[IMPROVE] split into uprobe core handlers (for x86)

split into atomic and non-atomic context

Change-Id: Ia7af60514ceb0d4fe11929910bbb150eda7c2d07
Signed-off-by: Vyacheslav Cherkashin <v.cherkashin@samsung.com>

diff --git a/uprobe/arch/x86/swap-asm/swap_uprobes.c b/uprobe/arch/x86/swap-asm/swap_uprobes.c
index 2936f52..639a7d3 100644 (file)
--- a/uprobe/arch/x86/swap-asm/swap_uprobes.c
+++ b/uprobe/arch/x86/swap-asm/swap_uprobes.c
@@ -44,7 +44,7 @@ struct save_context {
        struct pt_regs save_regs;
        struct pt_regs *ptr_regs;
        unsigned long val;
-       int (*handler)(struct pt_regs *);
+       int (*handler)(struct uprobe *, struct pt_regs *);
 };
 
 /**
@@ -470,43 +470,6 @@ static void prepare_ss(struct pt_regs *regs)
        regs->flags &= ~IF_MASK;
 }
 
-static int uprobe_handler(struct pt_regs *regs)
-{
-       struct uprobe *p;
-       uprobe_opcode_t *addr;
-       struct task_struct *task = current;
-       pid_t tgid = task->tgid;
-
-       save_current_flags(regs);
-
-       addr = (uprobe_opcode_t *)(regs->EREG(ip) - sizeof(uprobe_opcode_t));
-       p = get_uprobe(addr, tgid);
-
-       if (p == NULL) {
-               void *tramp_addr = (void *)addr - UPROBES_TRAMP_RET_BREAK_IDX;
-
-               p = get_uprobe_by_insn_slot(tramp_addr, tgid, regs);
-               if (p == NULL) {
-                       printk(KERN_INFO "no_uprobe\n");
-                       return 0;
-               }
-
-               trampoline_uprobe_handler(p, regs);
-               return 1;
-       } else {
-               if (!p->pre_handler || !p->pre_handler(p, regs)) {
-                       prepare_tramp(p, regs);
-                       if (p->ainsn.boostable == 1 && !p->post_handler)
-                               return 1;
-
-                       set_current_probe(p);
-                       prepare_ss(regs);
-               }
-       }
-
-       return 1;
-}
-
 
 static unsigned long resume_userspace_addr;
 
@@ -514,13 +477,13 @@ static void __used __up_handler(void)
 {
        struct pt_regs *regs = current_ctx()->ptr_regs;
        struct thread_info *tinfo = current_thread_info();
-       int (*handler)(struct pt_regs *) = current_ctx()->handler;
+       struct uprobe *p = current_ucb()->p;
 
        /* restore KS regs */
        *regs = current_ctx()->save_regs;
 
        /* call handler */
-       handler(regs);
+       current_ctx()->handler(p, regs);
 
        /* resume_userspace */
        asm volatile (
@@ -541,7 +504,7 @@ __asm(
 );
 
 static int exceptions_handler(struct pt_regs *regs,
-                             int (*handler)(struct pt_regs *))
+                             int (*handler)(struct uprobe *, struct pt_regs *))
 {
        /* save regs */
        current_ctx()->save_regs = *regs;
@@ -562,27 +525,78 @@ static int exceptions_handler(struct pt_regs *regs,
        return 1;
 }
 
-static int post_uprobe_handler(struct pt_regs *regs)
+static int uprobe_handler_part2(struct uprobe *p, struct pt_regs *regs)
 {
-       struct uprobe *p = get_current_probe();
-       unsigned long flags = current_ucb()->flags;
+       if (!p->pre_handler(p, regs)) {
+               prepare_tramp(p, regs);
+               if (p->ainsn.boostable == 1 && !p->post_handler)
+                       return 1;
+
+               save_current_flags(regs);
+               set_current_probe(p);
+               prepare_ss(regs);
+       }
+
+       return 1;
+}
 
-       if (p == NULL) {
-               printk("task[%u %u %s] current uprobe is not found\n",
-                      current->tgid, current->pid, current->comm);
-               return 0;
+static int uprobe_handler_atomic(struct pt_regs *regs)
+{
+       pid_t tgid = current->tgid;
+       unsigned long vaddr = regs->ip - 1;
+       struct uprobe *p = get_uprobe((void *)vaddr, tgid);
+
+       if (p) {
+               if (p->pre_handler) {
+                       set_current_probe(p);
+                       exceptions_handler(regs, uprobe_handler_part2);
+               } else {
+                       uprobe_handler_part2(p, regs);
+               }
+       } else {
+               unsigned long tramp_vaddr;
+
+               tramp_vaddr = vaddr - UPROBES_TRAMP_RET_BREAK_IDX;
+               p = get_uprobe_by_insn_slot((void *)tramp_vaddr, tgid, regs);
+               if (p == NULL) {
+                       pr_info("no_uprobe\n");
+                       return 0;
+               }
+
+               set_current_probe(p);
+               exceptions_handler(regs, trampoline_uprobe_handler);
        }
 
+       return 1;
+}
+
+static int post_uprobe_handler(struct uprobe *p, struct pt_regs *regs)
+{
+       unsigned long flags = current_ucb()->flags;
+
        resume_execution(p, regs, flags);
        restore_current_flags(regs, flags);
 
-       /* clean stack */
-       current_ucb()->p = 0;
-       current_ucb()->flags = 0;
+       /* reset current probe */
+       set_current_probe(NULL);
 
        return 1;
 }
 
+static int post_uprobe_handler_atomic(struct pt_regs *regs)
+{
+       struct uprobe *p = get_current_probe();
+
+       if (p) {
+               exceptions_handler(regs, post_uprobe_handler);
+       } else {
+               pr_info("task[%u %u %s] current uprobe is not found\n",
+                       current->tgid, current->pid, current->comm);
+       }
+
+       return !!p;
+}
+
 static int uprobe_exceptions_notify(struct notifier_block *self,
                                    unsigned long val, void *data)
 {
@@ -598,11 +612,11 @@ static int uprobe_exceptions_notify(struct notifier_block *self,
 #else
        case DIE_TRAP:
 #endif
-               if (exceptions_handler(args->regs, uprobe_handler))
+               if (uprobe_handler_atomic(args->regs))
                        ret = NOTIFY_STOP;
                break;
        case DIE_DEBUG:
-               if (exceptions_handler(args->regs, post_uprobe_handler))
+               if (post_uprobe_handler_atomic(args->regs))
                        ret = NOTIFY_STOP;
                break;
        default: