fix ppc64 linkage error on G5

When 2.6.12-rc1-mm1 is configured for a ppc64/G5, so CONFIG_PPC_PSERIES is disabled, linking of vmlinux fails with:

arch/ppc64/kernel/built-in.o(.text+0x7de0): In function `.sys_call_table32':
: undefined reference to .ppc_rtas' arch/ppc64/kernel/built-in.o(.text+0x8668): In function .sys_call_table':
: undefined reference to `.ppc_rtas'
make: *** [.tmp_vmlinux1] Error 1

This is because 2.6.12-rc1-mm1 contains the apparently broken patch:

@@ -680,7 +680,7 @@ _GLOBAL(kernel_thread)
 	ld	r30,-16(r1)
 	blr
 
-#ifdef CONFIG_PPC_RTAS /* hack hack hack */
+#ifndef CONFIG_PPC_RTAS /* hack hack hack */
 #define ppc_rtas	sys_ni_syscall
 #endif
 

It turns out we are trying to fix this problem twice, we may as well remove the #define hack and use cond_syscall.

--

Move the ppc64 specific cond_syscall(ppc_rtas) into sys_ni.c so that it takes effect. With this fixed we can remove the #define hack.

diff -puN arch/ppc64/kernel/misc.S~fix_ppc_rtas arch/ppc64/kernel/misc.S
@@ -680,10 +680,6 @@ _GLOBAL(kernel_thread)
 	ld	r30,-16(r1)
 	blr
 
-#ifdef CONFIG_PPC_RTAS /* hack hack hack */
-#define ppc_rtas	sys_ni_syscall
-#endif
-
 /* Why isn't this a) automatic, b) written in 'C'? */	
 	.balign 8
 _GLOBAL(sys_call_table32)

diff -puN arch/ppc64/kernel/syscalls.c~fix_ppc_rtas arch/ppc64/kernel/syscalls.c
@@ -256,6 +256,3 @@ void do_show_syscall_exit(unsigned long 
 {
 	printk(" -> %lx, current=%p cpu=%d\n", r3, current, smp_processor_id());
 }
-
-/* Only exists on P-series. */
-cond_syscall(ppc_rtas);

diff -puN kernel/sys_ni.c~fix_ppc_rtas kernel/sys_ni.c
@@ -83,3 +83,4 @@ cond_syscall(sys_pciconfig_write);
 cond_syscall(sys_pciconfig_iobase);
 cond_syscall(sys32_ipc);
 cond_syscall(sys32_sysctl);
+cond_syscall(ppc_rtas);