* [PATCH V3 0/5] riscv: ftrace: Fixup ftrace detour code & Optimization
@ 2022-11-23 15:39 ` guoren
0 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren
From: Guo Ren <guoren@linux.alibaba.com>
The previous ftrace detour implementation fc76b8b8011 ("riscv: Using
PATCHABLE_FUNCTION_ENTRY instead of MCOUNT") contain three problems.
- The most horrible bug is preemption panic which found by Andy [1].
Let's disable preemption for ftrace first, and Andy could continue
the ftrace preemption work.
- The "-fpatchable-function-entry= CFLAG" wasted code size !RISCV_ISA_C.
- The ftrace detour implementation wasted code size.
The first three patches solve the above problems, and the last two
patches is from [2]:
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.
Test log:
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
[1]: https://lpc.events/event/16/contributions/1171/
[2]: https://lore.kernel.org/lkml/20221120084230.910152-1-suagrfillet@gmail.com/
Changes in V3
- Include [2] for maintenance. [Song Shuai]
Changes in V2:
https://lore.kernel.org/linux-riscv/20220921034910.3142465-1-guoren@kernel.org/
- Add Signed-off for preemption fixup.
Changes in V1:
https://lore.kernel.org/linux-riscv/20220916103817.9490-1-guoren@kernel.org/
Andy Chiu (1):
riscv: ftrace: Fixup panic by disabling preemption
Guo Ren (2):
riscv: ftrace: Remove wasted nops for !RISCV_ISA_C
riscv: ftrace: Reduce the detour code size to half
Song Shuai (2):
riscv: ftrace: Add ftrace_graph_func
riscv: ftrace: Make ftrace_caller call ftrace_graph_func
arch/riscv/Kconfig | 2 +-
arch/riscv/Makefile | 6 +-
arch/riscv/include/asm/ftrace.h | 63 +++++++++---
arch/riscv/kernel/ftrace.c | 91 ++++++----------
arch/riscv/kernel/mcount-dyn.S | 177 +++++++++++++++++++++-----------
5 files changed, 202 insertions(+), 137 deletions(-)
--
2.36.1
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 20+ messages in thread* [PATCH V3 1/5] riscv: ftrace: Fixup panic by disabling preemption
2022-11-23 15:39 ` guoren
@ 2022-11-23 15:39 ` guoren
-1 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren
From: Andy Chiu <andy.chiu@sifive.com>
In RISCV, we must use an AUIPC + JALR pair to encode an immediate,
forming a jump that jumps to an address over 4K. This may cause errors
if we want to enable kernel preemption and remove dependency from
patching code with stop_machine(). For example, if a task was switched
out on auipc. And, if we changed the ftrace function before it was
switched back, then it would jump to an address that has updated 11:0
bits mixing with previous XLEN:12 part.
p: patched area performed by dynamic ftrace
ftrace_prologue:
p| REG_S ra, -SZREG(sp)
p| auipc ra, 0x? ------------> preempted
...
change ftrace function
...
p| jalr -?(ra) <------------- switched back
p| REG_L ra, -SZREG(sp)
func:
xxx
ret
Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
@Andy, could you give the patch a Signed-off-by? I just copy your most
important comment, so the first author should be you. First, let's fix
the problem caused by my previous patch, and you can continue your
ftrace preemption work.
---
arch/riscv/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 7cd981f96f48..1d0e5838b11b 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -280,7 +280,7 @@ config ARCH_RV64I
select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
select HAVE_FUNCTION_GRAPH_TRACER
- select HAVE_FUNCTION_TRACER if !XIP_KERNEL
+ select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
select SWIOTLB if MMU
endchoice
--
2.36.1
^ permalink raw reply related [flat|nested] 20+ messages in thread* [PATCH V3 1/5] riscv: ftrace: Fixup panic by disabling preemption
@ 2022-11-23 15:39 ` guoren
0 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren
From: Andy Chiu <andy.chiu@sifive.com>
In RISCV, we must use an AUIPC + JALR pair to encode an immediate,
forming a jump that jumps to an address over 4K. This may cause errors
if we want to enable kernel preemption and remove dependency from
patching code with stop_machine(). For example, if a task was switched
out on auipc. And, if we changed the ftrace function before it was
switched back, then it would jump to an address that has updated 11:0
bits mixing with previous XLEN:12 part.
p: patched area performed by dynamic ftrace
ftrace_prologue:
p| REG_S ra, -SZREG(sp)
p| auipc ra, 0x? ------------> preempted
...
change ftrace function
...
p| jalr -?(ra) <------------- switched back
p| REG_L ra, -SZREG(sp)
func:
xxx
ret
Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
@Andy, could you give the patch a Signed-off-by? I just copy your most
important comment, so the first author should be you. First, let's fix
the problem caused by my previous patch, and you can continue your
ftrace preemption work.
---
arch/riscv/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 7cd981f96f48..1d0e5838b11b 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -280,7 +280,7 @@ config ARCH_RV64I
select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
select HAVE_FUNCTION_GRAPH_TRACER
- select HAVE_FUNCTION_TRACER if !XIP_KERNEL
+ select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION
select SWIOTLB if MMU
endchoice
--
2.36.1
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply related [flat|nested] 20+ messages in thread* Re: [PATCH V3 1/5] riscv: ftrace: Fixup panic by disabling preemption
2022-11-23 15:39 ` guoren
@ 2022-11-23 20:07 ` Conor Dooley
-1 siblings, 0 replies; 20+ messages in thread
From: Conor Dooley @ 2022-11-23 20:07 UTC (permalink / raw)
To: guoren
Cc: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu,
linux-riscv, linux-kernel
On Wed, Nov 23, 2022 at 10:39:46AM -0500, guoren@kernel.org wrote:
> From: Andy Chiu <andy.chiu@sifive.com>
>
> In RISCV, we must use an AUIPC + JALR pair to encode an immediate,
> forming a jump that jumps to an address over 4K. This may cause errors
> if we want to enable kernel preemption and remove dependency from
> patching code with stop_machine(). For example, if a task was switched
> out on auipc. And, if we changed the ftrace function before it was
> switched back, then it would jump to an address that has updated 11:0
> bits mixing with previous XLEN:12 part.
>
> p: patched area performed by dynamic ftrace
> ftrace_prologue:
> p| REG_S ra, -SZREG(sp)
> p| auipc ra, 0x? ------------> preempted
> ...
> change ftrace function
> ...
> p| jalr -?(ra) <------------- switched back
> p| REG_L ra, -SZREG(sp)
> func:
> xxx
> ret
>
> Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
==========
verify_fixes - FAILED
Commit: be26b864dac9 ("riscv: ftrace: Fixup panic by disabling preemption")
Fixes tag: Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Has these problem(s):
- Target SHA1 does not exist
This should instead be:
Fixes: afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Thanks,
Conor.
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 20+ messages in thread* Re: [PATCH V3 1/5] riscv: ftrace: Fixup panic by disabling preemption
@ 2022-11-23 20:07 ` Conor Dooley
0 siblings, 0 replies; 20+ messages in thread
From: Conor Dooley @ 2022-11-23 20:07 UTC (permalink / raw)
To: guoren
Cc: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu,
linux-riscv, linux-kernel
On Wed, Nov 23, 2022 at 10:39:46AM -0500, guoren@kernel.org wrote:
> From: Andy Chiu <andy.chiu@sifive.com>
>
> In RISCV, we must use an AUIPC + JALR pair to encode an immediate,
> forming a jump that jumps to an address over 4K. This may cause errors
> if we want to enable kernel preemption and remove dependency from
> patching code with stop_machine(). For example, if a task was switched
> out on auipc. And, if we changed the ftrace function before it was
> switched back, then it would jump to an address that has updated 11:0
> bits mixing with previous XLEN:12 part.
>
> p: patched area performed by dynamic ftrace
> ftrace_prologue:
> p| REG_S ra, -SZREG(sp)
> p| auipc ra, 0x? ------------> preempted
> ...
> change ftrace function
> ...
> p| jalr -?(ra) <------------- switched back
> p| REG_L ra, -SZREG(sp)
> func:
> xxx
> ret
>
> Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
==========
verify_fixes - FAILED
Commit: be26b864dac9 ("riscv: ftrace: Fixup panic by disabling preemption")
Fixes tag: Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Has these problem(s):
- Target SHA1 does not exist
This should instead be:
Fixes: afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Thanks,
Conor.
^ permalink raw reply [flat|nested] 20+ messages in thread* Re: [PATCH V3 1/5] riscv: ftrace: Fixup panic by disabling preemption
2022-11-23 20:07 ` Conor Dooley
@ 2022-11-24 2:10 ` Guo Ren
-1 siblings, 0 replies; 20+ messages in thread
From: Guo Ren @ 2022-11-24 2:10 UTC (permalink / raw)
To: Conor Dooley
Cc: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu,
linux-riscv, linux-kernel
On Thu, Nov 24, 2022 at 4:07 AM Conor Dooley <conor@kernel.org> wrote:
>
> On Wed, Nov 23, 2022 at 10:39:46AM -0500, guoren@kernel.org wrote:
> > From: Andy Chiu <andy.chiu@sifive.com>
> >
> > In RISCV, we must use an AUIPC + JALR pair to encode an immediate,
> > forming a jump that jumps to an address over 4K. This may cause errors
> > if we want to enable kernel preemption and remove dependency from
> > patching code with stop_machine(). For example, if a task was switched
> > out on auipc. And, if we changed the ftrace function before it was
> > switched back, then it would jump to an address that has updated 11:0
> > bits mixing with previous XLEN:12 part.
> >
> > p: patched area performed by dynamic ftrace
> > ftrace_prologue:
> > p| REG_S ra, -SZREG(sp)
> > p| auipc ra, 0x? ------------> preempted
> > ...
> > change ftrace function
> > ...
> > p| jalr -?(ra) <------------- switched back
> > p| REG_L ra, -SZREG(sp)
> > func:
> > xxx
> > ret
> >
> > Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
>
> ==========
> verify_fixes - FAILED
>
> Commit: be26b864dac9 ("riscv: ftrace: Fixup panic by disabling preemption")
> Fixes tag: Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
> Has these problem(s):
> - Target SHA1 does not exist
>
> This should instead be:
> Fixes: afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Thank you! Sorry, I missed the first letter :P
>
> Thanks,
> Conor.
>
--
Best Regards
Guo Ren
^ permalink raw reply [flat|nested] 20+ messages in thread* Re: [PATCH V3 1/5] riscv: ftrace: Fixup panic by disabling preemption
@ 2022-11-24 2:10 ` Guo Ren
0 siblings, 0 replies; 20+ messages in thread
From: Guo Ren @ 2022-11-24 2:10 UTC (permalink / raw)
To: Conor Dooley
Cc: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu,
linux-riscv, linux-kernel
On Thu, Nov 24, 2022 at 4:07 AM Conor Dooley <conor@kernel.org> wrote:
>
> On Wed, Nov 23, 2022 at 10:39:46AM -0500, guoren@kernel.org wrote:
> > From: Andy Chiu <andy.chiu@sifive.com>
> >
> > In RISCV, we must use an AUIPC + JALR pair to encode an immediate,
> > forming a jump that jumps to an address over 4K. This may cause errors
> > if we want to enable kernel preemption and remove dependency from
> > patching code with stop_machine(). For example, if a task was switched
> > out on auipc. And, if we changed the ftrace function before it was
> > switched back, then it would jump to an address that has updated 11:0
> > bits mixing with previous XLEN:12 part.
> >
> > p: patched area performed by dynamic ftrace
> > ftrace_prologue:
> > p| REG_S ra, -SZREG(sp)
> > p| auipc ra, 0x? ------------> preempted
> > ...
> > change ftrace function
> > ...
> > p| jalr -?(ra) <------------- switched back
> > p| REG_L ra, -SZREG(sp)
> > func:
> > xxx
> > ret
> >
> > Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
>
> ==========
> verify_fixes - FAILED
>
> Commit: be26b864dac9 ("riscv: ftrace: Fixup panic by disabling preemption")
> Fixes tag: Fixes: fc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
> Has these problem(s):
> - Target SHA1 does not exist
>
> This should instead be:
> Fixes: afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Thank you! Sorry, I missed the first letter :P
>
> Thanks,
> Conor.
>
--
Best Regards
Guo Ren
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH V3 2/5] riscv: ftrace: Remove wasted nops for !RISCV_ISA_C
2022-11-23 15:39 ` guoren
@ 2022-11-23 15:39 ` guoren
-1 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren, Guo Ren
From: Guo Ren <guoren@linux.alibaba.com>
When CONFIG_RISCV_ISA_C=n, -fpatchable-function-entry=8 would generate
more nops than we expect. Because it treat nop opcode as 0x00000013
instead of 0x0001.
Dump of assembler code for function dw_pcie_free_msi:
0xffffffff806fce94 <+0>: sd ra,-8(sp)
0xffffffff806fce98 <+4>: auipc ra,0xff90f
0xffffffff806fce9c <+8>: jalr -684(ra) # 0xffffffff8000bbec
<ftrace_caller>
0xffffffff806fcea0 <+12>: ld ra,-8(sp)
0xffffffff806fcea4 <+16>: nop /* wasted */
0xffffffff806fcea8 <+20>: nop /* wasted */
0xffffffff806fceac <+24>: nop /* wasted */
0xffffffff806fceb0 <+28>: nop /* wasted */
0xffffffff806fceb4 <+0>: addi sp,sp,-48
0xffffffff806fceb8 <+4>: sd s0,32(sp)
0xffffffff806fcebc <+8>: sd s1,24(sp)
0xffffffff806fcec0 <+12>: sd s2,16(sp)
0xffffffff806fcec4 <+16>: sd s3,8(sp)
0xffffffff806fcec8 <+20>: sd ra,40(sp)
0xffffffff806fcecc <+24>: addi s0,sp,48
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
arch/riscv/Makefile | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 1c8ec656e916..36cc609c5d03 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -11,7 +11,11 @@ LDFLAGS_vmlinux :=
ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
LDFLAGS_vmlinux := --no-relax
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
+ifeq ($(CONFIG_RISCV_ISA_C),y)
CC_FLAGS_FTRACE := -fpatchable-function-entry=8
+else
+ CC_FLAGS_FTRACE := -fpatchable-function-entry=4
+endif
endif
ifeq ($(CONFIG_CMODEL_MEDLOW),y)
--
2.36.1
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH V3 2/5] riscv: ftrace: Remove wasted nops for !RISCV_ISA_C
@ 2022-11-23 15:39 ` guoren
0 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren, Guo Ren
From: Guo Ren <guoren@linux.alibaba.com>
When CONFIG_RISCV_ISA_C=n, -fpatchable-function-entry=8 would generate
more nops than we expect. Because it treat nop opcode as 0x00000013
instead of 0x0001.
Dump of assembler code for function dw_pcie_free_msi:
0xffffffff806fce94 <+0>: sd ra,-8(sp)
0xffffffff806fce98 <+4>: auipc ra,0xff90f
0xffffffff806fce9c <+8>: jalr -684(ra) # 0xffffffff8000bbec
<ftrace_caller>
0xffffffff806fcea0 <+12>: ld ra,-8(sp)
0xffffffff806fcea4 <+16>: nop /* wasted */
0xffffffff806fcea8 <+20>: nop /* wasted */
0xffffffff806fceac <+24>: nop /* wasted */
0xffffffff806fceb0 <+28>: nop /* wasted */
0xffffffff806fceb4 <+0>: addi sp,sp,-48
0xffffffff806fceb8 <+4>: sd s0,32(sp)
0xffffffff806fcebc <+8>: sd s1,24(sp)
0xffffffff806fcec0 <+12>: sd s2,16(sp)
0xffffffff806fcec4 <+16>: sd s3,8(sp)
0xffffffff806fcec8 <+20>: sd ra,40(sp)
0xffffffff806fcecc <+24>: addi s0,sp,48
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
arch/riscv/Makefile | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 1c8ec656e916..36cc609c5d03 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -11,7 +11,11 @@ LDFLAGS_vmlinux :=
ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
LDFLAGS_vmlinux := --no-relax
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
+ifeq ($(CONFIG_RISCV_ISA_C),y)
CC_FLAGS_FTRACE := -fpatchable-function-entry=8
+else
+ CC_FLAGS_FTRACE := -fpatchable-function-entry=4
+endif
endif
ifeq ($(CONFIG_CMODEL_MEDLOW),y)
--
2.36.1
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH V3 3/5] riscv: ftrace: Reduce the detour code size to half
2022-11-23 15:39 ` guoren
@ 2022-11-23 15:39 ` guoren
-1 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren, Guo Ren
From: Guo Ren <guoren@linux.alibaba.com>
Use a temporary register to reduce the size of detour code from
16 bytes to 8 bytes. The previous implementation is from
afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of
MCOUNT").
Before the patch:
<func_prolog>:
0: REG_S ra, -SZREG(sp)
4: auipc ra, ?
8: jalr ?(ra)
12: REG_L ra, -SZREG(sp)
(func_boddy)
After the patch:
<func_prolog>:
0: auipc t0, ?
4: jalr t0, ?(t0)
(func_boddy)
Link: https://lore.kernel.org/linux-riscv/20221122075440.1165172-1-suagrfillet@gmail.com/
Co-developed-by: Song Shuai <suagrfillet@gmail.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
Changes in v3:
- Fixup ftrace_modify_call without "caller = rec->ip + 4". [Song Shuai]
- Optimize .macro make_call_ra & make_call_t0
---
arch/riscv/Makefile | 4 +-
arch/riscv/include/asm/ftrace.h | 50 +++++++++++++++++++------
arch/riscv/kernel/ftrace.c | 65 ++++++++++-----------------------
arch/riscv/kernel/mcount-dyn.S | 43 +++++++++-------------
4 files changed, 76 insertions(+), 86 deletions(-)
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 36cc609c5d03..d60939e2c596 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -12,9 +12,9 @@ ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
LDFLAGS_vmlinux := --no-relax
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
ifeq ($(CONFIG_RISCV_ISA_C),y)
- CC_FLAGS_FTRACE := -fpatchable-function-entry=8
-else
CC_FLAGS_FTRACE := -fpatchable-function-entry=4
+else
+ CC_FLAGS_FTRACE := -fpatchable-function-entry=2
endif
endif
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
index 04dad3380041..9e73922e1e2e 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -42,6 +42,14 @@ struct dyn_arch_ftrace {
* 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to
* return address (original pc + 4)
*
+ *<ftrace enable>:
+ * 0: auipc t0/ra, 0x?
+ * 4: jalr t0/ra, ?(t0/ra)
+ *
+ *<ftrace disable>:
+ * 0: nop
+ * 4: nop
+ *
* Dynamic ftrace generates probes to call sites, so we must deal with
* both auipc and jalr at the same time.
*/
@@ -52,25 +60,43 @@ struct dyn_arch_ftrace {
#define AUIPC_OFFSET_MASK (0xfffff000)
#define AUIPC_PAD (0x00001000)
#define JALR_SHIFT 20
-#define JALR_BASIC (0x000080e7)
-#define AUIPC_BASIC (0x00000097)
+#define JALR_RA (0x000080e7)
+#define AUIPC_RA (0x00000097)
+#define JALR_T0 (0x000282e7)
+#define AUIPC_T0 (0x00000297)
#define NOP4 (0x00000013)
-#define make_call(caller, callee, call) \
+#define to_jalr_t0(offset) \
+ (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_T0)
+
+#define to_auipc_t0(offset) \
+ ((offset & JALR_SIGN_MASK) ? \
+ (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_T0) : \
+ ((offset & AUIPC_OFFSET_MASK) | AUIPC_T0))
+
+#define make_call_t0(caller, callee, call) \
do { \
- call[0] = to_auipc_insn((unsigned int)((unsigned long)callee - \
- (unsigned long)caller)); \
- call[1] = to_jalr_insn((unsigned int)((unsigned long)callee - \
- (unsigned long)caller)); \
+ unsigned int offset = \
+ (unsigned long) callee - (unsigned long) caller; \
+ call[0] = to_auipc_t0(offset); \
+ call[1] = to_jalr_t0(offset); \
} while (0)
-#define to_jalr_insn(offset) \
- (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_BASIC)
+#define to_jalr_ra(offset) \
+ (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_RA)
-#define to_auipc_insn(offset) \
+#define to_auipc_ra(offset) \
((offset & JALR_SIGN_MASK) ? \
- (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_BASIC) : \
- ((offset & AUIPC_OFFSET_MASK) | AUIPC_BASIC))
+ (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_RA) : \
+ ((offset & AUIPC_OFFSET_MASK) | AUIPC_RA))
+
+#define make_call_ra(caller, callee, call) \
+do { \
+ unsigned int offset = \
+ (unsigned long) callee - (unsigned long) caller; \
+ call[0] = to_auipc_ra(offset); \
+ call[1] = to_jalr_ra(offset); \
+} while (0)
/*
* Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here.
diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
index 2086f6585773..61b24d767e2e 100644
--- a/arch/riscv/kernel/ftrace.c
+++ b/arch/riscv/kernel/ftrace.c
@@ -55,12 +55,15 @@ static int ftrace_check_current_call(unsigned long hook_pos,
}
static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target,
- bool enable)
+ bool enable, bool ra)
{
unsigned int call[2];
unsigned int nops[2] = {NOP4, NOP4};
- make_call(hook_pos, target, call);
+ if (ra)
+ make_call_ra(hook_pos, target, call);
+ else
+ make_call_t0(hook_pos, target, call);
/* Replace the auipc-jalr pair at once. Return -EPERM on write error. */
if (patch_text_nosync
@@ -70,42 +73,13 @@ static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target,
return 0;
}
-/*
- * Put 5 instructions with 16 bytes at the front of function within
- * patchable function entry nops' area.
- *
- * 0: REG_S ra, -SZREG(sp)
- * 1: auipc ra, 0x?
- * 2: jalr -?(ra)
- * 3: REG_L ra, -SZREG(sp)
- *
- * So the opcodes is:
- * 0: 0xfe113c23 (sd)/0xfe112e23 (sw)
- * 1: 0x???????? -> auipc
- * 2: 0x???????? -> jalr
- * 3: 0xff813083 (ld)/0xffc12083 (lw)
- */
-#if __riscv_xlen == 64
-#define INSN0 0xfe113c23
-#define INSN3 0xff813083
-#elif __riscv_xlen == 32
-#define INSN0 0xfe112e23
-#define INSN3 0xffc12083
-#endif
-
-#define FUNC_ENTRY_SIZE 16
-#define FUNC_ENTRY_JMP 4
-
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
- unsigned int call[4] = {INSN0, 0, 0, INSN3};
- unsigned long target = addr;
- unsigned long caller = rec->ip + FUNC_ENTRY_JMP;
+ unsigned int call[2];
- call[1] = to_auipc_insn((unsigned int)(target - caller));
- call[2] = to_jalr_insn((unsigned int)(target - caller));
+ make_call_t0(rec->ip, addr, call);
- if (patch_text_nosync((void *)rec->ip, call, FUNC_ENTRY_SIZE))
+ if (patch_text_nosync((void *)rec->ip, call, 8))
return -EPERM;
return 0;
@@ -114,15 +88,14 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
unsigned long addr)
{
- unsigned int nops[4] = {NOP4, NOP4, NOP4, NOP4};
+ unsigned int nops[2] = {NOP4, NOP4};
- if (patch_text_nosync((void *)rec->ip, nops, FUNC_ENTRY_SIZE))
+ if (patch_text_nosync((void *)rec->ip, nops, MCOUNT_INSN_SIZE))
return -EPERM;
return 0;
}
-
/*
* This is called early on, and isn't wrapped by
* ftrace_arch_code_modify_{prepare,post_process}() and therefor doesn't hold
@@ -144,10 +117,10 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
int ftrace_update_ftrace_func(ftrace_func_t func)
{
int ret = __ftrace_modify_call((unsigned long)&ftrace_call,
- (unsigned long)func, true);
+ (unsigned long)func, true, true);
if (!ret) {
ret = __ftrace_modify_call((unsigned long)&ftrace_regs_call,
- (unsigned long)func, true);
+ (unsigned long)func, true, true);
}
return ret;
@@ -159,16 +132,16 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
{
unsigned int call[2];
- unsigned long caller = rec->ip + FUNC_ENTRY_JMP;
+ unsigned long caller = rec->ip;
int ret;
- make_call(caller, old_addr, call);
+ make_call_t0(caller, old_addr, call);
ret = ftrace_check_current_call(caller, call);
if (ret)
return ret;
- return __ftrace_modify_call(caller, addr, true);
+ return __ftrace_modify_call(caller, addr, true, false);
}
#endif
@@ -203,12 +176,12 @@ int ftrace_enable_ftrace_graph_caller(void)
int ret;
ret = __ftrace_modify_call((unsigned long)&ftrace_graph_call,
- (unsigned long)&prepare_ftrace_return, true);
+ (unsigned long)&prepare_ftrace_return, true, true);
if (ret)
return ret;
return __ftrace_modify_call((unsigned long)&ftrace_graph_regs_call,
- (unsigned long)&prepare_ftrace_return, true);
+ (unsigned long)&prepare_ftrace_return, true, true);
}
int ftrace_disable_ftrace_graph_caller(void)
@@ -216,12 +189,12 @@ int ftrace_disable_ftrace_graph_caller(void)
int ret;
ret = __ftrace_modify_call((unsigned long)&ftrace_graph_call,
- (unsigned long)&prepare_ftrace_return, false);
+ (unsigned long)&prepare_ftrace_return, false, true);
if (ret)
return ret;
return __ftrace_modify_call((unsigned long)&ftrace_graph_regs_call,
- (unsigned long)&prepare_ftrace_return, false);
+ (unsigned long)&prepare_ftrace_return, false, true);
}
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
index d171eca623b6..64bc79816f5e 100644
--- a/arch/riscv/kernel/mcount-dyn.S
+++ b/arch/riscv/kernel/mcount-dyn.S
@@ -13,8 +13,8 @@
.text
-#define FENTRY_RA_OFFSET 12
-#define ABI_SIZE_ON_STACK 72
+#define FENTRY_RA_OFFSET 8
+#define ABI_SIZE_ON_STACK 80
#define ABI_A0 0
#define ABI_A1 8
#define ABI_A2 16
@@ -23,10 +23,10 @@
#define ABI_A5 40
#define ABI_A6 48
#define ABI_A7 56
-#define ABI_RA 64
+#define ABI_T0 64
+#define ABI_RA 72
.macro SAVE_ABI
- addi sp, sp, -SZREG
addi sp, sp, -ABI_SIZE_ON_STACK
REG_S a0, ABI_A0(sp)
@@ -37,6 +37,7 @@
REG_S a5, ABI_A5(sp)
REG_S a6, ABI_A6(sp)
REG_S a7, ABI_A7(sp)
+ REG_S t0, ABI_T0(sp)
REG_S ra, ABI_RA(sp)
.endm
@@ -49,24 +50,18 @@
REG_L a5, ABI_A5(sp)
REG_L a6, ABI_A6(sp)
REG_L a7, ABI_A7(sp)
+ REG_L t0, ABI_T0(sp)
REG_L ra, ABI_RA(sp)
addi sp, sp, ABI_SIZE_ON_STACK
- addi sp, sp, SZREG
.endm
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
.macro SAVE_ALL
- addi sp, sp, -SZREG
addi sp, sp, -PT_SIZE_ON_STACK
- REG_S x1, PT_EPC(sp)
- addi sp, sp, PT_SIZE_ON_STACK
- REG_L x1, (sp)
- addi sp, sp, -PT_SIZE_ON_STACK
+ REG_S t0, PT_EPC(sp)
REG_S x1, PT_RA(sp)
- REG_L x1, PT_EPC(sp)
-
REG_S x2, PT_SP(sp)
REG_S x3, PT_GP(sp)
REG_S x4, PT_TP(sp)
@@ -100,11 +95,8 @@
.endm
.macro RESTORE_ALL
+ REG_L t0, PT_EPC(sp)
REG_L x1, PT_RA(sp)
- addi sp, sp, PT_SIZE_ON_STACK
- REG_S x1, (sp)
- addi sp, sp, -PT_SIZE_ON_STACK
- REG_L x1, PT_EPC(sp)
REG_L x2, PT_SP(sp)
REG_L x3, PT_GP(sp)
REG_L x4, PT_TP(sp)
@@ -137,17 +129,16 @@
REG_L x31, PT_T6(sp)
addi sp, sp, PT_SIZE_ON_STACK
- addi sp, sp, SZREG
.endm
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
ENTRY(ftrace_caller)
SAVE_ABI
- addi a0, ra, -FENTRY_RA_OFFSET
+ addi a0, t0, -FENTRY_RA_OFFSET
la a1, function_trace_op
REG_L a2, 0(a1)
- REG_L a1, ABI_SIZE_ON_STACK(sp)
+ mv a1, ra
mv a3, sp
ftrace_call:
@@ -155,8 +146,8 @@ ftrace_call:
call ftrace_stub
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- addi a0, sp, ABI_SIZE_ON_STACK
- REG_L a1, ABI_RA(sp)
+ addi a0, sp, ABI_RA
+ REG_L a1, ABI_T0(sp)
addi a1, a1, -FENTRY_RA_OFFSET
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
mv a2, s0
@@ -166,17 +157,17 @@ ftrace_graph_call:
call ftrace_stub
#endif
RESTORE_ABI
- ret
+ jr t0
ENDPROC(ftrace_caller)
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
ENTRY(ftrace_regs_caller)
SAVE_ALL
- addi a0, ra, -FENTRY_RA_OFFSET
+ addi a0, t0, -FENTRY_RA_OFFSET
la a1, function_trace_op
REG_L a2, 0(a1)
- REG_L a1, PT_SIZE_ON_STACK(sp)
+ REG_L a1, PT_RA(sp)
mv a3, sp
ftrace_regs_call:
@@ -185,7 +176,7 @@ ftrace_regs_call:
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
addi a0, sp, PT_RA
- REG_L a1, PT_EPC(sp)
+ REG_L a1, PT_T0(sp)
addi a1, a1, -FENTRY_RA_OFFSET
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
mv a2, s0
@@ -196,6 +187,6 @@ ftrace_graph_regs_call:
#endif
RESTORE_ALL
- ret
+ jr t0
ENDPROC(ftrace_regs_caller)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
--
2.36.1
^ permalink raw reply related [flat|nested] 20+ messages in thread* [PATCH V3 3/5] riscv: ftrace: Reduce the detour code size to half
@ 2022-11-23 15:39 ` guoren
0 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren, Guo Ren
From: Guo Ren <guoren@linux.alibaba.com>
Use a temporary register to reduce the size of detour code from
16 bytes to 8 bytes. The previous implementation is from
afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of
MCOUNT").
Before the patch:
<func_prolog>:
0: REG_S ra, -SZREG(sp)
4: auipc ra, ?
8: jalr ?(ra)
12: REG_L ra, -SZREG(sp)
(func_boddy)
After the patch:
<func_prolog>:
0: auipc t0, ?
4: jalr t0, ?(t0)
(func_boddy)
Link: https://lore.kernel.org/linux-riscv/20221122075440.1165172-1-suagrfillet@gmail.com/
Co-developed-by: Song Shuai <suagrfillet@gmail.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
Changes in v3:
- Fixup ftrace_modify_call without "caller = rec->ip + 4". [Song Shuai]
- Optimize .macro make_call_ra & make_call_t0
---
arch/riscv/Makefile | 4 +-
arch/riscv/include/asm/ftrace.h | 50 +++++++++++++++++++------
arch/riscv/kernel/ftrace.c | 65 ++++++++++-----------------------
arch/riscv/kernel/mcount-dyn.S | 43 +++++++++-------------
4 files changed, 76 insertions(+), 86 deletions(-)
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 36cc609c5d03..d60939e2c596 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -12,9 +12,9 @@ ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
LDFLAGS_vmlinux := --no-relax
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
ifeq ($(CONFIG_RISCV_ISA_C),y)
- CC_FLAGS_FTRACE := -fpatchable-function-entry=8
-else
CC_FLAGS_FTRACE := -fpatchable-function-entry=4
+else
+ CC_FLAGS_FTRACE := -fpatchable-function-entry=2
endif
endif
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
index 04dad3380041..9e73922e1e2e 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -42,6 +42,14 @@ struct dyn_arch_ftrace {
* 2) jalr: setting low-12 offset to ra, jump to ra, and set ra to
* return address (original pc + 4)
*
+ *<ftrace enable>:
+ * 0: auipc t0/ra, 0x?
+ * 4: jalr t0/ra, ?(t0/ra)
+ *
+ *<ftrace disable>:
+ * 0: nop
+ * 4: nop
+ *
* Dynamic ftrace generates probes to call sites, so we must deal with
* both auipc and jalr at the same time.
*/
@@ -52,25 +60,43 @@ struct dyn_arch_ftrace {
#define AUIPC_OFFSET_MASK (0xfffff000)
#define AUIPC_PAD (0x00001000)
#define JALR_SHIFT 20
-#define JALR_BASIC (0x000080e7)
-#define AUIPC_BASIC (0x00000097)
+#define JALR_RA (0x000080e7)
+#define AUIPC_RA (0x00000097)
+#define JALR_T0 (0x000282e7)
+#define AUIPC_T0 (0x00000297)
#define NOP4 (0x00000013)
-#define make_call(caller, callee, call) \
+#define to_jalr_t0(offset) \
+ (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_T0)
+
+#define to_auipc_t0(offset) \
+ ((offset & JALR_SIGN_MASK) ? \
+ (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_T0) : \
+ ((offset & AUIPC_OFFSET_MASK) | AUIPC_T0))
+
+#define make_call_t0(caller, callee, call) \
do { \
- call[0] = to_auipc_insn((unsigned int)((unsigned long)callee - \
- (unsigned long)caller)); \
- call[1] = to_jalr_insn((unsigned int)((unsigned long)callee - \
- (unsigned long)caller)); \
+ unsigned int offset = \
+ (unsigned long) callee - (unsigned long) caller; \
+ call[0] = to_auipc_t0(offset); \
+ call[1] = to_jalr_t0(offset); \
} while (0)
-#define to_jalr_insn(offset) \
- (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_BASIC)
+#define to_jalr_ra(offset) \
+ (((offset & JALR_OFFSET_MASK) << JALR_SHIFT) | JALR_RA)
-#define to_auipc_insn(offset) \
+#define to_auipc_ra(offset) \
((offset & JALR_SIGN_MASK) ? \
- (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_BASIC) : \
- ((offset & AUIPC_OFFSET_MASK) | AUIPC_BASIC))
+ (((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) | AUIPC_RA) : \
+ ((offset & AUIPC_OFFSET_MASK) | AUIPC_RA))
+
+#define make_call_ra(caller, callee, call) \
+do { \
+ unsigned int offset = \
+ (unsigned long) callee - (unsigned long) caller; \
+ call[0] = to_auipc_ra(offset); \
+ call[1] = to_jalr_ra(offset); \
+} while (0)
/*
* Let auipc+jalr be the basic *mcount unit*, so we make it 8 bytes here.
diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
index 2086f6585773..61b24d767e2e 100644
--- a/arch/riscv/kernel/ftrace.c
+++ b/arch/riscv/kernel/ftrace.c
@@ -55,12 +55,15 @@ static int ftrace_check_current_call(unsigned long hook_pos,
}
static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target,
- bool enable)
+ bool enable, bool ra)
{
unsigned int call[2];
unsigned int nops[2] = {NOP4, NOP4};
- make_call(hook_pos, target, call);
+ if (ra)
+ make_call_ra(hook_pos, target, call);
+ else
+ make_call_t0(hook_pos, target, call);
/* Replace the auipc-jalr pair at once. Return -EPERM on write error. */
if (patch_text_nosync
@@ -70,42 +73,13 @@ static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target,
return 0;
}
-/*
- * Put 5 instructions with 16 bytes at the front of function within
- * patchable function entry nops' area.
- *
- * 0: REG_S ra, -SZREG(sp)
- * 1: auipc ra, 0x?
- * 2: jalr -?(ra)
- * 3: REG_L ra, -SZREG(sp)
- *
- * So the opcodes is:
- * 0: 0xfe113c23 (sd)/0xfe112e23 (sw)
- * 1: 0x???????? -> auipc
- * 2: 0x???????? -> jalr
- * 3: 0xff813083 (ld)/0xffc12083 (lw)
- */
-#if __riscv_xlen == 64
-#define INSN0 0xfe113c23
-#define INSN3 0xff813083
-#elif __riscv_xlen == 32
-#define INSN0 0xfe112e23
-#define INSN3 0xffc12083
-#endif
-
-#define FUNC_ENTRY_SIZE 16
-#define FUNC_ENTRY_JMP 4
-
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
- unsigned int call[4] = {INSN0, 0, 0, INSN3};
- unsigned long target = addr;
- unsigned long caller = rec->ip + FUNC_ENTRY_JMP;
+ unsigned int call[2];
- call[1] = to_auipc_insn((unsigned int)(target - caller));
- call[2] = to_jalr_insn((unsigned int)(target - caller));
+ make_call_t0(rec->ip, addr, call);
- if (patch_text_nosync((void *)rec->ip, call, FUNC_ENTRY_SIZE))
+ if (patch_text_nosync((void *)rec->ip, call, 8))
return -EPERM;
return 0;
@@ -114,15 +88,14 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
unsigned long addr)
{
- unsigned int nops[4] = {NOP4, NOP4, NOP4, NOP4};
+ unsigned int nops[2] = {NOP4, NOP4};
- if (patch_text_nosync((void *)rec->ip, nops, FUNC_ENTRY_SIZE))
+ if (patch_text_nosync((void *)rec->ip, nops, MCOUNT_INSN_SIZE))
return -EPERM;
return 0;
}
-
/*
* This is called early on, and isn't wrapped by
* ftrace_arch_code_modify_{prepare,post_process}() and therefor doesn't hold
@@ -144,10 +117,10 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
int ftrace_update_ftrace_func(ftrace_func_t func)
{
int ret = __ftrace_modify_call((unsigned long)&ftrace_call,
- (unsigned long)func, true);
+ (unsigned long)func, true, true);
if (!ret) {
ret = __ftrace_modify_call((unsigned long)&ftrace_regs_call,
- (unsigned long)func, true);
+ (unsigned long)func, true, true);
}
return ret;
@@ -159,16 +132,16 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
{
unsigned int call[2];
- unsigned long caller = rec->ip + FUNC_ENTRY_JMP;
+ unsigned long caller = rec->ip;
int ret;
- make_call(caller, old_addr, call);
+ make_call_t0(caller, old_addr, call);
ret = ftrace_check_current_call(caller, call);
if (ret)
return ret;
- return __ftrace_modify_call(caller, addr, true);
+ return __ftrace_modify_call(caller, addr, true, false);
}
#endif
@@ -203,12 +176,12 @@ int ftrace_enable_ftrace_graph_caller(void)
int ret;
ret = __ftrace_modify_call((unsigned long)&ftrace_graph_call,
- (unsigned long)&prepare_ftrace_return, true);
+ (unsigned long)&prepare_ftrace_return, true, true);
if (ret)
return ret;
return __ftrace_modify_call((unsigned long)&ftrace_graph_regs_call,
- (unsigned long)&prepare_ftrace_return, true);
+ (unsigned long)&prepare_ftrace_return, true, true);
}
int ftrace_disable_ftrace_graph_caller(void)
@@ -216,12 +189,12 @@ int ftrace_disable_ftrace_graph_caller(void)
int ret;
ret = __ftrace_modify_call((unsigned long)&ftrace_graph_call,
- (unsigned long)&prepare_ftrace_return, false);
+ (unsigned long)&prepare_ftrace_return, false, true);
if (ret)
return ret;
return __ftrace_modify_call((unsigned long)&ftrace_graph_regs_call,
- (unsigned long)&prepare_ftrace_return, false);
+ (unsigned long)&prepare_ftrace_return, false, true);
}
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
index d171eca623b6..64bc79816f5e 100644
--- a/arch/riscv/kernel/mcount-dyn.S
+++ b/arch/riscv/kernel/mcount-dyn.S
@@ -13,8 +13,8 @@
.text
-#define FENTRY_RA_OFFSET 12
-#define ABI_SIZE_ON_STACK 72
+#define FENTRY_RA_OFFSET 8
+#define ABI_SIZE_ON_STACK 80
#define ABI_A0 0
#define ABI_A1 8
#define ABI_A2 16
@@ -23,10 +23,10 @@
#define ABI_A5 40
#define ABI_A6 48
#define ABI_A7 56
-#define ABI_RA 64
+#define ABI_T0 64
+#define ABI_RA 72
.macro SAVE_ABI
- addi sp, sp, -SZREG
addi sp, sp, -ABI_SIZE_ON_STACK
REG_S a0, ABI_A0(sp)
@@ -37,6 +37,7 @@
REG_S a5, ABI_A5(sp)
REG_S a6, ABI_A6(sp)
REG_S a7, ABI_A7(sp)
+ REG_S t0, ABI_T0(sp)
REG_S ra, ABI_RA(sp)
.endm
@@ -49,24 +50,18 @@
REG_L a5, ABI_A5(sp)
REG_L a6, ABI_A6(sp)
REG_L a7, ABI_A7(sp)
+ REG_L t0, ABI_T0(sp)
REG_L ra, ABI_RA(sp)
addi sp, sp, ABI_SIZE_ON_STACK
- addi sp, sp, SZREG
.endm
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
.macro SAVE_ALL
- addi sp, sp, -SZREG
addi sp, sp, -PT_SIZE_ON_STACK
- REG_S x1, PT_EPC(sp)
- addi sp, sp, PT_SIZE_ON_STACK
- REG_L x1, (sp)
- addi sp, sp, -PT_SIZE_ON_STACK
+ REG_S t0, PT_EPC(sp)
REG_S x1, PT_RA(sp)
- REG_L x1, PT_EPC(sp)
-
REG_S x2, PT_SP(sp)
REG_S x3, PT_GP(sp)
REG_S x4, PT_TP(sp)
@@ -100,11 +95,8 @@
.endm
.macro RESTORE_ALL
+ REG_L t0, PT_EPC(sp)
REG_L x1, PT_RA(sp)
- addi sp, sp, PT_SIZE_ON_STACK
- REG_S x1, (sp)
- addi sp, sp, -PT_SIZE_ON_STACK
- REG_L x1, PT_EPC(sp)
REG_L x2, PT_SP(sp)
REG_L x3, PT_GP(sp)
REG_L x4, PT_TP(sp)
@@ -137,17 +129,16 @@
REG_L x31, PT_T6(sp)
addi sp, sp, PT_SIZE_ON_STACK
- addi sp, sp, SZREG
.endm
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
ENTRY(ftrace_caller)
SAVE_ABI
- addi a0, ra, -FENTRY_RA_OFFSET
+ addi a0, t0, -FENTRY_RA_OFFSET
la a1, function_trace_op
REG_L a2, 0(a1)
- REG_L a1, ABI_SIZE_ON_STACK(sp)
+ mv a1, ra
mv a3, sp
ftrace_call:
@@ -155,8 +146,8 @@ ftrace_call:
call ftrace_stub
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- addi a0, sp, ABI_SIZE_ON_STACK
- REG_L a1, ABI_RA(sp)
+ addi a0, sp, ABI_RA
+ REG_L a1, ABI_T0(sp)
addi a1, a1, -FENTRY_RA_OFFSET
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
mv a2, s0
@@ -166,17 +157,17 @@ ftrace_graph_call:
call ftrace_stub
#endif
RESTORE_ABI
- ret
+ jr t0
ENDPROC(ftrace_caller)
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
ENTRY(ftrace_regs_caller)
SAVE_ALL
- addi a0, ra, -FENTRY_RA_OFFSET
+ addi a0, t0, -FENTRY_RA_OFFSET
la a1, function_trace_op
REG_L a2, 0(a1)
- REG_L a1, PT_SIZE_ON_STACK(sp)
+ REG_L a1, PT_RA(sp)
mv a3, sp
ftrace_regs_call:
@@ -185,7 +176,7 @@ ftrace_regs_call:
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
addi a0, sp, PT_RA
- REG_L a1, PT_EPC(sp)
+ REG_L a1, PT_T0(sp)
addi a1, a1, -FENTRY_RA_OFFSET
#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
mv a2, s0
@@ -196,6 +187,6 @@ ftrace_graph_regs_call:
#endif
RESTORE_ALL
- ret
+ jr t0
ENDPROC(ftrace_regs_caller)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
--
2.36.1
_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply related [flat|nested] 20+ messages in thread* Re: [PATCH V3 3/5] riscv: ftrace: Reduce the detour code size to half
2022-11-23 15:39 ` guoren
@ 2022-11-23 20:00 ` Conor Dooley
-1 siblings, 0 replies; 20+ messages in thread
From: Conor Dooley @ 2022-11-23 20:00 UTC (permalink / raw)
To: guoren
Cc: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu,
linux-riscv, linux-kernel, Guo Ren
On Wed, Nov 23, 2022 at 10:39:48AM -0500, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> Use a temporary register to reduce the size of detour code from
> 16 bytes to 8 bytes. The previous implementation is from
> afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of
> MCOUNT").
>
> Before the patch:
> <func_prolog>:
> 0: REG_S ra, -SZREG(sp)
> 4: auipc ra, ?
> 8: jalr ?(ra)
> 12: REG_L ra, -SZREG(sp)
> (func_boddy)
>
> After the patch:
> <func_prolog>:
> 0: auipc t0, ?
> 4: jalr t0, ?(t0)
> (func_boddy)
>
> Link: https://lore.kernel.org/linux-riscv/20221122075440.1165172-1-suagrfillet@gmail.com/
> Co-developed-by: Song Shuai <suagrfillet@gmail.com>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>
FYI missing a sign-off from Song Shuai. They were happy with you folding
their patch in during the discussion linked above - so I suppose that is
an accidental omission?
Thanks,
Conor.
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 20+ messages in thread* Re: [PATCH V3 3/5] riscv: ftrace: Reduce the detour code size to half
@ 2022-11-23 20:00 ` Conor Dooley
0 siblings, 0 replies; 20+ messages in thread
From: Conor Dooley @ 2022-11-23 20:00 UTC (permalink / raw)
To: guoren
Cc: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu,
linux-riscv, linux-kernel, Guo Ren
On Wed, Nov 23, 2022 at 10:39:48AM -0500, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> Use a temporary register to reduce the size of detour code from
> 16 bytes to 8 bytes. The previous implementation is from
> afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of
> MCOUNT").
>
> Before the patch:
> <func_prolog>:
> 0: REG_S ra, -SZREG(sp)
> 4: auipc ra, ?
> 8: jalr ?(ra)
> 12: REG_L ra, -SZREG(sp)
> (func_boddy)
>
> After the patch:
> <func_prolog>:
> 0: auipc t0, ?
> 4: jalr t0, ?(t0)
> (func_boddy)
>
> Link: https://lore.kernel.org/linux-riscv/20221122075440.1165172-1-suagrfillet@gmail.com/
> Co-developed-by: Song Shuai <suagrfillet@gmail.com>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>
FYI missing a sign-off from Song Shuai. They were happy with you folding
their patch in during the discussion linked above - so I suppose that is
an accidental omission?
Thanks,
Conor.
^ permalink raw reply [flat|nested] 20+ messages in thread* Re: [PATCH V3 3/5] riscv: ftrace: Reduce the detour code size to half
2022-11-23 20:00 ` Conor Dooley
@ 2022-11-24 2:11 ` Guo Ren
-1 siblings, 0 replies; 20+ messages in thread
From: Guo Ren @ 2022-11-24 2:11 UTC (permalink / raw)
To: Conor Dooley
Cc: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu,
linux-riscv, linux-kernel, Guo Ren
On Thu, Nov 24, 2022 at 4:00 AM Conor Dooley <conor@kernel.org> wrote:
>
> On Wed, Nov 23, 2022 at 10:39:48AM -0500, guoren@kernel.org wrote:
> > From: Guo Ren <guoren@linux.alibaba.com>
> >
> > Use a temporary register to reduce the size of detour code from
> > 16 bytes to 8 bytes. The previous implementation is from
> > afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of
> > MCOUNT").
> >
> > Before the patch:
> > <func_prolog>:
> > 0: REG_S ra, -SZREG(sp)
> > 4: auipc ra, ?
> > 8: jalr ?(ra)
> > 12: REG_L ra, -SZREG(sp)
> > (func_boddy)
> >
> > After the patch:
> > <func_prolog>:
> > 0: auipc t0, ?
> > 4: jalr t0, ?(t0)
> > (func_boddy)
> >
> > Link: https://lore.kernel.org/linux-riscv/20221122075440.1165172-1-suagrfillet@gmail.com/
> > Co-developed-by: Song Shuai <suagrfillet@gmail.com>
> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > Signed-off-by: Guo Ren <guoren@kernel.org>
>
> FYI missing a sign-off from Song Shuai. They were happy with you folding
> their patch in during the discussion linked above - so I suppose that is
> an accidental omission?
My fault, I missed that.
>
> Thanks,
> Conor.
>
--
Best Regards
Guo Ren
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 20+ messages in thread* Re: [PATCH V3 3/5] riscv: ftrace: Reduce the detour code size to half
@ 2022-11-24 2:11 ` Guo Ren
0 siblings, 0 replies; 20+ messages in thread
From: Guo Ren @ 2022-11-24 2:11 UTC (permalink / raw)
To: Conor Dooley
Cc: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu,
linux-riscv, linux-kernel, Guo Ren
On Thu, Nov 24, 2022 at 4:00 AM Conor Dooley <conor@kernel.org> wrote:
>
> On Wed, Nov 23, 2022 at 10:39:48AM -0500, guoren@kernel.org wrote:
> > From: Guo Ren <guoren@linux.alibaba.com>
> >
> > Use a temporary register to reduce the size of detour code from
> > 16 bytes to 8 bytes. The previous implementation is from
> > afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of
> > MCOUNT").
> >
> > Before the patch:
> > <func_prolog>:
> > 0: REG_S ra, -SZREG(sp)
> > 4: auipc ra, ?
> > 8: jalr ?(ra)
> > 12: REG_L ra, -SZREG(sp)
> > (func_boddy)
> >
> > After the patch:
> > <func_prolog>:
> > 0: auipc t0, ?
> > 4: jalr t0, ?(t0)
> > (func_boddy)
> >
> > Link: https://lore.kernel.org/linux-riscv/20221122075440.1165172-1-suagrfillet@gmail.com/
> > Co-developed-by: Song Shuai <suagrfillet@gmail.com>
> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > Signed-off-by: Guo Ren <guoren@kernel.org>
>
> FYI missing a sign-off from Song Shuai. They were happy with you folding
> their patch in during the discussion linked above - so I suppose that is
> an accidental omission?
My fault, I missed that.
>
> Thanks,
> Conor.
>
--
Best Regards
Guo Ren
^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH V3 4/5] riscv: ftrace: Add ftrace_graph_func
2022-11-23 15:39 ` guoren
@ 2022-11-23 15:39 ` guoren
-1 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren
From: Song Shuai <suagrfillet@gmail.com>
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 <suagrfillet@gmail.com>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
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 9e73922e1e2e..84f856a3286e 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 61b24d767e2e..20bf86557698 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 */
--
2.36.1
_______________________________________________
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^ permalink raw reply related [flat|nested] 20+ messages in thread* [PATCH V3 4/5] riscv: ftrace: Add ftrace_graph_func
@ 2022-11-23 15:39 ` guoren
0 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren
From: Song Shuai <suagrfillet@gmail.com>
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 <suagrfillet@gmail.com>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
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 9e73922e1e2e..84f856a3286e 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 61b24d767e2e..20bf86557698 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 */
--
2.36.1
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH V3 5/5] riscv: ftrace: Make ftrace_caller call ftrace_graph_func
2022-11-23 15:39 ` guoren
@ 2022-11-23 15:39 ` guoren
-1 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren
From: Song Shuai <suagrfillet@gmail.com>
In order to make the function graph use ftrace directly, ftrace_caller
should be adjusted to save the necessary regs against the pt_regs layout
so it can call ftrace_graph_func reasonably.
SAVE_ALL now saves all the regs according to the pt_regs struct. Here
supersedes SAVE_ALL by SAVE_ABI_REGS which has an extra option to allow
saving only the necessary ABI-related regs for ftrace_caller.
ftrace_caller and ftrace_regs_caller save their regs with the respective
option of SAVE_ABI_REGS, then call the tracing function, especially
graph_ops's ftrace_graph_func. So the ftrace_graph_[regs]_call labels
aren't needed anymore if FTRACE_WITH_REGS is defined.
As the previous patch described, the ftrace_caller remains with its
ftrace_graph_call if FTRACE_WITH_REGS isn't defined,
For convenience, the original argument setup for the tracing function in
ftrace_[regs]_caller is separated as PREPARE_ARGS.
Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
arch/riscv/kernel/mcount-dyn.S | 142 ++++++++++++++++++++++++---------
1 file changed, 104 insertions(+), 38 deletions(-)
diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
index 64bc79816f5e..466c6ef217b1 100644
--- a/arch/riscv/kernel/mcount-dyn.S
+++ b/arch/riscv/kernel/mcount-dyn.S
@@ -57,19 +57,52 @@
.endm
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- .macro SAVE_ALL
+
+/**
+* SAVE_ABI_REGS - save regs against the pt_regs struct
+*
+* @all: tell if saving all the regs
+*
+* If all is set, all the regs will be saved, otherwise only ABI
+* related regs (a0-a7,epc,ra and optional s0) will be saved.
+*
+* After the stack is established,
+*
+* 0(sp) stores the PC of the traced function which can be accessed
+* by &(fregs)->regs->epc in tracing function. Note that the real
+* function entry address should be computed with -FENTRY_RA_OFFSET.
+*
+* 8(sp) stores the function return address (i.e. parent IP) that
+* can be accessed by &(fregs)->regs->ra in tracing function.
+*
+* The other regs are saved at the respective localtion and accessed
+* by the respective pt_regs member.
+*
+* Here is the layout of stack for your reference.
+*
+* PT_SIZE_ON_STACK -> +++++++++
+* + ..... +
+* + t3-t6 +
+* + s2-s11+
+* + a0-a7 + --++++-> ftrace_caller saved
+* + s1 + +
+* + s0 + --+
+* + t0-t2 + +
+* + tp + +
+* + gp + +
+* + sp + +
+* + ra + --+ // parent IP
+* sp -> + epc + --+ // PC
+* +++++++++
+**/
+ .macro SAVE_ABI_REGS, all=0
addi sp, sp, -PT_SIZE_ON_STACK
REG_S t0, PT_EPC(sp)
REG_S x1, PT_RA(sp)
- REG_S x2, PT_SP(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)
+
+ // always save the ABI regs
+
REG_S x10, PT_A0(sp)
REG_S x11, PT_A1(sp)
REG_S x12, PT_A2(sp)
@@ -78,6 +111,18 @@
REG_S x15, PT_A5(sp)
REG_S x16, PT_A6(sp)
REG_S x17, PT_A7(sp)
+
+ // save the leftover regs
+
+ .if \all == 1
+ REG_S x2, PT_SP(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 x18, PT_S2(sp)
REG_S x19, PT_S3(sp)
REG_S x20, PT_S4(sp)
@@ -92,19 +137,19 @@
REG_S x29, PT_T4(sp)
REG_S x30, PT_T5(sp)
REG_S x31, PT_T6(sp)
+
+ // save s0 if FP_TEST defined
+
+ .else
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+ REG_S x8, PT_S0(sp)
+#endif
+ .endif
.endm
- .macro RESTORE_ALL
+ .macro RESTORE_ABI_REGS, all=0
REG_L t0, PT_EPC(sp)
REG_L x1, PT_RA(sp)
- REG_L x2, PT_SP(sp)
- 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)
@@ -113,6 +158,16 @@
REG_L x15, PT_A5(sp)
REG_L x16, PT_A6(sp)
REG_L x17, PT_A7(sp)
+
+ .if \all == 1
+ REG_L x2, PT_SP(sp)
+ 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 x18, PT_S2(sp)
REG_L x19, PT_S3(sp)
REG_L x20, PT_S4(sp)
@@ -128,10 +183,25 @@
REG_L x30, PT_T5(sp)
REG_L x31, PT_T6(sp)
+ .else
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+ REG_L x8, PT_S0(sp)
+#endif
+ .endif
addi sp, sp, PT_SIZE_ON_STACK
.endm
+
+ .macro PREPARE_ARGS
+ addi a0, t0, -FENTRY_RA_OFFSET // ip
+ la a1, function_trace_op
+ REG_L a2, 0(a1) // op
+ REG_L a1, PT_RA(sp) // parent_ip
+ mv a3, sp // fregs
+ .endm
+
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
+#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
ENTRY(ftrace_caller)
SAVE_ABI
@@ -160,33 +230,29 @@ ftrace_graph_call:
jr t0
ENDPROC(ftrace_caller)
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+#else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
ENTRY(ftrace_regs_caller)
- SAVE_ALL
-
- addi a0, t0, -FENTRY_RA_OFFSET
- la a1, function_trace_op
- REG_L a2, 0(a1)
- REG_L a1, PT_RA(sp)
- mv a3, sp
+ SAVE_ABI_REGS 1
+ PREPARE_ARGS
ftrace_regs_call:
.global ftrace_regs_call
call ftrace_stub
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- addi a0, sp, PT_RA
- REG_L a1, PT_T0(sp)
- addi a1, a1, -FENTRY_RA_OFFSET
-#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
- mv a2, s0
-#endif
-ftrace_graph_regs_call:
- .global ftrace_graph_regs_call
- call ftrace_stub
-#endif
- RESTORE_ALL
+ RESTORE_ABI_REGS 1
jr t0
ENDPROC(ftrace_regs_caller)
+
+ENTRY(ftrace_caller)
+ SAVE_ABI_REGS 0
+ PREPARE_ARGS
+
+ftrace_call:
+ .global ftrace_call
+ call ftrace_stub
+
+ RESTORE_ABI_REGS 0
+ jr t0
+ENDPROC(ftrace_caller)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
--
2.36.1
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH V3 5/5] riscv: ftrace: Make ftrace_caller call ftrace_graph_func
@ 2022-11-23 15:39 ` guoren
0 siblings, 0 replies; 20+ messages in thread
From: guoren @ 2022-11-23 15:39 UTC (permalink / raw)
To: anup, paul.walmsley, palmer, conor.dooley, heiko, rostedt,
mhiramat, jolsa, bp, jpoimboe, suagrfillet, andy.chiu
Cc: linux-riscv, linux-kernel, Guo Ren
From: Song Shuai <suagrfillet@gmail.com>
In order to make the function graph use ftrace directly, ftrace_caller
should be adjusted to save the necessary regs against the pt_regs layout
so it can call ftrace_graph_func reasonably.
SAVE_ALL now saves all the regs according to the pt_regs struct. Here
supersedes SAVE_ALL by SAVE_ABI_REGS which has an extra option to allow
saving only the necessary ABI-related regs for ftrace_caller.
ftrace_caller and ftrace_regs_caller save their regs with the respective
option of SAVE_ABI_REGS, then call the tracing function, especially
graph_ops's ftrace_graph_func. So the ftrace_graph_[regs]_call labels
aren't needed anymore if FTRACE_WITH_REGS is defined.
As the previous patch described, the ftrace_caller remains with its
ftrace_graph_call if FTRACE_WITH_REGS isn't defined,
For convenience, the original argument setup for the tracing function in
ftrace_[regs]_caller is separated as PREPARE_ARGS.
Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
arch/riscv/kernel/mcount-dyn.S | 142 ++++++++++++++++++++++++---------
1 file changed, 104 insertions(+), 38 deletions(-)
diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
index 64bc79816f5e..466c6ef217b1 100644
--- a/arch/riscv/kernel/mcount-dyn.S
+++ b/arch/riscv/kernel/mcount-dyn.S
@@ -57,19 +57,52 @@
.endm
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- .macro SAVE_ALL
+
+/**
+* SAVE_ABI_REGS - save regs against the pt_regs struct
+*
+* @all: tell if saving all the regs
+*
+* If all is set, all the regs will be saved, otherwise only ABI
+* related regs (a0-a7,epc,ra and optional s0) will be saved.
+*
+* After the stack is established,
+*
+* 0(sp) stores the PC of the traced function which can be accessed
+* by &(fregs)->regs->epc in tracing function. Note that the real
+* function entry address should be computed with -FENTRY_RA_OFFSET.
+*
+* 8(sp) stores the function return address (i.e. parent IP) that
+* can be accessed by &(fregs)->regs->ra in tracing function.
+*
+* The other regs are saved at the respective localtion and accessed
+* by the respective pt_regs member.
+*
+* Here is the layout of stack for your reference.
+*
+* PT_SIZE_ON_STACK -> +++++++++
+* + ..... +
+* + t3-t6 +
+* + s2-s11+
+* + a0-a7 + --++++-> ftrace_caller saved
+* + s1 + +
+* + s0 + --+
+* + t0-t2 + +
+* + tp + +
+* + gp + +
+* + sp + +
+* + ra + --+ // parent IP
+* sp -> + epc + --+ // PC
+* +++++++++
+**/
+ .macro SAVE_ABI_REGS, all=0
addi sp, sp, -PT_SIZE_ON_STACK
REG_S t0, PT_EPC(sp)
REG_S x1, PT_RA(sp)
- REG_S x2, PT_SP(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)
+
+ // always save the ABI regs
+
REG_S x10, PT_A0(sp)
REG_S x11, PT_A1(sp)
REG_S x12, PT_A2(sp)
@@ -78,6 +111,18 @@
REG_S x15, PT_A5(sp)
REG_S x16, PT_A6(sp)
REG_S x17, PT_A7(sp)
+
+ // save the leftover regs
+
+ .if \all == 1
+ REG_S x2, PT_SP(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 x18, PT_S2(sp)
REG_S x19, PT_S3(sp)
REG_S x20, PT_S4(sp)
@@ -92,19 +137,19 @@
REG_S x29, PT_T4(sp)
REG_S x30, PT_T5(sp)
REG_S x31, PT_T6(sp)
+
+ // save s0 if FP_TEST defined
+
+ .else
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+ REG_S x8, PT_S0(sp)
+#endif
+ .endif
.endm
- .macro RESTORE_ALL
+ .macro RESTORE_ABI_REGS, all=0
REG_L t0, PT_EPC(sp)
REG_L x1, PT_RA(sp)
- REG_L x2, PT_SP(sp)
- 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)
@@ -113,6 +158,16 @@
REG_L x15, PT_A5(sp)
REG_L x16, PT_A6(sp)
REG_L x17, PT_A7(sp)
+
+ .if \all == 1
+ REG_L x2, PT_SP(sp)
+ 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 x18, PT_S2(sp)
REG_L x19, PT_S3(sp)
REG_L x20, PT_S4(sp)
@@ -128,10 +183,25 @@
REG_L x30, PT_T5(sp)
REG_L x31, PT_T6(sp)
+ .else
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+ REG_L x8, PT_S0(sp)
+#endif
+ .endif
addi sp, sp, PT_SIZE_ON_STACK
.endm
+
+ .macro PREPARE_ARGS
+ addi a0, t0, -FENTRY_RA_OFFSET // ip
+ la a1, function_trace_op
+ REG_L a2, 0(a1) // op
+ REG_L a1, PT_RA(sp) // parent_ip
+ mv a3, sp // fregs
+ .endm
+
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
+#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
ENTRY(ftrace_caller)
SAVE_ABI
@@ -160,33 +230,29 @@ ftrace_graph_call:
jr t0
ENDPROC(ftrace_caller)
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+#else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
ENTRY(ftrace_regs_caller)
- SAVE_ALL
-
- addi a0, t0, -FENTRY_RA_OFFSET
- la a1, function_trace_op
- REG_L a2, 0(a1)
- REG_L a1, PT_RA(sp)
- mv a3, sp
+ SAVE_ABI_REGS 1
+ PREPARE_ARGS
ftrace_regs_call:
.global ftrace_regs_call
call ftrace_stub
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- addi a0, sp, PT_RA
- REG_L a1, PT_T0(sp)
- addi a1, a1, -FENTRY_RA_OFFSET
-#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
- mv a2, s0
-#endif
-ftrace_graph_regs_call:
- .global ftrace_graph_regs_call
- call ftrace_stub
-#endif
- RESTORE_ALL
+ RESTORE_ABI_REGS 1
jr t0
ENDPROC(ftrace_regs_caller)
+
+ENTRY(ftrace_caller)
+ SAVE_ABI_REGS 0
+ PREPARE_ARGS
+
+ftrace_call:
+ .global ftrace_call
+ call ftrace_stub
+
+ RESTORE_ABI_REGS 0
+ jr t0
+ENDPROC(ftrace_caller)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
--
2.36.1
^ permalink raw reply related [flat|nested] 20+ messages in thread