This patch implements CONFIG_DYNAMIC_FTRACE_WITH_REGS on LoongArch, which allows
a traced function's arguments (and some other registers) to be captured
into a struct pt_regs, allowing these to be inspected and modified.
Co-developed-by: Jinyang He <[email protected]>
Signed-off-by: Jinyang He <[email protected]>
Signed-off-by: Qing Zhang <[email protected]>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/ftrace.h | 3 +++
arch/loongarch/kernel/ftrace_dyn.c | 17 ++++++++++++++
arch/loongarch/kernel/mcount_dyn.S | 36 +++++++++++++++++++++++++++--
4 files changed, 55 insertions(+), 2 deletions(-)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 615ce62422b8..12e3e91a68ae 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -90,6 +90,7 @@ config LOONGARCH
select HAVE_DEBUG_STACKOVERFLOW
select HAVE_DMA_CONTIGUOUS
select HAVE_DYNAMIC_FTRACE
+ select HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_EBPF_JIT
select HAVE_EXIT_THREAD
select HAVE_FAST_GUP
diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
index 76ca58767f4d..a3f974a7a5ce 100644
--- a/arch/loongarch/include/asm/ftrace.h
+++ b/arch/loongarch/include/asm/ftrace.h
@@ -28,6 +28,9 @@ struct dyn_ftrace;
int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
#define ftrace_init_nop ftrace_init_nop
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+#define ARCH_SUPPORTS_FTRACE_OPS 1
+#endif
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_FUNCTION_TRACER */
diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c
index 3fe791b6783e..ec3d951be50c 100644
--- a/arch/loongarch/kernel/ftrace_dyn.c
+++ b/arch/loongarch/kernel/ftrace_dyn.c
@@ -99,6 +99,23 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
return ftrace_modify_code(pc, old, new, true);
}
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
+ unsigned long addr)
+{
+ unsigned long pc;
+ long offset;
+ u32 old, new;
+
+ pc = rec->ip + LOONGARCH_INSN_SIZE;
+
+ old = larch_insn_gen_bl(pc, old_addr);
+ new = larch_insn_gen_bl(pc, addr);
+
+ return ftrace_modify_code(pc, old, new, true);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
+
void arch_ftrace_update_code(int command)
{
command |= FTRACE_MAY_SLEEP;
diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S
index 0c12cc108e6f..02835186b463 100644
--- a/arch/loongarch/kernel/mcount_dyn.S
+++ b/arch/loongarch/kernel/mcount_dyn.S
@@ -27,7 +27,7 @@
* follows the LoongArch psABI well.
*/
- .macro ftrace_regs_entry
+ .macro ftrace_regs_entry allregs=0
PTR_ADDI sp, sp, -PT_SIZE
/* Save trace function ra at PT_ERA */
PTR_S ra, sp, PT_ERA
@@ -43,16 +43,48 @@
PTR_S a7, sp, PT_R11
PTR_S fp, sp, PT_R22
+ .if \allregs
+ PTR_S t0, sp, PT_R12
+ PTR_S t1, sp, PT_R13
+ PTR_S t2, sp, PT_R14
+ PTR_S t3, sp, PT_R15
+ PTR_S t4, sp, PT_R16
+ PTR_S t5, sp, PT_R17
+ PTR_S t6, sp, PT_R18
+ PTR_S t7, sp, PT_R19
+ PTR_S t8, sp, PT_R20
+ PTR_S s0, sp, PT_R23
+ PTR_S s1, sp, PT_R24
+ PTR_S s2, sp, PT_R25
+ PTR_S s3, sp, PT_R26
+ PTR_S s4, sp, PT_R27
+ PTR_S s5, sp, PT_R28
+ PTR_S s6, sp, PT_R29
+ PTR_S s7, sp, PT_R30
+ PTR_S s8, sp, PT_R31
+ PTR_S tp, sp, PT_R2
+ /* Clear it for later use as a flag sometimes. */
+ PTR_S zero, sp, PT_R0
+ PTR_S $r21, sp, PT_R21
+ .endif
+
PTR_ADDI t8, sp, PT_SIZE
PTR_S t8, sp, PT_R3
.endm
SYM_CODE_START(ftrace_caller)
- ftrace_regs_entry
+ ftrace_regs_entry allregs=0
b ftrace_common
SYM_CODE_END(ftrace_caller)
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+SYM_CODE_START(ftrace_regs_caller)
+ ftrace_regs_entry allregs=1
+ b ftrace_common
+SYM_CODE_END(ftrace_regs_caller)
+#endif
+
SYM_CODE_START(ftrace_common)
PTR_ADDI a0, ra, -8 /* arg0: ip */
move a1, t0 /* arg1: parent_ip */
--
2.36.0
Hi, Qing,
On Wed, Nov 16, 2022 at 10:53 AM Qing Zhang <[email protected]> wrote:
>
> This patch implements CONFIG_DYNAMIC_FTRACE_WITH_REGS on LoongArch, which allows
> a traced function's arguments (and some other registers) to be captured
> into a struct pt_regs, allowing these to be inspected and modified.
>
> Co-developed-by: Jinyang He <[email protected]>
> Signed-off-by: Jinyang He <[email protected]>
> Signed-off-by: Qing Zhang <[email protected]>
> ---
> arch/loongarch/Kconfig | 1 +
> arch/loongarch/include/asm/ftrace.h | 3 +++
> arch/loongarch/kernel/ftrace_dyn.c | 17 ++++++++++++++
> arch/loongarch/kernel/mcount_dyn.S | 36 +++++++++++++++++++++++++++--
> 4 files changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 615ce62422b8..12e3e91a68ae 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -90,6 +90,7 @@ config LOONGARCH
> select HAVE_DEBUG_STACKOVERFLOW
> select HAVE_DMA_CONTIGUOUS
> select HAVE_DYNAMIC_FTRACE
> + select HAVE_DYNAMIC_FTRACE_WITH_REGS
> select HAVE_EBPF_JIT
> select HAVE_EXIT_THREAD
> select HAVE_FAST_GUP
> diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
> index 76ca58767f4d..a3f974a7a5ce 100644
> --- a/arch/loongarch/include/asm/ftrace.h
> +++ b/arch/loongarch/include/asm/ftrace.h
> @@ -28,6 +28,9 @@ struct dyn_ftrace;
> int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
> #define ftrace_init_nop ftrace_init_nop
>
> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> +#define ARCH_SUPPORTS_FTRACE_OPS 1
> +#endif
This ifdef can be removed, because you have no chance to disable
DYNAMIC_FTRACE_WITH_REGS after this commit.
Huacai
> #endif /* CONFIG_DYNAMIC_FTRACE */
> #endif /* __ASSEMBLY__ */
> #endif /* CONFIG_FUNCTION_TRACER */
> diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c
> index 3fe791b6783e..ec3d951be50c 100644
> --- a/arch/loongarch/kernel/ftrace_dyn.c
> +++ b/arch/loongarch/kernel/ftrace_dyn.c
> @@ -99,6 +99,23 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
> return ftrace_modify_code(pc, old, new, true);
> }
>
> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
> + unsigned long addr)
> +{
> + unsigned long pc;
> + long offset;
> + u32 old, new;
> +
> + pc = rec->ip + LOONGARCH_INSN_SIZE;
> +
> + old = larch_insn_gen_bl(pc, old_addr);
> + new = larch_insn_gen_bl(pc, addr);
> +
> + return ftrace_modify_code(pc, old, new, true);
> +}
> +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
> +
> void arch_ftrace_update_code(int command)
> {
> command |= FTRACE_MAY_SLEEP;
> diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S
> index 0c12cc108e6f..02835186b463 100644
> --- a/arch/loongarch/kernel/mcount_dyn.S
> +++ b/arch/loongarch/kernel/mcount_dyn.S
> @@ -27,7 +27,7 @@
> * follows the LoongArch psABI well.
> */
>
> - .macro ftrace_regs_entry
> + .macro ftrace_regs_entry allregs=0
> PTR_ADDI sp, sp, -PT_SIZE
> /* Save trace function ra at PT_ERA */
> PTR_S ra, sp, PT_ERA
> @@ -43,16 +43,48 @@
> PTR_S a7, sp, PT_R11
> PTR_S fp, sp, PT_R22
>
> + .if \allregs
> + PTR_S t0, sp, PT_R12
> + PTR_S t1, sp, PT_R13
> + PTR_S t2, sp, PT_R14
> + PTR_S t3, sp, PT_R15
> + PTR_S t4, sp, PT_R16
> + PTR_S t5, sp, PT_R17
> + PTR_S t6, sp, PT_R18
> + PTR_S t7, sp, PT_R19
> + PTR_S t8, sp, PT_R20
> + PTR_S s0, sp, PT_R23
> + PTR_S s1, sp, PT_R24
> + PTR_S s2, sp, PT_R25
> + PTR_S s3, sp, PT_R26
> + PTR_S s4, sp, PT_R27
> + PTR_S s5, sp, PT_R28
> + PTR_S s6, sp, PT_R29
> + PTR_S s7, sp, PT_R30
> + PTR_S s8, sp, PT_R31
> + PTR_S tp, sp, PT_R2
> + /* Clear it for later use as a flag sometimes. */
> + PTR_S zero, sp, PT_R0
> + PTR_S $r21, sp, PT_R21
> + .endif
> +
> PTR_ADDI t8, sp, PT_SIZE
> PTR_S t8, sp, PT_R3
>
> .endm
>
> SYM_CODE_START(ftrace_caller)
> - ftrace_regs_entry
> + ftrace_regs_entry allregs=0
> b ftrace_common
> SYM_CODE_END(ftrace_caller)
>
> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> +SYM_CODE_START(ftrace_regs_caller)
> + ftrace_regs_entry allregs=1
> + b ftrace_common
> +SYM_CODE_END(ftrace_regs_caller)
> +#endif
> +
> SYM_CODE_START(ftrace_common)
> PTR_ADDI a0, ra, -8 /* arg0: ip */
> move a1, t0 /* arg1: parent_ip */
> --
> 2.36.0
>
>