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- // SPDX-License-Identifier: GPL-2.0-or-later
- #include <linux/err.h>
- #include <asm/asm-prototypes.h>
- #include <asm/kup.h>
- #include <asm/cputime.h>
- #include <asm/hw_irq.h>
- #include <asm/kprobes.h>
- #include <asm/paca.h>
- #include <asm/ptrace.h>
- #include <asm/reg.h>
- #include <asm/signal.h>
- #include <asm/switch_to.h>
- #include <asm/syscall.h>
- #include <asm/time.h>
- #include <asm/unistd.h>
- typedef long (*syscall_fn)(long, long, long, long, long, long);
- /* Has to run notrace because it is entered not completely "reconciled" */
- notrace long system_call_exception(long r3, long r4, long r5,
- long r6, long r7, long r8,
- unsigned long r0, struct pt_regs *regs)
- {
- syscall_fn f;
- if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))
- BUG_ON(irq_soft_mask_return() != IRQS_ALL_DISABLED);
- trace_hardirqs_off(); /* finish reconciling */
- if (IS_ENABLED(CONFIG_PPC_BOOK3S))
- BUG_ON(!(regs->msr & MSR_RI));
- BUG_ON(!(regs->msr & MSR_PR));
- BUG_ON(!FULL_REGS(regs));
- BUG_ON(regs->softe != IRQS_ENABLED);
- kuap_check_amr();
- account_cpu_user_entry();
- #ifdef CONFIG_PPC_SPLPAR
- if (IS_ENABLED(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) &&
- firmware_has_feature(FW_FEATURE_SPLPAR)) {
- struct lppaca *lp = local_paca->lppaca_ptr;
- if (unlikely(local_paca->dtl_ridx != be64_to_cpu(lp->dtl_idx)))
- accumulate_stolen_time();
- }
- #endif
- /*
- * This is not required for the syscall exit path, but makes the
- * stack frame look nicer. If this was initialised in the first stack
- * frame, or if the unwinder was taught the first stack frame always
- * returns to user with IRQS_ENABLED, this store could be avoided!
- */
- regs->softe = IRQS_ENABLED;
- local_irq_enable();
- if (unlikely(current_thread_info()->flags & _TIF_SYSCALL_DOTRACE)) {
- if (unlikely(regs->trap == 0x7ff0)) {
- /* Unsupported scv vector */
- _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
- return regs->gpr[3];
- }
- /*
- * We use the return value of do_syscall_trace_enter() as the
- * syscall number. If the syscall was rejected for any reason
- * do_syscall_trace_enter() returns an invalid syscall number
- * and the test against NR_syscalls will fail and the return
- * value to be used is in regs->gpr[3].
- */
- r0 = do_syscall_trace_enter(regs);
- if (unlikely(r0 >= NR_syscalls))
- return regs->gpr[3];
- r3 = regs->gpr[3];
- r4 = regs->gpr[4];
- r5 = regs->gpr[5];
- r6 = regs->gpr[6];
- r7 = regs->gpr[7];
- r8 = regs->gpr[8];
- } else if (unlikely(r0 >= NR_syscalls)) {
- if (unlikely(regs->trap == 0x7ff0)) {
- /* Unsupported scv vector */
- _exception(SIGILL, regs, ILL_ILLOPC, regs->nip);
- return regs->gpr[3];
- }
- return -ENOSYS;
- }
- /* May be faster to do array_index_nospec? */
- barrier_nospec();
- if (unlikely(is_32bit_task())) {
- f = (void *)compat_sys_call_table[r0];
- r3 &= 0x00000000ffffffffULL;
- r4 &= 0x00000000ffffffffULL;
- r5 &= 0x00000000ffffffffULL;
- r6 &= 0x00000000ffffffffULL;
- r7 &= 0x00000000ffffffffULL;
- r8 &= 0x00000000ffffffffULL;
- } else {
- f = (void *)sys_call_table[r0];
- }
- return f(r3, r4, r5, r6, r7, r8);
- }
- /*
- * local irqs must be disabled. Returns false if the caller must re-enable
- * them, check for new work, and try again.
- */
- static notrace inline bool prep_irq_for_enabled_exit(bool clear_ri)
- {
- /* This must be done with RI=1 because tracing may touch vmaps */
- trace_hardirqs_on();
- /* This pattern matches prep_irq_for_idle */
- if (clear_ri)
- __hard_EE_RI_disable();
- else
- __hard_irq_disable();
- if (unlikely(lazy_irq_pending_nocheck())) {
- /* Took an interrupt, may have more exit work to do. */
- if (clear_ri)
- __hard_RI_enable();
- trace_hardirqs_off();
- local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
- return false;
- }
- local_paca->irq_happened = 0;
- irq_soft_mask_set(IRQS_ENABLED);
- return true;
- }
- /*
- * 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_flagsp = ¤t_thread_info()->flags;
- unsigned long ti_flags;
- unsigned long ret = 0;
- kuap_check_amr();
- regs->result = r3;
- /* Check whether the syscall is issued inside a restartable sequence */
- rseq_syscall(regs);
- ti_flags = *ti_flagsp;
- if (unlikely(r3 >= (unsigned long)-MAX_ERRNO) && !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, ti_flagsp);
- } else {
- regs->gpr[3] = r3;
- }
- if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE)) {
- do_syscall_trace_leave(regs);
- ret |= _TIF_RESTOREALL;
- }
- again:
- local_irq_disable();
- ti_flags = READ_ONCE(*ti_flagsp);
- while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
- local_irq_enable();
- if (ti_flags & _TIF_NEED_RESCHED) {
- schedule();
- } else {
- /*
- * SIGPENDING must restore signal handler function
- * argument GPRs, and some non-volatiles (e.g., r1).
- * Restore all for now. This could be made lighter.
- */
- if (ti_flags & _TIF_SIGPENDING)
- ret |= _TIF_RESTOREALL;
- do_notify_resume(regs, ti_flags);
- }
- local_irq_disable();
- ti_flags = READ_ONCE(*ti_flagsp);
- }
- if (IS_ENABLED(CONFIG_PPC_BOOK3S) && 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;
- /*
- * 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);
- }
- }
- /* scv need not set RI=0 because SRRs are not used */
- if (unlikely(!prep_irq_for_enabled_exit(!scv))) {
- local_irq_enable();
- goto again;
- }
- #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
- local_paca->tm_scratch = regs->msr;
- #endif
- account_cpu_user_exit();
- return ret;
- }
- #ifdef CONFIG_PPC_BOOK3S /* BOOK3E not yet using this */
- notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned long msr)
- {
- #ifdef CONFIG_PPC_BOOK3E
- struct thread_struct *ts = ¤t->thread;
- #endif
- unsigned long *ti_flagsp = ¤t_thread_info()->flags;
- unsigned long ti_flags;
- unsigned long flags;
- unsigned long ret = 0;
- if (IS_ENABLED(CONFIG_PPC_BOOK3S))
- BUG_ON(!(regs->msr & MSR_RI));
- BUG_ON(!(regs->msr & MSR_PR));
- BUG_ON(!FULL_REGS(regs));
- BUG_ON(regs->softe != IRQS_ENABLED);
- /*
- * 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_check_amr();
- local_irq_save(flags);
- again:
- ti_flags = READ_ONCE(*ti_flagsp);
- 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);
- }
- local_irq_disable();
- ti_flags = READ_ONCE(*ti_flagsp);
- }
- if (IS_ENABLED(CONFIG_PPC_BOOK3S) && 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(!prep_irq_for_enabled_exit(true))) {
- local_irq_enable();
- local_irq_disable();
- goto again;
- }
- #ifdef CONFIG_PPC_BOOK3E
- if (unlikely(ts->debug.dbcr0 & DBCR0_IDM)) {
- /*
- * Check to see if the dbcr0 register is set up to debug.
- * Use the internal debug mode bit to do this.
- */
- mtmsr(mfmsr() & ~MSR_DE);
- mtspr(SPRN_DBCR0, ts->debug.dbcr0);
- mtspr(SPRN_DBSR, -1);
- }
- #endif
- #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
- local_paca->tm_scratch = regs->msr;
- #endif
- account_cpu_user_exit();
- return ret;
- }
- void unrecoverable_exception(struct pt_regs *regs);
- void preempt_schedule_irq(void);
- notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsigned long msr)
- {
- unsigned long *ti_flagsp = ¤t_thread_info()->flags;
- unsigned long flags;
- unsigned long ret = 0;
- unsigned long amr;
- if (IS_ENABLED(CONFIG_PPC_BOOK3S) && unlikely(!(regs->msr & MSR_RI)))
- unrecoverable_exception(regs);
- BUG_ON(regs->msr & MSR_PR);
- BUG_ON(!FULL_REGS(regs));
- amr = kuap_get_and_check_amr();
- if (unlikely(*ti_flagsp & _TIF_EMULATE_STACK_STORE)) {
- clear_bits(_TIF_EMULATE_STACK_STORE, ti_flagsp);
- ret = 1;
- }
- local_irq_save(flags);
- if (regs->softe == IRQS_ENABLED) {
- /* Returning to a kernel context with local irqs enabled. */
- WARN_ON_ONCE(!(regs->msr & MSR_EE));
- again:
- if (IS_ENABLED(CONFIG_PREEMPT)) {
- /* Return to preemptible kernel context */
- if (unlikely(*ti_flagsp & _TIF_NEED_RESCHED)) {
- if (preempt_count() == 0)
- preempt_schedule_irq();
- }
- }
- if (unlikely(!prep_irq_for_enabled_exit(true))) {
- /*
- * Can't local_irq_restore to replay if we were in
- * interrupt context. Must replay directly.
- */
- if (irqs_disabled_flags(flags)) {
- replay_soft_interrupts();
- } else {
- local_irq_restore(flags);
- local_irq_save(flags);
- }
- /* Took an interrupt, may have more exit work to do. */
- goto again;
- }
- } else {
- /* Returning to a kernel context with local irqs disabled. */
- __hard_EE_RI_disable();
- if (regs->msr & MSR_EE)
- local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS;
- }
- #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
- local_paca->tm_scratch = regs->msr;
- #endif
- /*
- * Don't want to mfspr(SPRN_AMR) here, because this comes after mtmsr,
- * which would cause Read-After-Write stalls. Hence, we take the AMR
- * value from the check above.
- */
- kuap_restore_amr(regs, amr);
- return ret;
- }
- #endif
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