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Mon, 28 Oct 2024 08:27:40 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 55390) id F3A1FE0733; Mon, 28 Oct 2024 09:27:39 +0100 (CET) From: Sven Schnelle To: "Masami Hiramatsu (Google)" Cc: "Steven Rostedt" , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, "Heiko Carstens" Subject: [PATCH 1/1] s390/tracing: Enable HAVE_FTRACE_GRAPH_FUNC Date: Mon, 28 Oct 2024 09:27:38 +0100 Message-ID: <20241028082738.3293096-2-svens@linux.ibm.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <172991731968.443985.4558065903004844780.stgit@devnote2> References: <20241028082738.3293096-1-svens@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 6n7F5oHJDQK4K42GiEMNqP7VjsZYHP3Z X-Proofpoint-ORIG-GUID: 6n7F5oHJDQK4K42GiEMNqP7VjsZYHP3Z X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-15_01,2024-10-11_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=967 clxscore=1015 adultscore=0 mlxscore=0 priorityscore=1501 spamscore=0 malwarescore=0 impostorscore=0 lowpriorityscore=0 bulkscore=0 phishscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2409260000 definitions=main-2410280068 Content-Type: text/plain; charset="utf-8" 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(). Signed-off-by: Sven Schnelle --- arch/s390/Kconfig | 1 + arch/s390/include/asm/ftrace.h | 5 ++++ arch/s390/kernel/entry.h | 1 - arch/s390/kernel/ftrace.c | 48 ++++++++++------------------------ arch/s390/kernel/mcount.S | 11 -------- 5 files changed, 20 insertions(+), 46 deletions(-) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index eeb95342ddeb..87178183f952 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -182,6 +182,7 @@ 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 diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h index 8c94a330c70c..a3b73a4f626e 100644 --- a/arch/s390/include/asm/ftrace.h +++ b/arch/s390/include/asm/ftrace.h @@ -39,6 +39,7 @@ struct dyn_arch_ftrace { }; =20 struct module; struct dyn_ftrace; +struct ftrace_ops; =20 bool ftrace_need_init_nop(void); #define ftrace_need_init_nop ftrace_need_init_nop @@ -128,6 +129,10 @@ static inline bool arch_syscall_match_sym_name(const c= har *sym, return !strcmp(sym + 7, name) || !strcmp(sym + 8, name); } =20 +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__ */ =20 #ifdef CONFIG_FUNCTION_TRACER diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h index 21969520f947..a1f28879c87e 100644 --- a/arch/s390/kernel/entry.h +++ b/arch/s390/kernel/entry.h @@ -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); =20 struct s390_mmap_arg_struct; struct fadvise64_64_args; diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 51439a71e392..c0b2c97efefb 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -261,43 +261,23 @@ void ftrace_arch_code_modify_post_process(void) } =20 #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 =3D &arch_ftrace_regs(fregs)->regs.gprs[14]; + int bit; + if (unlikely(ftrace_graph_is_dead())) - goto out; + return; if (unlikely(atomic_read(¤t->tracing_graph_pause))) - goto out; - ip -=3D MCOUNT_INSN_SIZE; - if (!function_graph_enter(ra, ip, 0, (void *) sp)) - ra =3D (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 =3D ftrace_test_recursion_trylock(ip, *parent); + if (bit < 0) + return; + if (!function_graph_enter_regs(*parent, ip, 0, parent, fregs)) + *parent =3D (unsigned long)&return_to_handler; + ftrace_test_recursion_unlock(bit); } =20 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S index 2b628aa3d809..1fec370fecf4 100644 --- a/arch/s390/kernel/mcount.S +++ b/arch/s390/kernel/mcount.S @@ -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) --=20 2.45.2