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59dc5bfca0
When an interrupt is taken, the SRR registers are set to return to where it left off. Unless they are modified in the meantime, or the return address or MSR are modified, there is no need to reload these registers when returning from interrupt. Introduce per-CPU flags that track the validity of SRR and HSRR registers. These are cleared when returning from interrupt, when using the registers for something else (e.g., OPAL calls), when adjusting the return address or MSR of a context, and when context switching (which changes the return address and MSR). This improves the performance of interrupt returns. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> [mpe: Fold in fixup patch from Nick] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210617155116.2167984-5-npiggin@gmail.com
129 lines
3.3 KiB
C
129 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Implementation of various system calls for Linux/PowerPC
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*
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Derived from "arch/i386/kernel/sys_i386.c"
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* Adapted from the i386 version by Gary Thomas
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* Modified by Cort Dougan (cort@cs.nmt.edu)
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* and Paul Mackerras (paulus@cs.anu.edu.au).
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*
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* This file contains various random system calls that
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* have a non-standard calling sequence on the Linux/PPC
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* platform.
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*/
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/syscalls.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/smp.h>
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#include <linux/sem.h>
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#include <linux/msg.h>
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#include <linux/shm.h>
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#include <linux/stat.h>
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#include <linux/mman.h>
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#include <linux/sys.h>
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#include <linux/ipc.h>
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#include <linux/utsname.h>
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#include <linux/file.h>
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#include <linux/personality.h>
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#include <linux/uaccess.h>
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#include <asm/syscalls.h>
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#include <asm/time.h>
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#include <asm/unistd.h>
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#include <asm/asm-prototypes.h>
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static inline long do_mmap2(unsigned long addr, size_t len,
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unsigned long prot, unsigned long flags,
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unsigned long fd, unsigned long off, int shift)
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{
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long ret = -EINVAL;
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if (!arch_validate_prot(prot, addr))
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goto out;
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if (shift) {
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if (off & ((1 << shift) - 1))
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goto out;
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off >>= shift;
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}
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ret = ksys_mmap_pgoff(addr, len, prot, flags, fd, off);
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out:
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return ret;
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}
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SYSCALL_DEFINE6(mmap2, unsigned long, addr, size_t, len,
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unsigned long, prot, unsigned long, flags,
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unsigned long, fd, unsigned long, pgoff)
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{
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return do_mmap2(addr, len, prot, flags, fd, pgoff, PAGE_SHIFT-12);
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}
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SYSCALL_DEFINE6(mmap, unsigned long, addr, size_t, len,
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unsigned long, prot, unsigned long, flags,
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unsigned long, fd, off_t, offset)
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{
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return do_mmap2(addr, len, prot, flags, fd, offset, PAGE_SHIFT);
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}
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#ifdef CONFIG_PPC32
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/*
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* Due to some executables calling the wrong select we sometimes
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* get wrong args. This determines how the args are being passed
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* (a single ptr to them all args passed) then calls
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* sys_select() with the appropriate args. -- Cort
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*/
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int
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ppc_select(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, struct __kernel_old_timeval __user *tvp)
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{
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if ( (unsigned long)n >= 4096 )
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return sys_old_select((void __user *)n);
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return sys_select(n, inp, outp, exp, tvp);
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}
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#endif
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#ifdef CONFIG_PPC64
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long ppc64_personality(unsigned long personality)
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{
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long ret;
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if (personality(current->personality) == PER_LINUX32
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&& personality(personality) == PER_LINUX)
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personality = (personality & ~PER_MASK) | PER_LINUX32;
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ret = sys_personality(personality);
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if (personality(ret) == PER_LINUX32)
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ret = (ret & ~PER_MASK) | PER_LINUX;
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return ret;
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}
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#endif
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long ppc_fadvise64_64(int fd, int advice, u32 offset_high, u32 offset_low,
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u32 len_high, u32 len_low)
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{
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return ksys_fadvise64_64(fd, (u64)offset_high << 32 | offset_low,
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(u64)len_high << 32 | len_low, advice);
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}
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SYSCALL_DEFINE0(switch_endian)
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{
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struct thread_info *ti;
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regs_set_return_msr(current->thread.regs,
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current->thread.regs->msr ^ MSR_LE);
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/*
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* Set TIF_RESTOREALL so that r3 isn't clobbered on return to
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* userspace. That also has the effect of restoring the non-volatile
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* GPRs, so we saved them on the way in here.
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*/
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ti = current_thread_info();
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ti->flags |= _TIF_RESTOREALL;
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return 0;
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}
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