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s390/tracing: Enable HAVE_FTRACE_GRAPH_FUNC

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Add ftrace_graph_func() which is required for fprobe to access registers.
This also eliminates the need for calling prepare_ftrace_return() from
ftrace_caller().

Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/173519002875.391279.7060964632119674159.stgit@devnote2
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Sven Schnelle 2024-12-26 14:13:48 +09:00 committed by Steven Rostedt (Google)
parent a762e9267d
commit 7495e179b4
5 changed files with 20 additions and 46 deletions
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1
arch/s390/Kconfig
View File

@ -190,6 +190,7 @@ config S390
select HAVE_EFFICIENT_UNALIGNED_ACCESS
select HAVE_GUP_FAST
select HAVE_FENTRY
select HAVE_FTRACE_GRAPH_FUNC
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_ARG_ACCESS_API
select HAVE_FUNCTION_ERROR_INJECTION

5
arch/s390/include/asm/ftrace.h
View File

@ -39,6 +39,7 @@ struct dyn_arch_ftrace { };
struct module;
struct dyn_ftrace;
struct ftrace_ops;
bool ftrace_need_init_nop(void);
#define ftrace_need_init_nop ftrace_need_init_nop
@ -122,6 +123,10 @@ static inline bool arch_syscall_match_sym_name(const char *sym,
return !strcmp(sym + 7, name) || !strcmp(sym + 8, name);
}
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs);
#define ftrace_graph_func ftrace_graph_func
#endif /* __ASSEMBLY__ */
#ifdef CONFIG_FUNCTION_TRACER

1
arch/s390/kernel/entry.h
View File

@ -41,7 +41,6 @@ void do_restart(void *arg);
void __init startup_init(void);
void die(struct pt_regs *regs, const char *str);
int setup_profiling_timer(unsigned int multiplier);
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long sp, unsigned long ip);
struct s390_mmap_arg_struct;
struct fadvise64_64_args;

48
arch/s390/kernel/ftrace.c
View File

@ -261,43 +261,23 @@ void ftrace_arch_code_modify_post_process(void)
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/*
* Hook the return address and push it in the stack of return addresses
* in current thread info.
*/
unsigned long prepare_ftrace_return(unsigned long ra, unsigned long sp,
unsigned long ip)
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs)
{
unsigned long *parent = &arch_ftrace_regs(fregs)->regs.gprs[14];
int bit;
if (unlikely(ftrace_graph_is_dead()))
goto out;
return;
if (unlikely(atomic_read(&current->tracing_graph_pause)))
goto out;
ip -= MCOUNT_INSN_SIZE;
if (!function_graph_enter(ra, ip, 0, (void *) sp))
ra = (unsigned long) return_to_handler;
out:
return ra;
}
NOKPROBE_SYMBOL(prepare_ftrace_return);
/*
* Patch the kernel code at ftrace_graph_caller location. The instruction
* there is branch relative on condition. To enable the ftrace graph code
* block, we simply patch the mask field of the instruction to zero and
* turn the instruction into a nop.
* To disable the ftrace graph code the mask field will be patched to
* all ones, which turns the instruction into an unconditional branch.
*/
int ftrace_enable_ftrace_graph_caller(void)
{
/* Expect brc 0xf,... */
return ftrace_patch_branch_mask(ftrace_graph_caller, 0xa7f4, false);
}
int ftrace_disable_ftrace_graph_caller(void)
{
/* Expect brc 0x0,... */
return ftrace_patch_branch_mask(ftrace_graph_caller, 0xa704, true);
return;
bit = ftrace_test_recursion_trylock(ip, *parent);
if (bit < 0)
return;
if (!function_graph_enter_regs(*parent, ip, 0, parent, fregs))
*parent = (unsigned long)&return_to_handler;
ftrace_test_recursion_unlock(bit);
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

11
arch/s390/kernel/mcount.S
View File

@ -104,17 +104,6 @@ SYM_CODE_START(ftrace_common)
lgr %r3,%r14
la %r5,STACK_FREGS(%r15)
BASR_EX %r14,%r1
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
# The j instruction gets runtime patched to a nop instruction.
# See ftrace_enable_ftrace_graph_caller.
SYM_INNER_LABEL(ftrace_graph_caller, SYM_L_GLOBAL)
j .Lftrace_graph_caller_end
lmg %r2,%r3,(STACK_FREGS_PTREGS_GPRS+14*8)(%r15)
lg %r4,(STACK_FREGS_PTREGS_PSW+8)(%r15)
brasl %r14,prepare_ftrace_return
stg %r2,(STACK_FREGS_PTREGS_GPRS+14*8)(%r15)
.Lftrace_graph_caller_end:
#endif
lg %r0,(STACK_FREGS_PTREGS_PSW+8)(%r15)
#ifdef MARCH_HAS_Z196_FEATURES
ltg %r1,STACK_FREGS_PTREGS_ORIG_GPR2(%r15)