/*
* Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <arch.h>
#include <arm_arch_svc.h>
#include <asm_macros.S>
#include <context.h>
.globl wa_cve_2017_5715_bpiall_vbar
#define EMIT_BPIALL 0xee070fd5
#define EMIT_SMC 0xe1600070
#define ESR_EL3_A64_SMC0 0x5e000000
.macro apply_cve_2017_5715_wa _from_vector
/*
* Save register state to enable a call to AArch32 S-EL1 and return
* Identify the original calling vector in w2 (==_from_vector)
* Use w3-w6 for additional register state preservation while in S-EL1
*/
/* 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]
/* Identify the original exception vector */
mov w2, \_from_vector
/* Preserve 32-bit system registers in GP registers through the workaround */
mrs x3, esr_el3
mrs x4, spsr_el3
mrs x5, scr_el3
mrs x6, sctlr_el1
/*
* Preserve LR and ELR_EL3 registers in the GP regs context.
* Temporarily use the CTX_GPREG_SP_EL0 slot to preserve ELR_EL3
* through the workaround. This is OK because at this point the
* current state for this context's SP_EL0 is in the live system
* register, which is unmodified by the workaround.
*/
mrs x7, elr_el3
stp x30, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
/*
* Load system registers for entry to S-EL1.
*/
/* Mask all interrupts and set AArch32 Supervisor mode */
movz w8, SPSR_MODE32(MODE32_svc, SPSR_T_ARM, SPSR_E_LITTLE, SPSR_AIF_MASK)
/* Switch EL3 exception vectors while the workaround is executing. */
adr x9, wa_cve_2017_5715_bpiall_ret_vbar
/* Setup SCTLR_EL1 with MMU off and I$ on */
ldr x10, stub_sel1_sctlr
/* Land at the S-EL1 workaround stub */
adr x11, aarch32_stub
/*
* Setting SCR_EL3 to all zeroes means that the NS, RW
* and SMD bits are configured as expected.
*/
msr scr_el3, xzr
msr spsr_el3, x8
msr vbar_el3, x9
msr sctlr_el1, x10
msr elr_el3, x11
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 wa_cve_2017_5715_bpiall_vbar
/* ---------------------------------------------------------------------
* Current EL with SP_EL0 : 0x0 - 0x200
* ---------------------------------------------------------------------
*/
vector_entry bpiall_sync_exception_sp_el0
b sync_exception_sp_el0
nop /* to force 8 byte alignment for the following stub */
/*
* Since each vector table entry is 128 bytes, we can store the
* stub context in the unused space to minimize memory footprint.
*/
stub_sel1_sctlr:
.quad SCTLR_AARCH32_EL1_RES1 | SCTLR_I_BIT
aarch32_stub:
.word EMIT_BPIALL
.word EMIT_SMC
check_vector_size bpiall_sync_exception_sp_el0
vector_entry bpiall_irq_sp_el0
b irq_sp_el0
check_vector_size bpiall_irq_sp_el0
vector_entry bpiall_fiq_sp_el0
b fiq_sp_el0
check_vector_size bpiall_fiq_sp_el0
vector_entry bpiall_serror_sp_el0
b serror_sp_el0
check_vector_size bpiall_serror_sp_el0
/* ---------------------------------------------------------------------
* Current EL with SP_ELx: 0x200 - 0x400
* ---------------------------------------------------------------------
*/
vector_entry bpiall_sync_exception_sp_elx
b sync_exception_sp_elx
check_vector_size bpiall_sync_exception_sp_elx
vector_entry bpiall_irq_sp_elx
b irq_sp_elx
check_vector_size bpiall_irq_sp_elx
vector_entry bpiall_fiq_sp_elx
b fiq_sp_elx
check_vector_size bpiall_fiq_sp_elx
vector_entry bpiall_serror_sp_elx
b serror_sp_elx
check_vector_size bpiall_serror_sp_elx
/* ---------------------------------------------------------------------
* Lower EL using AArch64 : 0x400 - 0x600
* ---------------------------------------------------------------------
*/
vector_entry bpiall_sync_exception_aarch64
apply_cve_2017_5715_wa 1
check_vector_size bpiall_sync_exception_aarch64
vector_entry bpiall_irq_aarch64
apply_cve_2017_5715_wa 2
check_vector_size bpiall_irq_aarch64
vector_entry bpiall_fiq_aarch64
apply_cve_2017_5715_wa 4
check_vector_size bpiall_fiq_aarch64
vector_entry bpiall_serror_aarch64
apply_cve_2017_5715_wa 8
check_vector_size bpiall_serror_aarch64
/* ---------------------------------------------------------------------
* Lower EL using AArch32 : 0x600 - 0x800
* ---------------------------------------------------------------------
*/
vector_entry bpiall_sync_exception_aarch32
apply_cve_2017_5715_wa 1
check_vector_size bpiall_sync_exception_aarch32
vector_entry bpiall_irq_aarch32
apply_cve_2017_5715_wa 2
check_vector_size bpiall_irq_aarch32
vector_entry bpiall_fiq_aarch32
apply_cve_2017_5715_wa 4
check_vector_size bpiall_fiq_aarch32
vector_entry bpiall_serror_aarch32
apply_cve_2017_5715_wa 8
check_vector_size bpiall_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 wa_cve_2017_5715_bpiall_ret_vbar
/* ---------------------------------------------------------------------
* Current EL with SP_EL0 : 0x0 - 0x200 (UNUSED)
* ---------------------------------------------------------------------
*/
vector_entry bpiall_ret_sync_exception_sp_el0
b report_unhandled_exception
check_vector_size bpiall_ret_sync_exception_sp_el0
vector_entry bpiall_ret_irq_sp_el0
b report_unhandled_interrupt
check_vector_size bpiall_ret_irq_sp_el0
vector_entry bpiall_ret_fiq_sp_el0
b report_unhandled_interrupt
check_vector_size bpiall_ret_fiq_sp_el0
vector_entry bpiall_ret_serror_sp_el0
b report_unhandled_exception
check_vector_size bpiall_ret_serror_sp_el0
/* ---------------------------------------------------------------------
* Current EL with SP_ELx: 0x200 - 0x400 (UNUSED)
* ---------------------------------------------------------------------
*/
vector_entry bpiall_ret_sync_exception_sp_elx
b report_unhandled_exception
check_vector_size bpiall_ret_sync_exception_sp_elx
vector_entry bpiall_ret_irq_sp_elx
b report_unhandled_interrupt
check_vector_size bpiall_ret_irq_sp_elx
vector_entry bpiall_ret_fiq_sp_elx
b report_unhandled_interrupt
check_vector_size bpiall_ret_fiq_sp_elx
vector_entry bpiall_ret_serror_sp_elx
b report_unhandled_exception
check_vector_size bpiall_ret_serror_sp_elx
/* ---------------------------------------------------------------------
* Lower EL using AArch64 : 0x400 - 0x600 (UNUSED)
* ---------------------------------------------------------------------
*/
vector_entry bpiall_ret_sync_exception_aarch64
b report_unhandled_exception
check_vector_size bpiall_ret_sync_exception_aarch64
vector_entry bpiall_ret_irq_aarch64
b report_unhandled_interrupt
check_vector_size bpiall_ret_irq_aarch64
vector_entry bpiall_ret_fiq_aarch64
b report_unhandled_interrupt
check_vector_size bpiall_ret_fiq_aarch64
vector_entry bpiall_ret_serror_aarch64
b report_unhandled_exception
check_vector_size bpiall_ret_serror_aarch64
/* ---------------------------------------------------------------------
* Lower EL using AArch32 : 0x600 - 0x800
* ---------------------------------------------------------------------
*/
vector_entry bpiall_ret_sync_exception_aarch32
/*
* w2 indicates which SEL1 stub was run and thus which original vector was used
* w3-w6 contain saved system register state (esr_el3 in w3)
* Restore LR and ELR_EL3 register state from the GP regs context
*/
ldp x30, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
/* Apply the restored system register state */
msr esr_el3, x3
msr spsr_el3, x4
msr scr_el3, x5
msr sctlr_el1, x6
msr elr_el3, x7
/*
* Workaround is complete, so swap VBAR_EL3 to point
* to workaround entry table in preparation for subsequent
* Sync/IRQ/FIQ/SError exceptions.
*/
adr x0, wa_cve_2017_5715_bpiall_vbar
msr vbar_el3, x0
/*
* Restore all GP regs except x2 and x3 (esr). The value in x2
* indicates the type of the original exception.
*/
ldp x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
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]
/* Fast path Sync exceptions. Static predictor will fall through. */
tbz w2, #0, workaround_not_sync
/*
* Check if SMC is coming from A64 state on #0
* with W0 = SMCCC_ARCH_WORKAROUND_1
*
* This sequence evaluates as:
* (W0==SMCCC_ARCH_WORKAROUND_1) ? (ESR_EL3==SMC#0) : (NE)
* allowing use of a single branch operation
*/
orr w2, wzr, #SMCCC_ARCH_WORKAROUND_1
cmp w0, w2
mov_imm w2, ESR_EL3_A64_SMC0
ccmp w3, w2, #0, eq
/* Static predictor will predict a fall through */
bne 1f
eret
1:
ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
b sync_exception_aarch64
check_vector_size bpiall_ret_sync_exception_aarch32
vector_entry bpiall_ret_irq_aarch32
b report_unhandled_interrupt
/*
* Post-workaround fan-out for non-sync exceptions
*/
workaround_not_sync:
tbnz w2, #3, bpiall_ret_serror
tbnz w2, #2, bpiall_ret_fiq
/* IRQ */
ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
b irq_aarch64
bpiall_ret_fiq:
ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
b fiq_aarch64
bpiall_ret_serror:
ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
b serror_aarch64
check_vector_size bpiall_ret_irq_aarch32
vector_entry bpiall_ret_fiq_aarch32
b report_unhandled_interrupt
check_vector_size bpiall_ret_fiq_aarch32
vector_entry bpiall_ret_serror_aarch32
b report_unhandled_exception
check_vector_size bpiall_ret_serror_aarch32
