1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 #ifndef _ASM_X86_ENTRY_COMMON_H 3 #define _ASM_X86_ENTRY_COMMON_H 4 5 #include <linux/user-return-notifier.h> 6 7 #include <asm/nospec-branch.h> 8 #include <asm/io_bitmap.h> 9 #include <asm/fpu/api.h> 10 #include <asm/fred.h> 11 12 /* Check that the stack and regs on entry from user mode are sane. */ 13 static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) 14 { 15 if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) { 16 /* 17 * Make sure that the entry code gave us a sensible EFLAGS 18 * register. Native because we want to check the actual CPU 19 * state, not the interrupt state as imagined by Xen. 20 */ 21 unsigned long flags = native_save_fl(); 22 unsigned long mask = X86_EFLAGS_DF | X86_EFLAGS_NT; 23 24 /* 25 * For !SMAP hardware we patch out CLAC on entry. 26 */ 27 if (cpu_feature_enabled(X86_FEATURE_SMAP) || 28 cpu_feature_enabled(X86_FEATURE_XENPV)) 29 mask |= X86_EFLAGS_AC; 30 31 WARN_ON_ONCE(flags & mask); 32 33 /* We think we came from user mode. Make sure pt_regs agrees. */ 34 WARN_ON_ONCE(!user_mode(regs)); 35 36 /* 37 * All entries from user mode (except #DF) should be on the 38 * normal thread stack and should have user pt_regs in the 39 * correct location. 40 */ 41 WARN_ON_ONCE(!on_thread_stack()); 42 WARN_ON_ONCE(regs != task_pt_regs(current)); 43 } 44 } 45 #define arch_enter_from_user_mode arch_enter_from_user_mode 46 47 static inline void arch_exit_work(unsigned long ti_work) 48 { 49 if (ti_work & _TIF_USER_RETURN_NOTIFY) 50 fire_user_return_notifiers(); 51 52 if (unlikely(ti_work & _TIF_IO_BITMAP)) 53 tss_update_io_bitmap(); 54 55 if (unlikely(ti_work & _TIF_NEED_FPU_LOAD)) 56 switch_fpu_return(); 57 } 58 59 static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, 60 unsigned long ti_work) 61 { 62 fpregs_assert_state_consistent(); 63 64 if (unlikely(ti_work)) 65 arch_exit_work(ti_work); 66 67 fred_update_rsp0(); 68 69 #ifdef CONFIG_COMPAT 70 /* 71 * Compat syscalls set TS_COMPAT. Make sure we clear it before 72 * returning to user mode. We need to clear it *after* signal 73 * handling, because syscall restart has a fixup for compat 74 * syscalls. The fixup is exercised by the ptrace_syscall_32 75 * selftest. 76 * 77 * We also need to clear TS_REGS_POKED_I386: the 32-bit tracer 78 * special case only applies after poking regs and before the 79 * very next return to user mode. 80 */ 81 current_thread_info()->status &= ~(TS_COMPAT | TS_I386_REGS_POKED); 82 #endif 83 84 /* Avoid unnecessary reads of 'x86_ibpb_exit_to_user' */ 85 if (cpu_feature_enabled(X86_FEATURE_IBPB_EXIT_TO_USER) && 86 this_cpu_read(x86_ibpb_exit_to_user)) { 87 indirect_branch_prediction_barrier(); 88 this_cpu_write(x86_ibpb_exit_to_user, false); 89 } 90 } 91 #define arch_exit_to_user_mode_prepare arch_exit_to_user_mode_prepare 92 93 static __always_inline void arch_exit_to_user_mode(void) 94 { 95 amd_clear_divider(); 96 } 97 #define arch_exit_to_user_mode arch_exit_to_user_mode 98 99 extern void x86_entry_from_kvm(unsigned int entry_type, unsigned int vector); 100 101 #endif 102