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, ben@decadent.org.uk, bjorn@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, "Guo Ren" <guoren@linux.alibaba.com>, "Björn Töpel" <bjorn@rivosinc.com> Subject: Re: [PATCH -next V12 3/7] riscv: entry: Add noinstr to prevent instrumentation inserted Date: Wed, 4 Jan 2023 11:55:35 +0000 [thread overview] Message-ID: <Y7VpN/fFjqGJbxPu@FVFF77S0Q05N> (raw) In-Reply-To: <20230103033531.2011112-4-guoren@kernel.org> On Mon, Jan 02, 2023 at 10:35:27PM -0500, 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) That's generally true, and makes sense to me, but .... > Link: https://lore.kernel.org/linux-riscv/YxcQ6NoPf3AH0EXe@hirez.programming.kicks-ass.net/ > Reviewed-by: Björn Töpel <bjorn@rivosinc.com> > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Tested-by: Jisheng Zhang <jszhang@kernel.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 549bde5c970a..96ec76c54ff2 100644 > --- a/arch/riscv/kernel/traps.c > +++ b/arch/riscv/kernel/traps.c > @@ -95,9 +95,9 @@ 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") > #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 d86f7cebd4a7..b26f68eac61c 100644 > --- a/arch/riscv/mm/fault.c > +++ b/arch/riscv/mm/fault.c > @@ -204,7 +204,7 @@ 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) ... why do you need that for do_page_fault? That doesn't (currently) do any entry/exit logic, so this seems unnecessary per the commit description. Thanks, Mark. > { > struct task_struct *tsk; > struct vm_area_struct *vma; > -- > 2.36.1 >
WARNING: multiple messages have this Message-ID (diff)
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, ben@decadent.org.uk, bjorn@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, "Guo Ren" <guoren@linux.alibaba.com>, "Björn Töpel" <bjorn@rivosinc.com> Subject: Re: [PATCH -next V12 3/7] riscv: entry: Add noinstr to prevent instrumentation inserted Date: Wed, 4 Jan 2023 11:55:35 +0000 [thread overview] Message-ID: <Y7VpN/fFjqGJbxPu@FVFF77S0Q05N> (raw) In-Reply-To: <20230103033531.2011112-4-guoren@kernel.org> On Mon, Jan 02, 2023 at 10:35:27PM -0500, 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) That's generally true, and makes sense to me, but .... > Link: https://lore.kernel.org/linux-riscv/YxcQ6NoPf3AH0EXe@hirez.programming.kicks-ass.net/ > Reviewed-by: Björn Töpel <bjorn@rivosinc.com> > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Tested-by: Jisheng Zhang <jszhang@kernel.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 549bde5c970a..96ec76c54ff2 100644 > --- a/arch/riscv/kernel/traps.c > +++ b/arch/riscv/kernel/traps.c > @@ -95,9 +95,9 @@ 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") > #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 d86f7cebd4a7..b26f68eac61c 100644 > --- a/arch/riscv/mm/fault.c > +++ b/arch/riscv/mm/fault.c > @@ -204,7 +204,7 @@ 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) ... why do you need that for do_page_fault? That doesn't (currently) do any entry/exit logic, so this seems unnecessary per the commit description. Thanks, Mark. > { > struct task_struct *tsk; > struct vm_area_struct *vma; > -- > 2.36.1 > _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2023-01-04 11:56 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-01-03 3:35 [PATCH -next V12 0/7] riscv: Add GENERIC_ENTRY support guoren 2023-01-03 3:35 ` guoren 2023-01-03 3:35 ` [PATCH -next V12 1/7] compiler_types.h: Add __noinstr_section() for noinstr guoren 2023-01-03 3:35 ` guoren 2023-01-03 3:35 ` [PATCH -next V12 2/7] riscv: ptrace: Remove duplicate operation guoren 2023-01-03 3:35 ` guoren 2023-01-03 3:35 ` [PATCH -next V12 3/7] riscv: entry: Add noinstr to prevent instrumentation inserted guoren 2023-01-03 3:35 ` guoren 2023-01-03 9:11 ` Alexandre Ghiti 2023-01-03 9:11 ` Alexandre Ghiti 2023-01-04 1:40 ` Guo Ren 2023-01-04 1:40 ` Guo Ren 2023-01-04 12:03 ` Mark Rutland 2023-01-04 12:03 ` Mark Rutland 2023-01-07 11:48 ` Guo Ren 2023-01-07 11:48 ` Guo Ren 2023-01-04 11:55 ` Mark Rutland [this message] 2023-01-04 11:55 ` Mark Rutland 2023-01-07 11:49 ` Guo Ren 2023-01-07 11:49 ` Guo Ren 2023-01-03 3:35 ` [PATCH -next V12 4/7] riscv: entry: Convert to generic entry guoren 2023-01-03 3:35 ` guoren 2023-01-03 3:35 ` [PATCH -next V12 5/7] riscv: entry: Remove extra level wrappers of trace_hardirqs_{on,off} guoren 2023-01-03 3:35 ` guoren 2023-01-03 3:35 ` [PATCH -next V12 6/7] riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork guoren 2023-01-03 3:35 ` guoren 2023-01-03 3:35 ` [PATCH -next V12 7/7] riscv: entry: Consolidate general regs saving/restoring guoren 2023-01-03 3:35 ` guoren
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