RAS: Introduce handler for Uncontainable errors

Uncontainable errors are the most severe form of errors, which typically
mean that the system state can't be trusted any more. This further means
that normal error recovery process can't be followed, and an orderly
shutdown of the system is often desirable.

This patch allows for the platform to define a handler for Uncontainable
errors received. Due to the nature of Uncontainable error, the handler
is expected to initiate an orderly shutdown of the system, and therefore
is not expected to return. A default implementation is added which falls
back to platform unhandled exception.

Also fix ras_arch.h header guards.

Change-Id: I072e336a391a0b382e77e627eb9e40729d488b55
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

bl31/aarch64/ea_delegate.S

@@ -9,6 +9,7 @@
 #include <assert_macros.S>
 #include <context.h>
 #include <ea_handle.h>
+#include <ras_arch.h>
 
 
 	.globl	handle_lower_el_ea_esb
@@ -70,7 +71,7 @@ func enter_lower_el_sync_ea
 	mov	x0, #ERROR_EA_SYNC
 	mrs	x1, esr_el3
 	adr	x30, el3_exit
-	b	ea_proceed
+	b	delegate_sync_ea
 
 2:
 	/* Synchronous exceptions other than the above are assumed to be EA */
@@ -100,10 +101,76 @@ func enter_lower_el_async_ea
 	mov	x0, #ERROR_EA_ASYNC
 	mrs	x1, esr_el3
 	adr	x30, el3_exit
-	b	ea_proceed
+	b	delegate_async_ea
 endfunc enter_lower_el_async_ea
 
 
+/*
+ * Prelude for Synchronous External Abort handling. This function assumes that
+ * all GP registers have been saved by the caller.
+ *
+ * x0: EA reason
+ * x1: EA syndrome
+ */
+func delegate_sync_ea
+#if RAS_EXTENSION
+	/*
+	 * Check for Uncontainable error type. If so, route to the platform
+	 * fatal error handler rather than the generic EA one.
+	 */
+	ubfx    x2, x1, #EABORT_SET_SHIFT, #EABORT_SET_WIDTH
+	cmp     x2, #ERROR_STATUS_SET_UC
+	b.ne    1f
+
+	/* Check fault status code */
+	ubfx    x3, x1, #EABORT_DFSC_SHIFT, #EABORT_DFSC_WIDTH
+	cmp     x3, #SYNC_EA_FSC
+	b.ne    1f
+
+	no_ret  plat_handle_uncontainable_ea
+1:
+#endif
+
+	b       ea_proceed
+endfunc delegate_sync_ea
+
+
+/*
+ * Prelude for Asynchronous External Abort handling. This function assumes that
+ * all GP registers have been saved by the caller.
+ *
+ * x0: EA reason
+ * x1: EA syndrome
+ */
+func delegate_async_ea
+#if RAS_EXTENSION
+	/*
+	 * Check for Implementation Defined Syndrome. If so, skip checking
+	 * Uncontainable error type from the syndrome as the format is unknown.
+	 */
+	tbnz	x1, #SERROR_IDS_BIT, 1f
+
+	/*
+	 * Check for Uncontainable error type. If so, route to the platform
+	 * fatal error handler rather than the generic EA one.
+	 */
+	ubfx	x2, x1, #EABORT_AET_SHIFT, #EABORT_AET_WIDTH
+	cmp	x2, #ERROR_STATUS_UET_UC
+	b.ne	1f
+
+	/* Check DFSC for SError type */
+	ubfx	x3, x1, #EABORT_DFSC_SHIFT, #EABORT_DFSC_WIDTH
+	cmp	x3, #DFSC_SERROR
+	b.ne	1f
+
+	no_ret	plat_handle_uncontainable_ea
+1:
+#endif
+
+	b	ea_proceed
+endfunc delegate_async_ea
+
+
 /*
  * Delegate External Abort handling to platform's EA handler. This function
  * assumes that all GP registers have been saved by the caller.

include/lib/extensions/ras_arch.h

@@ -4,15 +4,8 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __RAS_H__
+#ifndef RAS_ARCH_H
-#define __RAS_H__
+#define RAS_ARCH_H
-
-#include <arch.h>
-#include <arch_helpers.h>
-#include <assert.h>
-#include <context.h>
-#include <mmio.h>
-#include <stdint.h>
 
 /*
  * Size of nodes implementing Standard Error Records - currently only 4k is
@@ -146,12 +139,53 @@
 #define ERR_CTLR_ENABLE_FIELD(_ctlr, _field) \
 	ERR_CTLR_SET_FIELD(_ctlr, _field, ERR_CTLR_ ##_field ##_MASK)
 
-/* Uncorrected error types */
+/* Uncorrected error types for Asynchronous exceptions */
 #define ERROR_STATUS_UET_UC	0x0	/* Uncontainable */
 #define ERROR_STATUS_UET_UEU	0x1	/* Unrecoverable */
 #define ERROR_STATUS_UET_UEO	0x2	/* Restable */
 #define ERROR_STATUS_UET_UER	0x3	/* Recoverable */
 
+/* Error types for Synchronous exceptions */
+#define ERROR_STATUS_SET_UER	0x0	/* Recoverable */
+#define ERROR_STATUS_SET_UEO	0x1	/* Restable */
+#define ERROR_STATUS_SET_UC	0x2     /* Uncontainable */
+#define ERROR_STATUS_SET_CE	0x3     /* Corrected */
+
+/* Implementation Defined Syndrome bit in ESR */
+#define SERROR_IDS_BIT		U(24)
+
+/*
+ * Asynchronous Error Type in exception syndrome. The field has same values in
+ * both DISR_EL1 and ESR_EL3 for SError.
+ */
+#define EABORT_AET_SHIFT	U(10)
+#define EABORT_AET_WIDTH	U(3)
+#define EABORT_AET_MASK		U(0x7)
+
+/* DFSC field in Asynchronous exception syndrome */
+#define EABORT_DFSC_SHIFT	U(0)
+#define EABORT_DFSC_WIDTH	U(6)
+#define EABORT_DFSC_MASK	U(0x3f)
+
+/* Synchronous Error Type in exception syndrome. */
+#define EABORT_SET_SHIFT	U(11)
+#define EABORT_SET_WIDTH	U(2)
+#define EABORT_SET_MASK		U(0x3)
+
+/* DFSC code for SErrors */
+#define DFSC_SERROR		0x11
+
+/* I/DFSC code for synchronous external abort */
+#define SYNC_EA_FSC		0x10
+
+#ifndef __ASSEMBLY__
+
+#include <arch.h>
+#include <arch_helpers.h>
+#include <assert.h>
+#include <context.h>
+#include <mmio.h>
+#include <stdint.h>
 
 /*
  * Standard Error Record accessors for memory-mapped registers.
@@ -221,5 +255,6 @@ static inline void ser_sys_select_record(unsigned int idx)
 /* Library functions to probe Standard Error Record */
 int ser_probe_memmap(uintptr_t base, unsigned int size_num_k, int *probe_data);
 int ser_probe_sysreg(unsigned int idx_start, unsigned int num_idx, int *probe_data);
+#endif /* __ASSEMBLY__ */
 
-#endif /* __RAS_H__ */
+#endif /* RAS_ARCH_H */

plat/common/aarch64/platform_helpers.S

@@ -20,6 +20,8 @@
 	.weak	bl31_plat_enable_mmu
 	.weak	bl32_plat_enable_mmu
 
+	.weak	plat_handle_uncontainable_ea
+
 #if !ENABLE_PLAT_COMPAT
 	.globl	platform_get_core_pos
 
@@ -186,3 +188,15 @@ endfunc bl31_plat_enable_mmu
 func bl32_plat_enable_mmu
 	b	enable_mmu_direct_el1
 endfunc bl32_plat_enable_mmu
+
+
+	/* -----------------------------------------------------
+	 * Platform handler for Uncontainable External Abort.
+	 *
+	 * x0: EA reason
+	 * x1: EA syndrome
+	 * -----------------------------------------------------
+	 */
+func plat_handle_uncontainable_ea
+	b	report_unhandled_exception
+endfunc plat_handle_uncontainable_ea