[PATCH 3.18 13/85] arm64: ptrace: remove addr_limit manipulation

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mark Rutland <mark.rutl...@arm.com>

[ Upstream commit 59275a0c037ed6fabd6354730f1e3104264ab719 ]

We transiently switch to KERNEL_DS in compat_ptrace_gethbpregs() and
compat_ptrace_sethbpregs(), but in either case this is pointless as we
don't perform any uaccess during this window.

let's rip out the redundant addr_limit manipulation.

Acked-by: Catalin Marinas <catalin.mari...@arm.com>
Signed-off-by: Mark Rutland <mark.rutl...@arm.com>
Cc: Will Deacon <will.dea...@arm.com>
Signed-off-by: Will Deacon <will.dea...@arm.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 arch/arm64/kernel/ptrace.c |    6 ------
 1 file changed, 6 deletions(-)

--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -945,9 +945,7 @@ static int compat_ptrace_gethbpregs(stru
 {
        int ret;
        u32 kdata;
-       mm_segment_t old_fs = get_fs();
 
-       set_fs(KERNEL_DS);
        /* Watchpoint */
        if (num < 0) {
                ret = compat_ptrace_hbp_get(NT_ARM_HW_WATCH, tsk, num, &kdata);
@@ -958,7 +956,6 @@ static int compat_ptrace_gethbpregs(stru
        } else {
                ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata);
        }
-       set_fs(old_fs);
 
        if (!ret)
                ret = put_user(kdata, data);
@@ -971,7 +968,6 @@ static int compat_ptrace_sethbpregs(stru
 {
        int ret;
        u32 kdata = 0;
-       mm_segment_t old_fs = get_fs();
 
        if (num == 0)
                return 0;
@@ -980,12 +976,10 @@ static int compat_ptrace_sethbpregs(stru
        if (ret)
                return ret;
 
-       set_fs(KERNEL_DS);
        if (num < 0)
                ret = compat_ptrace_hbp_set(NT_ARM_HW_WATCH, tsk, num, &kdata);
        else
                ret = compat_ptrace_hbp_set(NT_ARM_HW_BREAK, tsk, num, &kdata);
-       set_fs(old_fs);
 
        return ret;
 }