Commit 8778ba2c authored by Qing Zhang's avatar Qing Zhang Committed by Huacai Chen
Browse files

LoongArch/ftrace: Add HAVE_DYNAMIC_FTRACE_WITH_REGS support 



This patch implements CONFIG_DYNAMIC_FTRACE_WITH_REGS on LoongArch,
which allows a traced function's arguments (and some other registers)
to be captured into a struct pt_regs, allowing these to be inspected
and modified.

Co-developed-by: default avatarJinyang He <hejinyang@loongson.cn>
Signed-off-by: default avatarJinyang He <hejinyang@loongson.cn>
Signed-off-by: default avatarQing Zhang <zhangqing@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 5fcfad3d

arch/loongarch/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ config LOONGARCH 
	select HAVE_DEBUG_STACKOVERFLOW

	select HAVE_DMA_CONTIGUOUS

	select HAVE_DYNAMIC_FTRACE

	select HAVE_DYNAMIC_FTRACE_WITH_REGS

	select HAVE_EBPF_JIT

	select HAVE_EXIT_THREAD

	select HAVE_FAST_GUP

arch/loongarch/include/asm/ftrace.h

+2 −0
Original line number Diff line number Diff line
@@ -23,6 +23,8 @@ extern void prepare_ftrace_return(unsigned long self_addr, unsigned long callsit 
struct dyn_ftrace;

struct dyn_arch_ftrace { };



#define ARCH_SUPPORTS_FTRACE_OPS 1



#define ftrace_init_nop ftrace_init_nop

int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);

arch/loongarch/kernel/ftrace_dyn.c

+15 −0
Original line number Diff line number Diff line
@@ -28,6 +28,21 @@ static int ftrace_modify_code(unsigned long pc, u32 old, u32 new, bool validate) 
	return 0;

}



#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS

int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr)

{

	u32 old, new;

	unsigned long pc;



	pc = rec->ip + LOONGARCH_INSN_SIZE;



	new = larch_insn_gen_bl(pc, addr);

	old = larch_insn_gen_bl(pc, old_addr);



	return ftrace_modify_code(pc, old, new, true);

}

#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */



int ftrace_update_ftrace_func(ftrace_func_t func)

{

	u32 new;

arch/loongarch/kernel/mcount_dyn.S

+33 −2
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ 
 * follows the LoongArch's psABI as well.

 */



	.macro  ftrace_regs_entry

	.macro  ftrace_regs_entry allregs=0

	PTR_ADDI	sp, sp, -PT_SIZE

	PTR_S		t0, sp, PT_R1  /* Save parent ra at PT_R1(RA) */

	PTR_S		a0, sp, PT_R4
@@ -39,6 +39,30 @@ 
	PTR_S		a6, sp, PT_R10

	PTR_S		a7, sp, PT_R11

	PTR_S		fp, sp, PT_R22

	.if \allregs

	PTR_S		tp, sp, PT_R2

	PTR_S		t0, sp, PT_R12

	PTR_S		t1, sp, PT_R13

	PTR_S		t2, sp, PT_R14

	PTR_S		t3, sp, PT_R15

	PTR_S		t4, sp, PT_R16

	PTR_S		t5, sp, PT_R17

	PTR_S		t6, sp, PT_R18

	PTR_S		t7, sp, PT_R19

	PTR_S		t8, sp, PT_R20

	PTR_S		u0, sp, PT_R21

	PTR_S		s0, sp, PT_R23

	PTR_S		s1, sp, PT_R24

	PTR_S		s2, sp, PT_R25

	PTR_S		s3, sp, PT_R26

	PTR_S		s4, sp, PT_R27

	PTR_S		s5, sp, PT_R28

	PTR_S		s6, sp, PT_R29

	PTR_S		s7, sp, PT_R30

	PTR_S		s8, sp, PT_R31

	/* Clear it for later use as a flag sometimes. */

	PTR_S		zero, sp, PT_R0

	.endif

	PTR_S		ra, sp, PT_ERA /* Save trace function ra at PT_ERA */

	PTR_ADDI	t8, sp, PT_SIZE

	PTR_S		t8, sp, PT_R3
@@ -85,10 +109,17 @@ ftrace_common_return: 
SYM_CODE_END(ftrace_common)



SYM_CODE_START(ftrace_caller)

	ftrace_regs_entry

	ftrace_regs_entry allregs=0

	b		ftrace_common

SYM_CODE_END(ftrace_caller)



#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS

SYM_CODE_START(ftrace_regs_caller)

	ftrace_regs_entry allregs=1

	b		ftrace_common

SYM_CODE_END(ftrace_regs_caller)

#endif



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

SYM_CODE_START(ftrace_graph_caller)

	PTR_L		a0, sp, PT_ERA