[PATCH] rethook: add riscv rethook implementation.
From: Binglei Wang
Date: Thu Sep 22 2022 - 07:19:47 EST
From: Binglei Wang <l3b2w1@xxxxxxxxx>
Implement the kretprobes on riscv arch by using rethook machenism
which abstracts general kretprobe info into a struct rethook_node
to be embedded in the struct kretprobe_instance.
Signed-off-by: Binglei Wang <l3b2w1@xxxxxxxxx>
---
arch/riscv/Kconfig | 1 +
arch/riscv/kernel/probes/Makefile | 1 +
arch/riscv/kernel/probes/kprobes.c | 8 --
arch/riscv/kernel/probes/kprobes_trampoline.S | 73 +----------------
arch/riscv/kernel/probes/kprobes_trampoline.h | 79 +++++++++++++++++++
arch/riscv/kernel/probes/rethook.c | 26 ++++++
arch/riscv/kernel/probes/rethook_trampoline.S | 22 ++++++
include/linux/kprobes.h | 6 ++
8 files changed, 136 insertions(+), 80 deletions(-)
create mode 100644 arch/riscv/kernel/probes/kprobes_trampoline.h
create mode 100644 arch/riscv/kernel/probes/rethook.c
create mode 100644 arch/riscv/kernel/probes/rethook_trampoline.S
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index ed66c31e4..c5cae0825 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -97,6 +97,7 @@ config RISCV
select HAVE_KPROBES if !XIP_KERNEL
select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL
select HAVE_KRETPROBES if !XIP_KERNEL
+ select HAVE_RETHOOK if !XIP_KERNEL
select HAVE_MOVE_PMD
select HAVE_MOVE_PUD
select HAVE_PCI
diff --git a/arch/riscv/kernel/probes/Makefile b/arch/riscv/kernel/probes/Makefile
index 7f0840dcc..ee345e7e9 100644
--- a/arch/riscv/kernel/probes/Makefile
+++ b/arch/riscv/kernel/probes/Makefile
@@ -3,4 +3,5 @@ obj-$(CONFIG_KPROBES) += kprobes.o decode-insn.o simulate-insn.o
obj-$(CONFIG_KPROBES) += kprobes_trampoline.o
obj-$(CONFIG_KPROBES_ON_FTRACE) += ftrace.o
obj-$(CONFIG_UPROBES) += uprobes.o decode-insn.o simulate-insn.o
+obj-$(CONFIG_RETHOOK) += rethook.o rethook_trampoline.o
CFLAGS_REMOVE_simulate-insn.o = $(CC_FLAGS_FTRACE)
diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index e6e950b7c..04911cc42 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -350,14 +350,6 @@ void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
return (void *)kretprobe_trampoline_handler(regs, NULL);
}
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
- struct pt_regs *regs)
-{
- ri->ret_addr = (kprobe_opcode_t *)regs->ra;
- ri->fp = NULL;
- regs->ra = (unsigned long) &__kretprobe_trampoline;
-}
-
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
{
return 0;
diff --git a/arch/riscv/kernel/probes/kprobes_trampoline.S b/arch/riscv/kernel/probes/kprobes_trampoline.S
index 7bdb09ded..54937f342 100644
--- a/arch/riscv/kernel/probes/kprobes_trampoline.S
+++ b/arch/riscv/kernel/probes/kprobes_trampoline.S
@@ -2,78 +2,7 @@
/*
* Author: Patrick Stählin <me@xxxxxxxx>
*/
-#include <linux/linkage.h>
-
-#include <asm/asm.h>
-#include <asm/asm-offsets.h>
-
- .text
- .altmacro
-
- .macro save_all_base_regs
- REG_S x1, PT_RA(sp)
- REG_S x3, PT_GP(sp)
- REG_S x4, PT_TP(sp)
- REG_S x5, PT_T0(sp)
- REG_S x6, PT_T1(sp)
- REG_S x7, PT_T2(sp)
- REG_S x8, PT_S0(sp)
- REG_S x9, PT_S1(sp)
- REG_S x10, PT_A0(sp)
- REG_S x11, PT_A1(sp)
- REG_S x12, PT_A2(sp)
- REG_S x13, PT_A3(sp)
- REG_S x14, PT_A4(sp)
- REG_S x15, PT_A5(sp)
- REG_S x16, PT_A6(sp)
- REG_S x17, PT_A7(sp)
- REG_S x18, PT_S2(sp)
- REG_S x19, PT_S3(sp)
- REG_S x20, PT_S4(sp)
- REG_S x21, PT_S5(sp)
- REG_S x22, PT_S6(sp)
- REG_S x23, PT_S7(sp)
- REG_S x24, PT_S8(sp)
- REG_S x25, PT_S9(sp)
- REG_S x26, PT_S10(sp)
- REG_S x27, PT_S11(sp)
- REG_S x28, PT_T3(sp)
- REG_S x29, PT_T4(sp)
- REG_S x30, PT_T5(sp)
- REG_S x31, PT_T6(sp)
- .endm
-
- .macro restore_all_base_regs
- REG_L x3, PT_GP(sp)
- REG_L x4, PT_TP(sp)
- REG_L x5, PT_T0(sp)
- REG_L x6, PT_T1(sp)
- REG_L x7, PT_T2(sp)
- REG_L x8, PT_S0(sp)
- REG_L x9, PT_S1(sp)
- REG_L x10, PT_A0(sp)
- REG_L x11, PT_A1(sp)
- REG_L x12, PT_A2(sp)
- REG_L x13, PT_A3(sp)
- REG_L x14, PT_A4(sp)
- REG_L x15, PT_A5(sp)
- REG_L x16, PT_A6(sp)
- REG_L x17, PT_A7(sp)
- REG_L x18, PT_S2(sp)
- REG_L x19, PT_S3(sp)
- REG_L x20, PT_S4(sp)
- REG_L x21, PT_S5(sp)
- REG_L x22, PT_S6(sp)
- REG_L x23, PT_S7(sp)
- REG_L x24, PT_S8(sp)
- REG_L x25, PT_S9(sp)
- REG_L x26, PT_S10(sp)
- REG_L x27, PT_S11(sp)
- REG_L x28, PT_T3(sp)
- REG_L x29, PT_T4(sp)
- REG_L x30, PT_T5(sp)
- REG_L x31, PT_T6(sp)
- .endm
+#include "kprobes_trampoline.h"
ENTRY(__kretprobe_trampoline)
addi sp, sp, -(PT_SIZE_ON_STACK)
diff --git a/arch/riscv/kernel/probes/kprobes_trampoline.h b/arch/riscv/kernel/probes/kprobes_trampoline.h
new file mode 100644
index 000000000..48895a5e3
--- /dev/null
+++ b/arch/riscv/kernel/probes/kprobes_trampoline.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef _KPROBES_TRAMPOLINE_H
+#define _KPROBES_TRAMPOLINE_H
+/*
+ * Author: Patrick Stählin <me@xxxxxxxx>
+ */
+#include <linux/linkage.h>
+
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+
+ .text
+ .altmacro
+
+ .macro save_all_base_regs
+ REG_S x1, PT_RA(sp)
+ REG_S x3, PT_GP(sp)
+ REG_S x4, PT_TP(sp)
+ REG_S x5, PT_T0(sp)
+ REG_S x6, PT_T1(sp)
+ REG_S x7, PT_T2(sp)
+ REG_S x8, PT_S0(sp)
+ REG_S x9, PT_S1(sp)
+ REG_S x10, PT_A0(sp)
+ REG_S x11, PT_A1(sp)
+ REG_S x12, PT_A2(sp)
+ REG_S x13, PT_A3(sp)
+ REG_S x14, PT_A4(sp)
+ REG_S x15, PT_A5(sp)
+ REG_S x16, PT_A6(sp)
+ REG_S x17, PT_A7(sp)
+ REG_S x18, PT_S2(sp)
+ REG_S x19, PT_S3(sp)
+ REG_S x20, PT_S4(sp)
+ REG_S x21, PT_S5(sp)
+ REG_S x22, PT_S6(sp)
+ REG_S x23, PT_S7(sp)
+ REG_S x24, PT_S8(sp)
+ REG_S x25, PT_S9(sp)
+ REG_S x26, PT_S10(sp)
+ REG_S x27, PT_S11(sp)
+ REG_S x28, PT_T3(sp)
+ REG_S x29, PT_T4(sp)
+ REG_S x30, PT_T5(sp)
+ REG_S x31, PT_T6(sp)
+ .endm
+
+ .macro restore_all_base_regs
+ REG_L x3, PT_GP(sp)
+ REG_L x4, PT_TP(sp)
+ REG_L x5, PT_T0(sp)
+ REG_L x6, PT_T1(sp)
+ REG_L x7, PT_T2(sp)
+ REG_L x8, PT_S0(sp)
+ REG_L x9, PT_S1(sp)
+ REG_L x10, PT_A0(sp)
+ REG_L x11, PT_A1(sp)
+ REG_L x12, PT_A2(sp)
+ REG_L x13, PT_A3(sp)
+ REG_L x14, PT_A4(sp)
+ REG_L x15, PT_A5(sp)
+ REG_L x16, PT_A6(sp)
+ REG_L x17, PT_A7(sp)
+ REG_L x18, PT_S2(sp)
+ REG_L x19, PT_S3(sp)
+ REG_L x20, PT_S4(sp)
+ REG_L x21, PT_S5(sp)
+ REG_L x22, PT_S6(sp)
+ REG_L x23, PT_S7(sp)
+ REG_L x24, PT_S8(sp)
+ REG_L x25, PT_S9(sp)
+ REG_L x26, PT_S10(sp)
+ REG_L x27, PT_S11(sp)
+ REG_L x28, PT_T3(sp)
+ REG_L x29, PT_T4(sp)
+ REG_L x30, PT_T5(sp)
+ REG_L x31, PT_T6(sp)
+ .endm
+#endif
diff --git a/arch/riscv/kernel/probes/rethook.c b/arch/riscv/kernel/probes/rethook.c
new file mode 100644
index 000000000..4a41d5eb6
--- /dev/null
+++ b/arch/riscv/kernel/probes/rethook.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic return hook for riscv.
+ */
+
+#include <linux/kprobes.h>
+#include <linux/rethook.h>
+
+/* This is called from arch_rethook_trampoline() */
+unsigned long __used arch_rethook_trampoline_callback(struct pt_regs *regs)
+{
+ return rethook_trampoline_handler(regs, regs->s0);
+}
+NOKPROBE_SYMBOL(arch_rethook_trampoline_callback);
+
+
+void arch_rethook_prepare(struct rethook_node *rhn, struct pt_regs *regs, bool mcount)
+{
+ rhn->ret_addr = regs->ra;
+ rhn->frame = regs->s0;
+
+ /* replace return addr with trampoline */
+ regs->ra = (u64)arch_rethook_trampoline;
+}
+NOKPROBE_SYMBOL(arch_rethook_prepare);
+
diff --git a/arch/riscv/kernel/probes/rethook_trampoline.S b/arch/riscv/kernel/probes/rethook_trampoline.S
new file mode 100644
index 000000000..e81c3d4e0
--- /dev/null
+++ b/arch/riscv/kernel/probes/rethook_trampoline.S
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Author: Patrick Stählin <me@xxxxxxxx>
+ */
+#include "kprobes_trampoline.h"
+
+ENTRY(arch_rethook_trampoline)
+ addi sp, sp, -(PT_SIZE_ON_STACK)
+ save_all_base_regs
+
+ move a0, sp /* pt_regs */
+
+ call arch_rethook_trampoline_callback
+
+ /* use the result as the return-address */
+ move ra, a0
+
+ restore_all_base_regs
+ addi sp, sp, PT_SIZE_ON_STACK
+
+ ret
+ENDPROC(arch_rethook_trampoline)
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 55041d2f8..a3805b5b2 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -210,6 +210,12 @@ static nokprobe_inline unsigned long get_kretprobe_retaddr(struct kretprobe_inst
{
return ri->node.ret_addr;
}
+static nokprobe_inline
+unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
+ void *frame_pointer)
+{
+ return 0;
+}
#else
extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs);
--
2.27.0