arm64: ptrace: remove addr_limit manipulation

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>

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 71d99af24ef20852a18deea4d29a25c0197cf651..7a832ce6552f174307bf1ef0e020598273dc266d 100644 (file)
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1458,9 +1458,7 @@ 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);
@@ -1471,7 +1469,6 @@ 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);
@@ -1484,7 +1481,6 @@ 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;
@@ -1493,12 +1489,10 @@ 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;
 }