On Mon, Oct 3, 2022 at 7:41 PM Mark Rutland <mark.rutland@xxxxxxx> wrote: > > On Sat, Oct 01, 2022 at 09:24:45PM -0400, guoren@xxxxxxxxxx wrote: > > From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > > > > 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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/raw > > Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > > Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> > > Signed-off-by: Guo Ren <guoren@xxxxxxxxxx> > > --- > > 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? Correct! In riscv, "we select HAVE_KPROBES if !XIP_KERNEL", so don't worry about that. I don't think we could enable kprobe for XIP_KERNEL in the future. > > 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 > > -- Best Regards Guo Ren
