Last part of interrupt_exit_user_prepare() and syscall_exit_prepare() are identical.
Create a __interrupt_exit_user_prepare() function that is called by both. Note that it replaces a local_irq_save(flags) by local_irq_disable(). This is similar because the flags are never used. On ppc 8xx it is more efficient because it doesn't require reading MSR. Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu> --- It requires the following commits that are in powerpc/fixes-test: 5d510ed78bcf powerpc/syscall: Calling kuap_save_and_lock() is wrong a78339698ab1 powerpc/interrupts: Fix kuep_unlock() call Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu> --- arch/powerpc/kernel/interrupt.c | 147 ++++++++++---------------------- 1 file changed, 44 insertions(+), 103 deletions(-) diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index e0938ba298f2..d896fc6ed0be 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -231,56 +231,15 @@ static notrace void booke_load_dbcr0(void) #endif } -/* - * This should be called after a syscall returns, with r3 the return value - * from the syscall. If this function returns non-zero, the system call - * exit assembly should additionally load all GPR registers and CTR and XER - * from the interrupt frame. - * - * The function graph tracer can not trace the return side of this function, - * because RI=0 and soft mask state is "unreconciled", so it is marked notrace. - */ -notrace unsigned long syscall_exit_prepare(unsigned long r3, - struct pt_regs *regs, - long scv) +static notrace unsigned long __interrupt_exit_user_prepare(struct pt_regs *regs, unsigned long ret, + bool is_not_scv) { unsigned long ti_flags; - unsigned long ret = 0; - bool is_not_scv = !IS_ENABLED(CONFIG_PPC_BOOK3S_64) || !scv; CT_WARN_ON(ct_state() == CONTEXT_USER); kuap_assert_locked(); - regs->result = r3; - - /* Check whether the syscall is issued inside a restartable sequence */ - rseq_syscall(regs); - - ti_flags = current_thread_info()->flags; - - if (unlikely(r3 >= (unsigned long)-MAX_ERRNO) && is_not_scv) { - if (likely(!(ti_flags & (_TIF_NOERROR | _TIF_RESTOREALL)))) { - r3 = -r3; - regs->ccr |= 0x10000000; /* Set SO bit in CR */ - } - } - - if (unlikely(ti_flags & _TIF_PERSYSCALL_MASK)) { - if (ti_flags & _TIF_RESTOREALL) - ret = _TIF_RESTOREALL; - else - regs->gpr[3] = r3; - clear_bits(_TIF_PERSYSCALL_MASK, ¤t_thread_info()->flags); - } else { - regs->gpr[3] = r3; - } - - if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE)) { - do_syscall_trace_leave(regs); - ret |= _TIF_RESTOREALL; - } - local_irq_disable(); again: @@ -303,7 +262,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, ti_flags = READ_ONCE(current_thread_info()->flags); } - if (IS_ENABLED(CONFIG_PPC_BOOK3S) && IS_ENABLED(CONFIG_PPC_FPU)) { + if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && IS_ENABLED(CONFIG_PPC_FPU)) { if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && unlikely((ti_flags & _TIF_RESTORE_TM))) { restore_tm_state(regs); @@ -352,81 +311,63 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, return ret; } -notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned long msr) +/* + * This should be called after a syscall returns, with r3 the return value + * from the syscall. If this function returns non-zero, the system call + * exit assembly should additionally load all GPR registers and CTR and XER + * from the interrupt frame. + * + * The function graph tracer can not trace the return side of this function, + * because RI=0 and soft mask state is "unreconciled", so it is marked notrace. + */ +notrace unsigned long syscall_exit_prepare(unsigned long r3, + struct pt_regs *regs, + long scv) { unsigned long ti_flags; - unsigned long flags; unsigned long ret = 0; + bool is_not_scv = !IS_ENABLED(CONFIG_PPC_BOOK3S_64) || !scv; - if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x)) - BUG_ON(!(regs->msr & MSR_RI)); - BUG_ON(!(regs->msr & MSR_PR)); - BUG_ON(arch_irq_disabled_regs(regs)); - CT_WARN_ON(ct_state() == CONTEXT_USER); + regs->result = r3; - /* - * We don't need to restore AMR on the way back to userspace for KUAP. - * AMR can only have been unlocked if we interrupted the kernel. - */ - kuap_assert_locked(); + /* Check whether the syscall is issued inside a restartable sequence */ + rseq_syscall(regs); - local_irq_save(flags); + ti_flags = current_thread_info()->flags; -again: - ti_flags = READ_ONCE(current_thread_info()->flags); - while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) { - local_irq_enable(); /* returning to user: may enable */ - if (ti_flags & _TIF_NEED_RESCHED) { - schedule(); - } else { - if (ti_flags & _TIF_SIGPENDING) - ret |= _TIF_RESTOREALL; - do_notify_resume(regs, ti_flags); + if (unlikely(r3 >= (unsigned long)-MAX_ERRNO) && is_not_scv) { + if (likely(!(ti_flags & (_TIF_NOERROR | _TIF_RESTOREALL)))) { + r3 = -r3; + regs->ccr |= 0x10000000; /* Set SO bit in CR */ } - local_irq_disable(); - ti_flags = READ_ONCE(current_thread_info()->flags); } - if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && IS_ENABLED(CONFIG_PPC_FPU)) { - if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && - unlikely((ti_flags & _TIF_RESTORE_TM))) { - restore_tm_state(regs); - } else { - unsigned long 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; - - /* See above restore_math comment */ - if ((regs->msr & mathflags) != mathflags) - restore_math(regs); - } + if (unlikely(ti_flags & _TIF_PERSYSCALL_MASK)) { + if (ti_flags & _TIF_RESTOREALL) + ret = _TIF_RESTOREALL; + else + regs->gpr[3] = r3; + clear_bits(_TIF_PERSYSCALL_MASK, ¤t_thread_info()->flags); + } else { + regs->gpr[3] = r3; } - user_enter_irqoff(); - - if (unlikely(!__prep_irq_for_enabled_exit(true))) { - user_exit_irqoff(); - local_irq_enable(); - local_irq_disable(); - goto again; + if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE)) { + do_syscall_trace_leave(regs); + ret |= _TIF_RESTOREALL; } - booke_load_dbcr0(); - -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM - local_paca->tm_scratch = regs->msr; -#endif - - account_cpu_user_exit(); + return __interrupt_exit_user_prepare(regs, ret, is_not_scv); +} - /* Restore user access locks last */ - kuap_user_restore(regs); - kuep_unlock(); +notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned long msr) +{ + if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x)) + BUG_ON(!(regs->msr & MSR_RI)); + BUG_ON(!(regs->msr & MSR_PR)); + BUG_ON(arch_irq_disabled_regs(regs)); - return ret; + return __interrupt_exit_user_prepare(regs, 0, true); } void preempt_schedule_irq(void); -- 2.25.0