From: Mark Rutland <mark.rutland@arm.com>
To: guoren@kernel.org
Cc: arnd@arndb.de, palmer@rivosinc.com, tglx@linutronix.de,
peterz@infradead.org, luto@kernel.org,
conor.dooley@microchip.com, heiko@sntech.de, jszhang@kernel.org,
lazyparser@gmail.com, falcon@tinylab.org, chenhuacai@kernel.org,
apatel@ventanamicro.com, atishp@atishpatra.org,
palmer@dabbelt.com, paul.walmsley@sifive.com,
zouyipeng@huawei.com, bigeasy@linutronix.de,
David.Laight@aculab.com, chenzhongjin@huawei.com,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org,
Guo Ren <guoren@linux.alibaba.com>
Subject: Re: [PATCH V6 05/11] riscv: traps: Add noinstr to prevent instrumentation inserted
Date: Mon, 3 Oct 2022 12:40:50 +0100 [thread overview]
Message-ID: <YzrKQkK4Kfbd7Wik@FVFF77S0Q05N> (raw)
In-Reply-To: <20221002012451.2351127-6-guoren@kernel.org>
On Sat, Oct 01, 2022 at 09:24:45PM -0400, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> Without noinstr the compiler is free to insert instrumentation (think
> all the k*SAN, KCov, GCov, ftrace etc..) which can call code we're not
> yet ready to run this early in the entry path, for instance it could
> rely on RCU which isn't on yet, or expect lockdep state. (by peterz)
>
> Link: https://lore.kernel.org/linux-riscv/YxcQ6NoPf3AH0EXe@hirez.programming.kicks-ass.net/raw
> Suggested-by: Peter Zijlstra <peterz@infradead.org>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>
> ---
> arch/riscv/kernel/traps.c | 4 ++--
> arch/riscv/mm/fault.c | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> index 635e6ec26938..588e17c386c6 100644
> --- a/arch/riscv/kernel/traps.c
> +++ b/arch/riscv/kernel/traps.c
> @@ -92,9 +92,9 @@ static void do_trap_error(struct pt_regs *regs, int signo, int code,
> }
>
> #if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_RISCV_ALTERNATIVE)
> -#define __trap_section __section(".xip.traps")
> +#define __trap_section __noinstr_section(".xip.traps")
I assume that for CONFIG_XIP_KERNEL, KPROBES is not possible, and so functions
marked with __trap_section don't need to be excluded from kprobes.
Is that assumption correct, or does something need to be done to inhibit that?
Thanks,
Mark.
> #else
> -#define __trap_section
> +#define __trap_section noinstr
> #endif
> #define DO_ERROR_INFO(name, signo, code, str) \
> asmlinkage __visible __trap_section void name(struct pt_regs *regs) \
> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
> index f2fbd1400b7c..c7829289e806 100644
> --- a/arch/riscv/mm/fault.c
> +++ b/arch/riscv/mm/fault.c
> @@ -203,7 +203,7 @@ static inline bool access_error(unsigned long cause, struct vm_area_struct *vma)
> * This routine handles page faults. It determines the address and the
> * problem, and then passes it off to one of the appropriate routines.
> */
> -asmlinkage void do_page_fault(struct pt_regs *regs)
> +asmlinkage void noinstr do_page_fault(struct pt_regs *regs)
> {
> struct task_struct *tsk;
> struct vm_area_struct *vma;
> --
> 2.36.1
>
next prev parent reply other threads:[~2022-10-03 11:41 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-02 1:24 [PATCH V6 00/11] riscv: Add GENERIC_ENTRY support and related features guoren
2022-10-02 1:24 ` [PATCH V6 01/11] riscv: elf_kexec: Fixup compile warning guoren
2022-10-25 1:20 ` liaochang (A)
2022-10-25 2:36 ` Guo Ren
2022-10-02 1:24 ` [PATCH V6 02/11] riscv: compat_syscall_table: " guoren
2022-10-02 1:24 ` [PATCH V6 03/11] riscv: ptrace: Remove duplicate operation guoren
2022-10-02 1:24 ` [PATCH V6 04/11] compiler_types.h: Add __noinstr_section() for noinstr guoren
2022-10-03 11:38 ` Mark Rutland
2022-10-08 1:54 ` Guo Ren
2022-10-20 9:15 ` Mark Rutland
2022-10-20 12:29 ` Guo Ren
2022-10-24 11:56 ` Mark Rutland
2022-10-24 12:06 ` Peter Zijlstra
2022-10-24 12:14 ` Mark Rutland
2022-10-25 2:51 ` Guo Ren
2022-10-25 9:47 ` Mark Rutland
2022-10-02 1:24 ` [PATCH V6 05/11] riscv: traps: Add noinstr to prevent instrumentation inserted guoren
2022-10-03 11:40 ` Mark Rutland [this message]
2022-10-08 2:16 ` Guo Ren
2022-10-02 1:24 ` [PATCH V6 06/11] riscv: convert to generic entry guoren
2022-10-02 1:24 ` [PATCH V6 07/11] riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK guoren
2022-10-02 1:24 ` [PATCH V6 08/11] riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK guoren
2022-10-02 1:24 ` [PATCH V6 09/11] riscv: Add support for STACKLEAK gcc plugin guoren
2022-10-03 11:34 ` Mark Rutland
2022-10-08 0:16 ` Guo Ren
2022-10-08 3:26 ` Guo Ren
2022-10-08 3:44 ` Guo Ren
2022-10-02 1:24 ` [PATCH V6 10/11] riscv: Add config of thread stack size guoren
2022-10-02 1:24 ` [PATCH V6 11/11] riscv: remove extra level wrappers of trace_hardirqs_{on,off} guoren
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