kprobes/x86: Remove jprobe implementation

Remove arch dependent setjump/longjump functions
and unused fields in kprobe_ctlblk for jprobes
from arch/x86.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/lkml/152942433578.15209.14034551799624757792.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index 367d99c..06782c2 100644 (file)
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -111,9 +111,6 @@ struct kprobe_ctlblk {
        unsigned long kprobe_status;
        unsigned long kprobe_old_flags;
        unsigned long kprobe_saved_flags;
-       unsigned long *jprobe_saved_sp;
-       struct pt_regs jprobe_saved_regs;
-       kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
        struct prev_kprobe prev_kprobe;
 };
 

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 6f4d423..1b2d1ac 100644 (file)
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -66,8 +66,6 @@
 
 #include "common.h"
 
-void jprobe_return_end(void);
-
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
@@ -690,10 +688,9 @@ int kprobe_int3_handler(struct pt_regs *regs)
                        /*
                         * If we have no pre-handler or it returned 0, we
                         * continue with normal processing.  If we have a
-                        * pre-handler and it returned non-zero, it prepped
-                        * for calling the break_handler below on re-entry
-                        * for jprobe processing, so get out doing nothing
-                        * more here.
+                        * pre-handler and it returned non-zero, that means
+                        * user handler setup registers to exit to another
+                        * instruction, we must skip the single stepping.
                         */
                        if (!p->pre_handler || !p->pre_handler(p, regs))
                                setup_singlestep(p, regs, kcb, 0);
@@ -1083,93 +1080,6 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
 }
 NOKPROBE_SYMBOL(kprobe_exceptions_notify);
 
-int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
-{
-       struct jprobe *jp = container_of(p, struct jprobe, kp);
-       unsigned long addr;
-       struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
-       kcb->jprobe_saved_regs = *regs;
-       kcb->jprobe_saved_sp = stack_addr(regs);
-       addr = (unsigned long)(kcb->jprobe_saved_sp);
-
-       /*
-        * As Linus pointed out, gcc assumes that the callee
-        * owns the argument space and could overwrite it, e.g.
-        * tailcall optimization. So, to be absolutely safe
-        * we also save and restore enough stack bytes to cover
-        * the argument area.
-        * Use __memcpy() to avoid KASAN stack out-of-bounds reports as we copy
-        * raw stack chunk with redzones:
-        */
-       __memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr, MIN_STACK_SIZE(addr));
-       regs->ip = (unsigned long)(jp->entry);
-
-       /*
-        * jprobes use jprobe_return() which skips the normal return
-        * path of the function, and this messes up the accounting of the
-        * function graph tracer to get messed up.
-        *
-        * Pause function graph tracing while performing the jprobe function.
-        */
-       pause_graph_tracing();
-       return 1;
-}
-NOKPROBE_SYMBOL(setjmp_pre_handler);
-
-void jprobe_return(void)
-{
-       struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
-       /* Unpoison stack redzones in the frames we are going to jump over. */
-       kasan_unpoison_stack_above_sp_to(kcb->jprobe_saved_sp);
-
-       asm volatile (
-#ifdef CONFIG_X86_64
-                       "       xchg   %%rbx,%%rsp      \n"
-#else
-                       "       xchgl   %%ebx,%%esp     \n"
-#endif
-                       "       int3                    \n"
-                       "       .globl jprobe_return_end\n"
-                       "       jprobe_return_end:      \n"
-                       "       nop                     \n"::"b"
-                       (kcb->jprobe_saved_sp):"memory");
-}
-NOKPROBE_SYMBOL(jprobe_return);
-NOKPROBE_SYMBOL(jprobe_return_end);
-
-int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
-       struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-       u8 *addr = (u8 *) (regs->ip - 1);
-       struct jprobe *jp = container_of(p, struct jprobe, kp);
-       void *saved_sp = kcb->jprobe_saved_sp;
-
-       if ((addr > (u8 *) jprobe_return) &&
-           (addr < (u8 *) jprobe_return_end)) {
-               if (stack_addr(regs) != saved_sp) {
-                       struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
-                       printk(KERN_ERR
-                              "current sp %p does not match saved sp %p\n",
-                              stack_addr(regs), saved_sp);
-                       printk(KERN_ERR "Saved registers for jprobe %p\n", jp);
-                       show_regs(saved_regs);
-                       printk(KERN_ERR "Current registers\n");
-                       show_regs(regs);
-                       BUG();
-               }
-               /* It's OK to start function graph tracing again */
-               unpause_graph_tracing();
-               *regs = kcb->jprobe_saved_regs;
-               __memcpy(saved_sp, kcb->jprobes_stack, MIN_STACK_SIZE(saved_sp));
-               preempt_enable_no_resched();
-               return 1;
-       }
-       return 0;
-}
-NOKPROBE_SYMBOL(longjmp_break_handler);
-
 bool arch_within_kprobe_blacklist(unsigned long addr)
 {
        bool is_in_entry_trampoline_section = false;