[PATCH] Implemented sysconf for Arm

[Corinna Vinschen]

Adding Richard to this thread

On May 19 16:17, Torbjorn SVENSSON via Newlib wrote:
> Ping2!
> 
> If it's not clear to the reviewer, the use-case that we want to fulfill here is to be able to override the page size for the malloc() call for the project and not require a new build of newlib.
> With this approach, simply re-implementing the function sysconf(int) in the application to return the appropriate page size for the application and have the linker will select the local implementation over the newlib provided one is enough to reserve a smaller memory block for malloc.
> 
> I also need assistance to push the patch since I've not got commit access.
> 
> Thanks.
> 
> Torbjörn
> 
> -----Original Message-----
> From: Torbjorn SVENSSON 
> Sent: den 7 maj 2020 10:29
> To: Newlib <newlib-bounces@sourceware.org>
> Cc: Niklas DAHLQUIST <niklas.dahlquist@st.com>
> Subject: RE: [PATCH] Implemented sysconf for Arm
> 
> Ping
> 
> -----Original Message-----
> From: Newlib <newlib-bounces@sourceware.org> On Behalf Of Torbjorn SVENSSON via Newlib
> Sent: den 27 april 2020 17:31
> To: newlib@sourceware.org
> Cc: Niklas DAHLQUIST <niklas.dahlquist@st.com>
> Subject: [PATCH] Implemented sysconf for Arm
> 
> The default implementation can be overridden outside newlib to allow a
> different page size to improve malloc on devices with a small footprint
> without needing to rebuild newlib.
> 
> Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@st.com>
> Signed-off-by: Niklas DAHLQUIST <niklas.dahlquist@st.com>
> ---
>  newlib/libc/stdlib/mallocr.c    |  2 +-
>  newlib/libc/sys/arm/Makefile.am |  2 +-
>  newlib/libc/sys/arm/Makefile.in | 12 ++++++++++--
>  newlib/libc/sys/arm/sysconf.c   | 20 ++++++++++++++++++++
>  4 files changed, 32 insertions(+), 4 deletions(-)
>  create mode 100644 newlib/libc/sys/arm/sysconf.c
> 
> diff --git a/newlib/libc/stdlib/mallocr.c b/newlib/libc/stdlib/mallocr.c
> index 26d1c89cc..28d278f51 100644
> --- a/newlib/libc/stdlib/mallocr.c
> +++ b/newlib/libc/stdlib/mallocr.c
> @@ -316,7 +316,7 @@ extern "C" {
>  # undef WIN32
>  #endif
>  
> -#ifndef _WIN32
> +#if !defined(_WIN32) && !defined(__ARM_EABI__)
>  #ifdef SMALL_MEMORY
>  #define malloc_getpagesize (128)
>  #else
> diff --git a/newlib/libc/sys/arm/Makefile.am b/newlib/libc/sys/arm/Makefile.am
> index 711872de3..9111f3647 100644
> --- a/newlib/libc/sys/arm/Makefile.am
> +++ b/newlib/libc/sys/arm/Makefile.am
> @@ -14,7 +14,7 @@ else
>  extra_objs =
>  endif
>  
> -lib_a_SOURCES = access.c aeabi_atexit.c
> +lib_a_SOURCES = access.c aeabi_atexit.c sysconf.c
>  lib_a_LIBADD = $(extra_objs)
>  EXTRA_lib_a_SOURCES = trap.S syscalls.c libcfunc.c
>  lib_a_DEPENDENCIES = $(extra_objs)
> diff --git a/newlib/libc/sys/arm/Makefile.in b/newlib/libc/sys/arm/Makefile.in
> index c01e4e2ed..67fb695f5 100644
> --- a/newlib/libc/sys/arm/Makefile.in
> +++ b/newlib/libc/sys/arm/Makefile.in
> @@ -70,7 +70,8 @@ ARFLAGS = cru
>  lib_a_AR = $(AR) $(ARFLAGS)
>  @MAY_SUPPLY_SYSCALLS_TRUE@am__DEPENDENCIES_1 = $(lpfx)libcfunc.o \
>  @MAY_SUPPLY_SYSCALLS_TRUE@	$(lpfx)trap.o $(lpfx)syscalls.o
> -am_lib_a_OBJECTS = lib_a-access.$(OBJEXT) lib_a-aeabi_atexit.$(OBJEXT)
> +am_lib_a_OBJECTS = lib_a-access.$(OBJEXT) lib_a-aeabi_atexit.$(OBJEXT) \
> +	lib_a-sysconf.$(OBJEXT)
>  lib_a_OBJECTS = $(am_lib_a_OBJECTS)
>  DEFAULT_INCLUDES = -I.@am__isrc@
>  depcomp =
> @@ -183,6 +184,7 @@ pdfdir = @pdfdir@
>  prefix = @prefix@
>  program_transform_name = @program_transform_name@
>  psdir = @psdir@
> +runstatedir = @runstatedir@
>  sbindir = @sbindir@
>  sharedstatedir = @sharedstatedir@
>  srcdir = @srcdir@
> @@ -198,7 +200,7 @@ AM_CCASFLAGS = $(INCLUDES)
>  noinst_LIBRARIES = lib.a
>  @MAY_SUPPLY_SYSCALLS_FALSE@extra_objs = 
>  @MAY_SUPPLY_SYSCALLS_TRUE@extra_objs = $(lpfx)libcfunc.o $(lpfx)trap.o $(lpfx)syscalls.o
> -lib_a_SOURCES = access.c aeabi_atexit.c
> +lib_a_SOURCES = access.c aeabi_atexit.c sysconf.c
>  lib_a_LIBADD = $(extra_objs)
>  EXTRA_lib_a_SOURCES = trap.S syscalls.c libcfunc.c
>  lib_a_DEPENDENCIES = $(extra_objs)
> @@ -288,6 +290,12 @@ lib_a-aeabi_atexit.o: aeabi_atexit.c
>  lib_a-aeabi_atexit.obj: aeabi_atexit.c
>  	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-aeabi_atexit.obj `if test -f 'aeabi_atexit.c'; then $(CYGPATH_W) 'aeabi_atexit.c'; else $(CYGPATH_W) '$(srcdir)/aeabi_atexit.c'; fi`
>  
> +lib_a-sysconf.o: sysconf.c
> +	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-sysconf.o `test -f 'sysconf.c' || echo '$(srcdir)/'`sysconf.c
> +
> +lib_a-sysconf.obj: sysconf.c
> +	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-sysconf.obj `if test -f 'sysconf.c'; then $(CYGPATH_W) 'sysconf.c'; else $(CYGPATH_W) '$(srcdir)/sysconf.c'; fi`
> +
>  lib_a-syscalls.o: syscalls.c
>  	$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(lib_a_CFLAGS) $(CFLAGS) -c -o lib_a-syscalls.o `test -f 'syscalls.c' || echo '$(srcdir)/'`syscalls.c
>  
> diff --git a/newlib/libc/sys/arm/sysconf.c b/newlib/libc/sys/arm/sysconf.c
> new file mode 100644
> index 000000000..86a324fa4
> --- /dev/null
> +++ b/newlib/libc/sys/arm/sysconf.c
> @@ -0,0 +1,20 @@
> +/* libc/sys/arm/sysconf.c - The sysconf function */
> +
> +/* Copyright 2020, STMicroelectronics */
> +
> +#include <unistd.h>
> +#include <errno.h>
> +
> +long sysconf(int name)
> +{
> +  switch (name)
> +  {
> +  case _SC_PAGESIZE:
> +    return 4096;
> +
> +  default:
> +    errno = EINVAL;
> +    return -1;
> +  }
> +  return -1; /* Can't get here */
> +}
> -- 
> 2.18.0

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat