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https://github.com/edk2-porting/linux-next.git
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529d235a0e
We currently have a "special" syscall for switching endianness. This is syscall number 0x1ebe, which is handled explicitly in the 64-bit syscall exception entry. That has a few problems, firstly the syscall number is outside of the usual range, which confuses various tools. For example strace doesn't recognise the syscall at all. Secondly it's handled explicitly as a special case in the syscall exception entry, which is complicated enough without it. As a first step toward removing the special syscall, we need to add a regular syscall that implements the same functionality. The logic is simple, it simply toggles the MSR_LE bit in the userspace MSR. This is the same as the special syscall, with the caveat that the special syscall clobbers fewer registers. This version clobbers r9-r12, XER, CTR, and CR0-1,5-7. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
141 lines
3.8 KiB
C
141 lines
3.8 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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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 <asm/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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static inline unsigned 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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unsigned long ret = -EINVAL;
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if (!arch_validate_prot(prot))
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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 = sys_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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unsigned long sys_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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unsigned long sys_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 timeval __user *tvp)
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{
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if ( (unsigned long)n >= 4096 )
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{
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unsigned long __user *buffer = (unsigned long __user *)n;
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if (!access_ok(VERIFY_READ, buffer, 5*sizeof(unsigned long))
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|| __get_user(n, buffer)
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|| __get_user(inp, ((fd_set __user * __user *)(buffer+1)))
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|| __get_user(outp, ((fd_set __user * __user *)(buffer+2)))
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|| __get_user(exp, ((fd_set __user * __user *)(buffer+3)))
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|| __get_user(tvp, ((struct timeval __user * __user *)(buffer+4))))
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return -EFAULT;
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}
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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 sys_fadvise64(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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long sys_switch_endian(void)
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{
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struct thread_info *ti;
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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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