From 4b6ef05b3e89f5bdb888fbd5467e996a9193b884 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@libc.org>
Date: Mon, 15 Feb 2016 18:32:31 +0000
Subject: [PATCH] sh: SMP support for SH2 entry.S

The SH2 version of entry.S uses global variables, which need to be
cpu-local in order to work with SMP. For ease of access from asm,
simply use arrays indexed by cpu number, and require the availability
of an address (mmio register or properly setup per-cpu memory) from
which the current cpu's index can be read.

Signed-off-by: Rich Felker <dalias@libc.org>
---
 arch/sh/kernel/cpu/sh2/entry.S | 50 ++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/arch/sh/kernel/cpu/sh2/entry.S b/arch/sh/kernel/cpu/sh2/entry.S
index 16bde0efaca3..1ee0a6e774c6 100644
--- a/arch/sh/kernel/cpu/sh2/entry.S
+++ b/arch/sh/kernel/cpu/sh2/entry.S
@@ -47,6 +47,13 @@ ENTRY(exception_handler)
 	mov.l	r3,@-sp
 	cli
 	mov.l	$cpu_mode,r2
+#ifdef CONFIG_SMP
+	mov.l	$cpuid,r3
+	mov.l	@r3,r3
+	mov.l	@r3,r3
+	shll2	r3
+	add	r3,r2
+#endif
 	mov.l	@r2,r0
 	mov.l	@(5*4,r15),r3	! previous SR
 	or	r0,r3		! set MD
@@ -57,6 +64,13 @@ ENTRY(exception_handler)
 	mov.l	__md_bit,r0
 	mov.l	r0,@r2		! enter kernel mode
 	mov.l	$current_thread_info,r2
+#ifdef CONFIG_SMP
+	mov.l	$cpuid,r0
+	mov.l	@r0,r0
+	mov.l	@r0,r0
+	shll2	r0
+	add	r0,r2
+#endif
 	mov.l	@r2,r2
 	mov	#(THREAD_SIZE >> 8),r0
 	shll8	r0
@@ -265,6 +279,13 @@ restore_all:
 	lds.l	@r0+,macl
 	mov	r15,r0
 	mov.l	$cpu_mode,r2
+#ifdef CONFIG_SMP
+	mov.l	$cpuid,r3
+	mov.l	@r3,r3
+	mov.l	@r3,r3
+	shll2	r3
+	add	r3,r2
+#endif
 	mov	#OFF_SR,r3
 	mov.l	@(r0,r3),r1
 	mov.l	__md_bit,r3
@@ -281,6 +302,13 @@ restore_all:
 	mov.l	r1,@r2				! set pc
 	get_current_thread_info r0, r1
 	mov.l	$current_thread_info,r1
+#ifdef CONFIG_SMP
+	mov.l	$cpuid,r3
+	mov.l	@r3,r3
+	mov.l	@r3,r3
+	shll2	r3
+	add	r3,r1
+#endif
 	mov.l	r0,@r1
 	mov.l	@r15+,r0
 	mov.l	@r15+,r1
@@ -308,19 +336,41 @@ $current_thread_info:
 	.long	__current_thread_info
 $cpu_mode:	
 	.long	__cpu_mode
+#ifdef CONFIG_SMP
+$cpuid:
+	.long sh2_cpuid_addr
+#endif
 		
 ! common exception handler
 #include "../../entry-common.S"
+
+#ifdef CONFIG_NR_CPUS
+#define NR_CPUS CONFIG_NR_CPUS
+#else
+#define NR_CPUS 1
+#endif
 	
 	.data
 ! cpu operation mode 
 ! bit30 = MD (compatible SH3/4)
 __cpu_mode:
+	.rept	NR_CPUS
 	.long	0x40000000
+	.endr
+
+#ifdef CONFIG_SMP
+.global sh2_cpuid_addr
+sh2_cpuid_addr:
+	.long	dummy_cpuid
+dummy_cpuid:
+	.long	0
+#endif
 		
 	.section	.bss
 __current_thread_info:
+	.rept	NR_CPUS
 	.long	0
+	.endr
 
 ENTRY(exception_handling_table)
 	.space	4*32