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Peter Anvin" , Namhyung Kim , Andrii Nakryiko , Kees Cook , Sam James Subject: [RFC PATCH v1 24/25] unwind_user/eh_frame/s390: Enable eh_frame unwinding on s390 Date: Tue, 18 Aug 2026 16:49:53 +0200 Message-ID: <20260818144954.2320378-25-jremus@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260818144954.2320378-1-jremus@linux.ibm.com> References: <20260818144954.2320378-1-jremus@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=OfaoyBTY c=1 sm=1 tr=0 ts=6a847122 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=FmDO2REWYRq66Aip4RwA:9 X-Proofpoint-Spam-Info: AW1haW4tMjYwODE4MDEwNyBTYWx0ZWRfX5wVjcZ0xyjdM Lzy7ax1kAVWP3PXDqlOSto11EEVdaGp2Li6i5BBDDZKKDxWjsGtJSKjMxmWhd1N5cvJMxxajgRo 6ntVi8LspUC021Vw3bwtSNX9zL/21Pk= X-Proofpoint-GUID: IgMRSTd4jJA23VIoVhSwaq_Zm3bcp6WG X-Proofpoint-ORIG-GUID: a7c6cSCLn8_yDAVAlxdP3rutPXgUXNHD X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODE4MDEwNyBTYWx0ZWRfXzMyUJrO2E1W+ UYWKkXpaX66boNbxMAkgjmYKyZu4yA+ZPrr7nDT29A18CdgOOAmXC6bIUP/TUv6VFADZn4sqyZu G2s9ZVgNYqhC3Qm7oy85PvAXCDvXT8M21X6HRhivzmScoxoK/Wb6xci+CufWtuiBBJ0q6qDu4fy LZqgzxh2936fz1aP2aSOLcjSSkhrrjPjg5NDX7AxYBigETiWhhhACFpqiUqKcjSu2VqUJvQq+Sw 9EVFp9mjT9v5rnaQAeNyG7e3lPx+SXBn1Vvmd1vw+bcKnqsTu9graPpQCplgGaTdW2L7KJ0TQof Q7BhVzRroYVamuxv05qGy4gbRqSo+GBvMVXZPdZSa0NuQaqd3E1tXDlucXdwE92FtKEVIc3VTft 7D3eCFUR2xvzABqcpArrqhrIzSeiY2/GoHXVLye1uf0/HyxrX2qeB9BeUaKD42D4ePmvEP0MO4I TBappzOV5viuwLnsYqQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-18_02,2026-08-18_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 malwarescore=0 bulkscore=0 phishscore=0 priorityscore=1501 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608180107 The unwind user eh_frame implementation works well with GCC and Clang generated code on s390. Enable it. Signed-off-by: Jens Remus --- arch/s390/Kconfig | 1 + arch/s390/include/asm/unwind_user.h | 71 ++++++++++++++++++++ arch/s390/include/asm/unwind_user_eh_frame.h | 24 +++++++ 3 files changed, 96 insertions(+) create mode 100644 arch/s390/include/asm/unwind_user.h create mode 100644 arch/s390/include/asm/unwind_user_eh_frame.h diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 84404e6778d5..fa229ac92d5a 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -251,6 +251,7 @@ config S390 select HAVE_SOFTIRQ_ON_OWN_STACK select HAVE_STACKPROTECTOR if CC_HAS_STACKPROTECTOR_GLOBAL select HAVE_SYSCALL_TRACEPOINTS + select HAVE_UNWIND_USER_EH_FRAME select HAVE_VIRT_CPU_ACCOUNTING select HAVE_VIRT_CPU_ACCOUNTING_IDLE select HOTPLUG_SMT diff --git a/arch/s390/include/asm/unwind_user.h b/arch/s390/include/asm/unwind_user.h new file mode 100644 index 000000000000..41ff0b477626 --- /dev/null +++ b/arch/s390/include/asm/unwind_user.h @@ -0,0 +1,71 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_S390_UNWIND_USER_H +#define _ASM_S390_UNWIND_USER_H + +#include +#include +#include + +#ifdef CONFIG_UNWIND_USER + +static inline int unwind_user_word_size(struct pt_regs *regs) +{ + return 8; +} + +static inline int unwind_user_get_ra_reg(unsigned long *val) +{ + struct pt_regs *regs = task_pt_regs(current); + *val = regs->gprs[14]; + return 0; +} +#define unwind_user_get_ra_reg unwind_user_get_ra_reg + +static inline unsigned long __s390_dwarf_fpr_to_fpr(unsigned int regnum) +{ + unsigned int fpr; + + /* + * Convert from s390 DWARF floating-point register number (16..31) + * to floating-point register number (0..15): left rotate the least + * significant three bits and then return the least significant four + * bits. + */ + fpr = (regnum & 3) << 1; + fpr |= (regnum & 4) >> 2; + fpr |= (regnum & 8); + return fpr; +} + +static inline unsigned long __s390_get_dwarf_fpr(unsigned int regnum) +{ + struct fpu *fpu = ¤t->thread.ufpu; + + save_user_fpu_regs(); + return fpu->vxrs[__s390_dwarf_fpr_to_fpr(regnum)].high; +} + +static inline int unwind_user_get_reg(unsigned long *val, unsigned int regnum) +{ + if (regnum <= 15) { + /* DWARF register numbers 0..15 */ + struct pt_regs *regs = task_pt_regs(current); + *val = regs->gprs[regnum]; + return 0; + } else if (regnum <= 31) { + /* DWARF register numbers 16..31 */ + *val = __s390_get_dwarf_fpr(regnum); + return 0; + } + + pr_debug("%s (%d): %s(%u): unsupported register number\n", + current->comm, current->pid, __func__, regnum); + return -EINVAL; +} +#define unwind_user_get_reg unwind_user_get_reg + +#endif /* CONFIG_UNWIND_USER */ + +#include + +#endif /* _ASM_S390_UNWIND_USER_H */ diff --git a/arch/s390/include/asm/unwind_user_eh_frame.h b/arch/s390/include/asm/unwind_user_eh_frame.h new file mode 100644 index 000000000000..842d9f7c3d80 --- /dev/null +++ b/arch/s390/include/asm/unwind_user_eh_frame.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_S390_UNWIND_USER_EH_FRAME_H +#define _ASM_S390_UNWIND_USER_EH_FRAME_H + +#define EH_FRAME_REG_SP 15 /* designated stack pointer register */ +#define EH_FRAME_REG_FP 11 /* "preferred" frame pointer register */ +#define EH_FRAME_REG_RA 14 /* designaged return address register */ + +/* Instructions must be 2-byte aligned */ +#define EH_FRAME_MAX_CODE_ALIGN 2 + +/* CFA is defined as SP at call site + 160, so that SP = CFA - 160 */ +#define EH_FRAME_SP_VAL_OFFSET -160 + +/* SP may be saved on the stack or in a register */ +static inline bool eh_frame_reject_sp_rule(void) +{ + return false; +} +#define eh_frame_reject_sp_rule eh_frame_reject_sp_rule + +#include + +#endif /* _ASM_S390_UNWIND_USER_EH_FRAME_H */ -- 2.53.0