sh: Add sys_cacheflush() call for SH CPUs.

Adds a system call to allow user code to flush code from the cache.
You can use instructions for the data side, but the iside can
only be done by a flush ROM which really only works with a direct
mapped cache. The later SH4's have 2 way Iside, so this call allows
a portable way to flush the cache.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/Kbuild

@@ -1,6 +1,6 @@
 include include/asm-generic/Kbuild.asm
 
-header-y += cpu-features.h
+header-y += cachectl.h cpu-features.h
 
 unifdef-y += unistd_32.h
 unifdef-y += unistd_64.h

arch/sh/include/asm/cachectl.h

@@ -0,0 +1,12 @@
+#ifndef _SH_CACHECTL_H
+#define _SH_CACHECTL_H
+
+/* Definitions for the cacheflush system call.  */
+
+#define CACHEFLUSH_D_INVAL	0x1	/* invalidate (without write back) */
+#define CACHEFLUSH_D_WB		0x2	/* write back (without invalidate) */
+#define CACHEFLUSH_D_PURGE	0x3	/* writeback and invalidate */
+
+#define CACHEFLUSH_I		0x4
+
+#endif /* _SH_CACHECTL_H */

arch/sh/include/asm/unistd_32.h

@@ -132,7 +132,7 @@
 #define __NR_clone		120
 #define __NR_setdomainname	121
 #define __NR_uname		122
-#define __NR_modify_ldt		123
+#define __NR_cacheflush		123
 #define __NR_adjtimex		124
 #define __NR_mprotect		125
 #define __NR_sigprocmask	126

arch/sh/include/asm/unistd_64.h

@@ -137,7 +137,7 @@
 #define __NR_clone		120
 #define __NR_setdomainname	121
 #define __NR_uname		122
-#define __NR_modify_ldt		123
+#define __NR_cacheflush		123
 #define __NR_adjtimex		124
 #define __NR_mprotect		125
 #define __NR_sigprocmask	126

arch/sh/kernel/sys_sh.c

@@ -25,6 +25,8 @@
 #include <asm/syscalls.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
+#include <asm/cacheflush.h>
+#include <asm/cachectl.h>
 
 static inline long
 do_mmap2(unsigned long addr, unsigned long len, unsigned long prot,
@@ -179,6 +181,47 @@ asmlinkage int sys_ipc(uint call, int first, int second,
 	return -EINVAL;
 }
 
+/* sys_cacheflush -- flush (part of) the processor cache.  */
+asmlinkage int sys_cacheflush(unsigned long addr, unsigned long len, int op)
+{
+	struct vm_area_struct *vma;
+
+	if ((op < 0) || (op > (CACHEFLUSH_D_PURGE|CACHEFLUSH_I)))
+		return -EINVAL;
+
+	/*
+	 * Verify that the specified address region actually belongs
+	 * to this process.
+	 */
+	if (addr + len < addr)
+		return -EFAULT;
+
+	down_read(&current->mm->mmap_sem);
+	vma = find_vma (current->mm, addr);
+	if (vma == NULL || addr < vma->vm_start || addr + len > vma->vm_end) {
+		up_read(&current->mm->mmap_sem);
+		return -EFAULT;
+	}
+
+	switch (op & CACHEFLUSH_D_PURGE) {
+		case CACHEFLUSH_D_INVAL:
+			__flush_invalidate_region((void *)addr, len);
+			break;
+		case CACHEFLUSH_D_WB:
+			__flush_wback_region((void *)addr, len);
+			break;
+		case CACHEFLUSH_D_PURGE:
+			__flush_purge_region((void *)addr, len);
+			break;
+	}
+
+	if (op & CACHEFLUSH_I)
+		flush_cache_all();
+
+	up_read(&current->mm->mmap_sem);
+	return 0;
+}
+
 asmlinkage int sys_uname(struct old_utsname __user *name)
 {
 	int err;

arch/sh/kernel/syscalls_32.S

@@ -139,7 +139,7 @@ ENTRY(sys_call_table)
 	.long sys_clone		/* 120 */
 	.long sys_setdomainname
 	.long sys_newuname
-	.long sys_ni_syscall	/* sys_modify_ldt */
+	.long sys_cacheflush	/* x86: sys_modify_ldt */
 	.long sys_adjtimex
 	.long sys_mprotect		/* 125 */
 	.long sys_sigprocmask

arch/sh/kernel/syscalls_64.S

@@ -143,7 +143,7 @@ sys_call_table:
 	.long sys_clone			/* 120 */
 	.long sys_setdomainname
 	.long sys_newuname
-	.long sys_ni_syscall	/* sys_modify_ldt */
+	.long sys_cacheflush	/* x86: sys_modify_ldt */
 	.long sys_adjtimex
 	.long sys_mprotect		/* 125 */
 	.long sys_sigprocmask