In RISC-V architecture, when we enable the ftrace_graph tracer on some
functions, the function tracings on other functions will suffer extra
graph tracing work. In essence, graph_ops isn't limited by its func_hash
due to the global ftrace_graph_[regs]_call label. That should be corrected.
What inspires me is the commit 0c0593b45c9b ("x86/ftrace: Make function
graph use ftrace directly") that uses graph_ops::func function to install
return_hooker and makes the function called against its func_hash.
This series of patches makes function graph use ftrace directly for riscv.
If FTRACE_WITH_REGS isn't defined, ftrace_caller keeps ftrace_graph_call
so that it can be replaced with the calling of prepare_ftrace_return by
the enable/disable helper.
As for defining FTRACE_WITH_REGS, ftrace_caller is adjusted to save the
necessary regs against the pt_regs layout, so it can reasonably call the
graph_ops::func function - ftrace_graph_func. And ftrace_graph_[regs]_call
and its enable/disable helper aren't needed.
The tests generated by CONFIG_FTRACE_STARTUP_TEST have passed in the local
qemu-system-riscv64 virt machine. The following is the log during startup.
```
Nov 15 03:07:13 stage4 kernel: Testing tracer function: PASSED
Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace: PASSED
Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #1:
Nov 15 03:07:13 stage4 kernel: (1 0 1 0 0)
Nov 15 03:07:13 stage4 kernel: (1 1 2 0 0)
Nov 15 03:07:13 stage4 kernel: (2 1 3 0 365)
Nov 15 03:07:13 stage4 kernel: (2 2 4 0 399)
Nov 15 03:07:13 stage4 kernel: (3 2 4 0 146071)
Nov 15 03:07:13 stage4 kernel: (3 3 5 0 146105) PASSED
Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #2:
Nov 15 03:07:13 stage4 kernel: (1 0 1 589 0)
Nov 15 03:07:13 stage4 kernel: (1 1 2 635 0)
Nov 15 03:07:13 stage4 kernel: (2 1 3 1 2)
Nov 15 03:07:13 stage4 kernel: (2 2 4 125 126)
Nov 15 03:07:13 stage4 kernel: (3 2 4 146001 146078)
Nov 15 03:07:13 stage4 kernel: (3 3 5 146035 146112) PASSED
Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion: PASSED
Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion safe: PASSED
Nov 15 03:07:13 stage4 kernel: Testing ftrace regs: PASSED
Nov 15 03:07:13 stage4 kernel: Testing tracer nop: PASSED
Nov 15 03:07:13 stage4 kernel: Testing tracer irqsoff: PASSED
Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup:
Nov 15 03:07:13 stage4 kernel: sched: DL replenish lagged too much
Nov 15 03:07:13 stage4 kernel: PASSED
Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_rt: PASSED
Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_dl: PASSED
Nov 15 03:07:13 stage4 kernel: Testing tracer function_graph: PASSED
```
Note that the changes of mcount-dyn.S conflicts with this unmerged
commit (riscv: entry: consolidate general regs saving/restoring).
https://lore.kernel.org/linux-riscv/[email protected]
Changes since v2:
- line up the comments [Andrew]
- rename SAVE_ALL as SAVE_ABI_REGS [Guo Ren]
- consolidate the modifications of mcount-dyn.S into one patch [Guo Ren]
- adapt this series based on [riscv: ftrace: Fixup ftrace detour code][1] [Guo Ren]
[1]: https://lore.kernel.org/linux-riscv/[email protected]/
v2 Link: https://lore.kernel.org/linux-riscv/[email protected]/
Changes since v1:
- fix the checkpatch warnings in patch 1
v1 Link: https://lore.kernel.org/linux-riscv/[email protected]
Song Shuai (2):
riscv/ftrace: add ftrace_graph_func
riscv/ftrace: make ftrace_caller call ftrace_graph_func
arch/riscv/include/asm/ftrace.h | 13 ++-
arch/riscv/kernel/ftrace.c | 30 +++----
arch/riscv/kernel/mcount-dyn.S | 143 +++++++++++++++++++++++---------
3 files changed, 129 insertions(+), 57 deletions(-)
--
2.20.1
Here implements ftrace_graph_func as the function graph tracing function
with FTRACE_WITH_REGS defined.
function_graph_func gets the point of the parent IP and the frame pointer
from fregs and call prepare_ftrace_return for function graph tracing.
If FTRACE_WITH_REGS isn't defined, the enable/disable helpers of
ftrace_graph_[regs]_call are revised for serving only ftrace_graph_call
in the !FTRACE_WITH_REGS version ftrace_caller.
Signed-off-by: Song Shuai <[email protected]>
---
arch/riscv/include/asm/ftrace.h | 13 +++++++++++--
arch/riscv/kernel/ftrace.c | 30 +++++++++++++-----------------
2 files changed, 24 insertions(+), 19 deletions(-)
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
index 34b0b523865a..01bebb28eabe 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -107,8 +107,17 @@ do { \
struct dyn_ftrace;
int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
#define ftrace_init_nop ftrace_init_nop
-#endif
-#endif
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+struct ftrace_ops;
+struct ftrace_regs;
+void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct ftrace_regs *fregs);
+#define ftrace_graph_func ftrace_graph_func
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* _ASM_RISCV_FTRACE_H */
diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
index 8c77f236fc71..651ce5808b77 100644
--- a/arch/riscv/kernel/ftrace.c
+++ b/arch/riscv/kernel/ftrace.c
@@ -169,32 +169,28 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
}
#ifdef CONFIG_DYNAMIC_FTRACE
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+ struct pt_regs *regs = arch_ftrace_get_regs(fregs);
+ unsigned long *parent = (unsigned long *)®s->ra;
+
+ prepare_ftrace_return(parent, ip, frame_pointer(regs));
+}
+#else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
extern void ftrace_graph_call(void);
-extern void ftrace_graph_regs_call(void);
int ftrace_enable_ftrace_graph_caller(void)
{
- int ret;
-
- ret = __ftrace_modify_call((unsigned long)&ftrace_graph_call,
- (unsigned long)&prepare_ftrace_return, true, true);
- if (ret)
- return ret;
-
- return __ftrace_modify_call((unsigned long)&ftrace_graph_regs_call,
+ return __ftrace_modify_call((unsigned long)&ftrace_graph_call,
(unsigned long)&prepare_ftrace_return, true, true);
}
int ftrace_disable_ftrace_graph_caller(void)
{
- int ret;
-
- ret = __ftrace_modify_call((unsigned long)&ftrace_graph_call,
- (unsigned long)&prepare_ftrace_return, false, true);
- if (ret)
- return ret;
-
- return __ftrace_modify_call((unsigned long)&ftrace_graph_regs_call,
+ return __ftrace_modify_call((unsigned long)&ftrace_graph_call,
(unsigned long)&prepare_ftrace_return, false, true);
}
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
--
2.20.1
On Sat, Nov 19, 2022 at 1:32 AM Song Shuai <[email protected]> wrote:
>
> In RISC-V architecture, when we enable the ftrace_graph tracer on some
> functions, the function tracings on other functions will suffer extra
> graph tracing work. In essence, graph_ops isn't limited by its func_hash
> due to the global ftrace_graph_[regs]_call label. That should be corrected.
>
> What inspires me is the commit 0c0593b45c9b ("x86/ftrace: Make function
> graph use ftrace directly") that uses graph_ops::func function to install
> return_hooker and makes the function called against its func_hash.
>
> This series of patches makes function graph use ftrace directly for riscv.
>
> If FTRACE_WITH_REGS isn't defined, ftrace_caller keeps ftrace_graph_call
> so that it can be replaced with the calling of prepare_ftrace_return by
> the enable/disable helper.
>
> As for defining FTRACE_WITH_REGS, ftrace_caller is adjusted to save the
> necessary regs against the pt_regs layout, so it can reasonably call the
> graph_ops::func function - ftrace_graph_func. And ftrace_graph_[regs]_call
> and its enable/disable helper aren't needed.
>
> The tests generated by CONFIG_FTRACE_STARTUP_TEST have passed in the local
> qemu-system-riscv64 virt machine. The following is the log during startup.
>
> ```
> Nov 15 03:07:13 stage4 kernel: Testing tracer function: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #1:
> Nov 15 03:07:13 stage4 kernel: (1 0 1 0 0)
> Nov 15 03:07:13 stage4 kernel: (1 1 2 0 0)
> Nov 15 03:07:13 stage4 kernel: (2 1 3 0 365)
> Nov 15 03:07:13 stage4 kernel: (2 2 4 0 399)
> Nov 15 03:07:13 stage4 kernel: (3 2 4 0 146071)
> Nov 15 03:07:13 stage4 kernel: (3 3 5 0 146105) PASSED
> Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #2:
> Nov 15 03:07:13 stage4 kernel: (1 0 1 589 0)
> Nov 15 03:07:13 stage4 kernel: (1 1 2 635 0)
> Nov 15 03:07:13 stage4 kernel: (2 1 3 1 2)
> Nov 15 03:07:13 stage4 kernel: (2 2 4 125 126)
> Nov 15 03:07:13 stage4 kernel: (3 2 4 146001 146078)
> Nov 15 03:07:13 stage4 kernel: (3 3 5 146035 146112) PASSED
> Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion safe: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing ftrace regs: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing tracer nop: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing tracer irqsoff: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup:
> Nov 15 03:07:13 stage4 kernel: sched: DL replenish lagged too much
> Nov 15 03:07:13 stage4 kernel: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_rt: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_dl: PASSED
> Nov 15 03:07:13 stage4 kernel: Testing tracer function_graph: PASSED
> ```
>
> Note that the changes of mcount-dyn.S conflicts with this unmerged
> commit (riscv: entry: consolidate general regs saving/restoring).
> https://lore.kernel.org/linux-riscv/[email protected]
>
> Changes since v2:
> - line up the comments [Andrew]
> - rename SAVE_ALL as SAVE_ABI_REGS [Guo Ren]
> - consolidate the modifications of mcount-dyn.S into one patch [Guo Ren]
> - adapt this series based on [riscv: ftrace: Fixup ftrace detour code][1] [Guo Ren]
Tested-by: Guo Ren <[email protected]>
https://github.com/guoren83/linux/tree/ftrace_fixup_v3
>
> [1]: https://lore.kernel.org/linux-riscv/[email protected]/
> v2 Link: https://lore.kernel.org/linux-riscv/[email protected]/
>
> Changes since v1:
> - fix the checkpatch warnings in patch 1
> v1 Link: https://lore.kernel.org/linux-riscv/[email protected]
>
> Song Shuai (2):
> riscv/ftrace: add ftrace_graph_func
> riscv/ftrace: make ftrace_caller call ftrace_graph_func
>
> arch/riscv/include/asm/ftrace.h | 13 ++-
> arch/riscv/kernel/ftrace.c | 30 +++----
> arch/riscv/kernel/mcount-dyn.S | 143 +++++++++++++++++++++++---------
> 3 files changed, 129 insertions(+), 57 deletions(-)
>
> --
> 2.20.1
>
--
Best Regards
Guo Ren
Guo Ren <[email protected]> 于2022年11月20日周日 04:26写道：
>
> On Sat, Nov 19, 2022 at 1:32 AM Song Shuai <[email protected]> wrote:
> >
> > In RISC-V architecture, when we enable the ftrace_graph tracer on some
> > functions, the function tracings on other functions will suffer extra
> > graph tracing work. In essence, graph_ops isn't limited by its func_hash
> > due to the global ftrace_graph_[regs]_call label. That should be corrected.
> >
> > What inspires me is the commit 0c0593b45c9b ("x86/ftrace: Make function
> > graph use ftrace directly") that uses graph_ops::func function to install
> > return_hooker and makes the function called against its func_hash.
> >
> > This series of patches makes function graph use ftrace directly for riscv.
> >
> > If FTRACE_WITH_REGS isn't defined, ftrace_caller keeps ftrace_graph_call
> > so that it can be replaced with the calling of prepare_ftrace_return by
> > the enable/disable helper.
> >
> > As for defining FTRACE_WITH_REGS, ftrace_caller is adjusted to save the
> > necessary regs against the pt_regs layout, so it can reasonably call the
> > graph_ops::func function - ftrace_graph_func. And ftrace_graph_[regs]_call
> > and its enable/disable helper aren't needed.
> >
> > The tests generated by CONFIG_FTRACE_STARTUP_TEST have passed in the local
> > qemu-system-riscv64 virt machine. The following is the log during startup.
> >
> > ```
> > Nov 15 03:07:13 stage4 kernel: Testing tracer function: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #1:
> > Nov 15 03:07:13 stage4 kernel: (1 0 1 0 0)
> > Nov 15 03:07:13 stage4 kernel: (1 1 2 0 0)
> > Nov 15 03:07:13 stage4 kernel: (2 1 3 0 365)
> > Nov 15 03:07:13 stage4 kernel: (2 2 4 0 399)
> > Nov 15 03:07:13 stage4 kernel: (3 2 4 0 146071)
> > Nov 15 03:07:13 stage4 kernel: (3 3 5 0 146105) PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #2:
> > Nov 15 03:07:13 stage4 kernel: (1 0 1 589 0)
> > Nov 15 03:07:13 stage4 kernel: (1 1 2 635 0)
> > Nov 15 03:07:13 stage4 kernel: (2 1 3 1 2)
> > Nov 15 03:07:13 stage4 kernel: (2 2 4 125 126)
> > Nov 15 03:07:13 stage4 kernel: (3 2 4 146001 146078)
> > Nov 15 03:07:13 stage4 kernel: (3 3 5 146035 146112) PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion safe: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing ftrace regs: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing tracer nop: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing tracer irqsoff: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup:
> > Nov 15 03:07:13 stage4 kernel: sched: DL replenish lagged too much
> > Nov 15 03:07:13 stage4 kernel: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_rt: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_dl: PASSED
> > Nov 15 03:07:13 stage4 kernel: Testing tracer function_graph: PASSED
> > ```
> >
> > Note that the changes of mcount-dyn.S conflicts with this unmerged
> > commit (riscv: entry: consolidate general regs saving/restoring).
> > https://lore.kernel.org/linux-riscv/[email protected]
> >
> > Changes since v2:
> > - line up the comments [Andrew]
> > - rename SAVE_ALL as SAVE_ABI_REGS [Guo Ren]
> > - consolidate the modifications of mcount-dyn.S into one patch [Guo Ren]
> > - adapt this series based on [riscv: ftrace: Fixup ftrace detour code][1] [Guo Ren]
> Tested-by: Guo Ren <[email protected]>
>
> https://github.com/guoren83/linux/tree/ftrace_fixup_v3
>
Thanks for your tests.
And the PREPARE_ARGS you suggested has been added in the v4 thread.
Here is the link for your convenience.
https://lore.kernel.org/linux-riscv/[email protected]/
> >
> > [1]: https://lore.kernel.org/linux-riscv/[email protected]/
> > v2 Link: https://lore.kernel.org/linux-riscv/[email protected]/
> >
> > Changes since v1:
> > - fix the checkpatch warnings in patch 1
> > v1 Link: https://lore.kernel.org/linux-riscv/[email protected]
> >
> > Song Shuai (2):
> > riscv/ftrace: add ftrace_graph_func
> > riscv/ftrace: make ftrace_caller call ftrace_graph_func
> >
> > arch/riscv/include/asm/ftrace.h | 13 ++-
> > arch/riscv/kernel/ftrace.c | 30 +++----
> > arch/riscv/kernel/mcount-dyn.S | 143 +++++++++++++++++++++++---------
> > 3 files changed, 129 insertions(+), 57 deletions(-)
> >
> > --
> > 2.20.1
> >
>
>
> --
> Best Regards
> Guo Ren
Thanks,
Song