RAS: Introduce handler for Double Faults
Double fault is when the PE receives another error whilst one is being
handled. To detect double fault condition, a per-CPU flag is introduced
to track the status of error handling. The flag is checked/modified
while temporarily masking external aborts on the PE.
This patch routes double faults to a separate platform-defined handler.
Change-Id: I70e9b7ba4c817273c55a0af978d9755ff32cc702
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
diff --git a/bl31/aarch64/ea_delegate.S b/bl31/aarch64/ea_delegate.S
index 9faa503..9d7c5e8 100644
--- a/bl31/aarch64/ea_delegate.S
+++ b/bl31/aarch64/ea_delegate.S
@@ -5,6 +5,7 @@
*/
+#include <assert_macros.S>
#include <asm_macros.S>
#include <assert_macros.S>
#include <context.h>
@@ -179,6 +180,15 @@
* x1: EA syndrome
*/
func ea_proceed
+ /*
+ * If the ESR loaded earlier is not zero, we were processing an EA
+ * already, and this is a double fault.
+ */
+ ldr x5, [sp, #CTX_EL3STATE_OFFSET + CTX_ESR_EL3]
+ cbz x5, 1f
+ no_ret plat_handle_double_fault
+
+1:
/* Save EL3 state */
mrs x2, spsr_el3
mrs x3, elr_el3
@@ -216,7 +226,6 @@
mov x28, sp
#endif
bl plat_ea_handler
- mov x30, x29
#if ENABLE_ASSERTIONS
/*
@@ -232,7 +241,7 @@
/* Make SP point to context */
msr spsel, #1
- /* Restore EL3 state */
+ /* Restore EL3 state and ESR */
ldp x1, x2, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
msr spsr_el3, x1
msr elr_el3, x2
@@ -242,5 +251,13 @@
msr scr_el3, x3
msr esr_el3, x4
- ret
+#if ENABLE_ASSERTIONS
+ cmp x4, xzr
+ ASM_ASSERT(ne)
+#endif
+
+ /* Clear ESR storage */
+ str xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_ESR_EL3]
+
+ ret x29
endfunc ea_proceed
diff --git a/plat/common/aarch64/platform_helpers.S b/plat/common/aarch64/platform_helpers.S
index 13dfac8..8a07f8f 100644
--- a/plat/common/aarch64/platform_helpers.S
+++ b/plat/common/aarch64/platform_helpers.S
@@ -21,6 +21,7 @@
.weak bl32_plat_enable_mmu
.weak plat_handle_uncontainable_ea
+ .weak plat_handle_double_fault
#if !ENABLE_PLAT_COMPAT
.globl platform_get_core_pos
@@ -200,3 +201,14 @@
func plat_handle_uncontainable_ea
b report_unhandled_exception
endfunc plat_handle_uncontainable_ea
+
+ /* -----------------------------------------------------
+ * Platform handler for Double Fault.
+ *
+ * x0: EA reason
+ * x1: EA syndrome
+ * -----------------------------------------------------
+ */
+func plat_handle_double_fault
+ b report_unhandled_exception
+endfunc plat_handle_double_fault