From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 11CAB3858CD1; Thu, 28 Dec 2023 08:59:01 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 11CAB3858CD1
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1703753942;
	bh=IF6uKWKjMLuEdDFk1Whc/Suk+gBwfHaG5nPIz9yNzSI=;
	h=From:To:Subject:Date:From;
	b=YIYea0FXA4krrgwX+oXhweaz8Gug7hYWmcOu2KYM/6Bm/T5BIJ5Jz9CsdkJa+Efay
	 xeWcRiwh6eiDQjLPbAJmkPMQ5BC3NuJ2vCCNKdPD9lQMU0OMJLJrFO7yMJRa31IIwK
	 KD681sKAwW5+5y2U2EAebgpo4Vq+Gaxw43I2yxD8=
From: "kirdyankinsp at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/113161] New: Add a special "ramfunc" attribute for
 sections in the linker script (*.ld files)
Date: Thu, 28 Dec 2023 08:58:54 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Version: unknown
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: kirdyankinsp at gmail dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
Message-ID: <bug-113161-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113161

            Bug ID: 113161
           Summary: Add a special "ramfunc" attribute for sections in the
                    linker script (*.ld files)
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kirdyankinsp at gmail dot com
  Target Milestone: ---

In embedded systems (microcontrollers), time-critical functions (for exampl=
e,
functions used in interrupts) are often copied from slow FLASH memory to RA=
M at
startup for faster execution.
How to do it:
https://www.st.com/resource/en/application_note/dm00083249-use-stm32f3-stm3=
2g4-ccm-sram-with-iar-ewarm-keil-mdk-arm-and-gnu-based
-toolchains-stmicroelectronics.pdf
In this case, a problem is possible: inside such a function, a function loc=
ated
in slow (Flash) memory can be called. Which the programmer certainly doesn=
=E2=80=99t
want. If programmer copies a function into RAM, he of course wants everythi=
ng
that this function performs to be in RAM too.
I propose to add a warning output about calling a function located in slow
memory from a function located in fast memory.
Here's how it works in the IAR compiler:
"C:foo.c",44 Warning[Ta023]:
   Call to a non __ramfunc function (foo()) from within a __ramfunc function
foo2();

I think for this it is necessary to add a special attribute for sections in=
 the
linker script, which will indicate to the linker that all functions in this
section must call functions from the same section, otherwise they will issu=
e a
warning.=