linux/arch/arm64/include/asm/exception.h
Amit Daniel Kachhap e16aeb0726 arm64: ptrauth: Introduce Armv8.3 pointer authentication enhancements
Some Armv8.3 Pointer Authentication enhancements have been introduced
which are mandatory for Armv8.6 and optional for Armv8.3. These features
are,

* ARMv8.3-PAuth2 - An enhanced PAC generation logic is added which hardens
  finding the correct PAC value of the authenticated pointer.

* ARMv8.3-FPAC - Fault is generated now when the ptrauth authentication
  instruction fails in authenticating the PAC present in the address.
  This is different from earlier case when such failures just adds an
  error code in the top byte and waits for subsequent load/store to abort.
  The ptrauth instructions which may cause this fault are autiasp, retaa
  etc.

The above features are now represented by additional configurations
for the Address Authentication cpufeature and a new ESR exception class.

The userspace fault received in the kernel due to ARMv8.3-FPAC is treated
as Illegal instruction and hence signal SIGILL is injected with ILL_ILLOPN
as the signal code. Note that this is different from earlier ARMv8.3
ptrauth where signal SIGSEGV is issued due to Pointer authentication
failures. The in-kernel PAC fault causes kernel to crash.

Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20200914083656.21428-4-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
2020-09-14 12:07:02 +01:00

52 lines
1.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Based on arch/arm/include/asm/exception.h
*
* Copyright (C) 2012 ARM Ltd.
*/
#ifndef __ASM_EXCEPTION_H
#define __ASM_EXCEPTION_H
#include <asm/esr.h>
#include <asm/kprobes.h>
#include <asm/ptrace.h>
#include <linux/interrupt.h>
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
#define __exception_irq_entry __irq_entry
#else
#define __exception_irq_entry __kprobes
#endif
static inline u32 disr_to_esr(u64 disr)
{
unsigned int esr = ESR_ELx_EC_SERROR << ESR_ELx_EC_SHIFT;
if ((disr & DISR_EL1_IDS) == 0)
esr |= (disr & DISR_EL1_ESR_MASK);
else
esr |= (disr & ESR_ELx_ISS_MASK);
return esr;
}
asmlinkage void enter_from_user_mode(void);
void do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs);
void do_undefinstr(struct pt_regs *regs);
void do_bti(struct pt_regs *regs);
asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr);
void do_debug_exception(unsigned long addr_if_watchpoint, unsigned int esr,
struct pt_regs *regs);
void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs);
void do_sve_acc(unsigned int esr, struct pt_regs *regs);
void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs);
void do_sysinstr(unsigned int esr, struct pt_regs *regs);
void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs);
void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr);
void do_cp15instr(unsigned int esr, struct pt_regs *regs);
void do_el0_svc(struct pt_regs *regs);
void do_el0_svc_compat(struct pt_regs *regs);
void do_ptrauth_fault(struct pt_regs *regs, unsigned int esr);
#endif /* __ASM_EXCEPTION_H */