On Thu, Jan 16, 2014 at 12:26:53PM +0000, Jean Pihet wrote: > On 16 January 2014 12:56, Will Deacon <[email protected]> wrote: > > In your previous series, compat backtracing is actually split out into a > > separate function (compat_user_backtrace), so it would be more consistent to > > have a compat_user_stack_pointer macro, rather than add this check here. > > Do you mean this change instead?
I don't think so... > diff --git a/kernel/events/internal.h b/kernel/events/internal.h > index 569b2187..9b88d2e 100644 > --- a/kernel/events/internal.h > +++ b/kernel/events/internal.h > @@ -185,7 +185,8 @@ static inline bool arch_perf_have_user_stack_dump(void) > return true; > } > > -#define perf_user_stack_pointer(regs) user_stack_pointer(regs) > +#define perf_user_stack_pointer(regs) \ > + (!compat_user_mode(regs)) ? ((regs)->sp) : ((regs)->compat_sp) This doesn't belong in core code; compat_user_mode and the fields of regs are arm64-specific. So I suppose you need to rework your original patch to call compat_user_stack_pointer (which we already define in compat.h for arm64) if compat_user_mode(regs)). The problem there is the inconsistency with respect to the regs argument: user_stack_pointer(regs) // Returns user stack pointer for regs current_user_stack_pointer() // Returns current user stack pointer compat_user_stack_pointer() // Doesn't take a regs argument! On top of that, x86 treats those last two functions differently when current is a compat task. So the simplest thing would be to make compat_user_stack_pointer expand to user_stack_pointer(current_pt_regs()) on arm64 and merge that in with your original patch fixing user_stack_pointer. Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
