[PATCH bpf 4/4] arm64: rethook: Replace kretprobe trampoline with rethook

Masami Hiramatsu
2022-04-06T00:51:40Z

Replace the kretprobe's trampoline code with the rethook on arm64.
The rethook on arm64 is almost renamed from kretprobe trampoline
code. The mechanism is completely same.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/arm64/Kconfig | 1
arch/arm64/include/asm/kprobes.h | 2 -
arch/arm64/include/asm/stacktrace.h | 2 -
arch/arm64/kernel/Makefile | 1
arch/arm64/kernel/probes/Makefile | 1
arch/arm64/kernel/probes/kprobes.c | 15 ----
arch/arm64/kernel/probes/kprobes_trampoline.S | 86 -------------------------
arch/arm64/kernel/rethook.c | 26 +++++++
arch/arm64/kernel/rethook_trampoline.S | 87 +++++++++++++++++++++++++
arch/arm64/kernel/stacktrace.c | 9 +--
10 files changed, 121 insertions(+), 109 deletions(-)
delete mode 100644 arch/arm64/kernel/probes/kprobes_trampoline.S
create mode 100644 arch/arm64/kernel/rethook.c
create mode 100644 arch/arm64/kernel/rethook_trampoline.S

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 57c4c995965f..7d2945930283 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -204,6 +204,7 @@ config ARM64
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_KPROBES
select HAVE_KRETPROBES
+ select HAVE_RETHOOK
select HAVE_GENERIC_VDSO
select IOMMU_DMA if IOMMU_SUPPORT
select IRQ_DOMAIN
diff --git a/arch/arm64/include/asm/kprobes.h b/arch/arm64/include/asm/kprobes.h
index 05cd82eeca13..4ac558058377 100644
--- a/arch/arm64/include/asm/kprobes.h
+++ b/arch/arm64/include/asm/kprobes.h
@@ -39,8 +39,6 @@ void arch_remove_kprobe(struct kprobe *);
int kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr);
int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
-void __kretprobe_trampoline(void);
-void __kprobes *trampoline_probe_handler(struct pt_regs *regs);

#endif /* CONFIG_KPROBES */
#endif /* _ARM_KPROBES_H */
diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index e77cdef9ca29..f781874f1609 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -58,7 +58,7 @@ struct stackframe {
DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
unsigned long prev_fp;
enum stack_type prev_type;
-#ifdef CONFIG_KRETPROBES
+#if defined(CONFIG_RETHOOK)
struct llist_node *kr_cur;
#endif
};
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 986837d7ec82..62e033b1b095 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -60,6 +60,7 @@ obj-$(CONFIG_ACPI_NUMA) += acpi_numa.o
obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL) += acpi_parking_protocol.o
obj-$(CONFIG_PARAVIRT) += paravirt.o
obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
+obj-$(CONFIG_RETHOOK) += rethook.o rethook_trampoline.o
obj-$(CONFIG_HIBERNATION) += hibernate.o hibernate-asm.o
obj-$(CONFIG_ELF_CORE) += elfcore.o
obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o \
diff --git a/arch/arm64/kernel/probes/Makefile b/arch/arm64/kernel/probes/Makefile
index 8e4be92e25b1..1fa58cda64ff 100644
--- a/arch/arm64/kernel/probes/Makefile
+++ b/arch/arm64/kernel/probes/Makefile
@@ -1,6 +1,5 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_KPROBES) += kprobes.o decode-insn.o \
- kprobes_trampoline.o \
simulate-insn.o
obj-$(CONFIG_UPROBES) += uprobes.o decode-insn.o \
simulate-insn.o
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index d9dfa82c1f18..4a3cc266e77e 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -399,21 +399,6 @@ int __init arch_populate_kprobe_blacklist(void)
return ret;
}

-void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
-{
- return (void *)kretprobe_trampoline_handler(regs, (void *)regs->regs[29]);
-}
-
-void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
- struct pt_regs *regs)
-{
- ri->ret_addr = (kprobe_opcode_t *)regs->regs[30];
- ri->fp = (void *)regs->regs[29];
-
- /* replace return addr (x30) with trampoline */
- regs->regs[30] = (long)&__kretprobe_trampoline;
-}
-
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
{
return 0;
diff --git a/arch/arm64/kernel/probes/kprobes_trampoline.S b/arch/arm64/kernel/probes/kprobes_trampoline.S
deleted file mode 100644
index 9a6499bed58b..000000000000
--- a/arch/arm64/kernel/probes/kprobes_trampoline.S
+++ /dev/null
@@ -1,86 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * trampoline entry and return code for kretprobes.
- */
-
-#include <linux/linkage.h>
-#include <asm/asm-offsets.h>
-#include <asm/assembler.h>
-
- .text
-
- .macro save_all_base_regs
- stp x0, x1, [sp, #S_X0]
- stp x2, x3, [sp, #S_X2]
- stp x4, x5, [sp, #S_X4]
- stp x6, x7, [sp, #S_X6]
- stp x8, x9, [sp, #S_X8]
- stp x10, x11, [sp, #S_X10]
- stp x12, x13, [sp, #S_X12]
- stp x14, x15, [sp, #S_X14]
- stp x16, x17, [sp, #S_X16]
- stp x18, x19, [sp, #S_X18]
- stp x20, x21, [sp, #S_X20]
- stp x22, x23, [sp, #S_X22]
- stp x24, x25, [sp, #S_X24]
- stp x26, x27, [sp, #S_X26]
- stp x28, x29, [sp, #S_X28]
- add x0, sp, #PT_REGS_SIZE
- stp lr, x0, [sp, #S_LR]
- /*
- * Construct a useful saved PSTATE
- */
- mrs x0, nzcv
- mrs x1, daif
- orr x0, x0, x1
- mrs x1, CurrentEL
- orr x0, x0, x1
- mrs x1, SPSel
- orr x0, x0, x1
- stp xzr, x0, [sp, #S_PC]
- .endm
-
- .macro restore_all_base_regs
- ldr x0, [sp, #S_PSTATE]
- and x0, x0, #(PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT)
- msr nzcv, x0
- ldp x0, x1, [sp, #S_X0]
- ldp x2, x3, [sp, #S_X2]
- ldp x4, x5, [sp, #S_X4]
- ldp x6, x7, [sp, #S_X6]
- ldp x8, x9, [sp, #S_X8]
- ldp x10, x11, [sp, #S_X10]
- ldp x12, x13, [sp, #S_X12]
- ldp x14, x15, [sp, #S_X14]
- ldp x16, x17, [sp, #S_X16]
- ldp x18, x19, [sp, #S_X18]
- ldp x20, x21, [sp, #S_X20]
- ldp x22, x23, [sp, #S_X22]
- ldp x24, x25, [sp, #S_X24]
- ldp x26, x27, [sp, #S_X26]
- ldp x28, x29, [sp, #S_X28]
- .endm
-
-SYM_CODE_START(__kretprobe_trampoline)
- sub sp, sp, #PT_REGS_SIZE
-
- save_all_base_regs
-
- /* Setup a frame pointer. */
- add x29, sp, #S_FP
-
- mov x0, sp
- bl trampoline_probe_handler
- /*
- * Replace trampoline address in lr with actual orig_ret_addr return
- * address.
- */
- mov lr, x0
-
- /* The frame pointer (x29) is restored with other registers. */
- restore_all_base_regs
-
- add sp, sp, #PT_REGS_SIZE
- ret
-
-SYM_CODE_END(__kretprobe_trampoline)
diff --git a/arch/arm64/kernel/rethook.c b/arch/arm64/kernel/rethook.c
new file mode 100644
index 000000000000..78bb6b968de5
--- /dev/null
+++ b/arch/arm64/kernel/rethook.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic return hook for arm64.
+ * Most of the code is copied from arch/arm64/kernel/probes/kprobes.c
+ */
+
+#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->regs[29]);
+}
+NOKPROBE_SYMBOL(arch_rethook_trampoline_callback);
+
+int arch_rethook_prepare(struct rethook_node *rhn, struct pt_regs *regs, bool mcount)
+{
+ rhn->ret_addr = regs->regs[30];
+ rhn->frame = regs->regs[29];
+
+ /* replace return addr (x30) with trampoline */
+ regs->regs[30] = (u64)arch_rethook_trampoline;
+ return 0;
+}
+NOKPROBE_SYMBOL(arch_rethook_prepare);
diff --git a/arch/arm64/kernel/rethook_trampoline.S b/arch/arm64/kernel/rethook_trampoline.S
new file mode 100644
index 000000000000..146d4553674c
--- /dev/null
+++ b/arch/arm64/kernel/rethook_trampoline.S
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * trampoline entry and return code for rethook.
+ * Renamed from arch/arm64/kernel/probes/kprobes_trampoline.S
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/assembler.h>
+
+ .text
+
+ .macro save_all_base_regs
+ stp x0, x1, [sp, #S_X0]
+ stp x2, x3, [sp, #S_X2]
+ stp x4, x5, [sp, #S_X4]
+ stp x6, x7, [sp, #S_X6]
+ stp x8, x9, [sp, #S_X8]
+ stp x10, x11, [sp, #S_X10]
+ stp x12, x13, [sp, #S_X12]
+ stp x14, x15, [sp, #S_X14]
+ stp x16, x17, [sp, #S_X16]
+ stp x18, x19, [sp, #S_X18]
+ stp x20, x21, [sp, #S_X20]
+ stp x22, x23, [sp, #S_X22]
+ stp x24, x25, [sp, #S_X24]
+ stp x26, x27, [sp, #S_X26]
+ stp x28, x29, [sp, #S_X28]
+ add x0, sp, #PT_REGS_SIZE
+ stp lr, x0, [sp, #S_LR]
+ /*
+ * Construct a useful saved PSTATE
+ */
+ mrs x0, nzcv
+ mrs x1, daif
+ orr x0, x0, x1
+ mrs x1, CurrentEL
+ orr x0, x0, x1
+ mrs x1, SPSel
+ orr x0, x0, x1
+ stp xzr, x0, [sp, #S_PC]
+ .endm
+
+ .macro restore_all_base_regs
+ ldr x0, [sp, #S_PSTATE]
+ and x0, x0, #(PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT)
+ msr nzcv, x0
+ ldp x0, x1, [sp, #S_X0]
+ ldp x2, x3, [sp, #S_X2]
+ ldp x4, x5, [sp, #S_X4]
+ ldp x6, x7, [sp, #S_X6]
+ ldp x8, x9, [sp, #S_X8]
+ ldp x10, x11, [sp, #S_X10]
+ ldp x12, x13, [sp, #S_X12]
+ ldp x14, x15, [sp, #S_X14]
+ ldp x16, x17, [sp, #S_X16]
+ ldp x18, x19, [sp, #S_X18]
+ ldp x20, x21, [sp, #S_X20]
+ ldp x22, x23, [sp, #S_X22]
+ ldp x24, x25, [sp, #S_X24]
+ ldp x26, x27, [sp, #S_X26]
+ ldp x28, x29, [sp, #S_X28]
+ .endm
+
+SYM_CODE_START(arch_rethook_trampoline)
+ sub sp, sp, #PT_REGS_SIZE
+
+ save_all_base_regs
+
+ /* Setup a frame pointer. */
+ add x29, sp, #S_FP
+
+ mov x0, sp
+ bl arch_rethook_trampoline_callback
+ /*
+ * Replace trampoline address in lr with actual orig_ret_addr return
+ * address.
+ */
+ mov lr, x0
+
+ /* The frame pointer (x29) is restored with other registers. */
+ restore_all_base_regs
+
+ add sp, sp, #PT_REGS_SIZE
+ ret
+
+SYM_CODE_END(arch_rethook_trampoline)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index e4103e085681..5b717af4b555 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -8,6 +8,7 @@
#include <linux/export.h>
#include <linux/ftrace.h>
#include <linux/kprobes.h>
+#include <linux/rethook.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
@@ -38,7 +39,7 @@ static notrace void start_backtrace(struct stackframe *frame, unsigned long fp,
{
frame->fp = fp;
frame->pc = pc;
-#ifdef CONFIG_KRETPROBES
+#if defined(CONFIG_RETHOOK)
frame->kr_cur = NULL;
#endif

@@ -134,9 +135,9 @@ static int notrace unwind_frame(struct task_struct *tsk,
frame->pc = orig_pc;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-#ifdef CONFIG_KRETPROBES
- if (is_kretprobe_trampoline(frame->pc))
- frame->pc = kretprobe_find_ret_addr(tsk, (void *)frame->fp, &frame->kr_cur);
+#ifdef CONFIG_RETHOOK
+ if (is_rethook_trampoline(frame->pc))
+ frame->pc = rethook_find_ret_addr(tsk, frame->fp, &frame->kr_cur);
#endif

return 0;