From: Vyacheslav Cherkashin <v.cherkashin@samsung.com>
Date: Fri, 1 Jul 2016 18:48:20 +0000 (+0300)
Subject: ARM64: implement uretprobe
X-Git-Tag: submit/tizen/20170815.123151~31
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c84fd0450b802d6c514fd2e451fd76b121e40908;p=platform%2Fkernel%2Fswap-modules.git

ARM64: implement uretprobe

Change-Id: I9775576f8901eac71e62356ee0ae56942f1e5406
Signed-off-by: Vyacheslav Cherkashin <v.cherkashin@samsung.com>
---

diff --git a/uprobe/arch/arm64/swap-asm/swap_uprobes.c b/uprobe/arch/arm64/swap-asm/swap_uprobes.c
index b75cb28..f2e7a9a 100644
--- a/uprobe/arch/arm64/swap-asm/swap_uprobes.c
+++ b/uprobe/arch/arm64/swap-asm/swap_uprobes.c
@@ -31,8 +31,10 @@
 
 #define BRK_BP			0x45
 #define BRK_PSEUDO_SS		0x54
+#define BRK_URP			0x67
 #define BRK64_OPCODE_BP		MAKE_BRK(BRK_BP)
 #define BRK64_OPCODE_PSEUDO_SS	MAKE_BRK(BRK_PSEUDO_SS)
+#define BRK64_OPCODE_URP	MAKE_BRK(BRK_URP)
 
 
 struct uprobe_ctlblk {
@@ -62,6 +64,72 @@ static void reset_current_uprobe(void)
 }
 
 
+int arch_prepare_uretprobe(struct uretprobe_instance *ri,
+			   struct pt_regs *regs)
+{
+	unsigned long bp_addr = (unsigned long)(ri->rp->up.ainsn.insn +
+						URP_RET_BREAK_IDX);
+
+	ri->sp = (kprobe_opcode_t *)regs->sp;
+
+	/* replace the return address (regs[30] - lr) */
+	ri->ret_addr = (kprobe_opcode_t *)regs->regs[30];
+	regs->regs[30] = bp_addr;
+
+	return 0;
+}
+
+void arch_set_orig_ret_addr(unsigned long orig_ret_addr, struct pt_regs *regs)
+{
+	regs->pc = orig_ret_addr;
+}
+
+static int make_urp_arm64(struct uprobe *p)
+{
+	u32 *utramp, urp_brk;
+
+	if (p->ainsn.insn == NULL) {
+		utramp = swap_slot_alloc(p->sm);
+		if (utramp == NULL)
+			return -ENOMEM;
+
+		p->ainsn.insn = utramp;
+	}
+
+	utramp = p->ainsn.insn;
+	urp_brk = BRK64_OPCODE_URP;
+
+	if (!write_proc_vm_atomic(p->task,
+				  (long)&utramp[URP_RET_BREAK_IDX],
+				  &urp_brk, sizeof(urp_brk))) {
+		pr_err("%s failed to write memory %p!\n", __func__, utramp);
+	}
+
+	add_uprobe_table(p);
+
+	return 0;
+}
+
+static enum dbg_code urp_handler(struct pt_regs *regs, unsigned int esr)
+{
+	struct uprobe *p;
+	unsigned long pc = regs->pc;
+	unsigned long insn_addr = pc - sizeof(u32) * URP_RET_BREAK_IDX;
+
+	p = get_uprobe_by_insn_slot((void *)insn_addr, current->tgid, regs);
+	if (p == NULL) {
+		pr_err("no_uretprobe: Not one of ours: let "
+		       "kernel handle it %lx\n", pc);
+		return DBG_ERROR;
+	}
+
+	local_irq_enable();
+	trampoline_uprobe_handler(p, regs);
+
+	return DBG_HANDLED;
+}
+
+
 int arch_arm_uprobe(struct uprobe *p)
 {
 	uprobe_opcode_t insn = BRK64_OPCODE_BP;
@@ -247,6 +315,12 @@ static enum dbg_code uprobe_handler_arm64(struct pt_regs *regs)
 				pr_err("no_uprobe live\n");
 				goto out_ok;
 			}
+
+			if (make_urp_arm64(p)) {
+				disarm_uprobe(p, p->task);
+				pr_err("no_uretprobe\n");
+				goto out_ok;
+			}
 		}
 
 		if (!p->pre_handler || !p->pre_handler(p, regs))
@@ -298,6 +372,14 @@ static struct brk_hook dbg_up_ss = {
 	.fn = uprobe_ss_handler,
 };
 
+static struct brk_hook dbg_urp_bp = {
+	.spsr_mask = PSR_MODE_MASK,
+	.spsr_val = PSR_MODE_EL0t,
+	.esr_mask = DBG_BRK_ESR_MASK,
+	.esr_val = DBG_BRK_ESR(BRK_URP),
+	.fn = urp_handler,
+};
+
 
 int swap_arch_init_uprobes(void)
 {
@@ -309,12 +391,14 @@ int swap_arch_init_uprobes(void)
 
 	dbg_brk_hook_reg(&dbg_up_ss);
 	dbg_brk_hook_reg(&dbg_up_bp);
+	dbg_brk_hook_reg(&dbg_urp_bp);
 
 	return 0;
 }
 
 void swap_arch_exit_uprobes(void)
 {
+	dbg_brk_hook_unreg(&dbg_urp_bp);
 	dbg_brk_hook_unreg(&dbg_up_bp);
 	dbg_brk_hook_unreg(&dbg_up_ss);
 	swap_td_raw_unreg(&td_raw);
diff --git a/uprobe/arch/arm64/swap-asm/swap_uprobes.h b/uprobe/arch/arm64/swap-asm/swap_uprobes.h
index bfa205b..bca4f84 100644
--- a/uprobe/arch/arm64/swap-asm/swap_uprobes.h
+++ b/uprobe/arch/arm64/swap-asm/swap_uprobes.h
@@ -26,8 +26,9 @@
 #include <linux/types.h>
 
 
-#define UP_TRAMP_INSN_CNT  2 /* | opcode | ss_bp | */
+#define UP_TRAMP_INSN_CNT  3 /* | opcode | ss_bp | urp_bp | */
 #define UPROBES_TRAMP_LEN  (UP_TRAMP_INSN_CNT * 4) /* 4 - instruction size */
+#define URP_RET_BREAK_IDX  2
 
 
 struct uprobe;
@@ -127,18 +128,9 @@ static inline unsigned long arch_get_trampoline_addr(struct uprobe *p,
 	return 0;
 }
 
-static inline void arch_set_orig_ret_addr(unsigned long orig_ret_addr,
-					  struct pt_regs *regs)
-{
-	WARN(1, "not implemented"); /* FIXME: to implement */
-}
-
-static inline int arch_prepare_uretprobe(struct uretprobe_instance *ri,
-					 struct pt_regs *regs)
-{
-	WARN(1, "not implemented"); /* FIXME: to implement */
-	return 0;
-}
+void arch_set_orig_ret_addr(unsigned long orig_ret_addr, struct pt_regs *regs);
+int arch_prepare_uretprobe(struct uretprobe_instance *ri,
+			   struct pt_regs *regs);
 
 static inline int arch_opcode_analysis_uretprobe(struct uretprobe *rp)
 {