arm64: ptrace: remove addr_limit manipulation

[ 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.marinas@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 9cbb612..85e80a4 100644 (file)
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1194,9 +1194,7 @@ static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num,
 {
        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);
@@ -1207,7 +1205,6 @@ static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num,
        } else {
                ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata);
        }
-       set_fs(old_fs);
 
        if (!ret)
                ret = put_user(kdata, data);
@@ -1220,7 +1217,6 @@ static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num,
 {
        int ret;
        u32 kdata = 0;
-       mm_segment_t old_fs = get_fs();
 
        if (num == 0)
                return 0;
@@ -1229,12 +1225,10 @@ static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num,
        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;
 }