warp7: panic: hab: Call into BootROM failsafe on panic path
This patch adds a callback into the BootROM's provided High Assurance Boot
(HAB) failsafe function when panicking i.e. the call is done without making
use of stack.
The HAB failsafe function allows a piece of software to call into the
BootROM and place the processor into failsafe mode.
Failsafe mode is a special mode which presents a serial download protocol
interface over UART or USB at the time of writing.
If the board has been set into secure mode, then only a signed binary can
be used to recover the board.
Thus failsafe gives a putatively secure method of performing a secure
recovery over UART or USB.
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Ryan Harkin <ryan.harkin@linaro.org>
diff --git a/plat/imx/imx7/warp7/aarch32/warp7_helpers.S b/plat/imx/imx7/warp7/aarch32/warp7_helpers.S
index b12ff32..b1921cc 100644
--- a/plat/imx/imx7/warp7/aarch32/warp7_helpers.S
+++ b/plat/imx/imx7/warp7/aarch32/warp7_helpers.S
@@ -8,11 +8,13 @@
#include <asm_macros.S>
#include <assert_macros.S>
#include <platform_def.h>
+#include <imx_hab.h>
.globl platform_mem_init
.globl plat_get_my_entrypoint
.globl plat_crash_console_init
.globl plat_crash_console_putc
+ .globl plat_panic_handler
/* ---------------------------------------------
* int plat_mem_init(void)
@@ -42,3 +44,9 @@
mov_imm r1, PLAT_WARP7_BOOT_UART_BASE
b imx_crash_uart_putc
endfunc plat_crash_console_putc
+
+func plat_panic_handler
+ mov r3, #HAB_ROM_VECTOR_TABLE_FAILSAFE
+ ldr r3, [r3, #0]
+ blx r3
+endfunc plat_panic_handler