1 files changed, 42 insertions, 24 deletions

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index f21592d20306..8723390c7cad 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -6,12 +6,13 @@
 #include <linux/extable.h>
 #include <linux/slab.h>
 #include <linux/stop_machine.h>
+#include <linux/vmalloc.h>
 #include <asm/ptrace.h>
 #include <linux/uaccess.h>
 #include <asm/sections.h>
 #include <asm/cacheflush.h>
 #include <asm/bug.h>
-#include <asm/patch.h>
+#include <asm/text-patching.h>
 
 #include "decode-insn.h"
 
@@ -23,13 +24,13 @@ post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
 
 static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
 {
-	unsigned long offset = GET_INSN_LENGTH(p->opcode);
+	size_t len = GET_INSN_LENGTH(p->opcode);
+	u32 insn = __BUG_INSN_32;
 
-	p->ainsn.api.restore = (unsigned long)p->addr + offset;
+	p->ainsn.api.restore = (unsigned long)p->addr + len;
 
-	patch_text(p->ainsn.api.insn, p->opcode);
-	patch_text((void *)((unsigned long)(p->ainsn.api.insn) + offset),
-		   __BUG_INSN_32);
+	patch_text_nosync(p->ainsn.api.insn, &p->opcode, len);
+	patch_text_nosync((void *)p->ainsn.api.insn + len, &insn, GET_INSN_LENGTH(insn));
 }
 
 static void __kprobes arch_prepare_simulate(struct kprobe *p)
@@ -48,15 +49,40 @@ static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
 	post_kprobe_handler(p, kcb, regs);
 }
 
+static bool __kprobes arch_check_kprobe(unsigned long addr)
+{
+	unsigned long tmp, offset;
+
+	/* start iterating at the closest preceding symbol */
+	if (!kallsyms_lookup_size_offset(addr, NULL, &offset))
+		return false;
+
+	tmp = addr - offset;
+
+	while (tmp <= addr) {
+		if (tmp == addr)
+			return true;
+
+		tmp += GET_INSN_LENGTH(*(u16 *)tmp);
+	}
+
+	return false;
+}
+
 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
-	unsigned long probe_addr = (unsigned long)p->addr;
+	u16 *insn = (u16 *)p->addr;
+
+	if ((unsigned long)insn & 0x1)
+		return -EILSEQ;
 
-	if (probe_addr & 0x1)
+	if (!arch_check_kprobe((unsigned long)p->addr))
 		return -EILSEQ;
 
 	/* copy instruction */
-	p->opcode = *p->addr;
+	p->opcode = (kprobe_opcode_t)(*insn++);
+	if (GET_INSN_LENGTH(p->opcode) == 4)
+		p->opcode |= (kprobe_opcode_t)(*insn) << 16;
 
 	/* decode instruction */
 	switch (riscv_probe_decode_insn(p->addr, &p->ainsn.api)) {
@@ -83,29 +109,21 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	return 0;
 }
 
-#ifdef CONFIG_MMU
-void *alloc_insn_page(void)
-{
-	return  __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
-				     GFP_KERNEL, PAGE_KERNEL_READ_EXEC,
-				     VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
-				     __builtin_return_address(0));
-}
-#endif
-
 /* install breakpoint in text */
 void __kprobes arch_arm_kprobe(struct kprobe *p)
 {
-	if ((p->opcode & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
-		patch_text(p->addr, __BUG_INSN_32);
-	else
-		patch_text(p->addr, __BUG_INSN_16);
+	size_t len = GET_INSN_LENGTH(p->opcode);
+	u32 insn = len == 4 ? __BUG_INSN_32 : __BUG_INSN_16;
+
+	patch_text(p->addr, &insn, len);
 }
 
 /* remove breakpoint from text */
 void __kprobes arch_disarm_kprobe(struct kprobe *p)
 {
-	patch_text(p->addr, p->opcode);
+	size_t len = GET_INSN_LENGTH(p->opcode);
+
+	patch_text(p->addr, &p->opcode, len);
 }
 
 void __kprobes arch_remove_kprobe(struct kprobe *p)