[PATCH v2 01/27 5.10.y] overflow, tracing: Define the is_signed_type() macro once

Eliav Farber posted 27 patches 3 months, 3 weeks ago
There is a newer version of this series
[PATCH v2 01/27 5.10.y] overflow, tracing: Define the is_signed_type() macro once
Posted by Eliav Farber 3 months, 3 weeks ago
From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit 92d23c6e94157739b997cacce151586a0d07bb8a ]

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>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220826162116.1050972-3-bvanassche@acm.org
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 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 bbd74420fa21..004a030d5ad2 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -245,6 +245,12 @@ 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 73bc67ec2136..e6bf14f462e9 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -29,7 +29,6 @@
  * 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 5af2acb9fb7d..0c8c3cf36f96 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -700,8 +700,6 @@ 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,
-- 
2.47.3
Re: [PATCH v2 01/27 5.10.y] overflow, tracing: Define the is_signed_type() macro once
Posted by Greg KH 3 months, 3 weeks ago
On Fri, Oct 17, 2025 at 09:04:53AM +0000, Eliav Farber wrote:
> From: Bart Van Assche <bvanassche@acm.org>
> 
> [ Upstream commit 92d23c6e94157739b997cacce151586a0d07bb8a ]

This isn't in 5.15.y, why is it needed in 5.10.y?

thanks,

greg k-h
RE: [PATCH v2 01/27 5.10.y] overflow, tracing: Define the is_signed_type() macro once
Posted by Farber, Eliav 3 months, 3 weeks ago
> On Fri, Oct 17, 2025 at 09:04:53AM +0000, Eliav Farber wrote:
> > From: Bart Van Assche <bvanassche@acm.org>
> >
> > [ Upstream commit 92d23c6e94157739b997cacce151586a0d07bb8a ]
>
> This isn't in 5.15.y, why is it needed in 5.10.y?

This is the mainline commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/overflow.h?h=v6.18-rc1&id=92d23c6e94157739b997cacce151586a0d07bb8a

The commit hash is 92d23c6e94157739b997cacce151586a0d07bb8a, which is
the one I used for the backport.

And here is the corresponding commit in the 5.15.y branch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/include/linux/overflow.h?h=v5.15.194&id=ed6e37e30826b12572636c6bbfe6319233690c90
However, the commit message there references a different hash:
a49a64b5bf195381c09202c524f0f84b5f3e816f.

---
Regards, Eliav
Re: [PATCH v2 01/27 5.10.y] overflow, tracing: Define the is_signed_type() macro once
Posted by Greg KH 3 months, 3 weeks ago
On Fri, Oct 17, 2025 at 12:16:27PM +0000, Farber, Eliav wrote:
> > On Fri, Oct 17, 2025 at 09:04:53AM +0000, Eliav Farber wrote:
> > > From: Bart Van Assche <bvanassche@acm.org>
> > >
> > > [ Upstream commit 92d23c6e94157739b997cacce151586a0d07bb8a ]
> >
> > This isn't in 5.15.y, why is it needed in 5.10.y?
> 
> This is the mainline commit:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/overflow.h?h=v6.18-rc1&id=92d23c6e94157739b997cacce151586a0d07bb8a
> 
> The commit hash is 92d23c6e94157739b997cacce151586a0d07bb8a, which is
> the one I used for the backport.
> 
> And here is the corresponding commit in the 5.15.y branch:
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/include/linux/overflow.h?h=v5.15.194&id=ed6e37e30826b12572636c6bbfe6319233690c90
> However, the commit message there references a different hash:
> a49a64b5bf195381c09202c524f0f84b5f3e816f.

Ugh, that hash is invalid, I missed that :(

Thanks for the info, I'll go work on queueing these up.

greg k-h