make 2.4 compile with GCC-3.4.3...

I just upgraded to the most recent 2.4.29-pre1 sources from the CVS archive
with the intent of being able to compile with gcc-3.4.3.

It turns out that the compiler is splitting:

save_static_function(sys_fork);
static_unused int _sys_fork(struct pt_regs regs)

The result being an unusable kernel.

I think that this issue has been discussed before, but I couldn't find the solution in the mail group. So I applied this small hack. The modifications to syscall.c and signal.c may not be necessary, but I borrowed them from the 2.6 tree in hopes of fixing the problem and then moved to the Makefile change.

It may be that only the Makefile change is necessary (I suspect so), but I have not tried it alone.

The CVS versions in the diff are from my local cvs and do not correspond to the linux-mips.org CVS.

David Daney.

Index: kernel/Makefile
===================================================================
RCS file: /linux/linux/arch/mips/kernel/Makefile,v
retrieving revision 1.2
diff -c -p -r1.2 Makefile
*** kernel/Makefile 2 Dec 2004 19:50:05 -0000 1.2
--- kernel/Makefile 3 Dec 2004 03:00:44 -0000
*************** obj-y += branch.o cpu-probe.o irq.o pro
*** 18,23 ****
--- 18,27 ----
traps.o ptrace.o reset.o semaphore.o setup.o syscall.o \
sysmips.o ipc.o scall_o32.o time.o unaligned.o

+ check_gcc = $(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi) +
+ syscall.o signal.o : override CFLAGS += $(call check_gcc, -fno-unit-at-a-time,)
+
obj-$(CONFIG_MODULES) += mips_ksyms.o

obj-$(CONFIG_CPU_R3000) += r2300_fpu.o r2300_switch.o
Index: kernel/signal.c
===================================================================
RCS file: /linux/linux/arch/mips/kernel/signal.c,v retrieving revision 1.1.1.2
diff -c -p -r1.1.1.2 signal.c
*** kernel/signal.c 1 Dec 2004 21:50:39 -0000 1.1.1.2
--- kernel/signal.c 3 Dec 2004 03:00:44 -0000
***************
*** 18,23 ****
--- 18,24 ----
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/unistd.h>
+ #include <linux/compiler.h>

#include <asm/asm.h>
#include <asm/bitops.h>
*************** int copy_siginfo_to_user(siginfo_t *to, *** 76,82 ****
* Atomically swap in the new signal mask, and wait for a signal. */
save_static_function(sys_sigsuspend);
! static_unused int _sys_sigsuspend(struct pt_regs regs)
{
sigset_t *uset, saveset, newset;

--- 77,84 ----
* Atomically swap in the new signal mask, and wait for a signal. */
save_static_function(sys_sigsuspend);
! __attribute_used__ static int
! _sys_sigsuspend(struct pt_regs regs)
{
sigset_t *uset, saveset, newset;

*************** static_unused int _sys_sigsuspend(struct *** 102,108 ****
}

save_static_function(sys_rt_sigsuspend);
! static_unused int _sys_rt_sigsuspend(struct pt_regs regs)
{

  	sigset_t *unewset, saveset, newset;
          size_t sigsetsize;

--- 104,111 ----
}

save_static_function(sys_rt_sigsuspend);
! __attribute_used__ static int
! _sys_rt_sigsuspend(struct pt_regs regs)
{

  	sigset_t *unewset, saveset, newset;
          size_t sigsetsize;

Index: kernel/syscall.c
===================================================================
RCS file: /linux/linux/arch/mips/kernel/syscall.c,v retrieving revision 1.1.1.2
diff -c -p -r1.1.1.2 syscall.c
*** kernel/syscall.c 1 Dec 2004 21:50:39 -0000 1.1.1.2
--- kernel/syscall.c 3 Dec 2004 03:00:44 -0000
***************
*** 25,30 ****
--- 25,31 ----
#include <linux/slab.h>
#include <linux/utsname.h>
#include <linux/unistd.h>
+ #include <linux/compiler.h>
#include <asm/branch.h>
#include <asm/offset.h>
#include <asm/ptrace.h>
*************** sys_mmap2(unsigned long addr, unsigned l *** 158,164 ****
}

save_static_function(sys_fork);
! static_unused int _sys_fork(struct pt_regs regs)
{
int res;

--- 159,166 ----
}

save_static_function(sys_fork);
! __attribute_used__ static int
! _sys_fork(struct pt_regs regs)
{
int res;

*************** static_unused int _sys_fork(struct pt_re *** 168,174 ****

save_static_function(sys_clone);
! static_unused int _sys_clone(struct pt_regs regs)
{
unsigned long clone_flags;
unsigned long newsp;
--- 170,177 ----

save_static_function(sys_clone);
! __attribute_used__ static int
! _sys_clone(struct pt_regs regs)
{
unsigned long clone_flags;
unsigned long newsp;

David Daney wrote:
[snip]

What difference does this cause?

[snip]

These should also use "noinline", like 2.6.

Thiemo