From: Huacai Chen <chenhuacai@kernel.org>
To: Lorenz Hetterich <lorenz.hetterich@cispa.de>
Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] LoongArch: Set FAULT_FLAG_INSTRUCTION in __do_page_fault()
Date: Thu, 19 Mar 2026 16:30:50 +0800 [thread overview]
Message-ID: <CAAhV-H42kvs79-bTR+E-89Lthb9F=o8P4_q7ZYwMgEyjywT+kw@mail.gmail.com> (raw)
In-Reply-To: <20260318151821.190439-3-lorenz.hetterich@cispa.de>
Hi, Lorenz,
On Wed, Mar 18, 2026 at 11:18 PM Lorenz Hetterich
<lorenz.hetterich@cispa.de> wrote:
>
> The page-fault handler never sets the FAULT_FLAG_INSTRUCTION flag.
>
> Set FAULT_FLAG_INSTRUCTION for faults related to instruction fetches.
>
> Signed-off-by: Lorenz Hetterich <lorenz.hetterich@cispa.de>
> ---
> arch/loongarch/include/asm/exception.h | 3 +++
> arch/loongarch/mm/fault.c | 3 +++
> 2 files changed, 6 insertions(+)
>
> diff --git a/arch/loongarch/include/asm/exception.h b/arch/loongarch/include/asm/exception.h
> index c6d20736fd92..7305b7065a43 100644
> --- a/arch/loongarch/include/asm/exception.h
> +++ b/arch/loongarch/include/asm/exception.h
> @@ -6,6 +6,9 @@
> #include <asm/ptrace.h>
> #include <linux/kprobes.h>
>
> +#define EXC_PIF 3 /* Page Invalid Fetch */
> +#define EXC_PNX 6 /* Page Non-eXecutable */
Needn't, you can use EXCCODE_TLBI/EXCCODE_TLBNX in loongarch.h directly.
Huacai
> +
> extern void *exception_table[];
>
> void show_registers(struct pt_regs *regs);
> diff --git a/arch/loongarch/mm/fault.c b/arch/loongarch/mm/fault.c
> index c7703bdec4fc..7cd422c1224e 100644
> --- a/arch/loongarch/mm/fault.c
> +++ b/arch/loongarch/mm/fault.c
> @@ -215,6 +215,9 @@ static void __kprobes __do_page_fault(struct pt_regs *regs,
> if (user_mode(regs))
> flags |= FAULT_FLAG_USER;
>
> + if (current->thread.trap_nr == EXC_PIF || current->thread.trap_nr == EXC_PNX)
> + flags |= FAULT_FLAG_INSTRUCTION;
> +
> perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
>
> if (!(flags & FAULT_FLAG_USER))
> --
> 2.43.0
>
prev parent reply other threads:[~2026-03-19 8:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-18 15:18 [PATCH 0/2] Fix issues in LoongArch page fault handling Lorenz Hetterich
2026-03-18 15:18 ` [PATCH 1/2] Loongarch: Fix stale value in __do_page_fault() Lorenz Hetterich
2026-03-19 8:30 ` Huacai Chen
2026-03-18 15:18 ` [PATCH 2/2] LoongArch: Set FAULT_FLAG_INSTRUCTION " Lorenz Hetterich
2026-03-19 8:30 ` Huacai Chen [this message]
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