Messages in this thread | | | Date | Mon, 29 Aug 2022 12:30:53 -0700 | From | Kees Cook <> | Subject | Re: [PATCH 2/2] overflow, tracing: Define the is_signed_type() macro once |
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On Fri, Aug 26, 2022 at 09:21:16AM -0700, Bart Van Assche wrote: > There are two definitions of the is_signed_type() macro: one in > <linux/overflow.h> and a second definition in <linux/trace_events.h>. > > As suggested by Linus Torvalds, move the definition of the > is_signed_type() macro into the <linux/compiler.h> header file. Change > the definition of the is_signed_type() macro to make sure that it does > not trigger any sparse warnings with future versions of sparse for > bitwise types. See also: > https://lore.kernel.org/all/CAHk-=whjH6p+qzwUdx5SOVVHjS3WvzJQr6mDUwhEyTf6pJWzaQ@mail.gmail.com/ > https://lore.kernel.org/all/CAHk-=wjQGnVfb4jehFR0XyZikdQvCZouE96xR_nnf5kqaM5qqQ@mail.gmail.com/ > > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Dan Williams <dan.j.williams@intel.com> > Cc: Eric Dumazet <edumazet@google.com> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Isabella Basso <isabbasso@riseup.net> > Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> > Cc: Josh Poimboeuf <jpoimboe@kernel.org> > Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> > Cc: Masami Hiramatsu <mhiramat@kernel.org> > Cc: Nathan Chancellor <nathan@kernel.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> > Cc: Sander Vanheule <sander@svanheule.net> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Vlastimil Babka <vbabka@suse.cz> > Cc: Yury Norov <yury.norov@gmail.com> > Signed-off-by: Bart Van Assche <bvanassche@acm.org> > --- > include/linux/compiler.h | 6 ++++++ > include/linux/overflow.h | 1 - > include/linux/trace_events.h | 2 -- > 3 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > index 01ce94b58b42..7713d7bcdaea 100644 > --- a/include/linux/compiler.h > +++ b/include/linux/compiler.h > @@ -239,6 +239,12 @@ static inline void *offset_to_ptr(const int *off) > /* &a[0] degrades to a pointer: a different type from an array */ > #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) > > +/* > + * Whether 'type' is a signed type or an unsigned type. Supports scalar types, > + * bool and also pointer types. > + */ > +#define is_signed_type(type) (((type)(-1)) < (__force type)1) > + > /* > * This is needed in functions which generate the stack canary, see > * arch/x86/kernel/smpboot.c::start_secondary() for an example. > diff --git a/include/linux/overflow.h b/include/linux/overflow.h > index f1221d11f8e5..0eb3b192f07a 100644 > --- a/include/linux/overflow.h > +++ b/include/linux/overflow.h > @@ -30,7 +30,6 @@ > * https://mail-index.netbsd.org/tech-misc/2007/02/05/0000.html - > * credit to Christian Biere. > */ > -#define is_signed_type(type) (((type)(-1)) < (type)1) > #define __type_half_max(type) ((type)1 << (8*sizeof(type) - 1 - is_signed_type(type))) > #define type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T))) > #define type_min(T) ((T)((T)-type_max(T)-(T)1)) > diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h > index b18759a673c6..8401dec93c15 100644 > --- a/include/linux/trace_events.h > +++ b/include/linux/trace_events.h > @@ -814,8 +814,6 @@ extern int trace_add_event_call(struct trace_event_call *call); > extern int trace_remove_event_call(struct trace_event_call *call); > extern int trace_event_get_offsets(struct trace_event_call *call); > > -#define is_signed_type(type) (((type)(-1)) < (type)1) > - > int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set); > int trace_set_clr_event(const char *system, const char *event, int set); > int trace_array_set_clr_event(struct trace_array *tr, const char *system,
Yeah, this looks good. I'll take these as part of the hardening tree since it's touching overflow.h, unless I hear otherwise. :)
-- Kees Cook
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