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Peter Anvin" , Namhyung Kim , Andrii Nakryiko , Kees Cook , Sam James , Fangrui Song Subject: [RFC PATCH v2 23/24] unwind_user/eh_frame/s390: Enable eh_frame unwinding on s390 Date: Fri, 21 Aug 2026 21:52:58 +0200 Message-ID: <20260821195259.2688377-24-jremus@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260821195259.2688377-1-jremus@linux.ibm.com> References: <20260821195259.2688377-1-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-Proofpoint-Spam-Info: AW1haW4tMjYwODIxMDE1NSBTYWx0ZWRfXzKG+S2u53BzP hqy+2y2eBLsMuAyXCGbVawq72lSScsbNJz2QBM8GHbKjMux/2gIhPSukvKMSA7oG/MbgdbfegmF LXqxfdluZWsF3/GctKUrLyfHKa1iTRs= X-Proofpoint-GUID: ismV3-0PHheBjc3lL-v0KI1YRoSnqBTU X-Proofpoint-ORIG-GUID: fh0wHN0Grpa8vy5clGXhKBYq-SjqqQM1 X-Authority-Analysis: v=2.4 cv=RPmD2Yi+ c=1 sm=1 tr=0 ts=6a88acad cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=FmDO2REWYRq66Aip4RwA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODIxMDE1NSBTYWx0ZWRfX2Xt7KTGJ0tcn jUt54EXZmbaP4rKr+60qBjMsiMxVUT7F/D2spaFaf24XGFV2jam59DxRof9obOnyHn7A9j4w4P1 lIYANRQp6kylxUgd4IMoPK87Yr2Gm7YI94bx+PG2YDn5kC7k5Vk0PGFW7t2cpx7suCkkLe4S0kw 2BYVjcbcEvDmblSMoM+Z0bX/WM5TK9nOxqDUZbmb2EowFvrKKYkj8L5v2jxh21yAc1Q4SVLSuAN E9wZghJECHta9UQ871tupgBHyEZt+/GvL5kmnZcICkerSFRdeNzhrEXeiy4i3NGO0FJ16ReaurX MJjFd+hYpu5dzEULoddLKMvfclco6brQx6+MqUzLDEkiHtnoY+GJXHRWlfaRzv0PZCAa5iAXGhF 0L7Vqm8eSrgZb/p79ezXVyxHsZZXKmkB3u6wzjhzEKevMxzCOsTLitzv006b+KII3Nw63hD0k5a UuqtQgWrWQu06mPuyrQ== 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=2026-08-21_06,2026-08-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 adultscore=0 spamscore=0 priorityscore=1501 bulkscore=0 impostorscore=0 malwarescore=0 lowpriorityscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608210155 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