diff options
Diffstat (limited to 'arch/powerpc/kernel/syscall_64.c')
| -rw-r--r-- | arch/powerpc/kernel/syscall_64.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c new file mode 100644 index 000000000000..75be20fdb270 --- /dev/null +++ b/arch/powerpc/kernel/syscall_64.c @@ -0,0 +1,214 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <linux/err.h> +#include <asm/asm-prototypes.h> +#include <asm/book3s/64/kup-radix.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 "unreconciled" */ +notrace long system_call_exception(long r3, long r4, long r5, long r6, long r7, long r8, + unsigned long r0, struct pt_regs *regs) +{ + unsigned long ti_flags; + syscall_fn f; + + BUG_ON(!(regs->msr & MSR_PR)); + + 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 + + kuap_check_amr(); + + /* + * A syscall should always be called with interrupts enabled + * so we just unconditionally hard-enable here. When some kind + * of irq tracing is used, we additionally check that condition + * is correct + */ + if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG)) { + WARN_ON(irq_soft_mask_return() != IRQS_ENABLED); + WARN_ON(local_paca->irq_happened); + } + /* + * 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; + + __hard_irq_enable(); + + ti_flags = current_thread_info()->flags; + if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE)) { + /* + * 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)) { + return -ENOSYS; + } + + /* May be faster to do array_index_nospec? */ + barrier_nospec(); + + if (unlikely(ti_flags & _TIF_32BIT)) { + 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); +} + +/* + * 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) +{ + unsigned long *ti_flagsp = ¤t_thread_info()->flags; + unsigned long ti_flags; + unsigned long ret = 0; + + 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)) { + 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 ((regs->msr & mathflags) != mathflags) + restore_math(regs); + } + } + + /* This must be done with RI=1 because tracing may touch vmaps */ + trace_hardirqs_on(); + + /* This pattern matches prep_irq_for_idle */ + __hard_EE_RI_disable(); + if (unlikely(lazy_irq_pending())) { + __hard_RI_enable(); + trace_hardirqs_off(); + local_paca->irq_happened |= PACA_IRQ_HARD_DIS; + local_irq_enable(); + /* Took an interrupt which may have more exit work to do. */ + goto again; + } + local_paca->irq_happened = 0; + irq_soft_mask_set(IRQS_ENABLED); + +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM + local_paca->tm_scratch = regs->msr; +#endif + + kuap_check_amr(); + + account_cpu_user_exit(); + + return ret; +} |