diff options
Diffstat (limited to 'lib/cpus/aarch64/wa_cve_2017_5715_bpiall.S')
| -rw-r--r-- | lib/cpus/aarch64/wa_cve_2017_5715_bpiall.S | 368 |
1 files changed, 368 insertions, 0 deletions
diff --git a/lib/cpus/aarch64/wa_cve_2017_5715_bpiall.S b/lib/cpus/aarch64/wa_cve_2017_5715_bpiall.S new file mode 100644 index 0000000..0222818 --- /dev/null +++ b/lib/cpus/aarch64/wa_cve_2017_5715_bpiall.S @@ -0,0 +1,368 @@ +/* + * Copyright (c) 2017-2022, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <arch.h> +#include <asm_macros.S> +#include <context.h> +#include <services/arm_arch_svc.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 + +end_vector_entry bpiall_sync_exception_sp_el0 + +vector_entry bpiall_irq_sp_el0 + b irq_sp_el0 +end_vector_entry bpiall_irq_sp_el0 + +vector_entry bpiall_fiq_sp_el0 + b fiq_sp_el0 +end_vector_entry bpiall_fiq_sp_el0 + +vector_entry bpiall_serror_sp_el0 + b serror_sp_el0 +end_vector_entry bpiall_serror_sp_el0 + + /* --------------------------------------------------------------------- + * Current EL with SP_ELx: 0x200 - 0x400 + * --------------------------------------------------------------------- + */ +vector_entry bpiall_sync_exception_sp_elx + b sync_exception_sp_elx +end_vector_entry bpiall_sync_exception_sp_elx + +vector_entry bpiall_irq_sp_elx + b irq_sp_elx +end_vector_entry bpiall_irq_sp_elx + +vector_entry bpiall_fiq_sp_elx + b fiq_sp_elx +end_vector_entry bpiall_fiq_sp_elx + +vector_entry bpiall_serror_sp_elx + b serror_sp_elx +end_vector_entry bpiall_serror_sp_elx + + /* --------------------------------------------------------------------- + * Lower EL using AArch64 : 0x400 - 0x600 + * --------------------------------------------------------------------- + */ +vector_entry bpiall_sync_exception_aarch64 + apply_cve_2017_5715_wa 1 +end_vector_entry bpiall_sync_exception_aarch64 + +vector_entry bpiall_irq_aarch64 + apply_cve_2017_5715_wa 2 +end_vector_entry bpiall_irq_aarch64 + +vector_entry bpiall_fiq_aarch64 + apply_cve_2017_5715_wa 4 +end_vector_entry bpiall_fiq_aarch64 + +vector_entry bpiall_serror_aarch64 + apply_cve_2017_5715_wa 8 +end_vector_entry bpiall_serror_aarch64 + + /* --------------------------------------------------------------------- + * Lower EL using AArch32 : 0x600 - 0x800 + * --------------------------------------------------------------------- + */ +vector_entry bpiall_sync_exception_aarch32 + apply_cve_2017_5715_wa 1 +end_vector_entry bpiall_sync_exception_aarch32 + +vector_entry bpiall_irq_aarch32 + apply_cve_2017_5715_wa 2 +end_vector_entry bpiall_irq_aarch32 + +vector_entry bpiall_fiq_aarch32 + apply_cve_2017_5715_wa 4 +end_vector_entry bpiall_fiq_aarch32 + +vector_entry bpiall_serror_aarch32 + apply_cve_2017_5715_wa 8 +end_vector_entry 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 +end_vector_entry bpiall_ret_sync_exception_sp_el0 + +vector_entry bpiall_ret_irq_sp_el0 + b report_unhandled_interrupt +end_vector_entry bpiall_ret_irq_sp_el0 + +vector_entry bpiall_ret_fiq_sp_el0 + b report_unhandled_interrupt +end_vector_entry bpiall_ret_fiq_sp_el0 + +vector_entry bpiall_ret_serror_sp_el0 + b report_unhandled_exception +end_vector_entry 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 +end_vector_entry bpiall_ret_sync_exception_sp_elx + +vector_entry bpiall_ret_irq_sp_elx + b report_unhandled_interrupt +end_vector_entry bpiall_ret_irq_sp_elx + +vector_entry bpiall_ret_fiq_sp_elx + b report_unhandled_interrupt +end_vector_entry bpiall_ret_fiq_sp_elx + +vector_entry bpiall_ret_serror_sp_elx + b report_unhandled_exception +end_vector_entry bpiall_ret_serror_sp_elx + + /* --------------------------------------------------------------------- + * Lower EL using AArch64 : 0x400 - 0x600 (UNUSED) + * --------------------------------------------------------------------- + */ +vector_entry bpiall_ret_sync_exception_aarch64 + b report_unhandled_exception +end_vector_entry bpiall_ret_sync_exception_aarch64 + +vector_entry bpiall_ret_irq_aarch64 + b report_unhandled_interrupt +end_vector_entry bpiall_ret_irq_aarch64 + +vector_entry bpiall_ret_fiq_aarch64 + b report_unhandled_interrupt +end_vector_entry bpiall_ret_fiq_aarch64 + +vector_entry bpiall_ret_serror_aarch64 + b report_unhandled_exception +end_vector_entry 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 or W0 = SMCCC_ARCH_WORKAROUND_3 + * + * This sequence evaluates as: + * (W0==SMCCC_ARCH_WORKAROUND_1) || (W0==SMCCC_ARCH_WORKAROUND_3) ? + * (ESR_EL3==SMC#0) : (NE) + * allowing use of a single branch operation + */ + orr w2, wzr, #SMCCC_ARCH_WORKAROUND_1 + cmp w0, w2 + orr w2, wzr, #SMCCC_ARCH_WORKAROUND_3 + ccmp w0, w2, #4, ne + mov_imm w2, ESR_EL3_A64_SMC0 + ccmp w3, w2, #0, eq + /* Static predictor will predict a fall through */ + bne 1f + eret +1: + /* restore x2 and x3 and continue sync exception handling */ + b bpiall_ret_sync_exception_aarch32_tail +end_vector_entry 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 +end_vector_entry bpiall_ret_irq_aarch32 + +vector_entry bpiall_ret_fiq_aarch32 + b report_unhandled_interrupt +end_vector_entry bpiall_ret_fiq_aarch32 + +vector_entry bpiall_ret_serror_aarch32 + b report_unhandled_exception +end_vector_entry bpiall_ret_serror_aarch32 + + /* + * Part of bpiall_ret_sync_exception_aarch32 to save vector space + */ +func bpiall_ret_sync_exception_aarch32_tail + ldp x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2] + b sync_exception_aarch64 +endfunc bpiall_ret_sync_exception_aarch32_tail |