linux/arch/s390/include/asm/ftrace.h
Vasily Gorbik c9343637d6 s390/ftrace: assume -mhotpatch or -mrecord-mcount always available
Currently the kernel minimal compiler requirement is gcc 4.9 or
clang 10.0.1.
* gcc -mhotpatch option is supported since 4.8.
* A combination of -pg -mrecord-mcount -mnop-mcount -mfentry flags is
supported since gcc 9 and since clang 10.

Drop support for old -pg function prologues. Which leaves binary
compatible -mhotpatch / -mnop-mcount -mfentry prologues in a form:
	brcl	0,0
Which are also do not require initial nop optimization / conversion and
presence of _mcount symbol.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-11-20 19:19:11 +01:00

107 lines
2.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_S390_FTRACE_H
#define _ASM_S390_FTRACE_H
#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
#define ARCH_SUPPORTS_FTRACE_OPS 1
#define MCOUNT_INSN_SIZE 6
#ifndef __ASSEMBLY__
#ifdef CONFIG_CC_IS_CLANG
/* https://bugs.llvm.org/show_bug.cgi?id=41424 */
#define ftrace_return_address(n) 0UL
#else
#define ftrace_return_address(n) __builtin_return_address(n)
#endif
void ftrace_caller(void);
extern char ftrace_graph_caller_end;
extern unsigned long ftrace_plt;
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;
/*
* Either -mhotpatch or -mnop-mcount is used - no explicit init is required
*/
static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) { return 0; }
#define ftrace_init_nop ftrace_init_nop
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
return addr;
}
struct ftrace_insn {
u16 opc;
s32 disp;
} __packed;
static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
{
#ifdef CONFIG_FUNCTION_TRACER
/* brcl 0,0 */
insn->opc = 0xc004;
insn->disp = 0;
#endif
}
static inline int is_ftrace_nop(struct ftrace_insn *insn)
{
#ifdef CONFIG_FUNCTION_TRACER
if (insn->disp == 0)
return 1;
#endif
return 0;
}
static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
unsigned long ip)
{
#ifdef CONFIG_FUNCTION_TRACER
unsigned long target;
/* brasl r0,ftrace_caller */
target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
insn->opc = 0xc005;
insn->disp = (target - ip) / 2;
#endif
}
/*
* 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__ */
#endif /* _ASM_S390_FTRACE_H */