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>

7 files changed, 60 insertions, 5 deletions

diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild
index 43910cdf78a5..e121c30f797d 100644
--- a/arch/sh/include/asm/Kbuild
+++ b/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
diff --git a/arch/sh/include/asm/cachectl.h b/arch/sh/include/asm/cachectl.h
new file mode 100644
index 000000000000..305dd7082a66
--- /dev/null
+++ b/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 */
diff --git a/arch/sh/include/asm/unistd_32.h b/arch/sh/include/asm/unistd_32.h
index 61d6ad93d786..925dd40d9d55 100644
--- a/arch/sh/include/asm/unistd_32.h
+++ b/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
diff --git a/arch/sh/include/asm/unistd_64.h b/arch/sh/include/asm/unistd_64.h
index a751699afda3..2b84bc916bc5 100644
--- a/arch/sh/include/asm/unistd_64.h
+++ b/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
diff --git a/arch/sh/kernel/sys_sh.c b/arch/sh/kernel/sys_sh.c
index 90d00e47264d..ec65dd8842b1 100644
--- a/arch/sh/kernel/sys_sh.c
+++ b/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;
diff --git a/arch/sh/kernel/syscalls_32.S b/arch/sh/kernel/syscalls_32.S
index f9e21fa2f592..16ba225ede89 100644
--- a/arch/sh/kernel/syscalls_32.S
+++ b/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
diff --git a/arch/sh/kernel/syscalls_64.S b/arch/sh/kernel/syscalls_64.S
index bf420b616ae0..af6fb7410c21 100644
--- a/arch/sh/kernel/syscalls_64.S
+++ b/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