powerpc: split compat syscall table out from native table

PowerPC uses a syscall table with native and compat calls
interleaved, which is a slightly simpler way to define two
matching tables.

As we move to having the tables generated, that advantage
is no longer important, but the interleaved table gets in
the way of using the same scripts as on the other archit-
ectures.

Split out a new compat_sys_call_table symbol that contains
all the compat calls, and leave the main table for the nat-
ive calls, to more closely match the method we use every-
where else.

Suggested-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Firoz Khan <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>

arch/powerpc/include/asm/syscall.h

···
 #include <linux/thread_info.h>
 
 /* ftrace syscalls requires exporting the sys_call_table */
-#ifdef CONFIG_FTRACE_SYSCALLS
 extern const unsigned long sys_call_table[];
-#endif /* CONFIG_FTRACE_SYSCALLS */
+extern const unsigned long compat_sys_call_table[];
 
 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
 {

arch/powerpc/kernel/entry_64.S

···
 SYS_CALL_TABLE:
 	.tc sys_call_table[TC],sys_call_table
 
+COMPAT_SYS_CALL_TABLE:
+	.tc compat_sys_call_table[TC],compat_sys_call_table
+
 /* This value is used to mark exception frames on the stack. */
 exception_marker:
 	.tc	ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER
···
 	ld	r11,SYS_CALL_TABLE@toc(2)
 	andis.	r10,r10,_TIF_32BIT@h
 	beq	15f
-	addi	r11,r11,8	/* use 32-bit syscall entries */
+	ld	r11,COMPAT_SYS_CALL_TABLE@toc(2)
 	clrldi	r3,r3,32
 	clrldi	r4,r4,32
 	clrldi	r5,r5,32
···
 	clrldi	r7,r7,32
 	clrldi	r8,r8,32
 15:
-	slwi	r0,r0,4
+	slwi	r0,r0,3
 
 	barrier_nospec_asm
 	/*

arch/powerpc/kernel/systbl.S

···
 #include <asm/ppc_asm.h>
 
 #ifdef CONFIG_PPC64
-#define SYSCALL(func)		.8byte	DOTSYM(sys_##func),DOTSYM(sys_##func)
-#define COMPAT_SYS(func)	.8byte	DOTSYM(sys_##func),DOTSYM(compat_sys_##func)
-#define PPC_SYS(func)		.8byte	DOTSYM(ppc_##func),DOTSYM(ppc_##func)
-#define OLDSYS(func)		.8byte	DOTSYM(sys_ni_syscall),DOTSYM(sys_ni_syscall)
-#define SYS32ONLY(func)		.8byte	DOTSYM(sys_ni_syscall),DOTSYM(compat_sys_##func)
-#define PPC64ONLY(func)		.8byte	DOTSYM(ppc_##func),DOTSYM(sys_ni_syscall)
-#define SYSX(f, f3264, f32)	.8byte	DOTSYM(f),DOTSYM(f3264)
+#define SYSCALL(func)		.8byte	DOTSYM(sys_##func)
+#define COMPAT_SYS(func)	.8byte	DOTSYM(sys_##func)
+#define PPC_SYS(func)		.8byte	DOTSYM(ppc_##func)
+#define OLDSYS(func)		.8byte	DOTSYM(sys_ni_syscall)
+#define SYS32ONLY(func)		.8byte	DOTSYM(sys_ni_syscall)
+#define PPC64ONLY(func)		.8byte	DOTSYM(ppc_##func)
+#define SYSX(f, f3264, f32)	.8byte	DOTSYM(f)
 #else
 #define SYSCALL(func)		.long	sys_##func
 #define COMPAT_SYS(func)	.long	sys_##func
···
 
 .globl sys_call_table
 sys_call_table:
+#include <asm/systbl.h>
 
+#undef SYSCALL
+#undef COMPAT_SYS
+#undef PPC_SYS
+#undef OLDSYS
+#undef SYS32ONLY
+#undef PPC64ONLY
+#undef SYSX
+
+#ifdef CONFIG_COMPAT
+#define SYSCALL(func)		.8byte	DOTSYM(sys_##func)
+#define COMPAT_SYS(func)	.8byte	DOTSYM(compat_sys_##func)
+#define PPC_SYS(func)		.8byte	DOTSYM(ppc_##func)
+#define OLDSYS(func)		.8byte	DOTSYM(sys_ni_syscall)
+#define SYS32ONLY(func)		.8byte	DOTSYM(compat_sys_##func)
+#define PPC64ONLY(func)		.8byte	DOTSYM(sys_ni_syscall)
+#define SYSX(f, f3264, f32)	.8byte	DOTSYM(f3264)
+
+.globl compat_sys_call_table
+compat_sys_call_table:
 #define compat_sys_sigsuspend	sys_sigsuspend
 #include <asm/systbl.h>
+#endif

arch/powerpc/kernel/vdso.c

···
 {
 	unsigned int i;
 	extern unsigned long *sys_call_table;
+#ifdef CONFIG_PPC64
+	extern unsigned long *compat_sys_call_table;
+#endif
 	extern unsigned long sys_ni_syscall;
 
 
 	for (i = 0; i < NR_syscalls; i++) {
 #ifdef CONFIG_PPC64
-		if (sys_call_table[i*2] != sys_ni_syscall)
+		if (sys_call_table[i] != sys_ni_syscall)
 			vdso_data->syscall_map_64[i >> 5] |=
 				0x80000000UL >> (i & 0x1f);
-		if (sys_call_table[i*2+1] != sys_ni_syscall)
+		if (compat_sys_call_table[i] != sys_ni_syscall)
 			vdso_data->syscall_map_32[i >> 5] |=
 				0x80000000UL >> (i & 0x1f);
 #else /* CONFIG_PPC64 */