Workaround for CVE-2017-5715 on Cortex A73 and A75

Invalidate the Branch Target Buffer (BTB) on entry to EL3 by
temporarily dropping into AArch32 Secure-EL1 and executing the
`BPIALL` instruction.

This is achieved by using 3 vector tables.  There is the runtime
vector table which is used to handle exceptions and 2 additional
tables which are required to implement this workaround.  The
additional tables are `vbar0` and `vbar1`.

The sequence of events for handling a single exception is
as follows:

1) Install vector table `vbar0` which saves the CPU context on entry
   to EL3 and sets up the Secure-EL1 context to execute in AArch32 mode
   with the MMU disabled and I$ enabled.  This is the default vector table.

2) Before doing an ERET into Secure-EL1, switch vbar to point to
   another vector table `vbar1`.  This is required to restore EL3 state
   when returning from the workaround, before proceeding with normal EL3
   exception handling.

3) While in Secure-EL1, the `BPIALL` instruction is executed and an
   SMC call back to EL3 is performed.

4) On entry to EL3 from Secure-EL1, the saved context from step 1) is
   restored.  The vbar is switched to point to `vbar0` in preparation to
   handle further exceptions.  Finally a branch to the runtime vector
   table entry is taken to complete the handling of the original
   exception.

This workaround is enabled by default on the affected CPUs.

NOTE
====

There are 4 different stubs in Secure-EL1.  Each stub corresponds to
an exception type such as Sync/IRQ/FIQ/SError.  Each stub will move a
different value in `R0` before doing an SMC call back into EL3.
Without this piece of information it would not be possible to know
what the original exception type was as we cannot use `ESR_EL3` to
distinguish between IRQs and FIQs.

Change-Id: I90b32d14a3735290b48685d43c70c99daaa4b434
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>

bl31/bl31.mk

@@ -59,7 +59,8 @@ BL31_SOURCES		+=	lib/extensions/sve/sve.c
 endif
 
 ifeq (${WORKAROUND_CVE_2017_5715},1)
-BL31_SOURCES		+=	lib/cpus/aarch64/workaround_cve_2017_5715_mmu.S
+BL31_SOURCES		+=	lib/cpus/aarch64/workaround_cve_2017_5715_mmu.S		\
+				lib/cpus/aarch64/workaround_cve_2017_5715_bpiall.S
 endif
 
 BL31_LINKERFILE		:=	bl31/bl31.ld.S

include/lib/aarch64/arch.h

@@ -337,6 +337,11 @@
 #define SPSR_T_ARM		U(0x0)
 #define SPSR_T_THUMB		U(0x1)
 
+#define SPSR_M_SHIFT		U(4)
+#define SPSR_M_MASK		U(0x1)
+#define SPSR_M_AARCH64		U(0x0)
+#define SPSR_M_AARCH32		U(0x1)
+
 #define DISABLE_ALL_EXCEPTIONS \
 		(DAIF_FIQ_BIT | DAIF_IRQ_BIT | DAIF_ABT_BIT | DAIF_DBG_BIT)
 

include/lib/el3_runtime/aarch64/context.h

@@ -46,12 +46,26 @@
 #define CTX_GPREG_SP_EL0	U(0xf8)
 #define CTX_GPREGS_END		U(0x100)
 
+#if WORKAROUND_CVE_2017_5715
+#define CTX_CVE_2017_5715_OFFSET	(CTX_GPREGS_OFFSET + CTX_GPREGS_END)
+#define CTX_CVE_2017_5715_QUAD0		U(0x0)
+#define CTX_CVE_2017_5715_QUAD1		U(0x8)
+#define	CTX_CVE_2017_5715_QUAD2		U(0x10)
+#define CTX_CVE_2017_5715_QUAD3		U(0x18)
+#define CTX_CVE_2017_5715_QUAD4		U(0x20)
+#define CTX_CVE_2017_5715_QUAD5		U(0x28)
+#define CTX_CVE_2017_5715_END		U(0x30)
+#else
+#define CTX_CVE_2017_5715_OFFSET	CTX_GPREGS_OFFSET
+#define CTX_CVE_2017_5715_END		CTX_GPREGS_END
+#endif
+
 /*******************************************************************************
  * Constants that allow assembler code to access members of and the 'el3_state'
  * structure at their correct offsets. Note that some of the registers are only
  * 32-bits wide but are stored as 64-bit values for convenience
  ******************************************************************************/
-#define CTX_EL3STATE_OFFSET	(CTX_GPREGS_OFFSET + CTX_GPREGS_END)
+#define CTX_EL3STATE_OFFSET	(CTX_CVE_2017_5715_OFFSET + CTX_CVE_2017_5715_END)
 #define CTX_SCR_EL3		U(0x0)
 #define CTX_RUNTIME_SP		U(0x8)
 #define CTX_SPSR_EL3		U(0x10)
@@ -186,6 +200,9 @@
 
 /* Constants to determine the size of individual context structures */
 #define CTX_GPREG_ALL		(CTX_GPREGS_END >> DWORD_SHIFT)
+#if WORKAROUND_CVE_2017_5715
+#define CTX_CVE_2017_5715_ALL	(CTX_CVE_2017_5715_END >> DWORD_SHIFT)
+#endif
 #define CTX_SYSREG_ALL		(CTX_SYSREGS_END >> DWORD_SHIFT)
 #if CTX_INCLUDE_FPREGS
 #define CTX_FPREG_ALL		(CTX_FPREGS_END >> DWORD_SHIFT)
@@ -201,6 +218,10 @@
  */
 DEFINE_REG_STRUCT(gp_regs, CTX_GPREG_ALL);
 
+#if WORKAROUND_CVE_2017_5715
+DEFINE_REG_STRUCT(cve_2017_5715_regs, CTX_CVE_2017_5715_ALL);
+#endif
+
 /*
  * AArch64 EL1 system register context structure for preserving the
  * architectural state during switches from one security state to
@@ -242,6 +263,9 @@ DEFINE_REG_STRUCT(el3_state, CTX_EL3STATE_ALL);
  */
 typedef struct cpu_context {
 	gp_regs_t gpregs_ctx;
+#if WORKAROUND_CVE_2017_5715
+	cve_2017_5715_regs_t cve_2017_5715_regs_ctx;
+#endif
 	el3_state_t el3state_ctx;
 	el1_sys_regs_t sysregs_ctx;
 #if CTX_INCLUDE_FPREGS

lib/cpus/aarch64/cortex_a73.S

@@ -36,6 +36,11 @@ func cortex_a73_disable_smp
 endfunc cortex_a73_disable_smp
 
 func cortex_a73_reset_func
+#if IMAGE_BL31 && WORKAROUND_CVE_2017_5715
+	adr	x0, workaround_bpiall_vbar0_runtime_exceptions
+	msr	vbar_el3, x0
+#endif
+
 	/* ---------------------------------------------
 	 * Enable the SMP bit.
 	 * Clobbers : x0

lib/cpus/aarch64/cortex_a75.S

@@ -12,6 +12,11 @@
 #include <cortex_a75.h>
 
 func cortex_a75_reset_func
+#if IMAGE_BL31 && WORKAROUND_CVE_2017_5715
+	adr	x0, workaround_bpiall_vbar0_runtime_exceptions
+	msr	vbar_el3, x0
+#endif
+
 #if ENABLE_AMU
 	/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
 	mrs	x0, actlr_el3

lib/cpus/aarch64/workaround_cve_2017_5715_bpiall.S

+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <context.h>
+
+	.globl	workaround_bpiall_vbar0_runtime_exceptions
+
+#define EMIT_BPIALL		0xee070fd5
+#define EMIT_MOV_R0_IMM(v)	0xe3a0000##v
+#define EMIT_SMC		0xe1600070
+
+	.macro	enter_workaround _stub_name
+	/* Save GP regs */
+	stp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+	stp	x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
+	stp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
+	stp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
+	stp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
+	stp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
+	stp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
+	stp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
+	stp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
+	stp	x18, x19, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
+	stp	x20, x21, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X20]
+	stp	x22, x23, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X22]
+	stp	x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24]
+	stp	x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26]
+	stp	x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28]
+
+	adr	x4, \_stub_name
+
+	/*
+	 * Load SPSR_EL3 and VBAR_EL3.  SPSR_EL3 is set up to have
+	 * all interrupts masked in preparation to running the workaround
+	 * stub in S-EL1.  VBAR_EL3 points to the vector table that
+	 * will handle the SMC back from the workaround stub.
+	 */
+	ldp	x0, x1, [x4, #0]
+
+	/*
+	 * Load SCTLR_EL1 and ELR_EL3.  SCTLR_EL1 is configured to disable
+	 * the MMU in S-EL1.  ELR_EL3 points to the appropriate stub in S-EL1.
+	 */
+	ldp	x2, x3, [x4, #16]
+
+	mrs	x4, scr_el3
+	mrs	x5, spsr_el3
+	mrs	x6, elr_el3
+	mrs	x7, sctlr_el1
+	mrs	x8, esr_el3
+
+	/* Preserve system registers in the workaround context */
+	stp	x4, x5, [sp, #CTX_CVE_2017_5715_OFFSET + CTX_CVE_2017_5715_QUAD0]
+	stp	x6, x7, [sp, #CTX_CVE_2017_5715_OFFSET + CTX_CVE_2017_5715_QUAD2]
+	stp	x8, x30, [sp, #CTX_CVE_2017_5715_OFFSET + CTX_CVE_2017_5715_QUAD4]
+
+	/*
+	 * Setting SCR_EL3 to all zeroes means that the NS, RW
+	 * and SMD bits are configured as expected.
+	 */
+	msr	scr_el3, xzr
+
+	/*
+	 * Reload system registers with the crafted values
+	 * in preparation for entry in S-EL1.
+	 */
+	msr	spsr_el3, x0
+	msr	vbar_el3, x1
+	msr	sctlr_el1, x2
+	msr	elr_el3, x3
+
+	eret
+	.endm
+
+	/* ---------------------------------------------------------------------
+	 * This vector table is used at runtime to enter the workaround at
+	 * AArch32 S-EL1 for Sync/IRQ/FIQ/SError exceptions.  If the workaround
+	 * is not enabled, the existing runtime exception vector table is used.
+	 * ---------------------------------------------------------------------
+	 */
+vector_base workaround_bpiall_vbar0_runtime_exceptions
+
+	/* ---------------------------------------------------------------------
+	 * Current EL with SP_EL0 : 0x0 - 0x200
+	 * ---------------------------------------------------------------------
+	 */
+vector_entry workaround_bpiall_vbar0_sync_exception_sp_el0
+	b	sync_exception_sp_el0
+	/*
+	 * Since each vector table entry is 128 bytes, we can store the
+	 * stub context in the unused space to minimize memory footprint.
+	 */
+aarch32_stub_smc:
+	.word	EMIT_BPIALL
+	.word	EMIT_MOV_R0_IMM(1)
+	.word	EMIT_SMC
+aarch32_stub_ctx_smc:
+	/* Mask all interrupts and set AArch32 Supervisor mode */
+	.quad	(SPSR_AIF_MASK << SPSR_AIF_SHIFT | \
+	         SPSR_M_AARCH32 << SPSR_M_SHIFT | \
+	         MODE32_svc << MODE32_SHIFT)
+
+	/*
+	 * VBAR_EL3 points to vbar1 which is the vector table
+	 * used while the workaround is executing.
+	 */
+	.quad	workaround_bpiall_vbar1_runtime_exceptions
+
+	/* Setup SCTLR_EL1 with MMU off and I$ on */
+	.quad	SCTLR_AARCH32_EL1_RES1 | SCTLR_I_BIT
+
+	/* ELR_EL3 is setup to point to the sync exception stub in AArch32 */
+	.quad	aarch32_stub_smc
+	check_vector_size workaround_bpiall_vbar0_sync_exception_sp_el0
+
+vector_entry workaround_bpiall_vbar0_irq_sp_el0
+	b	irq_sp_el0
+aarch32_stub_irq:
+	.word	EMIT_BPIALL
+	.word	EMIT_MOV_R0_IMM(2)
+	.word	EMIT_SMC
+aarch32_stub_ctx_irq:
+	.quad	(SPSR_AIF_MASK << SPSR_AIF_SHIFT | \
+	         SPSR_M_AARCH32 << SPSR_M_SHIFT | \
+	         MODE32_svc << MODE32_SHIFT)
+	.quad	workaround_bpiall_vbar1_runtime_exceptions
+	.quad	SCTLR_AARCH32_EL1_RES1 | SCTLR_I_BIT
+	.quad	aarch32_stub_irq
+	check_vector_size workaround_bpiall_vbar0_irq_sp_el0
+
+vector_entry workaround_bpiall_vbar0_fiq_sp_el0
+	b	fiq_sp_el0
+aarch32_stub_fiq:
+	.word	EMIT_BPIALL
+	.word	EMIT_MOV_R0_IMM(4)
+	.word	EMIT_SMC
+aarch32_stub_ctx_fiq:
+	.quad	(SPSR_AIF_MASK << SPSR_AIF_SHIFT | \
+	         SPSR_M_AARCH32 << SPSR_M_SHIFT | \
+	         MODE32_svc << MODE32_SHIFT)
+	.quad	workaround_bpiall_vbar1_runtime_exceptions
+	.quad	SCTLR_AARCH32_EL1_RES1 | SCTLR_I_BIT
+	.quad	aarch32_stub_fiq
+	check_vector_size workaround_bpiall_vbar0_fiq_sp_el0
+
+vector_entry workaround_bpiall_vbar0_serror_sp_el0
+	b	serror_sp_el0
+aarch32_stub_serror:
+	.word	EMIT_BPIALL
+	.word	EMIT_MOV_R0_IMM(8)
+	.word	EMIT_SMC
+aarch32_stub_ctx_serror:
+	.quad	(SPSR_AIF_MASK << SPSR_AIF_SHIFT | \
+	         SPSR_M_AARCH32 << SPSR_M_SHIFT | \
+	         MODE32_svc << MODE32_SHIFT)
+	.quad	workaround_bpiall_vbar1_runtime_exceptions
+	.quad	SCTLR_AARCH32_EL1_RES1 | SCTLR_I_BIT
+	.quad	aarch32_stub_serror
+	check_vector_size workaround_bpiall_vbar0_serror_sp_el0
+
+	/* ---------------------------------------------------------------------
+	 * Current EL with SP_ELx: 0x200 - 0x400
+	 * ---------------------------------------------------------------------
+	 */
+vector_entry workaround_bpiall_vbar0_sync_exception_sp_elx
+	b	sync_exception_sp_elx
+	check_vector_size workaround_bpiall_vbar0_sync_exception_sp_elx
+
+vector_entry workaround_bpiall_vbar0_irq_sp_elx
+	b	irq_sp_elx
+	check_vector_size workaround_bpiall_vbar0_irq_sp_elx
+
+vector_entry workaround_bpiall_vbar0_fiq_sp_elx
+	b	fiq_sp_elx
+	check_vector_size workaround_bpiall_vbar0_fiq_sp_elx
+
+vector_entry workaround_bpiall_vbar0_serror_sp_elx
+	b	serror_sp_elx
+	check_vector_size workaround_bpiall_vbar0_serror_sp_elx
+
+	/* ---------------------------------------------------------------------
+	 * Lower EL using AArch64 : 0x400 - 0x600
+	 * ---------------------------------------------------------------------
+	 */
+vector_entry workaround_bpiall_vbar0_sync_exception_aarch64
+	enter_workaround aarch32_stub_ctx_smc
+	check_vector_size workaround_bpiall_vbar0_sync_exception_aarch64
+
+vector_entry workaround_bpiall_vbar0_irq_aarch64
+	enter_workaround aarch32_stub_ctx_irq
+	check_vector_size workaround_bpiall_vbar0_irq_aarch64
+
+vector_entry workaround_bpiall_vbar0_fiq_aarch64
+	enter_workaround aarch32_stub_ctx_fiq
+	check_vector_size workaround_bpiall_vbar0_fiq_aarch64
+
+vector_entry workaround_bpiall_vbar0_serror_aarch64
+	enter_workaround aarch32_stub_ctx_serror
+	check_vector_size workaround_bpiall_vbar0_serror_aarch64
+
+	/* ---------------------------------------------------------------------
+	 * Lower EL using AArch32 : 0x600 - 0x800
+	 * ---------------------------------------------------------------------
+	 */
+vector_entry workaround_bpiall_vbar0_sync_exception_aarch32
+	enter_workaround aarch32_stub_ctx_smc
+	check_vector_size workaround_bpiall_vbar0_sync_exception_aarch32
+
+vector_entry workaround_bpiall_vbar0_irq_aarch32
+	enter_workaround aarch32_stub_ctx_irq
+	check_vector_size workaround_bpiall_vbar0_irq_aarch32
+
+vector_entry workaround_bpiall_vbar0_fiq_aarch32
+	enter_workaround aarch32_stub_ctx_fiq
+	check_vector_size workaround_bpiall_vbar0_fiq_aarch32
+
+vector_entry workaround_bpiall_vbar0_serror_aarch32
+	enter_workaround aarch32_stub_ctx_serror
+	check_vector_size workaround_bpiall_vbar0_serror_aarch32
+
+	/* ---------------------------------------------------------------------
+	 * This vector table is used while the workaround is executing.  It
+	 * installs a simple SMC handler to allow the Sync/IRQ/FIQ/SError
+	 * workaround stubs to enter EL3 from S-EL1.  It restores the previous
+	 * EL3 state before proceeding with the normal runtime exception vector.
+	 * ---------------------------------------------------------------------
+	 */
+vector_base workaround_bpiall_vbar1_runtime_exceptions
+
+	/* ---------------------------------------------------------------------
+	 * Current EL with SP_EL0 : 0x0 - 0x200 (UNUSED)
+	 * ---------------------------------------------------------------------
+	 */
+vector_entry workaround_bpiall_vbar1_sync_exception_sp_el0
+	b	report_unhandled_exception
+	check_vector_size workaround_bpiall_vbar1_sync_exception_sp_el0
+
+vector_entry workaround_bpiall_vbar1_irq_sp_el0
+	b	report_unhandled_interrupt
+	check_vector_size workaround_bpiall_vbar1_irq_sp_el0
+
+vector_entry workaround_bpiall_vbar1_fiq_sp_el0
+	b	report_unhandled_interrupt
+	check_vector_size workaround_bpiall_vbar1_fiq_sp_el0
+
+vector_entry workaround_bpiall_vbar1_serror_sp_el0
+	b	report_unhandled_exception
+	check_vector_size workaround_bpiall_vbar1_serror_sp_el0
+
+	/* ---------------------------------------------------------------------
+	 * Current EL with SP_ELx: 0x200 - 0x400 (UNUSED)
+	 * ---------------------------------------------------------------------
+	 */
+vector_entry workaround_bpiall_vbar1_sync_exception_sp_elx
+	b	report_unhandled_exception
+	check_vector_size workaround_bpiall_vbar1_sync_exception_sp_elx
+
+vector_entry workaround_bpiall_vbar1_irq_sp_elx
+	b	report_unhandled_interrupt
+	check_vector_size workaround_bpiall_vbar1_irq_sp_elx
+
+vector_entry workaround_bpiall_vbar1_fiq_sp_elx
+	b	report_unhandled_interrupt
+	check_vector_size workaround_bpiall_vbar1_fiq_sp_elx
+
+vector_entry workaround_bpiall_vbar1_serror_sp_elx
+	b	report_unhandled_exception
+	check_vector_size workaround_bpiall_vbar1_serror_sp_elx
+
+	/* ---------------------------------------------------------------------
+	 * Lower EL using AArch64 : 0x400 - 0x600 (UNUSED)
+	 * ---------------------------------------------------------------------
+	 */
+vector_entry workaround_bpiall_vbar1_sync_exception_aarch64
+	b	report_unhandled_exception
+	check_vector_size workaround_bpiall_vbar1_sync_exception_aarch64
+
+vector_entry workaround_bpiall_vbar1_irq_aarch64
+	b	report_unhandled_interrupt
+	check_vector_size workaround_bpiall_vbar1_irq_aarch64
+
+vector_entry workaround_bpiall_vbar1_fiq_aarch64
+	b	report_unhandled_interrupt
+	check_vector_size workaround_bpiall_vbar1_fiq_aarch64
+
+vector_entry workaround_bpiall_vbar1_serror_aarch64
+	b	report_unhandled_exception
+	check_vector_size workaround_bpiall_vbar1_serror_aarch64
+
+	/* ---------------------------------------------------------------------
+	 * Lower EL using AArch32 : 0x600 - 0x800
+	 * ---------------------------------------------------------------------
+	 */
+vector_entry workaround_bpiall_vbar1_sync_exception_aarch32
+	/* Restore register state from the workaround context */
+	ldp	x2, x3, [sp, #CTX_CVE_2017_5715_OFFSET + CTX_CVE_2017_5715_QUAD0]
+	ldp	x4, x5, [sp, #CTX_CVE_2017_5715_OFFSET + CTX_CVE_2017_5715_QUAD2]
+	ldp	x6, x30, [sp, #CTX_CVE_2017_5715_OFFSET + CTX_CVE_2017_5715_QUAD4]
+
+	/* Apply the restored system register state */
+	msr	scr_el3, x2
+	msr	spsr_el3, x3
+	msr	elr_el3, x4
+	msr	sctlr_el1, x5
+	msr	esr_el3, x6
+
+	/*
+	 * Workaround is complete, so swap VBAR_EL3 to point
+	 * to workaround entry table in preparation for subsequent
+	 * Sync/IRQ/FIQ/SError exceptions.
+	 */
+	adr	x2, workaround_bpiall_vbar0_runtime_exceptions
+	msr	vbar_el3, x2
+
+	/*
+	 * Restore all GP regs except x0 and x1.  The value in x0
+	 * indicates the type of the original exception.
+	 */
+	ldp	x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
+	ldp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
+	ldp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
+	ldp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
+	ldp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
+	ldp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
+	ldp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
+	ldp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
+	ldp	x18, x19, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
+	ldp	x20, x21, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X20]
+	ldp	x22, x23, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X22]
+	ldp	x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24]
+	ldp	x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26]
+	ldp	x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28]
+
+	/*
+	 * Each of these handlers will first restore x0 and x1 from
+	 * the context and the branch to the common implementation for
+	 * each of the exception types.
+	 */
+	tbnz	x0, #1, workaround_bpiall_vbar1_irq
+	tbnz	x0, #2, workaround_bpiall_vbar1_fiq
+	tbnz	x0, #3, workaround_bpiall_vbar1_serror
+
+	/* Fallthrough case for Sync exception */
+	ldp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+	b	sync_exception_aarch64
+	check_vector_size workaround_bpiall_vbar1_sync_exception_aarch32
+
+vector_entry workaround_bpiall_vbar1_irq_aarch32
+	b	report_unhandled_interrupt
+workaround_bpiall_vbar1_irq:
+	ldp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+	b	irq_aarch64
+	check_vector_size workaround_bpiall_vbar1_irq_aarch32
+
+vector_entry workaround_bpiall_vbar1_fiq_aarch32
+	b	report_unhandled_interrupt
+workaround_bpiall_vbar1_fiq:
+	ldp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+	b	fiq_aarch64
+	check_vector_size workaround_bpiall_vbar1_fiq_aarch32
+
+vector_entry workaround_bpiall_vbar1_serror_aarch32
+	b	report_unhandled_exception
+workaround_bpiall_vbar1_serror:
+	ldp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+	b	serror_aarch64
+	check_vector_size workaround_bpiall_vbar1_serror_aarch32