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riscv: ftrace: Make function graph use ftrace directly

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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>
Link: https://lore.kernel.org/r/20231130121531.1178502-3-bjorn@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Song Shuai 2023-11-30 13:15:29 +01:00 committed by Palmer Dabbelt
parent b546d6363a
commit 35e61e8827
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
3 changed files with 175 additions and 56 deletions
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11
arch/riscv/include/asm/ftrace.h
View File

@ -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 */

30
arch/riscv/kernel/ftrace.c
View File

@ -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 */

190
arch/riscv/kernel/mcount-dyn.S
View File

@ -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)
call ftrace_stub
#endif
RESTORE_ALL
jr t0
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
RESTORE_ABI_REGS 0
jr t0
SYM_FUNC_END(ftrace_caller)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */