RE: [PATCH] Implemented sysconf for Arm

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 <[email protected]>
Cc: Niklas DAHLQUIST <[email protected]>
Subject: RE: [PATCH] Implemented sysconf for Arm

Ping

-----Original Message-----
From: Newlib <[email protected]> On Behalf Of Torbjorn SVENSSON via Newlib
Sent: den 27 april 2020 17:31
To: [email protected]
Cc: Niklas DAHLQUIST <[email protected]>
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 <[email protected]>
Signed-off-by: Niklas DAHLQUIST <[email protected]>
---
 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