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Wed, 19 Nov 2025 14:59:15 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DD0F020043; Wed, 19 Nov 2025 14:59:14 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4A1E620040; Wed, 19 Nov 2025 14:59:14 +0000 (GMT) Received: from [9.155.200.37] (unknown [9.155.200.37]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 19 Nov 2025 14:59:14 +0000 (GMT) Message-ID: <910e6b23-4637-4c95-8202-01212af2d59c@linux.ibm.com> Date: Wed, 19 Nov 2025 15:59:13 +0100 Precedence: bulk X-Mailing-List: linux-toolchains@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/6] unwind: build kernel with sframe info To: Dylan Hatch , Josh Poimboeuf , Steven Rostedt , Indu Bhagat , Peter Zijlstra , Will Deacon , Catalin Marinas , Jiri Kosina Cc: Roman Gushchin , Weinan Liu , Mark Rutland , Ian Rogers , linux-toolchains@vger.kernel.org, linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, joe.lawrence@redhat.com, Puranjay Mohan , Song Liu , Prasanna Kumar T S M , Heiko Carstens , Vasily Gorbik References: <20250904223850.884188-1-dylanbhatch@google.com> <20250904223850.884188-2-dylanbhatch@google.com> Content-Language: en-US From: Jens Remus Organization: IBM Deutschland Research & Development GmbH In-Reply-To: <20250904223850.884188-2-dylanbhatch@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: NEdPukv-2rmKzllanEEmhPyb_jj2ddAt X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTE1MDAzMiBTYWx0ZWRfX8a1N485PEj5y UcLfylynUtHgUK1q1h1QjhwFkQaxeuloMYjkc0SQtT8FG4yQfJCtJBSa9nj4cwke+3iPrdzdKl5 5ULlVLaRRdbF09kEDIwp5Uxezd1/dk8bQcxUhwAkm93smsfMH6w4G1Dp81T7AfgiMX2VmzMYXw8 ru2gsSoqTnRpf7LsXnXvdRrx6hoB+wB4PoEfrRq3hRwVUxUAhhpr41MIBSBDOtKWoTQ5JOO2hhp Z/dU7GSpbFYqhFyEScjVqFYFq4T2g1ui0asxAnEbdOln0ssAB8DePhTizo+yazB+0MYI61BHn2o PluTwLz8hmp3Dsz3twZ0rnIHO9GIVDzHHP0Daamf/hqnMz2i4fU4cAKCHqxmcP7xXAl6GrN8Kqv fnENiRYM3Rm0aEZRN/80chC/Marvxw== X-Proofpoint-ORIG-GUID: FJ9z7NAljrLNQL8LudJtIC6IJKFAu6Ei X-Authority-Analysis: v=2.4 cv=XtL3+FF9 c=1 sm=1 tr=0 ts=691ddb48 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=1XWaLZrsAAAA:8 a=yMhMjlubAAAA:8 a=9Xp0JMHa146bnEPpIwAA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-19_04,2025-11-18_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 spamscore=0 bulkscore=0 priorityscore=1501 impostorscore=0 adultscore=0 lowpriorityscore=0 phishscore=0 suspectscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511150032 Hello Dylan! On 9/5/2025 12:38 AM, Dylan Hatch wrote: > Use the -Wa,--gsframe flags to build the code, so GAS will generate > a new .sframe section for the stack trace information. > Currently, the sframe format only supports arm64 and x86_64 > architectures. Add this configuration on arm64 to enable sframe > unwinder in the future. > > Signed-off-by: Weinan Liu > Signed-off-by: Dylan Hatch > Reviewed-by: Prasanna Kumar T S M > diff --git a/arch/Kconfig b/arch/Kconfig > @@ -1782,4 +1782,10 @@ config ARCH_WANTS_PRE_LINK_VMLINUX > config ARCH_HAS_CPU_ATTACK_VECTORS > bool > > +config AS_SFRAME > + def_bool $(as-instr,.cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc) As you will soon be requiring SFrame V2 with the new PC-relative FDE function start address encoding you may want to extend this check as follows: config AS_SFRAME def_bool y depends on $(as-instr,.cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc) depends on $(success,printf "%b\n" ".cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc" | $(CC) $(CLANG_FLAGS) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o "$$TMP" - && $(OBJDUMP) --sframe "$$TMP" | grep -q "SFRAME_VERSION_2") depends on $(success,printf "%b\n" ".cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc" | $(CC) $(CLANG_FLAGS) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o "$$TMP" - && $(OBJDUMP) --sframe "$$TMP" | grep -q "SFRAME_F_FDE_FUNC_START_PCREL") Or you could change it into multiple config options, which might be overkill: config AS_SFRAME def_bool $(as-instr,.cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc) config AS_SFRAME_V2 def_bool y depends on AS_SFRAME depends on $(success,printf "%b\n" ".cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc" | $(CC) $(CLANG_FLAGS) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o "$$TMP" - && $(OBJDUMP) --sframe "$$TMP" | grep -q "SFRAME_VERSION_2") config AS_SFRAME_V2_PCREL_FDE def_bool y depends on AS_SFRAME_V2 depends on $(success,printf "%b\n" ".cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc" | $(CC) $(CLANG_FLAGS) -Wa$(comma)--fatal-warnings -c -x assembler-with-cpp -o "$$TMP" - && $(OBJDUMP) --sframe "$$TMP" | grep -q "SFRAME_F_FDE_FUNC_START_PCREL") > + > +config SFRAME_UNWIND_TABLE > + bool > + > endmenu Regards, Jens -- Jens Remus Linux on Z Development (D3303) +49-7031-16-1128 Office jremus@de.ibm.com IBM IBM Deutschland Research & Development GmbH; Vorsitzender des Aufsichtsrats: Wolfgang Wendt; Geschäftsführung: David Faller; Sitz der Gesellschaft: Böblingen; Registergericht: Amtsgericht Stuttgart, HRB 243294 IBM Data Privacy Statement: https://www.ibm.com/privacy/