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Fri, 23 Jan 2026 07:40:01 +0000 (GMT) From: Mukesh Kumar Chaurasiya To: maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, oleg@redhat.com, kees@kernel.org, luto@amacapital.net, wad@chromium.org, mchauras@linux.ibm.com, thuth@redhat.com, ruanjinjie@huawei.com, sshegde@linux.ibm.com, akpm@linux-foundation.org, charlie@rivosinc.com, deller@gmx.de, ldv@strace.io, macro@orcam.me.uk, segher@kernel.crashing.org, peterz@infradead.org, bigeasy@linutronix.de, namcao@linutronix.de, tglx@linutronix.de, mark.barnett@arm.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com Subject: [PATCH v4 4/8] powerpc: Introduce syscall exit arch functions Date: Fri, 23 Jan 2026 13:09:12 +0530 Message-ID: <20260123073916.956498-5-mkchauras@linux.ibm.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260123073916.956498-1-mkchauras@linux.ibm.com> References: <20260123073916.956498-1-mkchauras@linux.ibm.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=WMdyn3sR c=1 sm=1 tr=0 ts=697325de cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=vUbySO9Y5rIA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=K2hBjdrW4GR3aseOdFMA:9 X-Proofpoint-GUID: xep7M4Oh8a1rGfznsv4u2iiH8eUKcOEV X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTIzMDA1NSBTYWx0ZWRfXx40x3gp6YmGp /n+EX5nrzbWHZJjzNXIgWFFE8C4t64lv3W/C/8dlUbLJ3BtXg97OaFkQlDxxhmsA27TTmbGasYj 2Sv+k60S6zpdCpLEiXxHfeLBwlGt8VOcKXzfF+6TVS5kf/hcLEc11rTbkvotcHRz9Ej2kbuHrh+ vSMtg1PqB/Knu2ucjIilw45ACtNsKOWjr3fAOSiuWf5yl57BQykPnOIzqvh1GXzqLxfsoSJQWqZ nwn1f8hM2xwrDWLMb4COrkeSfCluqXsIHNIebOqOu4F4Gu713sLwtIiKQUyQF2wN4anWV9n8PCe 1du01vB+rXeLMZseiLbVbxLSHy6aILFGiMeoxkeSNhaiRHcTf6SXHyN42r0Tdj5bb2hx5BxLJws JcMFMFvkZTMpi21g3SR/rBiIJE6Wr4ejb1AJFkuCdkETYftOiARJXcUY/aYXSivJUggkc49Z/w4 x8na4j0EXSluT5ttQgA== X-Proofpoint-ORIG-GUID: RAxMs7eKSHxnsMBpZ30WVDw9ZnroqVmc X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.20,FMLib:17.12.100.49 definitions=2026-01-22_06,2026-01-22_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 malwarescore=0 suspectscore=0 bulkscore=0 adultscore=0 impostorscore=0 spamscore=0 clxscore=1011 priorityscore=1501 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2601230055 From: Mukesh Kumar Chaurasiya Add PowerPC-specific implementations of the generic syscall exit hooks used by the generic entry/exit framework: - arch_exit_to_user_mode_work_prepare() - arch_exit_to_user_mode_work() These helpers handle user state restoration when returning from the kernel to userspace, including FPU/VMX/VSX state, transactional memory, KUAP restore, and per-CPU accounting. Additionally, move check_return_regs_valid() from interrupt.c to interrupt.h so it can be shared by the new entry/exit logic. No functional change is intended with this patch. Signed-off-by: Mukesh Kumar Chaurasiya --- arch/powerpc/include/asm/entry-common.h | 49 +++++++++++++++++++++++++ 1 file changed, 49 insertions(+) diff --git a/arch/powerpc/include/asm/entry-common.h b/arch/powerpc/include/asm/entry-common.h index 837a7e020e82..ff0625e04778 100644 --- a/arch/powerpc/include/asm/entry-common.h +++ b/arch/powerpc/include/asm/entry-common.h @@ -6,6 +6,7 @@ #include #include #include +#include #include static __always_inline void booke_load_dbcr0(void) @@ -123,4 +124,52 @@ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) #define arch_enter_from_user_mode arch_enter_from_user_mode +static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, + unsigned long ti_work) +{ + unsigned long mathflags; + + if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && IS_ENABLED(CONFIG_PPC_FPU)) { + if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && + unlikely((ti_work & _TIF_RESTORE_TM))) { + restore_tm_state(regs); + } else { + mathflags = MSR_FP; + + if (cpu_has_feature(CPU_FTR_VSX)) + mathflags |= MSR_VEC | MSR_VSX; + else if (cpu_has_feature(CPU_FTR_ALTIVEC)) + mathflags |= MSR_VEC; + + /* + * If userspace MSR has all available FP bits set, + * then they are live and no need to restore. If not, + * it means the regs were given up and restore_math + * may decide to restore them (to avoid taking an FP + * fault). + */ + if ((regs->msr & mathflags) != mathflags) + restore_math(regs); + } + } + + check_return_regs_valid(regs); +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM + local_paca->tm_scratch = regs->msr; +#endif + /* Restore user access locks last */ + kuap_user_restore(regs); +} + +#define arch_exit_to_user_mode_prepare arch_exit_to_user_mode_prepare + +static __always_inline void arch_exit_to_user_mode(void) +{ + booke_load_dbcr0(); + + account_cpu_user_exit(); +} + +#define arch_exit_to_user_mode arch_exit_to_user_mode + #endif /* _ASM_PPC_ENTRY_COMMON_H */ -- 2.52.0