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// SPDX-License-Identifier: GPL-2.0
/*
* Exception handling code
*
* Copyright (C) 2019 ARM Ltd.
*/
#include <linux/context_tracking.h>
#include <linux/ptrace.h>
#include <linux/thread_info.h>
#include <asm/cpufeature.h>
#include <asm/daifflags.h>
#include <asm/esr.h>
#include <asm/exception.h>
#include <asm/kprobes.h>
#include <asm/mmu.h>
#include <asm/sysreg.h>
/*
* This is intended to match the logic in irqentry_enter(), handling the kernel
* mode transitions only.
*/
static void noinstr enter_from_kernel_mode(struct pt_regs *regs)
{
regs->exit_rcu = false;
if (!IS_ENABLED(CONFIG_TINY_RCU) && is_idle_task(current)) {
lockdep_hardirqs_off(CALLER_ADDR0);
rcu_irq_enter();
trace_hardirqs_off_finish();
regs->exit_rcu = true;
return;
}
lockdep_hardirqs_off(CALLER_ADDR0);
rcu_irq_enter_check_tick();
trace_hardirqs_off_finish();
}
/*
* This is intended to match the logic in irqentry_exit(), handling the kernel
* mode transitions only, and with preemption handled elsewhere.
*/
static void noinstr exit_to_kernel_mode(struct pt_regs *regs)
{
lockdep_assert_irqs_disabled();
if (interrupts_enabled(regs)) {
if (regs->exit_rcu) {
trace_hardirqs_on_prepare();
lockdep_hardirqs_on_prepare(CALLER_ADDR0);
rcu_irq_exit();
lockdep_hardirqs_on(CALLER_ADDR0);
return;
}
trace_hardirqs_on();
} else {
if (regs->exit_rcu)
rcu_irq_exit();
}
}
asmlinkage void noinstr enter_el1_irq_or_nmi(struct pt_regs *regs)
{
if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))
nmi_enter();
else
enter_from_kernel_mode(regs);
}
asmlinkage void noinstr exit_el1_irq_or_nmi(struct pt_regs *regs)
{
if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))
nmi_exit();
else
exit_to_kernel_mode(regs);
}
static void noinstr el1_abort(struct pt_regs *regs, unsigned long esr)
{
unsigned long far = read_sysreg(far_el1);
enter_from_kernel_mode(regs);
local_daif_inherit(regs);
far = untagged_addr(far);
do_mem_abort(far, esr, regs);
local_daif_mask();
exit_to_kernel_mode(regs);
}
static void noinstr el1_pc(struct pt_regs *regs, unsigned long esr)
{
unsigned long far = read_sysreg(far_el1);
enter_from_kernel_mode(regs);
local_daif_inherit(regs);
do_sp_pc_abort(far, esr, regs);
local_daif_mask();
exit_to_kernel_mode(regs);
}
static void noinstr el1_undef(struct pt_regs *regs)
{
enter_from_kernel_mode(regs);
local_daif_inherit(regs);
do_undefinstr(regs);
local_daif_mask();
exit_to_kernel_mode(regs);
}
static void noinstr el1_inv(struct pt_regs *regs, unsigned long esr)
{
enter_from_kernel_mode(regs);
local_daif_inherit(regs);
bad_mode(regs, 0, esr);
local_daif_mask();
exit_to_kernel_mode(regs);
}
static void noinstr el1_dbg(struct pt_regs *regs, unsigned long esr)
{
unsigned long far = read_sysreg(far_el1);
/*
* The CPU masked interrupts, and we are leaving them masked during
* do_debug_exception(). Update PMR as if we had called
* local_daif_mask().
*/
if (system_uses_irq_prio_masking())
gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
do_debug_exception(far, esr, regs);
}
static void noinstr el1_fpac(struct pt_regs *regs, unsigned long esr)
{
enter_from_kernel_mode(regs);
local_daif_inherit(regs);
do_ptrauth_fault(regs, esr);
local_daif_mask();
exit_to_kernel_mode(regs);
}
asmlinkage void noinstr el1_sync_handler(struct pt_regs *regs)
{
unsigned long esr = read_sysreg(esr_el1);
switch (ESR_ELx_EC(esr)) {
case ESR_ELx_EC_DABT_CUR:
case ESR_ELx_EC_IABT_CUR:
el1_abort(regs, esr);
break;
/*
* We don't handle ESR_ELx_EC_SP_ALIGN, since we will have hit a
* recursive exception when trying to push the initial pt_regs.
*/
case ESR_ELx_EC_PC_ALIGN:
el1_pc(regs, esr);
break;
case ESR_ELx_EC_SYS64:
case ESR_ELx_EC_UNKNOWN:
el1_undef(regs);
break;
case ESR_ELx_EC_BREAKPT_CUR:
case ESR_ELx_EC_SOFTSTP_CUR:
case ESR_ELx_EC_WATCHPT_CUR:
case ESR_ELx_EC_BRK64:
el1_dbg(regs, esr);
break;
case ESR_ELx_EC_FPAC:
el1_fpac(regs, esr);
break;
default:
el1_inv(regs, esr);
}
}
asmlinkage void noinstr enter_from_user_mode(void)
{
lockdep_hardirqs_off(CALLER_ADDR0);
CT_WARN_ON(ct_state() != CONTEXT_USER);
user_exit_irqoff();
trace_hardirqs_off_finish();
}
asmlinkage void noinstr exit_to_user_mode(void)
{
trace_hardirqs_on_prepare();
lockdep_hardirqs_on_prepare(CALLER_ADDR0);
user_enter_irqoff();
lockdep_hardirqs_on(CALLER_ADDR0);
}
static void noinstr el0_da(struct pt_regs *regs, unsigned long esr)
{
unsigned long far = read_sysreg(far_el1);
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
far = untagged_addr(far);
do_mem_abort(far, esr, regs);
}
static void noinstr el0_ia(struct pt_regs *regs, unsigned long esr)
{
unsigned long far = read_sysreg(far_el1);
/*
* We've taken an instruction abort from userspace and not yet
* re-enabled IRQs. If the address is a kernel address, apply
* BP hardening prior to enabling IRQs and pre-emption.
*/
if (!is_ttbr0_addr(far))
arm64_apply_bp_hardening();
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_mem_abort(far, esr, regs);
}
static void noinstr el0_fpsimd_acc(struct pt_regs *regs, unsigned long esr)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_fpsimd_acc(esr, regs);
}
static void noinstr el0_sve_acc(struct pt_regs *regs, unsigned long esr)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_sve_acc(esr, regs);
}
static void noinstr el0_fpsimd_exc(struct pt_regs *regs, unsigned long esr)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_fpsimd_exc(esr, regs);
}
static void noinstr el0_sys(struct pt_regs *regs, unsigned long esr)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_sysinstr(esr, regs);
}
static void noinstr el0_pc(struct pt_regs *regs, unsigned long esr)
{
unsigned long far = read_sysreg(far_el1);
if (!is_ttbr0_addr(instruction_pointer(regs)))
arm64_apply_bp_hardening();
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_sp_pc_abort(far, esr, regs);
}
static void noinstr el0_sp(struct pt_regs *regs, unsigned long esr)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_sp_pc_abort(regs->sp, esr, regs);
}
static void noinstr el0_undef(struct pt_regs *regs)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_undefinstr(regs);
}
static void noinstr el0_bti(struct pt_regs *regs)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_bti(regs);
}
static void noinstr el0_inv(struct pt_regs *regs, unsigned long esr)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
bad_el0_sync(regs, 0, esr);
}
static void noinstr el0_dbg(struct pt_regs *regs, unsigned long esr)
{
/* Only watchpoints write FAR_EL1, otherwise its UNKNOWN */
unsigned long far = read_sysreg(far_el1);
if (system_uses_irq_prio_masking())
gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
enter_from_user_mode();
do_debug_exception(far, esr, regs);
local_daif_restore(DAIF_PROCCTX_NOIRQ);
}
static void noinstr el0_svc(struct pt_regs *regs)
{
if (system_uses_irq_prio_masking())
gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
enter_from_user_mode();
do_el0_svc(regs);
}
static void noinstr el0_fpac(struct pt_regs *regs, unsigned long esr)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_ptrauth_fault(regs, esr);
}
asmlinkage void noinstr el0_sync_handler(struct pt_regs *regs)
{
unsigned long esr = read_sysreg(esr_el1);
switch (ESR_ELx_EC(esr)) {
case ESR_ELx_EC_SVC64:
el0_svc(regs);
break;
case ESR_ELx_EC_DABT_LOW:
el0_da(regs, esr);
break;
case ESR_ELx_EC_IABT_LOW:
el0_ia(regs, esr);
break;
case ESR_ELx_EC_FP_ASIMD:
el0_fpsimd_acc(regs, esr);
break;
case ESR_ELx_EC_SVE:
el0_sve_acc(regs, esr);
break;
case ESR_ELx_EC_FP_EXC64:
el0_fpsimd_exc(regs, esr);
break;
case ESR_ELx_EC_SYS64:
case ESR_ELx_EC_WFx:
el0_sys(regs, esr);
break;
case ESR_ELx_EC_SP_ALIGN:
el0_sp(regs, esr);
break;
case ESR_ELx_EC_PC_ALIGN:
el0_pc(regs, esr);
break;
case ESR_ELx_EC_UNKNOWN:
el0_undef(regs);
break;
case ESR_ELx_EC_BTI:
el0_bti(regs);
break;
case ESR_ELx_EC_BREAKPT_LOW:
case ESR_ELx_EC_SOFTSTP_LOW:
case ESR_ELx_EC_WATCHPT_LOW:
case ESR_ELx_EC_BRK64:
el0_dbg(regs, esr);
break;
case ESR_ELx_EC_FPAC:
el0_fpac(regs, esr);
break;
default:
el0_inv(regs, esr);
}
}
#ifdef CONFIG_COMPAT
static void noinstr el0_cp15(struct pt_regs *regs, unsigned long esr)
{
enter_from_user_mode();
local_daif_restore(DAIF_PROCCTX);
do_cp15instr(esr, regs);
}
static void noinstr el0_svc_compat(struct pt_regs *regs)
{
if (system_uses_irq_prio_masking())
gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
enter_from_user_mode();
do_el0_svc_compat(regs);
}
asmlinkage void noinstr el0_sync_compat_handler(struct pt_regs *regs)
{
unsigned long esr = read_sysreg(esr_el1);
switch (ESR_ELx_EC(esr)) {
case ESR_ELx_EC_SVC32:
el0_svc_compat(regs);
break;
case ESR_ELx_EC_DABT_LOW:
el0_da(regs, esr);
break;
case ESR_ELx_EC_IABT_LOW:
el0_ia(regs, esr);
break;
case ESR_ELx_EC_FP_ASIMD:
el0_fpsimd_acc(regs, esr);
break;
case ESR_ELx_EC_FP_EXC32:
el0_fpsimd_exc(regs, esr);
break;
case ESR_ELx_EC_PC_ALIGN:
el0_pc(regs, esr);
break;
case ESR_ELx_EC_UNKNOWN:
case ESR_ELx_EC_CP14_MR:
case ESR_ELx_EC_CP14_LS:
case ESR_ELx_EC_CP14_64:
el0_undef(regs);
break;
case ESR_ELx_EC_CP15_32:
case ESR_ELx_EC_CP15_64:
el0_cp15(regs, esr);
break;
case ESR_ELx_EC_BREAKPT_LOW:
case ESR_ELx_EC_SOFTSTP_LOW:
case ESR_ELx_EC_WATCHPT_LOW:
case ESR_ELx_EC_BKPT32:
el0_dbg(regs, esr);
break;
default:
el0_inv(regs, esr);
}
}
#endif /* CONFIG_COMPAT */
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