nds32/ftrace: Support dynamic function tracer (6b1d6d2f) · Commits · e / devices / android_kernel_oneplus_sm7250

arch/nds32/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -43,6 +43,7 @@ config NDS32
		select HAVE_FUNCTION_TRACER
		select HAVE_FUNCTION_GRAPH_TRACER
		select HAVE_FTRACE_MCOUNT_RECORD
		select HAVE_DYNAMIC_FTRACE
		help
		Andes(nds32) Linux support.

arch/nds32/include/asm/ftrace.h

+26 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,32 @@

		extern void _mcount(unsigned long parent_ip);

		#ifdef CONFIG_DYNAMIC_FTRACE

		#define FTRACE_ADDR ((unsigned long)_ftrace_caller)

		#ifdef __NDS32_EL__
		#define INSN_NOP 0x09000040
		#define INSN_SIZE(insn) (((insn & 0x00000080) == 0) ? 4 : 2)
		#define IS_SETHI(insn) ((insn & 0x000000fe) == 0x00000046)
		#define ENDIAN_CONVERT(insn) be32_to_cpu(insn)
		#else /* __NDS32_EB__ */
		#define INSN_NOP 0x40000009
		#define INSN_SIZE(insn) (((insn & 0x80000000) == 0) ? 4 : 2)
		#define IS_SETHI(insn) ((insn & 0xfe000000) == 0x46000000)
		#define ENDIAN_CONVERT(insn) (insn)
		#endif

		extern void _ftrace_caller(unsigned long parent_ip);
		static inline unsigned long ftrace_call_adjust(unsigned long addr)
		{
		return addr;
		}
		struct dyn_arch_ftrace {
		};

		#endif /* CONFIG_DYNAMIC_FTRACE */

		#endif /* CONFIG_FUNCTION_TRACER */

		#endif /* __ASM_NDS32_FTRACE_H */

arch/nds32/kernel/ftrace.c

+164 −0

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@
		#include <linux/uaccess.h>
		#include <asm/cacheflush.h>

		#ifndef CONFIG_DYNAMIC_FTRACE
		extern void (*ftrace_trace_function)(unsigned long, unsigned long,
		struct ftrace_ops, struct pt_regs);
		extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
		@@ -35,6 +36,168 @@ noinline void _mcount(unsigned long parent_ip)
		}
		EXPORT_SYMBOL(_mcount);

		#else /* CONFIG_DYNAMIC_FTRACE */

		noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
		struct ftrace_ops op, struct pt_regs regs)
		{
		__asm__ (""); /* avoid to optimize as pure function */
		}

		noinline void __naked _mcount(unsigned long parent_ip)
		{
		__asm__ (""); /* avoid to optimize as pure function */
		}
		EXPORT_SYMBOL(_mcount);

		#define XSTR(s) STR(s)
		#define STR(s) #s
		void _ftrace_caller(unsigned long parent_ip)
		{
		/* save all state needed by the compiler prologue */

		/*
		* prepare arguments for real tracing function
		* first arg : __builtin_return_address(0) - MCOUNT_INSN_SIZE
		* second arg : parent_ip
		*/
		__asm__ __volatile__ (
		"move $r1, %0 \n\t"
		"addi $r0, %1, #-" XSTR(MCOUNT_INSN_SIZE) "\n\t"
		:
		: "r" (parent_ip), "r" (__builtin_return_address(0)));

		/* a placeholder for the call to a real tracing function */
		__asm__ __volatile__ (
		"ftrace_call: \n\t"
		"nop \n\t"
		"nop \n\t"
		"nop \n\t");

		/* restore all state needed by the compiler epilogue */
		}

		int __init ftrace_dyn_arch_init(void)
		{
		return 0;
		}

		int ftrace_arch_code_modify_prepare(void)
		{
		set_all_modules_text_rw();
		return 0;
		}

		int ftrace_arch_code_modify_post_process(void)
		{
		set_all_modules_text_ro();
		return 0;
		}

		static unsigned long gen_sethi_insn(unsigned long addr)
		{
		unsigned long opcode = 0x46000000;
		unsigned long imm = addr >> 12;
		unsigned long rt_num = 0xf << 20;

		return ENDIAN_CONVERT(opcode \| rt_num \| imm);
		}

		static unsigned long gen_ori_insn(unsigned long addr)
		{
		unsigned long opcode = 0x58000000;
		unsigned long imm = addr & 0x0000fff;
		unsigned long rt_num = 0xf << 20;
		unsigned long ra_num = 0xf << 15;

		return ENDIAN_CONVERT(opcode \| rt_num \| ra_num \| imm);
		}

		static unsigned long gen_jral_insn(unsigned long addr)
		{
		unsigned long opcode = 0x4a000001;
		unsigned long rt_num = 0x1e << 20;
		unsigned long rb_num = 0xf << 10;

		return ENDIAN_CONVERT(opcode \| rt_num \| rb_num);
		}

		static void ftrace_gen_call_insn(unsigned long *call_insns,
		unsigned long addr)
		{
		call_insns[0] = gen_sethi_insn(addr); /* sethi $r15, imm20u */
		call_insns[1] = gen_ori_insn(addr); /* ori $r15, $r15, imm15u */
		call_insns[2] = gen_jral_insn(addr); /* jral $lp, $r15 */
		}

		static int __ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
		unsigned long *new_insn, bool validate)
		{
		unsigned long orig_insn[3];

		if (validate) {
		if (probe_kernel_read(orig_insn, (void *)pc, MCOUNT_INSN_SIZE))
		return -EFAULT;
		if (memcmp(orig_insn, old_insn, MCOUNT_INSN_SIZE))
		return -EINVAL;
		}

		if (probe_kernel_write((void *)pc, new_insn, MCOUNT_INSN_SIZE))
		return -EPERM;

		return 0;
		}

		static int ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
		unsigned long *new_insn, bool validate)
		{
		int ret;

		ret = __ftrace_modify_code(pc, old_insn, new_insn, validate);
		if (ret)
		return ret;

		flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);

		return ret;
		}

		int ftrace_update_ftrace_func(ftrace_func_t func)
		{
		unsigned long pc = (unsigned long)&ftrace_call;
		unsigned long old_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
		unsigned long new_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};

		if (func != ftrace_stub)
		ftrace_gen_call_insn(new_insn, (unsigned long)func);

		return ftrace_modify_code(pc, old_insn, new_insn, false);
		}

		int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
		{
		unsigned long pc = rec->ip;
		unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
		unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};

		ftrace_gen_call_insn(call_insn, addr);

		return ftrace_modify_code(pc, nop_insn, call_insn, true);
		}

		int ftrace_make_nop(struct module mod, struct dyn_ftrace rec,
		unsigned long addr)
		{
		unsigned long pc = rec->ip;
		unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
		unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};

		ftrace_gen_call_insn(call_insn, addr);

		return ftrace_modify_code(pc, call_insn, nop_insn, true);
		}
		#endif /* CONFIG_DYNAMIC_FTRACE */

		#ifdef CONFIG_FUNCTION_GRAPH_TRACER
		void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
		unsigned long frame_pointer)
		@@ -94,4 +257,5 @@ void __naked return_to_handler(void)
		/* restore state nedded by the ABI */
		"lmw.bim $r0,[$sp],$r1,#0x0 \n\t");
		}

		#endif /* CONFIG_FUNCTION_GRAPH_TRACER */