twx-linux/arch/s390/include/asm/ftrace.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_S390_FTRACE_H
#define _ASM_S390_FTRACE_H

#define ARCH_SUPPORTS_FTRACE_OPS 1
#define MCOUNT_INSN_SIZE	6

#ifndef __ASSEMBLY__
#include <asm/stacktrace.h>

static __always_inline unsigned long return_address(unsigned int n)
{
	struct stack_frame *sf;

	if (!n)
		return (unsigned long)__builtin_return_address(0);

	sf = (struct stack_frame *)current_frame_address();
	do {
		sf = (struct stack_frame *)sf->back_chain;
		if (!sf)
			return 0;
	} while (--n);
	return sf->gprs[8];
}
#define ftrace_return_address(n) return_address(n)

void ftrace_caller(void);

extern void *ftrace_func;

struct dyn_arch_ftrace { };

#define MCOUNT_ADDR 0
#define FTRACE_ADDR ((unsigned long)ftrace_caller)

#define KPROBE_ON_FTRACE_NOP	0
#define KPROBE_ON_FTRACE_CALL	1

struct module;
struct dyn_ftrace;

bool ftrace_need_init_nop(void);
#define ftrace_need_init_nop ftrace_need_init_nop

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

static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
	return addr;
}

struct ftrace_regs {
	struct pt_regs regs;
};

static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
{
	struct pt_regs *regs = &fregs->regs;

	if (test_pt_regs_flag(regs, PIF_FTRACE_FULL_REGS))
		return regs;
	return NULL;
}

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
struct fgraph_ret_regs {
	unsigned long gpr2;
	unsigned long fp;
};

static __always_inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs)
{
	return ret_regs->gpr2;
}

static __always_inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs)
{
	return ret_regs->fp;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

static __always_inline unsigned long
ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs)
{
	return fregs->regs.psw.addr;
}

static __always_inline void
ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
				    unsigned long ip)
{
	fregs->regs.psw.addr = ip;
}

#define ftrace_regs_get_argument(fregs, n) \
	regs_get_kernel_argument(&(fregs)->regs, n)
#define ftrace_regs_get_stack_pointer(fregs) \
	kernel_stack_pointer(&(fregs)->regs)
#define ftrace_regs_return_value(fregs) \
	regs_return_value(&(fregs)->regs)
#define ftrace_regs_set_return_value(fregs, ret) \
	regs_set_return_value(&(fregs)->regs, ret)
#define ftrace_override_function_with_return(fregs) \
	override_function_with_return(&(fregs)->regs)
#define ftrace_regs_query_register_offset(name) \
	regs_query_register_offset(name)

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/*
 * When an ftrace registered caller is tracing a function that is
 * also set by a register_ftrace_direct() call, it needs to be
 * differentiated in the ftrace_caller trampoline. To do this,
 * place the direct caller in the ORIG_GPR2 part of pt_regs. This
 * tells the ftrace_caller that there's a direct caller.
 */
static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr)
{
	struct pt_regs *regs = &fregs->regs;
	regs->orig_gpr2 = addr;
}
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */

/*
 * Even though the system call numbers are identical for s390/s390x a
 * different system call table is used for compat tasks. This may lead
 * to e.g. incorrect or missing trace event sysfs files.
 * Therefore simply do not trace compat system calls at all.
 * See kernel/trace/trace_syscalls.c.
 */
#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
{
	return is_compat_task();
}

#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
static inline bool arch_syscall_match_sym_name(const char *sym,
					       const char *name)
{
	/*
	 * Skip __s390_ and __s390x_ prefix - due to compat wrappers
	 * and aliasing some symbols of 64 bit system call functions
	 * may get the __s390_ prefix instead of the __s390x_ prefix.
	 */
	return !strcmp(sym + 7, name) || !strcmp(sym + 8, name);
}

#endif /* __ASSEMBLY__ */

#ifdef CONFIG_FUNCTION_TRACER

#define FTRACE_NOP_INSN .word 0xc004, 0x0000, 0x0000 /* brcl 0,0 */

#ifndef CC_USING_HOTPATCH

#define FTRACE_GEN_MCOUNT_RECORD(name)		\
	.section __mcount_loc, "a", @progbits;	\
	.quad name;				\
	.previous;

#else /* !CC_USING_HOTPATCH */

#define FTRACE_GEN_MCOUNT_RECORD(name)

#endif /* !CC_USING_HOTPATCH */

#define FTRACE_GEN_NOP_ASM(name)		\
	FTRACE_GEN_MCOUNT_RECORD(name)		\
	FTRACE_NOP_INSN

#else /* CONFIG_FUNCTION_TRACER */

#define FTRACE_GEN_NOP_ASM(name)

#endif /* CONFIG_FUNCTION_TRACER */

#endif /* _ASM_S390_FTRACE_H */