61d64a376e
In general, exceptions taken from EL1 need to be handled separately from
exceptions taken from EL0, as the logic to handle the two cases can be
significantly divergent, and exceptions taken from EL1 typically have
more stringent requirements on locking and instrumentation.
Subsequent patches will rework the way EL1 UNDEFs are handled in order
to address longstanding soundness issues with instrumentation and RCU.
In preparation for that rework, this patch splits the existing
do_undefinstr() handler into separate do_el0_undef() and do_el1_undef()
handlers.
Prior to this patch, do_undefinstr() was marked with NOKPROBE_SYMBOL(),
preventing instrumentation via kprobes. However, do_undefinstr() invokes
other code which can be instrumented, and:
* For UNDEFINED exceptions taken from EL0, there is no risk of recursion
within kprobes. Therefore it is safe for do_el0_undef to be
instrumented with kprobes, and it does not need to be marked with
NOKPROBE_SYMBOL().
* For UNDEFINED exceptions taken from EL1, either:
(a) The exception is has been taken when manipulating SSBS; these cases
are limited and do not occur within code that can be invoked
recursively via kprobes. Hence, in these cases instrumentation
with kprobes is benign.
(b) The exception has been taken for an unknown reason, as other than
manipulating SSBS we do not expect to take UNDEFINED exceptions
from EL1. Any handling of these exception is best-effort.
... and in either case, marking do_el1_undef() with NOKPROBE_SYMBOL()
isn't sufficient to prevent recursion via kprobes as functions it
calls (including die()) are instrumentable via kprobes.
Hence, it's not worthwhile to mark do_el1_undef() with
NOKPROBE_SYMBOL(). The same applies to do_el1_bti() and do_el1_fpac(),
so their NOKPROBE_SYMBOL() annotations are also removed.
Aside from the new instrumentability, there should be no functional
change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20221019144123.612388-3-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
85 lines
3.2 KiB
C
85 lines
3.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Based on arch/arm/include/asm/exception.h
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*
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* Copyright (C) 2012 ARM Ltd.
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*/
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#ifndef __ASM_EXCEPTION_H
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#define __ASM_EXCEPTION_H
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#include <asm/esr.h>
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#include <asm/kprobes.h>
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#include <asm/ptrace.h>
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#include <linux/interrupt.h>
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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#define __exception_irq_entry __irq_entry
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#else
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#define __exception_irq_entry __kprobes
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#endif
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static inline unsigned long disr_to_esr(u64 disr)
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{
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unsigned long esr = ESR_ELx_EC_SERROR << ESR_ELx_EC_SHIFT;
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if ((disr & DISR_EL1_IDS) == 0)
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esr |= (disr & DISR_EL1_ESR_MASK);
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else
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esr |= (disr & ESR_ELx_ISS_MASK);
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return esr;
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}
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asmlinkage void handle_bad_stack(struct pt_regs *regs);
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asmlinkage void el1t_64_sync_handler(struct pt_regs *regs);
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asmlinkage void el1t_64_irq_handler(struct pt_regs *regs);
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asmlinkage void el1t_64_fiq_handler(struct pt_regs *regs);
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asmlinkage void el1t_64_error_handler(struct pt_regs *regs);
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asmlinkage void el1h_64_sync_handler(struct pt_regs *regs);
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asmlinkage void el1h_64_irq_handler(struct pt_regs *regs);
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asmlinkage void el1h_64_fiq_handler(struct pt_regs *regs);
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asmlinkage void el1h_64_error_handler(struct pt_regs *regs);
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asmlinkage void el0t_64_sync_handler(struct pt_regs *regs);
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asmlinkage void el0t_64_irq_handler(struct pt_regs *regs);
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asmlinkage void el0t_64_fiq_handler(struct pt_regs *regs);
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asmlinkage void el0t_64_error_handler(struct pt_regs *regs);
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asmlinkage void el0t_32_sync_handler(struct pt_regs *regs);
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asmlinkage void el0t_32_irq_handler(struct pt_regs *regs);
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asmlinkage void el0t_32_fiq_handler(struct pt_regs *regs);
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asmlinkage void el0t_32_error_handler(struct pt_regs *regs);
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asmlinkage void call_on_irq_stack(struct pt_regs *regs,
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void (*func)(struct pt_regs *));
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asmlinkage void asm_exit_to_user_mode(struct pt_regs *regs);
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void do_mem_abort(unsigned long far, unsigned long esr, struct pt_regs *regs);
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void do_el0_undef(struct pt_regs *regs, unsigned long esr);
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void do_el1_undef(struct pt_regs *regs, unsigned long esr);
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void do_el0_bti(struct pt_regs *regs);
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void do_el1_bti(struct pt_regs *regs, unsigned long esr);
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void do_debug_exception(unsigned long addr_if_watchpoint, unsigned long esr,
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struct pt_regs *regs);
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void do_fpsimd_acc(unsigned long esr, struct pt_regs *regs);
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void do_sve_acc(unsigned long esr, struct pt_regs *regs);
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void do_sme_acc(unsigned long esr, struct pt_regs *regs);
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void do_fpsimd_exc(unsigned long esr, struct pt_regs *regs);
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void do_el0_sys(unsigned long esr, struct pt_regs *regs);
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void do_sp_pc_abort(unsigned long addr, unsigned long esr, struct pt_regs *regs);
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void bad_el0_sync(struct pt_regs *regs, int reason, unsigned long esr);
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void do_el0_cp15(unsigned long esr, struct pt_regs *regs);
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int do_compat_alignment_fixup(unsigned long addr, struct pt_regs *regs);
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void do_el0_svc(struct pt_regs *regs);
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void do_el0_svc_compat(struct pt_regs *regs);
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void do_el0_fpac(struct pt_regs *regs, unsigned long esr);
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void do_el1_fpac(struct pt_regs *regs, unsigned long esr);
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void do_serror(struct pt_regs *regs, unsigned long esr);
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void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags);
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void panic_bad_stack(struct pt_regs *regs, unsigned long esr, unsigned long far);
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#endif /* __ASM_EXCEPTION_H */
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