[PATCH v12 for-next 0/4] riscv: ftrace: Miscellaneous ftrace improvements

[PATCH v12 for-next 0/4] riscv: ftrace: Miscellaneous ftrace improvements

[Björn Töpel]

From: Björn Töpel <bjorn@rivosinc.com>

NB! Song told me that he would not have the time work on this series,
so I picked it up.

This series includes a three ftrace improvements for RISC-V:

1. Do not require to run recordmcount at build time (patch 1)
2. Simplification of the function graph functionality (patch 2)
3. Enable DYNAMIC_FTRACE_WITH_DIRECT_CALLS (patch 3 and 4)

The series has been tested on Qemu/rv64 virt/Debian sid with the
following test configs:
  CONFIG_FTRACE_SELFTEST=y
  CONFIG_FTRACE_STARTUP_TEST=y
  CONFIG_SAMPLE_FTRACE_DIRECT=m
  CONFIG_SAMPLE_FTRACE_DIRECT_MULTI=m
  CONFIG_SAMPLE_FTRACE_OPS=m

All tests pass.


Cheers,
Björn


Changes in v12:
- Massaged the commit messages a bit.
- Squashed the samples patches, so that the rv32 support is included
  from the start.
- Minor whitespace changes in the mcount-dyn.S.
- Minor style changes.

Changes in v11:
https://lore.kernel.org/linux-riscv/20230627111612.761164-1-suagrfillet@gmail.com/

- append a patch that makes the DIRECT_CALL samples support RV32I in
  this series fixing the rv32 build failure reported by Palmer
- validated with ftrace boottime selftest and manual sample modules test
  in qemu-system for RV32I and RV64I

Changes in v10:
https://lore.kernel.org/all/20230511093234.3123181-1-suagrfillet@gmail.com/

- add Acked-by from Björn Töpel in patch 2 and patch 4 
- replace `move` with `mv` in patch3 
- prettify patch 2/4 with proper tabs

Changes in v9:
https://lore.kernel.org/linux-riscv/20230510101857.2953955-1-suagrfillet@gmail.com/

1. add Acked-by from Björn Töpel in patch 1

2. rebase patch2/patch3 on Linux v6.4-rc1

  - patch 2: to make the `SAVE_ABI_REGS` configurable, revert the
    modification of mcount-dyn.S from commit (45b32b946a97 "riscv:
entry: Consolidate general regs saving/restoring")

  - patch 3: to pass the trace_selftest, add the implement of
    `ftrace_stub_direct_tramp` from commit (fee86a4ed536 "ftrace:
selftest: remove broken trace_direct_tramp") ; and fixup the context
conflict in Kconfig 

Changes in v8:
https://lore.kernel.org/linux-riscv/20230324033342.3177979-1-suagrfillet@gmail.com/
 - Fix incorrect address values in the 4nd patch 
 - Rebased on v6.3-rc2

Changes in v7:
https://lore.kernel.org/linux-riscv/20230112090603.1295340-1-guoren@kernel.org/
 - Fixup RESTORE_ABI_REGS by remove PT_T0(sp) overwrite.
 - Add FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY [1]
 - Fixup kconfig with HAVE_SAMPLE_FTRACE_DIRECT &
   HAVE_SAMPLE_FTRACE_DIRECT_MULTI

Changes in v6:
https://lore.kernel.org/linux-riscv/20230107133549.4192639-1-guoren@kernel.org/
 - Replace 8 with MCOUNT_INSN_SIZE
 - Replace "REG_L a1, PT_RA(sp)" with "mv a1, ra"
 - Add Evgenii Shatokhin comment

Changes in v5:
https://lore.kernel.org/linux-riscv/20221208091244.203407-1-guoren@kernel.org/
 - Sort Kconfig entries in alphabetical order.

Changes in v4:
https://lore.kernel.org/linux-riscv/20221129033230.255947-1-guoren@kernel.org/
 - Include [3] for maintenance. [Song Shuai]

Changes in V3:
https://lore.kernel.org/linux-riscv/20221123153950.2911981-1-guoren@kernel.org/
 - Include [2] for maintenance. [Song Shuai]

[1]: https://lore.kernel.org/linux-riscv/CAAYs2=j3Eak9vU6xbAw0zPuoh00rh8v5C2U3fePkokZFibWs2g@mail.gmail.com/T/#t
[2]: https://lore.kernel.org/lkml/20221120084230.910152-1-suagrfillet@gmail.com/
[3]: https://lore.kernel.org/linux-riscv/20221123142025.1504030-1-suagrfillet@gmail.com/ 


Song Shuai (4):
  riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
  riscv: ftrace: Make function graph use ftrace directly
  riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support
  samples: ftrace: Add RISC-V support for SAMPLE_FTRACE_DIRECT[_MULTI]

 arch/riscv/Kconfig                          |   4 +
 arch/riscv/include/asm/ftrace.h             |  18 +-
 arch/riscv/kernel/ftrace.c                  |  30 ++-
 arch/riscv/kernel/mcount-dyn.S              | 198 ++++++++++++++++----
 samples/ftrace/ftrace-direct-modify.c       |  35 ++++
 samples/ftrace/ftrace-direct-multi-modify.c |  41 ++++
 samples/ftrace/ftrace-direct-multi.c        |  25 +++
 samples/ftrace/ftrace-direct-too.c          |  28 +++
 samples/ftrace/ftrace-direct.c              |  24 +++
 9 files changed, 348 insertions(+), 55 deletions(-)


base-commit: 3ca112b71f35dd5d99fc4571a56b5fc6f0c15814
-- 
2.40.1

[PATCH v12 for-next 1/4] riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY

[Björn Töpel]

From: Song Shuai <suagrfillet@gmail.com>

In commit afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead
of MCOUNT") RISC-V added support for -fpatchable-function-entry, which
removes the need for recordmcount.

Select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY to tell the build
system not to run recordmcount.

Link: https://lore.kernel.org/linux-riscv/CAAYs2=j3Eak9vU6xbAw0zPuoh00rh8v5C2U3fePkokZFibWs2g@mail.gmail.com/T/#t
Link: https://lore.kernel.org/linux-riscv/Y4jtfrJt+%2FQ5nMOz@spud/
Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
Acked-by: Björn Töpel <bjorn@rivosinc.com>
---
 arch/riscv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 95a2a06acc6a..69c95e42be9f 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -68,6 +68,7 @@ config RISCV
 	select CPU_PM if CPU_IDLE || HIBERNATION
 	select EDAC_SUPPORT
 	select FRAME_POINTER if PERF_EVENTS || (FUNCTION_TRACER && !DYNAMIC_FTRACE)
+	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if DYNAMIC_FTRACE
 	select GENERIC_ARCH_TOPOLOGY
 	select GENERIC_ATOMIC64 if !64BIT
 	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
-- 
2.40.1

[PATCH v12 for-next 2/4] riscv: ftrace: Make function graph use ftrace directly

[Björn Töpel]

From: Song Shuai <suagrfillet@gmail.com>

Similar to commit 0c0593b45c9b ("x86/ftrace: Make function graph use
ftrace directly") and commit c4a0ebf87ceb ("arm64/ftrace: Make
function graph use ftrace directly"), RISC-V has no need for a special
graph tracer hook. The graph_ops::func function can be used to install
the return_hooker.

This cleanup only changes the FTRACE_WITH_REGS implementation, leaving
the mcount-based implementation is unaffected.

Perform the simplification, and also cleanup the register save/restore
macros.

Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
Acked-by: Björn Töpel <bjorn@rivosinc.com>
---
 arch/riscv/include/asm/ftrace.h |  11 +-
 arch/riscv/kernel/ftrace.c      |  30 +++--
 arch/riscv/kernel/mcount-dyn.S  | 190 +++++++++++++++++++++++++-------
 3 files changed, 175 insertions(+), 56 deletions(-)

diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
index 2b2f5df7ef2c..b383926f73be 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -128,7 +128,16 @@ do {									\
 struct dyn_ftrace;
 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
 #define ftrace_init_nop ftrace_init_nop
-#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 */
 
diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
index 03a6434a8cdd..f5aa24d9e1c1 100644
--- a/arch/riscv/kernel/ftrace.c
+++ b/arch/riscv/kernel/ftrace.c
@@ -178,32 +178,28 @@ 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 *)&regs->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 */
diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
index 58dd96a2a153..c902a7ddb310 100644
--- a/arch/riscv/kernel/mcount-dyn.S
+++ b/arch/riscv/kernel/mcount-dyn.S
@@ -57,31 +57,150 @@
 	.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)
-	save_from_x6_to_x31
+	REG_S	t0,  PT_EPC(sp)
+	REG_S	x1,  PT_RA(sp)
+
+	// save the ABI regs
+
+	REG_S	x10, PT_A0(sp)
+	REG_S	x11, PT_A1(sp)
+	REG_S	x12, PT_A2(sp)
+	REG_S	x13, PT_A3(sp)
+	REG_S	x14, PT_A4(sp)
+	REG_S	x15, PT_A5(sp)
+	REG_S	x16, PT_A6(sp)
+	REG_S	x17, PT_A7(sp)
+
+	// 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)
+	REG_S	x21, PT_S5(sp)
+	REG_S	x22, PT_S6(sp)
+	REG_S	x23, PT_S7(sp)
+	REG_S	x24, PT_S8(sp)
+	REG_S	x25, PT_S9(sp)
+	REG_S	x26, PT_S10(sp)
+	REG_S	x27, PT_S11(sp)
+	REG_S	x28, PT_T3(sp)
+	REG_S	x29, PT_T4(sp)
+	REG_S	x30, PT_T5(sp)
+	REG_S	x31, PT_T6(sp)
+
+	// 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
-	REG_L x1,  PT_RA(sp)
-	REG_L x2,  PT_SP(sp)
-	REG_L x3,  PT_GP(sp)
-	REG_L x4,  PT_TP(sp)
-	/* Restore t0 with PT_EPC */
-	REG_L x5,  PT_EPC(sp)
-	restore_from_x6_to_x31
-
+	.macro RESTORE_ABI_REGS, all=0
+	REG_L	t0, PT_EPC(sp)
+	REG_L	x1, PT_RA(sp)
+	REG_L	x10, PT_A0(sp)
+	REG_L	x11, PT_A1(sp)
+	REG_L	x12, PT_A2(sp)
+	REG_L	x13, PT_A3(sp)
+	REG_L	x14, PT_A4(sp)
+	REG_L	x15, PT_A5(sp)
+	REG_L	x16, PT_A6(sp)
+	REG_L	x17, PT_A7(sp)
+
+	.if \all == 1
+	REG_L	x2, PT_SP(sp)
+	REG_L	x3, PT_GP(sp)
+	REG_L	x4, PT_TP(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)
+	REG_L	x21, PT_S5(sp)
+	REG_L	x22, PT_S6(sp)
+	REG_L	x23, PT_S7(sp)
+	REG_L	x24, PT_S8(sp)
+	REG_L	x25, PT_S9(sp)
+	REG_L	x26, PT_S10(sp)
+	REG_L	x27, PT_S11(sp)
+	REG_L	x28, PT_T3(sp)
+	REG_L	x29, PT_T4(sp)
+	REG_L	x30, PT_T5(sp)
+	REG_L	x31, PT_T6(sp)
+
+	.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
+	la	a1, function_trace_op
+	REG_L	a2, 0(a1)
+	mv	a1, ra
+	mv	a3, sp
+	.endm
+
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
 
+#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 SYM_FUNC_START(ftrace_caller)
 	SAVE_ABI
 
@@ -105,34 +224,29 @@ SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL)
 	call	ftrace_stub
 #endif
 	RESTORE_ABI
-	jr t0
+	jr	t0
 SYM_FUNC_END(ftrace_caller)
 
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+#else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
 SYM_FUNC_START(ftrace_regs_caller)
-	SAVE_ALL
-
-	addi	a0, t0, -FENTRY_RA_OFFSET
-	la	a1, function_trace_op
-	REG_L	a2, 0(a1)
-	mv	a1, ra
-	mv	a3, sp
+	SAVE_ABI_REGS 1
+	PREPARE_ARGS
 
 SYM_INNER_LABEL(ftrace_regs_call, SYM_L_GLOBAL)
 	call	ftrace_stub
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	addi	a0, sp, PT_RA
-	REG_L	a1, PT_EPC(sp)
-	addi	a1, a1, -FENTRY_RA_OFFSET
-#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
-	mv	a2, s0
-#endif
-SYM_INNER_LABEL(ftrace_graph_regs_call, SYM_L_GLOBAL)
+	RESTORE_ABI_REGS 1
+	jr	t0
+SYM_FUNC_END(ftrace_regs_caller)
+
+SYM_FUNC_START(ftrace_caller)
+	SAVE_ABI_REGS 0
+	PREPARE_ARGS
+
+SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
 	call	ftrace_stub
-#endif
 
-	RESTORE_ALL
-	jr t0
-SYM_FUNC_END(ftrace_regs_caller)
+	RESTORE_ABI_REGS 0
+	jr	t0
+SYM_FUNC_END(ftrace_caller)
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
-- 
2.40.1

[PATCH v12 for-next 3/4] riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support

[Björn Töpel]

From: Song Shuai <suagrfillet@gmail.com>

Select the DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide the
register_ftrace_direct[_multi] interfaces allowing users to register
the customed trampoline (direct_caller) as the mcount for one or more
target functions. And modify_ftrace_direct[_multi] are also provided
for modifying direct_caller.

To make the direct_caller and the other ftrace hooks (e.g.
function/fgraph tracer, k[ret]probes) co-exist, a temporary register
is nominated to store the address of direct_caller in
ftrace_regs_caller. After the setting of the address direct_caller by
direct_ops->func and the RESTORE_REGS in ftrace_regs_caller,
direct_caller will be jumped to by the `jr` inst.

Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support for RISC-V.

Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
Acked-by: Björn Töpel <bjorn@rivosinc.com>
---
 arch/riscv/Kconfig              |  1 +
 arch/riscv/include/asm/ftrace.h |  7 +++++++
 arch/riscv/kernel/mcount-dyn.S  | 10 ++++++++++
 3 files changed, 18 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 69c95e42be9f..4684cdc754a0 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -114,6 +114,7 @@ config RISCV
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_CONTIGUOUS if MMU
 	select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && (CLANG_SUPPORTS_DYNAMIC_FTRACE || GCC_SUPPORTS_DYNAMIC_FTRACE)
+	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
 	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
 	select HAVE_FUNCTION_GRAPH_TRACER
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
index b383926f73be..329172122952 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -135,6 +135,13 @@ 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
+
+static inline void __arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned long addr)
+{
+		regs->t1 = addr;
+}
+#define arch_ftrace_set_direct_caller(fregs, addr) \
+	__arch_ftrace_set_direct_caller(&(fregs)->regs, addr)
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
index c902a7ddb310..b7ce001779c1 100644
--- a/arch/riscv/kernel/mcount-dyn.S
+++ b/arch/riscv/kernel/mcount-dyn.S
@@ -229,6 +229,7 @@ SYM_FUNC_END(ftrace_caller)
 
 #else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
 SYM_FUNC_START(ftrace_regs_caller)
+	mv	t1, zero
 	SAVE_ABI_REGS 1
 	PREPARE_ARGS
 
@@ -236,7 +237,10 @@ SYM_INNER_LABEL(ftrace_regs_call, SYM_L_GLOBAL)
 	call	ftrace_stub
 
 	RESTORE_ABI_REGS 1
+	bnez	t1, .Ldirect
 	jr	t0
+.Ldirect:
+	jr	t1
 SYM_FUNC_END(ftrace_regs_caller)
 
 SYM_FUNC_START(ftrace_caller)
@@ -250,3 +254,9 @@ SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
 	jr	t0
 SYM_FUNC_END(ftrace_caller)
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+SYM_CODE_START(ftrace_stub_direct_tramp)
+	jr	t0
+SYM_CODE_END(ftrace_stub_direct_tramp)
+#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
-- 
2.40.1

[PATCH v12 for-next 4/4] samples: ftrace: Add RISC-V support for SAMPLE_FTRACE_DIRECT[_MULTI]

[Björn Töpel]

From: Song Shuai <suagrfillet@gmail.com>

Add RISC-V variants of the ftrace-direct* samples.

Tested-by: Evgenii Shatokhin <e.shatokhin@yadro.com>
Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Tested-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
Acked-by: Björn Töpel <bjorn@rivosinc.com>
---
 arch/riscv/Kconfig                          |  2 +
 samples/ftrace/ftrace-direct-modify.c       | 35 ++++++++++++++++++
 samples/ftrace/ftrace-direct-multi-modify.c | 41 +++++++++++++++++++++
 samples/ftrace/ftrace-direct-multi.c        | 25 +++++++++++++
 samples/ftrace/ftrace-direct-too.c          | 28 ++++++++++++++
 samples/ftrace/ftrace-direct.c              | 24 ++++++++++++
 6 files changed, 155 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 4684cdc754a0..0ee79a92918d 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -142,6 +142,8 @@ config RISCV
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RETHOOK if !XIP_KERNEL
 	select HAVE_RSEQ
+	select HAVE_SAMPLE_FTRACE_DIRECT
+	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index e2a6a69352df..81220390851a 100644
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -24,6 +24,41 @@ extern void my_tramp2(void *);
 
 static unsigned long my_ip = (unsigned long)schedule;
 
+#ifdef CONFIG_RISCV
+#include <asm/asm.h>
+
+asm (
+"	.pushsection    .text, \"ax\", @progbits\n"
+"	.type		my_tramp1, @function\n"
+"	.globl		my_tramp1\n"
+"   my_tramp1:\n"
+"	addi	sp,sp,-2*"SZREG"\n"
+"	"REG_S"	t0,0*"SZREG"(sp)\n"
+"	"REG_S"	ra,1*"SZREG"(sp)\n"
+"	call	my_direct_func1\n"
+"	"REG_L"	t0,0*"SZREG"(sp)\n"
+"	"REG_L"	ra,1*"SZREG"(sp)\n"
+"	addi	sp,sp,2*"SZREG"\n"
+"	jr	t0\n"
+"	.size		my_tramp1, .-my_tramp1\n"
+"	.type		my_tramp2, @function\n"
+"	.globl		my_tramp2\n"
+
+"   my_tramp2:\n"
+"	addi	sp,sp,-2*"SZREG"\n"
+"	"REG_S"	t0,0*"SZREG"(sp)\n"
+"	"REG_S"	ra,1*"SZREG"(sp)\n"
+"	call	my_direct_func2\n"
+"	"REG_L"	t0,0*"SZREG"(sp)\n"
+"	"REG_L"	ra,1*"SZREG"(sp)\n"
+"	addi	sp,sp,2*"SZREG"\n"
+"	jr	t0\n"
+"	.size		my_tramp2, .-my_tramp2\n"
+"	.popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
 #ifdef CONFIG_X86_64
 
 #include <asm/ibt.h>
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
index 2e349834d63c..f943e40d57fd 100644
--- a/samples/ftrace/ftrace-direct-multi-modify.c
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -22,6 +22,47 @@ void my_direct_func2(unsigned long ip)
 extern void my_tramp1(void *);
 extern void my_tramp2(void *);
 
+#ifdef CONFIG_RISCV
+#include <asm/asm.h>
+
+asm (
+"	.pushsection    .text, \"ax\", @progbits\n"
+"	.type		my_tramp1, @function\n"
+"	.globl		my_tramp1\n"
+"   my_tramp1:\n"
+"       addi	sp,sp,-3*"SZREG"\n"
+"       "REG_S"	a0,0*"SZREG"(sp)\n"
+"       "REG_S"	t0,1*"SZREG"(sp)\n"
+"       "REG_S"	ra,2*"SZREG"(sp)\n"
+"       mv	a0,t0\n"
+"       call	my_direct_func1\n"
+"       "REG_L"	a0,0*"SZREG"(sp)\n"
+"       "REG_L"	t0,1*"SZREG"(sp)\n"
+"       "REG_L"	ra,2*"SZREG"(sp)\n"
+"       addi	sp,sp,3*"SZREG"\n"
+"	jr	t0\n"
+"	.size		my_tramp1, .-my_tramp1\n"
+
+"	.type		my_tramp2, @function\n"
+"	.globl		my_tramp2\n"
+"   my_tramp2:\n"
+"       addi	sp,sp,-3*"SZREG"\n"
+"       "REG_S"	a0,0*"SZREG"(sp)\n"
+"       "REG_S"	t0,1*"SZREG"(sp)\n"
+"       "REG_S"	ra,2*"SZREG"(sp)\n"
+"       mv	a0,t0\n"
+"       call	my_direct_func2\n"
+"       "REG_L"	a0,0*"SZREG"(sp)\n"
+"       "REG_L"	t0,1*"SZREG"(sp)\n"
+"       "REG_L"	ra,2*"SZREG"(sp)\n"
+"       addi	sp,sp,3*"SZREG"\n"
+"	jr	t0\n"
+"	.size		my_tramp2, .-my_tramp2\n"
+"	.popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
 #ifdef CONFIG_X86_64
 
 #include <asm/ibt.h>
diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
index 9243dbfe4d0c..aed6df2927ce 100644
--- a/samples/ftrace/ftrace-direct-multi.c
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -17,6 +17,31 @@ void my_direct_func(unsigned long ip)
 
 extern void my_tramp(void *);
 
+#ifdef CONFIG_RISCV
+#include <asm/asm.h>
+
+asm (
+"       .pushsection    .text, \"ax\", @progbits\n"
+"       .type           my_tramp, @function\n"
+"       .globl          my_tramp\n"
+"   my_tramp:\n"
+"       addi	sp,sp,-3*"SZREG"\n"
+"       "REG_S"	a0,0*"SZREG"(sp)\n"
+"       "REG_S"	t0,1*"SZREG"(sp)\n"
+"       "REG_S"	ra,2*"SZREG"(sp)\n"
+"       mv	a0,t0\n"
+"       call	my_direct_func\n"
+"       "REG_L"	a0,0*"SZREG"(sp)\n"
+"       "REG_L"	t0,1*"SZREG"(sp)\n"
+"       "REG_L"	ra,2*"SZREG"(sp)\n"
+"       addi	sp,sp,3*"SZREG"\n"
+"       jr	t0\n"
+"       .size           my_tramp, .-my_tramp\n"
+"       .popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
 #ifdef CONFIG_X86_64
 
 #include <asm/ibt.h>
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index e39c3563ae4e..6ff546a5d7eb 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -19,6 +19,34 @@ void my_direct_func(struct vm_area_struct *vma, unsigned long address,
 
 extern void my_tramp(void *);
 
+#ifdef CONFIG_RISCV
+#include <asm/asm.h>
+
+asm (
+"       .pushsection    .text, \"ax\", @progbits\n"
+"       .type           my_tramp, @function\n"
+"       .globl          my_tramp\n"
+"   my_tramp:\n"
+"       addi	sp,sp,-5*"SZREG"\n"
+"       "REG_S"	a0,0*"SZREG"(sp)\n"
+"       "REG_S"	a1,1*"SZREG"(sp)\n"
+"       "REG_S"	a2,2*"SZREG"(sp)\n"
+"       "REG_S"	t0,3*"SZREG"(sp)\n"
+"       "REG_S"	ra,4*"SZREG"(sp)\n"
+"       call	my_direct_func\n"
+"       "REG_L"	a0,0*"SZREG"(sp)\n"
+"       "REG_L"	a1,1*"SZREG"(sp)\n"
+"       "REG_L"	a2,2*"SZREG"(sp)\n"
+"       "REG_L"	t0,3*"SZREG"(sp)\n"
+"       "REG_L"	ra,4*"SZREG"(sp)\n"
+"       addi	sp,sp,5*"SZREG"\n"
+"       jr	t0\n"
+"       .size           my_tramp, .-my_tramp\n"
+"       .popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
 #ifdef CONFIG_X86_64
 
 #include <asm/ibt.h>
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index 32c477da1e9a..ef0945670e1e 100644
--- a/samples/ftrace/ftrace-direct.c
+++ b/samples/ftrace/ftrace-direct.c
@@ -16,6 +16,30 @@ void my_direct_func(struct task_struct *p)
 
 extern void my_tramp(void *);
 
+#ifdef CONFIG_RISCV
+#include <asm/asm.h>
+
+asm (
+"       .pushsection    .text, \"ax\", @progbits\n"
+"       .type           my_tramp, @function\n"
+"       .globl          my_tramp\n"
+"   my_tramp:\n"
+"       addi	sp,sp,-3*"SZREG"\n"
+"       "REG_S"	a0,0*"SZREG"(sp)\n"
+"       "REG_S"	t0,1*"SZREG"(sp)\n"
+"       "REG_S"	ra,2*"SZREG"(sp)\n"
+"       call	my_direct_func\n"
+"       "REG_L"	a0,0*"SZREG"(sp)\n"
+"       "REG_L"	t0,1*"SZREG"(sp)\n"
+"       "REG_L"	ra,2*"SZREG"(sp)\n"
+"       addi	sp,sp,3*"SZREG"\n"
+"       jr	t0\n"
+"       .size           my_tramp, .-my_tramp\n"
+"       .popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
 #ifdef CONFIG_X86_64
 
 #include <asm/ibt.h>
-- 
2.40.1

Re: [PATCH v12 for-next 0/4] riscv: ftrace: Miscellaneous ftrace improvements

[patchwork-bot+linux-riscv]

Hello:

This series was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <palmer@rivosinc.com>:

On Thu, 30 Nov 2023 13:15:27 +0100 you wrote:
> From: Björn Töpel <bjorn@rivosinc.com>
> 
> NB! Song told me that he would not have the time work on this series,
> so I picked it up.
> 
> This series includes a three ftrace improvements for RISC-V:
> 
> [...]

Here is the summary with links:
  - [v12,for-next,1/4] riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
    https://git.kernel.org/riscv/c/b546d6363af4
  - [v12,for-next,2/4] riscv: ftrace: Make function graph use ftrace directly
    https://git.kernel.org/riscv/c/35e61e8827ee
  - [v12,for-next,3/4] riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support
    https://git.kernel.org/riscv/c/196c79f19a92
  - [v12,for-next,4/4] samples: ftrace: Add RISC-V support for SAMPLE_FTRACE_DIRECT[_MULTI]
    https://git.kernel.org/riscv/c/629291dd8499

You are awesome, thank you!
-- 
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