m68k: Use get_kernel_nofault() in show_registers()

Use the proper get_kernel_nofault() helper to access an unsafe kernel
pointer without faulting instead of playing with set_fs() and
get_user().

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20200720114314.196686-1-hch@lst.de
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c
index 546e819..9e12614 100644 (file)
--- a/arch/m68k/kernel/traps.c
+++ b/arch/m68k/kernel/traps.c
@@ -845,7 +845,6 @@ static void show_trace(unsigned long *stack, const char *loglvl)
 void show_registers(struct pt_regs *regs)
 {
        struct frame *fp = (struct frame *)regs;
-       mm_segment_t old_fs = get_fs();
        u16 c, *cp;
        unsigned long addr;
        int i;
@@ -918,10 +917,9 @@ void show_registers(struct pt_regs *regs)
        show_stack(NULL, (unsigned long *)addr, KERN_INFO);
 
        pr_info("Code:");
-       set_fs(KERNEL_DS);
        cp = (u16 *)regs->pc;
        for (i = -8; i < 16; i++) {
-               if (get_user(c, cp + i) && i >= 0) {
+               if (get_kernel_nofault(c, cp + i) && i >= 0) {
                        pr_cont(" Bad PC value.");
                        break;
                }
@@ -930,7 +928,6 @@ void show_registers(struct pt_regs *regs)
                else
                        pr_cont(" <%04x>", c);
        }
-       set_fs(old_fs);
        pr_cont("\n");
 }