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Peter Anvin" References: <20250425023750.669174660@goodmis.org> <20250425024023.173709192@goodmis.org> Content-Language: en-US From: Jens Remus Organization: IBM Deutschland Research & Development GmbH In-Reply-To: <20250425024023.173709192@goodmis.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=FMYWBuos c=1 sm=1 tr=0 ts=68f641d9 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=x6icFKpwvdMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=VwQbUJbxAAAA:8 a=meVymXHHAAAA:8 a=3JhgRXgks4luCjnt5rcA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=2JgSa4NbpEOStq-L5dxp:22 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-GUID: OpqjzTxfXFzaza0fv9DNz8e_-0M5Q33C X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMDE4MDAyMiBTYWx0ZWRfX53QSAeovpUvh BLVZ6yZMPkT0ELun7735ePODuR+TJv3E2Zo4clCXMnsfb0lJlNkDLFsjc0D47pec6zhK+3S+9ey b1w3UHvR1sfgRymY1y9GqjdTSKKaXNYZRSi5YCPzijDw2NwGmbfXz3Shg4kkCWXfY8GfOpZcAgL tGcQxPCQIf/3VBL5L5PPhwwf3KZyaS2s5ALuM6I9K8aQHsbyYI8nWVouGqu2CaIeUogN91075eA FDAvfk8zGQeeBMxYvg77qouDoePEY+KURawZgZRxmhjOfxFUYl5w/lVvPkBo4mAG5KnSKWU5tMd oLbcOalcrSl7xsWZaLz88MRE4cYrXF9dIi8jAvKPMe7cYQB054IFzCPtduOC3gc0xeTtkFVQAgF tVHsPXAn9tVt/0hySP+ozV5lfF3IdA== X-Proofpoint-ORIG-GUID: OpqjzTxfXFzaza0fv9DNz8e_-0M5Q33C X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-10-20_04,2025-10-13_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 impostorscore=0 priorityscore=1501 adultscore=0 bulkscore=0 lowpriorityscore=0 suspectscore=0 phishscore=0 spamscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510020000 definitions=main-2510180022 On 4/25/2025 4:37 AM, Steven Rostedt wrote: > From: Josh Poimboeuf > > Enable sframe generation in the VDSO library so kernel and user space > can unwind through it. > > Signed-off-by: Josh Poimboeuf > Signed-off-by: Steven Rostedt (Google) > diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S > @@ -87,6 +88,7 @@ SECTIONS > * Very old versions of ld do not recognize this name token; use the constant. > */ > #define PT_GNU_EH_FRAME 0x6474e550 > +#define PT_GNU_SFRAME 0x6474e554 > > /* > * We must supply the ELF program headers explicitly to get just one > @@ -98,4 +100,5 @@ PHDRS > dynamic PT_DYNAMIC FLAGS(4); /* PF_R */ > note PT_NOTE FLAGS(4); /* PF_R */ > eh_frame_hdr PT_GNU_EH_FRAME; On s390 I found that the respective s390-change needs to be guarded to prevent the vDSO from erroneously getting generated with a bogus GNU_SFRAME program table entry, if CONFIG_AS_SFRAME is not enabled: $ readelf -Wl arch/s390/kernel/vdso64/vdso64.so ... Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align LOAD 0x000000 0x0000000000000000 0x0000000000000000 0x001508 0x001508 R E 0x1000 DYNAMIC 0x001190 0x0000000000001190 0x0000000000001190 0x000100 0x000100 R 0x8 NOTE 0x000420 0x0000000000000420 0x0000000000000420 0x00003c 0x00003c R 0x4 GNU_EH_FRAME 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 0x8 GNU_SFRAME 0x0014f0 0x00000000000014f0 0x00000000000014f0 0x000018 0x000018 RW 0x8 ... $ xxd arch/s390/kernel/vdso64/vdso64.so ... 000014f0: 0000 0000 0000 1190 0000 0000 0000 0000 ................ 00001500: 0000 0000 0000 0000 4743 433a 2028 5562 ........GCC: (Ub 00001510: 756e 7475 2031 342e 322e 302d 3139 7562 untu 14.2.0-19ub 00001520: 756e 7475 3229 2031 342e 322e 3000 0000 untu2) 14.2.0... ... Following would be the guard for x86 (same as the one used below in arch/x86/include/asm/dwarf2.h): #if defined(__x86_64__) && defined(CONFIG_AS_SFRAME) > + sframe PT_GNU_SFRAME; #endif > } > diff --git a/arch/x86/include/asm/dwarf2.h b/arch/x86/include/asm/dwarf2.h > @@ -12,8 +12,11 @@ > * For the vDSO, emit both runtime unwind information and debug > * symbols for the .dbg file. > */ > - > +#if defined(__x86_64__) && defined(CONFIG_AS_SFRAME) > + .cfi_sections .eh_frame, .debug_frame, .sframe > +#else > .cfi_sections .eh_frame, .debug_frame > +#endif > > #define CFI_STARTPROC .cfi_startproc > #define CFI_ENDPROC .cfi_endproc 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/