image_type(uint32_t security_state);
 uint32_t bl31_get_next_image_type(void);