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-rw-r--r--arch/powerpc/kernel/syscall_64.c407
1 files changed, 407 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
new file mode 100644
index 000000000..310bcd768
--- /dev/null
+++ b/arch/powerpc/kernel/syscall_64.c
@@ -0,0 +1,407 @@
+// 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 = &current_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 = &current->thread;
+#endif
+ unsigned long *ti_flagsp = &current_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 = &current_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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