In order to introduce new arch_prctls that are not 64 bit only, rename the
existing 64 bit implementation to do_arch_prctl_64. Also rename the second
argument to arch_prctl, which will no longer always be an address.

Signed-off-by: Kyle Huey <kh...@kylehuey.com>
Reviewed-by: Andy Lutomirski <l...@kernel.org>
---
 arch/x86/include/asm/proto.h |  4 +++-
 arch/x86/kernel/process_64.c | 32 +++++++++++++++++---------------
 arch/x86/kernel/ptrace.c     |  8 ++++----
 arch/x86/um/syscalls_64.c    |  4 ++--
 4 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h
index 9b9b30b..95c3e51 100644
--- a/arch/x86/include/asm/proto.h
+++ b/arch/x86/include/asm/proto.h
@@ -25,11 +25,13 @@ void entry_SYSCALL_compat(void);
 void entry_INT80_compat(void);
 #endif
 
 void x86_configure_nx(void);
 void x86_report_nx(void);
 
 extern int reboot_force;
 
-long do_arch_prctl(struct task_struct *task, int code, unsigned long addr);
+#ifdef CONFIG_X86_64
+long do_arch_prctl_64(struct task_struct *task, int code, unsigned long arg2);
+#endif
 
 #endif /* _ASM_X86_PROTO_H */
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 2718cf9..611df20 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -193,17 +193,17 @@ int copy_thread_tls(unsigned long clone_flags, unsigned 
long sp,
         */
        if (clone_flags & CLONE_SETTLS) {
 #ifdef CONFIG_IA32_EMULATION
                if (in_ia32_syscall())
                        err = do_set_thread_area(p, -1,
                                (struct user_desc __user *)tls, 0);
                else
 #endif
-                       err = do_arch_prctl(p, ARCH_SET_FS, tls);
+                       err = do_arch_prctl_64(p, ARCH_SET_FS, tls);
                if (err)
                        goto out;
        }
        err = 0;
 out:
        if (err && p->thread.io_bitmap_ptr) {
                kfree(p->thread.io_bitmap_ptr);
                p->thread.io_bitmap_max = 0;
@@ -534,91 +534,93 @@ static long prctl_map_vdso(const struct vdso_image 
*image, unsigned long addr)
        ret = map_vdso_once(image, addr);
        if (ret)
                return ret;
 
        return (long)image->size;
 }
 #endif
 
-long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
+long do_arch_prctl_64(struct task_struct *task, int code, unsigned long arg2)
 {
        int ret = 0;
        int doit = task == current;
        int cpu;
 
        switch (code) {
        case ARCH_SET_GS:
-               if (addr >= TASK_SIZE_MAX)
+               if (arg2 >= TASK_SIZE_MAX)
                        return -EPERM;
                cpu = get_cpu();
                task->thread.gsindex = 0;
-               task->thread.gsbase = addr;
+               task->thread.gsbase = arg2;
                if (doit) {
                        load_gs_index(0);
-                       ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr);
+                       ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, arg2);
                }
                put_cpu();
                break;
        case ARCH_SET_FS:
                /* Not strictly needed for fs, but do it for symmetry
                   with gs */
-               if (addr >= TASK_SIZE_MAX)
+               if (arg2 >= TASK_SIZE_MAX)
                        return -EPERM;
                cpu = get_cpu();
                task->thread.fsindex = 0;
-               task->thread.fsbase = addr;
+               task->thread.fsbase = arg2;
                if (doit) {
                        /* set the selector to 0 to not confuse __switch_to */
                        loadsegment(fs, 0);
-                       ret = wrmsrl_safe(MSR_FS_BASE, addr);
+                       ret = wrmsrl_safe(MSR_FS_BASE, arg2);
                }
                put_cpu();
                break;
        case ARCH_GET_FS: {
                unsigned long base;
+
                if (doit)
                        rdmsrl(MSR_FS_BASE, base);
                else
                        base = task->thread.fsbase;
-               ret = put_user(base, (unsigned long __user *)addr);
+               ret = put_user(base, (unsigned long __user *)arg2);
                break;
        }
        case ARCH_GET_GS: {
                unsigned long base;
+
                if (doit)
                        rdmsrl(MSR_KERNEL_GS_BASE, base);
                else
                        base = task->thread.gsbase;
-               ret = put_user(base, (unsigned long __user *)addr);
+               ret = put_user(base, (unsigned long __user *)arg2);
                break;
        }
 
 #ifdef CONFIG_CHECKPOINT_RESTORE
 # ifdef CONFIG_X86_X32_ABI
        case ARCH_MAP_VDSO_X32:
-               return prctl_map_vdso(&vdso_image_x32, addr);
+               return prctl_map_vdso(&vdso_image_x32, arg2);
 # endif
 # if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
        case ARCH_MAP_VDSO_32:
-               return prctl_map_vdso(&vdso_image_32, addr);
+               return prctl_map_vdso(&vdso_image_32, arg2);
 # endif
        case ARCH_MAP_VDSO_64:
-               return prctl_map_vdso(&vdso_image_64, addr);
+               return prctl_map_vdso(&vdso_image_64, arg2);
 #endif
 
        default:
                ret = -EINVAL;
                break;
        }
 
        return ret;
 }
 
-SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, addr)
+SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, arg2)
 {
-       return do_arch_prctl(current, code, addr);
+       return do_arch_prctl_64(current, code, arg2);
 }
 
 unsigned long KSTK_ESP(struct task_struct *task)
 {
        return task_pt_regs(task)->sp;
 }
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 0e63c02..5004302 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -390,31 +390,31 @@ static int putreg(struct task_struct *child,
        case offsetof(struct user_regs_struct, flags):
                return set_flags(child, value);
 
 #ifdef CONFIG_X86_64
        case offsetof(struct user_regs_struct,fs_base):
                if (value >= TASK_SIZE_MAX)
                        return -EIO;
                /*
-                * When changing the segment base, use do_arch_prctl
+                * When changing the segment base, use do_arch_prctl_64
                 * to set either thread.fs or thread.fsindex and the
                 * corresponding GDT slot.
                 */
                if (child->thread.fsbase != value)
-                       return do_arch_prctl(child, ARCH_SET_FS, value);
+                       return do_arch_prctl_64(child, ARCH_SET_FS, value);
                return 0;
        case offsetof(struct user_regs_struct,gs_base):
                /*
                 * Exactly the same here as the %fs handling above.
                 */
                if (value >= TASK_SIZE_MAX)
                        return -EIO;
                if (child->thread.gsbase != value)
-                       return do_arch_prctl(child, ARCH_SET_GS, value);
+                       return do_arch_prctl_64(child, ARCH_SET_GS, value);
                return 0;
 #endif
        }
 
        *pt_regs_access(task_pt_regs(child), offset) = value;
        return 0;
 }
 
@@ -863,17 +863,17 @@ long arch_ptrace(struct task_struct *child, long request,
                break;
 #endif
 
 #ifdef CONFIG_X86_64
                /* normal 64bit interface to access TLS data.
                   Works just like arch_prctl, except that the arguments
                   are reversed. */
        case PTRACE_ARCH_PRCTL:
-               ret = do_arch_prctl(child, data, addr);
+               ret = do_arch_prctl_64(child, data, addr);
                break;
 #endif
 
        default:
                ret = ptrace_request(child, request, addr, data);
                break;
        }
 
diff --git a/arch/x86/um/syscalls_64.c b/arch/x86/um/syscalls_64.c
index ab3f7f4..3362c4e 100644
--- a/arch/x86/um/syscalls_64.c
+++ b/arch/x86/um/syscalls_64.c
@@ -68,19 +68,19 @@ long arch_prctl(struct task_struct *task, int code, 
unsigned long __user *addr)
        case ARCH_GET_GS:
                ret = put_user(tmp, addr);
                break;
        }
 
        return ret;
 }
 
-SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, addr)
+SYSCALL_DEFINE2(arch_prctl, int, code, unsigned long, arg2)
 {
-       return arch_prctl(current, code, (unsigned long __user *) addr);
+       return arch_prctl(current, code, (unsigned long __user *) arg2);
 }
 
 void arch_switch_to(struct task_struct *to)
 {
        if ((to->thread.arch.fs == 0) || (to->mm == NULL))
                return;
 
        arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);
-- 
2.10.2

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