rethook: add riscv rethook implementation.

Commit Message

Binglei Wang Sept. 20, 2022, 9:36 a.m. UTC

From: "wang.binglei" <[e-mail]>

Most of the code copied from
arch/riscv/kernel/probes/kprobes_trampoline.S

Signed-off-by: wang.binglei <[e-mail]>
---
 arch/riscv/Kconfig                            |  1 +
 arch/riscv/kernel/probes/Makefile             |  1 +
 arch/riscv/kernel/probes/kprobes.c            |  7 ++
 arch/riscv/kernel/probes/rethook.c            | 24 +++++
 arch/riscv/kernel/probes/rethook_trampoline.S | 94 +++++++++++++++++++
 5 files changed, 127 insertions(+)
 create mode 100644 arch/riscv/kernel/probes/rethook.c
 create mode 100644 arch/riscv/kernel/probes/rethook_trampoline.S

--
2.17.1

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Comments

Conor Dooley Sept. 20, 2022, 10:32 a.m. UTC | #1

On Tue, Sep 20, 2022 at 05:36:30PM +0800, Binglei Wang wrote:
> From: "wang.binglei" <[e-mail]>
> 
> Most of the code copied from
> arch/riscv/kernel/probes/kprobes_trampoline.S

Hey Wang Binglei,

Please use the commit log to explain the reasons behind the change you
are making:
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-your-changes

> 
> Signed-off-by: wang.binglei <[e-mail]>

Unfortunately I don't know much about Asian naming, but I assume that
the . is not part of your name?

> diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
> index e6e950b7c..2c1847921 100644
> --- a/arch/riscv/kernel/probes/kprobes.c
> +++ b/arch/riscv/kernel/probes/kprobes.c
> @@ -345,6 +345,7 @@ int __init arch_populate_kprobe_blacklist(void)
>         return ret;
>  }
> 
> +#ifndef CONFIG_KRETPROBE_ON_RETHOOK

This seems quite unusual, other archs don't seem to have ifdef-ery
using CONFIG_KRETPROBE_ON_RETHOOK in their arch code so why should
RISC-V?

>  void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
>  {
>         return (void *)kretprobe_trampoline_handler(regs, NULL);
> @@ -357,6 +358,12 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
>         ri->fp = NULL;
>         regs->ra = (unsigned long) &__kretprobe_trampoline;
>  }
> +#else
> +void __kprobes *trampoline_probe_handler(struct pt_regs *regs)
> +{
> +       return NULL;
> +}
> +#endif
 

> diff --git a/arch/riscv/kernel/probes/rethook_trampoline.S b/arch/riscv/kernel/probes/rethook_trampoline.S
> new file mode 100644
> index 000000000..aa79630ac
> --- /dev/null
> +++ b/arch/riscv/kernel/probes/rethook_trampoline.S
> @@ -0,0 +1,94 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * rethook trampoline.
> + * Copied from arch/riscv/kernel/probes/kprobes_trampoline.S

Is this a 1:1 copy? If so, could the code be shared?
 
> This e-mail and its attachments contain confidential information from New H3C, which is
> intended only for the person or entity whose address is listed above. Any use of the
> information contained herein in any way (including, but not limited to, total or partial
> disclosure, reproduction, or dissemination) by persons other than the intended
> recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender
> by phone or email immediately and delete it!

Uh-oh! You'll have to work with your IT to get this removed before your
patches can be accepted:
https://lore.kernel.org/all/[e-mail]/

The patch does not apply to -next for me either..

Thanks,
Conor.

Patch

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..2c1847921 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -345,6 +345,7 @@  int __init arch_populate_kprobe_blacklist(void)
        return ret;
 }

+#ifndef CONFIG_KRETPROBE_ON_RETHOOK
 void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
 {
        return (void *)kretprobe_trampoline_handler(regs, NULL);
@@ -357,6 +358,12 @@  void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
        ri->fp = NULL;
        regs->ra = (unsigned long) &__kretprobe_trampoline;
 }
+#else
+void __kprobes *trampoline_probe_handler(struct pt_regs *regs)
+{
+       return NULL;
+}
+#endif

 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
 {
diff --git a/arch/riscv/kernel/probes/rethook.c b/arch/riscv/kernel/probes/rethook.c
new file mode 100644
index 000000000..47853bc36
--- /dev/null
+++ b/arch/riscv/kernel/probes/rethook.c
@@ -0,0 +1,24 @@ 
+// 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..aa79630ac
--- /dev/null
+++ b/arch/riscv/kernel/probes/rethook_trampoline.S
@@ -0,0 +1,94 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * rethook trampoline.
+ * Copied from arch/riscv/kernel/probes/kprobes_trampoline.S
+ */
+#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
+
+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)