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LoongArch/ftrace: Add HAVE_DYNAMIC_FTRACE_WITH_REGS support

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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: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Qing Zhang
2022-12-10 22:40:15 +08:00
committed by Huacai Chen
parent 5fcfad3d41
commit 8778ba2c8a
4 changed files with 51 additions and 2 deletions
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1
arch/loongarch/Kconfig
View File

@@ -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

2
arch/loongarch/include/asm/ftrace.h
View File

@@ -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);

15
arch/loongarch/kernel/ftrace_dyn.c
View File

@@ -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;

35
arch/loongarch/kernel/mcount_dyn.S
View File

@@ -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