From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 74CD518E74F for ; Tue, 20 Aug 2024 11:42:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724154135; cv=none; b=cg4tQ1ONBbpy7663qudXtk7zytqd5HZTghoI5vOSXjEnxGO0PAdYzeYjFC6aQPpIdaRLsPU/SvOauFwIRjUc2xYl+TzjHXghI47XFFsGI78lg+cxHpYZ/6ghartFu2CtL/dnlKZ7JjdFVas0DT+3YWocqm08i20eRP22b/TpQek= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724154135; c=relaxed/simple; bh=KW3sUY5SFmPr5/j0wKszVuVVLqTZjHtMph0oPyZSxj0=; h=Message-ID:Date:MIME-Version:Subject:To:References:Cc:From: In-Reply-To:Content-Type; b=u65Aitrt2GfCOemfRPayE5mRFzQMjTa6hm4m/pDO4dvNNiRF7FmE41Ii2KNDh4TmAcEaMn7Bz5zO/1TG+uODprjamnTNt4EQUfp/uhpP9fGifaffsB2kRozaLw6RcgYM65ZA+OcDRgZny+FsgVoT4aXfguESJLfvDFCivoLIPQM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B573ADA7; Tue, 20 Aug 2024 04:42:37 -0700 (PDT) Received: from [10.57.70.240] (unknown [10.57.70.240]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 205673F73B; Tue, 20 Aug 2024 04:42:02 -0700 (PDT) Message-ID: <1ce09739-14a4-42a2-b5c9-66fdc72ae999@arm.com> Date: Tue, 20 Aug 2024 13:41:58 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/3] entry: Add some arch funcs to support arm64 to use generic entry To: Jinjie Ruan References: <20240629085601.470241-1-ruanjinjie@huawei.com> <20240629085601.470241-2-ruanjinjie@huawei.com> Content-Language: en-GB Cc: catalin.marinas@arm.com, will@kernel.org, oleg@redhat.com, tglx@linutronix.de, peterz@infradead.org, luto@kernel.org, kees@kernel.org, wad@chromium.org, rostedt@goodmis.org, arnd@arndb.de, ardb@kernel.org, broonie@kernel.org, mark.rutland@arm.com, rick.p.edgecombe@intel.com, leobras@redhat.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org From: Kevin Brodsky In-Reply-To: <20240629085601.470241-2-ruanjinjie@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 29/06/2024 10:55, Jinjie Ruan wrote: > Add some arch functions to support arm64 to use generic entry, which do not > affect existing architectures that use generic entry: > > - arch_prepare/post_report_syscall_entry/exit(). > > - arch_enter_from_kernel_mode(), arch_exit_to_kernel_mode_prepare(). > > - arch_irqentry_exit_need_resched() to support architecture-related > need_resched() check logic. > > Also make syscall_exit_work() not static and move report_single_step() to > thread_info.h, which can be used by arm64 later. > > x86 and Riscv compilation test ok after this patch. > > Signed-off-by: Jinjie Ruan > Suggested-by: Thomas Gleixner > --- > v3: > - Make the arch funcs not use __weak as Thomas suggested. > - Make arch_forget_syscall() folded in arch_post_report_syscall_entry(). > - __always_inline -> inline. > - Move report_single_step() to thread_info.h for arm64 > - Add Suggested-by. > - Update the commit message. > > v2: > - Fix a bug that not call arch_post_report_syscall_entry() in > syscall_trace_enter() if ptrace_report_syscall_entry() return not zero. > - Update the commit message. > --- > include/linux/entry-common.h | 90 ++++++++++++++++++++++++++++++++++++ > include/linux/thread_info.h | 13 ++++++ > kernel/entry/common.c | 37 +++++++-------- > 3 files changed, 122 insertions(+), 18 deletions(-) > > diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h > index b0fb775a600d..2aea23ca9d66 100644 > --- a/include/linux/entry-common.h > +++ b/include/linux/entry-common.h > @@ -290,6 +290,94 @@ static __always_inline void arch_exit_to_user_mode(void); > static __always_inline void arch_exit_to_user_mode(void) { } > #endif > > +/** > + * arch_enter_from_kernel_mode - Architecture specific check work. Maybe those comments could be expanded to be closer to the existing ones, like arch_enter_from_user_mode()? It would help if they were more specific as to where they are called (especially the *report_syscall* ones) and how they are expected to be used. > + */ > +static inline void arch_enter_from_kernel_mode(struct pt_regs *regs); > + > +#ifndef arch_enter_from_kernel_mode > +static inline void arch_enter_from_kernel_mode(struct pt_regs *regs) { } > +#endif > + > +/** > + * arch_exit_to_kernel_mode_prepare - Architecture specific final work before > + * exit to kernel mode. > + */ > +static inline void arch_exit_to_kernel_mode_prepare(struct pt_regs *regs); Any reason to suffix this function with "prepare"? Just arch_exit_to_kernel_mode() seems appropriate (symmetric with arch_enter_from_kernel_mode()). > + > +#ifndef arch_exit_to_kernel_mode_prepare > +static inline void arch_exit_to_kernel_mode_prepare(struct pt_regs *regs) { } > +#endif > + > +/** > + * arch_prepare_report_syscall_entry - Architecture specific work before > + * report_syscall_entry(). > + */ > +static inline unsigned long arch_prepare_report_syscall_entry(struct pt_regs *regs); The most common naming patterns for such arch helper pairs seems to be pre/post, so maybe arch_pre_report_syscall_entry()? > + > +#ifndef arch_prepare_report_syscall_entry > +static inline unsigned long arch_prepare_report_syscall_entry(struct pt_regs *regs) > +{ > + return 0; > +} > +#endif > + > +/** > + * arch_post_report_syscall_entry - Architecture specific work after > + * report_syscall_entry(). > + */ > +static inline void arch_post_report_syscall_entry(struct pt_regs *regs, > + unsigned long saved_reg, > + long ret); > + > +#ifndef arch_post_report_syscall_entry > +static inline void arch_post_report_syscall_entry(struct pt_regs *regs, > + unsigned long saved_reg, > + long ret) > +{ > +} > +#endif > + > +/** > + * arch_prepare_report_syscall_exit - Architecture specific work before > + * report_syscall_exit(). > + */ > +static inline unsigned long arch_prepare_report_syscall_exit(struct pt_regs *regs, > + unsigned long work); > + > +#ifndef arch_prepare_report_syscall_exit > +static inline unsigned long arch_prepare_report_syscall_exit(struct pt_regs *regs, > + unsigned long work) > +{ > + return 0; > +} > +#endif > + > +/** > + * arch_post_report_syscall_exit - Architecture specific work after > + * report_syscall_exit(). > + */ > +static inline void arch_post_report_syscall_exit(struct pt_regs *regs, > + unsigned long saved_reg, > + unsigned long work); > + > +#ifndef arch_post_report_syscall_exit > +static inline void arch_post_report_syscall_exit(struct pt_regs *regs, > + unsigned long saved_reg, > + unsigned long work) > +{ > +} > +#endif > + > +/** > + * arch_irqentry_exit_need_resched - Architecture specific need resched function > + */ > +static inline bool arch_irqentry_exit_need_resched(void); > + > +#ifndef arch_irqentry_exit_need_resched > +static inline bool arch_irqentry_exit_need_resched(void) { return true; } > +#endif Nit: the existing arch_* hooks seem to be declared close to the function they are called from (e.g. arch_enter_from_user_mode() just before enter_from_user_mode()), maybe we could do the same with those new hooks, where possible. > + > /** > * arch_do_signal_or_restart - Architecture specific signal delivery function > * @regs: Pointer to currents pt_regs > @@ -552,4 +640,6 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs); > */ > void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state); > > +void syscall_exit_work(struct pt_regs *regs, unsigned long work); > + > #endif > diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h > index 9ea0b28068f4..062de9666ef3 100644 > --- a/include/linux/thread_info.h > +++ b/include/linux/thread_info.h > @@ -55,6 +55,19 @@ enum syscall_work_bit { > #define SYSCALL_WORK_SYSCALL_AUDIT BIT(SYSCALL_WORK_BIT_SYSCALL_AUDIT) > #define SYSCALL_WORK_SYSCALL_USER_DISPATCH BIT(SYSCALL_WORK_BIT_SYSCALL_USER_DISPATCH) > #define SYSCALL_WORK_SYSCALL_EXIT_TRAP BIT(SYSCALL_WORK_BIT_SYSCALL_EXIT_TRAP) > + > +/* > + * If SYSCALL_EMU is set, then the only reason to report is when > + * SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP). This syscall > + * instruction has been already reported in syscall_enter_from_user_mode(). > + */ > +static inline bool report_single_step(unsigned long work) > +{ > + if (work & SYSCALL_WORK_SYSCALL_EMU) > + return false; > + > + return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP; > +} > #endif > > #include > diff --git a/kernel/entry/common.c b/kernel/entry/common.c > index 90843cc38588..cd76391ffcb9 100644 > --- a/kernel/entry/common.c > +++ b/kernel/entry/common.c > @@ -28,6 +28,7 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall) > long syscall_trace_enter(struct pt_regs *regs, long syscall, > unsigned long work) > { > + unsigned long saved_reg; Nit: could be declared inside the if block. Kevin > long ret = 0; > > /* > @@ -42,8 +43,10 @@ long syscall_trace_enter(struct pt_regs *regs, long syscall, > > /* Handle ptrace */ > if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) { > + saved_reg = arch_prepare_report_syscall_entry(regs); > ret = ptrace_report_syscall_entry(regs); > - if (ret || (work & SYSCALL_WORK_SYSCALL_EMU)) > + arch_post_report_syscall_entry(regs, saved_reg, ret); > + if (ret || work & SYSCALL_WORK_SYSCALL_EMU) > return -1L; > } > > [...]