Re: [PATCH v4 5/9] riscv: Add kprobes supported

2020-11-05 Thread Guo Ren 
On Fri, Nov 6, 2020 at 9:02 AM Palmer Dabbelt  wrote:
>
> On Sat, 17 Oct 2020 00:06:13 PDT (-0700), guo...@kernel.org wrote:
> > From: Guo Ren 
> >
> > This patch enables "kprobe & kretprobe" to work with ftrace
> > interface. It utilized software breakpoint as single-step
> > mechanism.
> >
> > Some instructions which can't be single-step executed must be
> > simulated in kernel execution slot, such as: branch, jal, auipc,
> > la ...
> >
> > Some instructions should be rejected for probing and we use a
> > blacklist to filter, such as: ecall, ebreak, ...
> >
> > We use ebreak & c.ebreak to replace origin instruction and the
> > kprobe handler prepares an executable memory slot for out-of-line
> > execution with a copy of the original instruction being probed.
> > In execution slot we add ebreak behind original instruction to
> > simulate a single-setp mechanism.
> >
> > The patch is based on packi's work [1] and csky's work [2].
> >  - The kprobes_trampoline.S is all from packi's patch
> >  - The single-step mechanism is new designed for riscv without hw
> >single-step trap
> >  - The simulation codes are from csky
> >  - Frankly, all codes refer to other archs' implementation
> >
> >  [1] https://lore.kernel.org/linux-riscv/20181113195804.22825-1...@packi.ch/
> >  [2] 
> > https://lore.kernel.org/linux-csky/20200403044150.20562-9-guo...@kernel.org/
> >
> > Signed-off-by: Guo Ren 
> > Co-Developed-by: Patrick Stählin 
>
> Checkpatch says
>
> WARNING: 'Co-developed-by:' is the preferred signature form
> #108:
> Co-Developed-by: Patrick Stählin 
>
> WARNING: Co-developed-by: must be immediately followed by Signed-off-by:
> #108:
> Co-Developed-by: Patrick Stählin 
> Acked-by: Masami Hiramatsu 
>
> There's some other checkpatch warnings throughout the patch set, but this is
> one I'm not supposed to fix up.  Can one of you re-post the patches with the
> correct DCO?
Ok, I'll fix it up in V5 and rebase 5.10-rc2

-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/

Re: [PATCH v4 5/9] riscv: Add kprobes supported

2020-11-05 Thread Palmer Dabbelt 

On Sat, 17 Oct 2020 00:06:13 PDT (-0700), guo...@kernel.org wrote:

From: Guo Ren 

This patch enables "kprobe & kretprobe" to work with ftrace
interface. It utilized software breakpoint as single-step
mechanism.

Some instructions which can't be single-step executed must be
simulated in kernel execution slot, such as: branch, jal, auipc,
la ...

Some instructions should be rejected for probing and we use a
blacklist to filter, such as: ecall, ebreak, ...

We use ebreak & c.ebreak to replace origin instruction and the
kprobe handler prepares an executable memory slot for out-of-line
execution with a copy of the original instruction being probed.
In execution slot we add ebreak behind original instruction to
simulate a single-setp mechanism.

The patch is based on packi's work [1] and csky's work [2].
 - The kprobes_trampoline.S is all from packi's patch
 - The single-step mechanism is new designed for riscv without hw
   single-step trap
 - The simulation codes are from csky
 - Frankly, all codes refer to other archs' implementation

 [1] https://lore.kernel.org/linux-riscv/20181113195804.22825-1...@packi.ch/
 [2] 
https://lore.kernel.org/linux-csky/20200403044150.20562-9-guo...@kernel.org/

Signed-off-by: Guo Ren 
Co-Developed-by: Patrick Stählin 


Checkpatch says

   WARNING: 'Co-developed-by:' is the preferred signature form
   #108: 
   Co-Developed-by: Patrick Stählin 
   
   WARNING: Co-developed-by: must be immediately followed by Signed-off-by:
   #108: 
   Co-Developed-by: Patrick Stählin 

   Acked-by: Masami Hiramatsu 

There's some other checkpatch warnings throughout the patch set, but this is
one I'm not supposed to fix up.  Can one of you re-post the patches with the
correct DCO?


Acked-by: Masami Hiramatsu 
Tested-by: Zong Li 
Reviewed-by: Pekka Enberg 
Cc: Patrick Stählin 
Cc: Palmer Dabbelt 
Cc: Björn Töpel 
---
 arch/riscv/Kconfig|   2 +
 arch/riscv/include/asm/kprobes.h  |  40 +++
 arch/riscv/include/asm/probes.h   |  24 ++
 arch/riscv/kernel/Makefile|   1 +
 arch/riscv/kernel/probes/Makefile |   4 +
 arch/riscv/kernel/probes/decode-insn.c|  48 
 arch/riscv/kernel/probes/decode-insn.h|  18 ++
 arch/riscv/kernel/probes/kprobes.c| 398 ++
 arch/riscv/kernel/probes/kprobes_trampoline.S |  93 ++
 arch/riscv/kernel/probes/simulate-insn.c  |  85 ++
 arch/riscv/kernel/probes/simulate-insn.h  |  47 +++
 arch/riscv/kernel/traps.c |   9 +
 arch/riscv/mm/fault.c |   4 +
 13 files changed, 773 insertions(+)
 create mode 100644 arch/riscv/include/asm/probes.h
 create mode 100644 arch/riscv/kernel/probes/Makefile
 create mode 100644 arch/riscv/kernel/probes/decode-insn.c
 create mode 100644 arch/riscv/kernel/probes/decode-insn.h
 create mode 100644 arch/riscv/kernel/probes/kprobes.c
 create mode 100644 arch/riscv/kernel/probes/kprobes_trampoline.S
 create mode 100644 arch/riscv/kernel/probes/simulate-insn.c
 create mode 100644 arch/riscv/kernel/probes/simulate-insn.h

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index e6424d8b..c07214a 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -67,6 +67,8 @@ config RISCV
select HAVE_FUTEX_CMPXCHG if FUTEX
select HAVE_GCC_PLUGINS
select HAVE_GENERIC_VDSO if MMU && 64BIT
+   select HAVE_KPROBES
+   select HAVE_KRETPROBES
select HAVE_PCI
select HAVE_PERF_EVENTS
select HAVE_PERF_REGS
diff --git a/arch/riscv/include/asm/kprobes.h b/arch/riscv/include/asm/kprobes.h
index 56a98ea3..4647d38 100644
--- a/arch/riscv/include/asm/kprobes.h
+++ b/arch/riscv/include/asm/kprobes.h
@@ -11,4 +11,44 @@

 #include 

+#ifdef CONFIG_KPROBES
+#include 
+#include 
+#include 
+
+#define __ARCH_WANT_KPROBES_INSN_SLOT
+#define MAX_INSN_SIZE  2
+
+#define flush_insn_slot(p) do { } while (0)
+#define kretprobe_blacklist_size   0
+
+#include 
+
+struct prev_kprobe {
+   struct kprobe *kp;
+   unsigned int status;
+};
+
+/* Single step context for kprobe */
+struct kprobe_step_ctx {
+   unsigned long ss_pending;
+   unsigned long match_addr;
+};
+
+/* per-cpu kprobe control block */
+struct kprobe_ctlblk {
+   unsigned int kprobe_status;
+   unsigned long saved_status;
+   struct prev_kprobe prev_kprobe;
+   struct kprobe_step_ctx ss_ctx;
+};
+
+void arch_remove_kprobe(struct kprobe *p);
+int kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr);
+bool kprobe_breakpoint_handler(struct pt_regs *regs);
+bool kprobe_single_step_handler(struct pt_regs *regs);
+void kretprobe_trampoline(void);
+void __kprobes *trampoline_probe_handler(struct pt_regs *regs);
+
+#endif /* CONFIG_KPROBES */
 #endif /* _ASM_RISCV_KPROBES_H */
diff --git a/arch/riscv/include/asm/probes.h b/arch/riscv/include/asm/probes.h
new file mode 100644
index ..a787e6d
---

[PATCH v4 5/9] riscv: Add kprobes supported

2020-10-17 Thread guoren 
From: Guo Ren 

This patch enables "kprobe & kretprobe" to work with ftrace
interface. It utilized software breakpoint as single-step
mechanism.

Some instructions which can't be single-step executed must be
simulated in kernel execution slot, such as: branch, jal, auipc,
la ...

Some instructions should be rejected for probing and we use a
blacklist to filter, such as: ecall, ebreak, ...

We use ebreak & c.ebreak to replace origin instruction and the
kprobe handler prepares an executable memory slot for out-of-line
execution with a copy of the original instruction being probed.
In execution slot we add ebreak behind original instruction to
simulate a single-setp mechanism.

The patch is based on packi's work [1] and csky's work [2].
 - The kprobes_trampoline.S is all from packi's patch
 - The single-step mechanism is new designed for riscv without hw
   single-step trap
 - The simulation codes are from csky
 - Frankly, all codes refer to other archs' implementation

 [1] https://lore.kernel.org/linux-riscv/20181113195804.22825-1...@packi.ch/
 [2] 
https://lore.kernel.org/linux-csky/20200403044150.20562-9-guo...@kernel.org/

Signed-off-by: Guo Ren 
Co-Developed-by: Patrick Stählin 
Acked-by: Masami Hiramatsu 
Tested-by: Zong Li 
Reviewed-by: Pekka Enberg 
Cc: Patrick Stählin 
Cc: Palmer Dabbelt 
Cc: Björn Töpel 
---
 arch/riscv/Kconfig|   2 +
 arch/riscv/include/asm/kprobes.h  |  40 +++
 arch/riscv/include/asm/probes.h   |  24 ++
 arch/riscv/kernel/Makefile|   1 +
 arch/riscv/kernel/probes/Makefile |   4 +
 arch/riscv/kernel/probes/decode-insn.c|  48 
 arch/riscv/kernel/probes/decode-insn.h|  18 ++
 arch/riscv/kernel/probes/kprobes.c| 398 ++
 arch/riscv/kernel/probes/kprobes_trampoline.S |  93 ++
 arch/riscv/kernel/probes/simulate-insn.c  |  85 ++
 arch/riscv/kernel/probes/simulate-insn.h  |  47 +++
 arch/riscv/kernel/traps.c |   9 +
 arch/riscv/mm/fault.c |   4 +
 13 files changed, 773 insertions(+)
 create mode 100644 arch/riscv/include/asm/probes.h
 create mode 100644 arch/riscv/kernel/probes/Makefile
 create mode 100644 arch/riscv/kernel/probes/decode-insn.c
 create mode 100644 arch/riscv/kernel/probes/decode-insn.h
 create mode 100644 arch/riscv/kernel/probes/kprobes.c
 create mode 100644 arch/riscv/kernel/probes/kprobes_trampoline.S
 create mode 100644 arch/riscv/kernel/probes/simulate-insn.c
 create mode 100644 arch/riscv/kernel/probes/simulate-insn.h

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index e6424d8b..c07214a 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -67,6 +67,8 @@ config RISCV
select HAVE_FUTEX_CMPXCHG if FUTEX
select HAVE_GCC_PLUGINS
select HAVE_GENERIC_VDSO if MMU && 64BIT
+   select HAVE_KPROBES
+   select HAVE_KRETPROBES
select HAVE_PCI
select HAVE_PERF_EVENTS
select HAVE_PERF_REGS
diff --git a/arch/riscv/include/asm/kprobes.h b/arch/riscv/include/asm/kprobes.h
index 56a98ea3..4647d38 100644
--- a/arch/riscv/include/asm/kprobes.h
+++ b/arch/riscv/include/asm/kprobes.h
@@ -11,4 +11,44 @@
 
 #include 
 
+#ifdef CONFIG_KPROBES
+#include 
+#include 
+#include 
+
+#define __ARCH_WANT_KPROBES_INSN_SLOT
+#define MAX_INSN_SIZE  2
+
+#define flush_insn_slot(p) do { } while (0)
+#define kretprobe_blacklist_size   0
+
+#include 
+
+struct prev_kprobe {
+   struct kprobe *kp;
+   unsigned int status;
+};
+
+/* Single step context for kprobe */
+struct kprobe_step_ctx {
+   unsigned long ss_pending;
+   unsigned long match_addr;
+};
+
+/* per-cpu kprobe control block */
+struct kprobe_ctlblk {
+   unsigned int kprobe_status;
+   unsigned long saved_status;
+   struct prev_kprobe prev_kprobe;
+   struct kprobe_step_ctx ss_ctx;
+};
+
+void arch_remove_kprobe(struct kprobe *p);
+int kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr);
+bool kprobe_breakpoint_handler(struct pt_regs *regs);
+bool kprobe_single_step_handler(struct pt_regs *regs);
+void kretprobe_trampoline(void);
+void __kprobes *trampoline_probe_handler(struct pt_regs *regs);
+
+#endif /* CONFIG_KPROBES */
 #endif /* _ASM_RISCV_KPROBES_H */
diff --git a/arch/riscv/include/asm/probes.h b/arch/riscv/include/asm/probes.h
new file mode 100644
index ..a787e6d
--- /dev/null
+++ b/arch/riscv/include/asm/probes.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_RISCV_PROBES_H
+#define _ASM_RISCV_PROBES_H
+
+typedef u32 probe_opcode_t;
+typedef bool (probes_handler_t) (u32 opcode, unsigned long addr, struct 
pt_regs *);
+
+/* architecture specific copy of original instruction */
+struct arch_probe_insn {
+   probe_opcode_t *insn;
+   probes_handler_t *handler;
+   /* restore address after simulation */
+   unsigned long restore;
+};
+
+#ifdef