On Mon, Jan 02, 2023 at 10:35:27PM -0500, 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) That's generally true, and makes sense to me, but .... > Link: https://lore.kernel.org/linux-riscv/YxcQ6NoPf3AH0EXe@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > Reviewed-by: Björn Töpel <bjorn@xxxxxxxxxxxx> > Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Tested-by: Jisheng Zhang <jszhang@xxxxxxxxxx> > 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 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 >
