From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
Jiri Kosina <jikos@kernel.org>,
Joe Lawrence <joe.lawrence@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Miroslav Benes <mbenes@suse.cz>, Ingo Molnar <mingo@redhat.com>,
Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"live-patching@vger.kernel.org" <live-patching@vger.kernel.org>
Subject: Re: [PATCH v2 12/13] powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32
Date: Mon, 14 Feb 2022 23:21:56 +0530 [thread overview]
Message-ID: <1644860537.hyunv1mld0.naveen@linux.ibm.com> (raw)
In-Reply-To: <82a732915dc71ee766e31809350939331944006d.1640017960.git.christophe.leroy@csgroup.eu>
Christophe Leroy wrote:
> PPC64 mprofile versions and PPC32 are very similar.
>
> Modify PPC64 version so that if can be reused for PPC32.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> ---
> .../powerpc/kernel/trace/ftrace_64_mprofile.S | 73 +++++++++++++------
> 1 file changed, 51 insertions(+), 22 deletions(-)
While I agree that ppc32 and -mprofile-kernel ftrace code are very
similar, I think this patch adds way too many #ifdefs. IMHO, this
makes the resultant code quite difficult to follow.
- Naveen
>
> diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
> index 6071e0122797..56da60e98327 100644
> --- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
> +++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
> @@ -34,13 +34,16 @@
> */
> _GLOBAL(ftrace_regs_caller)
> /* Save the original return address in A's stack frame */
> - std r0,LRSAVE(r1)
> +#ifdef CONFIG_MPROFILE_KERNEL
> + PPC_STL r0,LRSAVE(r1)
> +#endif
>
> /* Create our stack frame + pt_regs */
> - stdu r1,-SWITCH_FRAME_SIZE(r1)
> + PPC_STLU r1,-SWITCH_FRAME_SIZE(r1)
>
> /* Save all gprs to pt_regs */
> SAVE_GPR(0, r1)
> +#ifdef CONFIG_PPC64
> SAVE_GPRS(2, 11, r1)
>
> /* Ok to continue? */
> @@ -49,10 +52,13 @@ _GLOBAL(ftrace_regs_caller)
> beq ftrace_no_trace
>
> SAVE_GPRS(12, 31, r1)
> +#else
> + stmw r2, GPR2(r1)
> +#endif
>
> /* Save previous stack pointer (r1) */
> addi r8, r1, SWITCH_FRAME_SIZE
> - std r8, GPR1(r1)
> + PPC_STL r8, GPR1(r1)
>
> /* Load special regs for save below */
> mfmsr r8
> @@ -63,10 +69,11 @@ _GLOBAL(ftrace_regs_caller)
> /* Get the _mcount() call site out of LR */
> mflr r7
> /* Save it as pt_regs->nip */
> - std r7, _NIP(r1)
> + PPC_STL r7, _NIP(r1)
> /* Save the read LR in pt_regs->link */
> - std r0, _LINK(r1)
> + PPC_STL r0, _LINK(r1)
>
> +#ifdef CONFIG_PPC64
> /* Save callee's TOC in the ABI compliant location */
> std r2, 24(r1)
> ld r2,PACATOC(r13) /* get kernel TOC in r2 */
> @@ -74,8 +81,12 @@ _GLOBAL(ftrace_regs_caller)
> addis r3,r2,function_trace_op@toc@ha
> addi r3,r3,function_trace_op@toc@l
> ld r5,0(r3)
> +#else
> + lis r3,function_trace_op@ha
> + lwz r5,function_trace_op@l(r3)
> +#endif
>
> -#ifdef CONFIG_LIVEPATCH
> +#ifdef CONFIG_LIVEPATCH_64
> mr r14,r7 /* remember old NIP */
> #endif
> /* Calculate ip from nip-4 into r3 for call below */
> @@ -85,10 +96,10 @@ _GLOBAL(ftrace_regs_caller)
> mr r4, r0
>
> /* Save special regs */
> - std r8, _MSR(r1)
> - std r9, _CTR(r1)
> - std r10, _XER(r1)
> - std r11, _CCR(r1)
> + PPC_STL r8, _MSR(r1)
> + PPC_STL r9, _CTR(r1)
> + PPC_STL r10, _XER(r1)
> + PPC_STL r11, _CCR(r1)
>
> /* Load &pt_regs in r6 for call below */
> addi r6, r1 ,STACK_FRAME_OVERHEAD
> @@ -100,27 +111,32 @@ ftrace_regs_call:
> nop
>
> /* Load ctr with the possibly modified NIP */
> - ld r3, _NIP(r1)
> + PPC_LL r3, _NIP(r1)
> mtctr r3
> -#ifdef CONFIG_LIVEPATCH
> +#ifdef CONFIG_LIVEPATCH_64
> cmpd r14, r3 /* has NIP been altered? */
> #endif
>
> /* Restore gprs */
> - REST_GPR(0, r1)
> +#ifdef CONFIG_PPC64
> REST_GPRS(2, 31, r1)
> +#else
> + lmw r2, GPR2(r1)
> +#endif
>
> /* Restore possibly modified LR */
> - ld r0, _LINK(r1)
> + PPC_LL r0, _LINK(r1)
> mtlr r0
>
> +#ifdef CONFIG_PPC64
> /* Restore callee's TOC */
> ld r2, 24(r1)
> +#endif
>
> /* Pop our stack frame */
> addi r1, r1, SWITCH_FRAME_SIZE
>
> -#ifdef CONFIG_LIVEPATCH
> +#ifdef CONFIG_LIVEPATCH_64
> /* Based on the cmpd above, if the NIP was altered handle livepatch */
> bne- livepatch_handler
> #endif
> @@ -129,6 +145,7 @@ ftrace_regs_call:
> _GLOBAL(ftrace_stub)
> blr
>
> +#ifdef CONFIG_PPC64
> ftrace_no_trace:
> mflr r3
> mtctr r3
> @@ -136,25 +153,31 @@ ftrace_no_trace:
> addi r1, r1, SWITCH_FRAME_SIZE
> mtlr r0
> bctr
> +#endif
>
> _GLOBAL(ftrace_caller)
> /* Save the original return address in A's stack frame */
> - std r0, LRSAVE(r1)
> +#ifdef CONFIG_MPROFILE_KERNEL
> + PPC_STL r0, LRSAVE(r1)
> +#endif
>
> /* Create our stack frame + pt_regs */
> - stdu r1, -SWITCH_FRAME_SIZE(r1)
> + PPC_STLU r1, -SWITCH_FRAME_SIZE(r1)
>
> /* Save all gprs to pt_regs */
> SAVE_GPRS(3, 10, r1)
>
> +#ifdef CONFIG_PPC64
> lbz r3, PACA_FTRACE_ENABLED(r13)
> cmpdi r3, 0
> beq ftrace_no_trace
> +#endif
>
> /* Get the _mcount() call site out of LR */
> mflr r7
> - std r7, _NIP(r1)
> + PPC_STL r7, _NIP(r1)
>
> +#ifdef CONFIG_PPC64
> /* Save callee's TOC in the ABI compliant location */
> std r2, 24(r1)
> ld r2, PACATOC(r13) /* get kernel TOC in r2 */
> @@ -162,6 +185,10 @@ _GLOBAL(ftrace_caller)
> addis r3, r2, function_trace_op@toc@ha
> addi r3, r3, function_trace_op@toc@l
> ld r5, 0(r3)
> +#else
> + lis r3,function_trace_op@ha
> + lwz r5,function_trace_op@l(r3)
> +#endif
>
> #ifdef CONFIG_LIVEPATCH_64
> SAVE_GPR(14, r1)
> @@ -171,7 +198,7 @@ _GLOBAL(ftrace_caller)
> subi r3, r7, MCOUNT_INSN_SIZE
>
> /* Put the original return address in r4 as parent_ip */
> - std r0, _LINK(r1)
> + PPC_STL r0, _LINK(r1)
> mr r4, r0
>
> /* Load &pt_regs in r6 for call below */
> @@ -183,7 +210,7 @@ ftrace_call:
> bl ftrace_stub
> nop
>
> - ld r3, _NIP(r1)
> + PPC_LL r3, _NIP(r1)
> mtctr r3
> #ifdef CONFIG_LIVEPATCH_64
> cmpd r14, r3 /* has NIP been altered? */
> @@ -193,11 +220,13 @@ ftrace_call:
> /* Restore gprs */
> REST_GPRS(3, 10, r1)
>
> +#ifdef CONFIG_PPC64
> /* Restore callee's TOC */
> ld r2, 24(r1)
> +#endif
>
> /* Restore possibly modified LR */
> - ld r0, _LINK(r1)
> + PPC_LL r0, _LINK(r1)
> mtlr r0
>
> /* Pop our stack frame */
> @@ -209,7 +238,7 @@ ftrace_call:
> #endif
> bctr /* jump after _mcount site */
>
> -#ifdef CONFIG_LIVEPATCH
> +#ifdef CONFIG_LIVEPATCH_64
> /*
> * This function runs in the mcount context, between two functions. As
> * such it can only clobber registers which are volatile and used in
> --
> 2.33.1
>
next prev parent reply other threads:[~2022-02-14 17:52 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-20 16:37 [PATCH v2 00/13] Implement livepatch on PPC32 and more Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 01/13] livepatch: Fix build failure on 32 bits processors Christophe Leroy
2021-12-22 13:47 ` Miroslav Benes
2022-01-04 19:35 ` Joe Lawrence
2021-12-20 16:38 ` [PATCH v2 02/13] tracing: Fix selftest config check for function graph start up test Christophe Leroy
2022-02-24 13:43 ` Christophe Leroy
2022-02-24 14:53 ` Steven Rostedt
2022-02-24 15:13 ` Christophe Leroy
2022-02-24 15:17 ` Steven Rostedt
2022-02-25 2:42 ` Michael Ellerman
2021-12-20 16:38 ` [PATCH v2 03/13] powerpc/module_32: Fix livepatching for RO modules Christophe Leroy
2022-01-04 19:44 ` Joe Lawrence
2021-12-20 16:38 ` [PATCH v2 04/13] powerpc/ftrace: Add support for livepatch to PPC32 Christophe Leroy
2021-12-22 14:00 ` Miroslav Benes
2021-12-20 16:38 ` [PATCH v2 05/13] powerpc/ftrace: Don't save again LR in ftrace_regs_caller() on PPC32 Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 06/13] powerpc/ftrace: Simplify PPC32's return_to_handler() Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 07/13] powerpc/ftrace: Prepare PPC32's ftrace_caller() for CONFIG_DYNAMIC_FTRACE_WITH_ARGS Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 08/13] powerpc/ftrace: Prepare PPC64's " Christophe Leroy
2022-02-14 15:19 ` Naveen N. Rao
2021-12-20 16:38 ` [PATCH v2 09/13] powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS Christophe Leroy
2021-12-22 14:19 ` Miroslav Benes
2022-02-14 15:25 ` Naveen N. Rao
2022-02-15 8:00 ` Christophe Leroy
2022-02-15 11:05 ` Michael Ellerman
2022-02-15 13:36 ` Naveen N. Rao
2022-02-15 14:28 ` Christophe Leroy
2022-02-15 14:51 ` Christophe Leroy
2022-02-15 16:25 ` Naveen N. Rao
2022-02-16 13:04 ` Heiko Carstens
2022-02-16 13:27 ` Sven Schnelle
2022-02-15 14:38 ` Steven Rostedt
2022-02-15 16:26 ` Naveen N. Rao
2021-12-20 16:38 ` [PATCH v2 10/13] powerpc/ftrace: Refactor ftrace_{en/dis}able_ftrace_graph_caller Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 11/13] powerpc/ftrace: directly call of function graph tracer by ftrace caller Christophe Leroy
2022-02-14 17:24 ` Naveen N. Rao
2022-02-14 19:03 ` Steven Rostedt
2021-12-20 16:38 ` [PATCH v2 12/13] powerpc/ftrace: Prepare ftrace_64_mprofile.S for reuse by PPC32 Christophe Leroy
2022-02-14 17:51 ` Naveen N. Rao [this message]
2022-02-15 8:33 ` Christophe Leroy
2021-12-20 16:38 ` [PATCH v2 13/13] powerpc/ftrace: Remove ftrace_32.S Christophe Leroy
2022-02-11 7:41 ` [PATCH] Fixup for next-test 3a1a8f078670 ("powerpc/ftrace: Remove ftrace_32.S") Christophe Leroy
2022-02-16 12:26 ` [PATCH v2 00/13] Implement livepatch on PPC32 and more Michael Ellerman
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