syscalls.cc

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#include "arch/x86/linux/syscalls.hh"
 
#include "arch/x86/linux/linux.hh"
#include "arch/x86/process.hh"
#include "arch/x86/registers.hh"
#include "base/trace.hh"
#include "cpu/thread_context.hh"
#include "kern/linux/linux.hh"
#include "sim/process.hh"
#include "sim/syscall_desc.hh"
#include "sim/syscall_emul.hh"
 
namespace X86ISA
{
 
SyscallReturn
unameFunc(SyscallDesc *desc, ThreadContext *tc, VPtr<Linux::utsname> name)
{
    auto process = tc->getProcessPtr();
 
    strcpy(name->sysname, "Linux");
    strcpy(name->nodename, "sim.gem5.org");
    strcpy(name->release, process->release.c_str());
    strcpy(name->version, "#1 Mon Aug 18 11:32:15 EDT 2003");
    strcpy(name->machine, "x86_64");
 
    return 0;
}
 
SyscallReturn
archPrctlFunc(SyscallDesc *desc, ThreadContext *tc, int code, uint64_t addr)
{
    enum ArchPrctlCodes
    {
        SetFS = 0x1002,
        GetFS = 0x1003,
        SetGS = 0x1001,
        GetGS = 0x1004
    };
 
    uint64_t fsBase, gsBase;
    PortProxy &p = tc->getVirtProxy();
    switch(code)
    {
      // Each of these valid options should actually check addr.
      case SetFS:
        tc->setMiscRegNoEffect(MISCREG_FS_BASE, addr);
        tc->setMiscRegNoEffect(MISCREG_FS_EFF_BASE, addr);
        return 0;
      case GetFS:
        fsBase = tc->readMiscRegNoEffect(MISCREG_FS_BASE);
        p.write(addr, fsBase);
        return 0;
      case SetGS:
        tc->setMiscRegNoEffect(MISCREG_GS_BASE, addr);
        tc->setMiscRegNoEffect(MISCREG_GS_EFF_BASE, addr);
        return 0;
      case GetGS:
        gsBase = tc->readMiscRegNoEffect(MISCREG_GS_BASE);
        p.write(addr, gsBase);
        return 0;
      default:
        return -EINVAL;
    }
}
 
SyscallReturn
setThreadArea32Func(SyscallDesc *desc, ThreadContext *tc,
                    VPtr<UserDesc32> userDesc)
{
    const int minTLSEntry = 6;
    const int numTLSEntries = 3;
    const int maxTLSEntry = minTLSEntry + numTLSEntries - 1;
 
    auto process = tc->getProcessPtr();
 
    X86Process *x86p = dynamic_cast<X86Process *>(process);
    assert(x86p);
 
    assert((maxTLSEntry + 1) * sizeof(uint64_t) <= x86p->gdtSize());
 
    TypedBufferArg<uint64_t>
        gdt(x86p->gdtStart() + minTLSEntry * sizeof(uint64_t),
            numTLSEntries * sizeof(uint64_t));
 
    if (!gdt.copyIn(tc->getVirtProxy()))
        panic("Failed to copy in GDT for %s.\n", desc->name());
 
    if (userDesc->entry_number == (uint32_t)(-1)) {
        // Find a free TLS entry.
        for (int i = 0; i < numTLSEntries; i++) {
            if (gdt[i] == 0) {
                userDesc->entry_number = i + minTLSEntry;
                break;
            }
        }
        // We failed to find one.
        if (userDesc->entry_number == (uint32_t)(-1))
            return -ESRCH;
    }
 
    int index = userDesc->entry_number;
 
    if (index < minTLSEntry || index > maxTLSEntry)
        return -EINVAL;
 
    index -= minTLSEntry;
 
    // Build the entry we're going to add.
    SegDescriptor segDesc = 0;
    UserDescFlags flags = userDesc->flags;
 
    segDesc.limitLow = bits(userDesc->limit, 15, 0);
    segDesc.baseLow = bits(userDesc->base_addr, 23, 0);
    segDesc.type.a = 1;
    if (!flags.read_exec_only)
        segDesc.type.w = 1;
    if (bits((uint8_t)flags.contents, 0))
        segDesc.type.e = 1;
    if (bits((uint8_t)flags.contents, 1))
        segDesc.type.codeOrData = 1;
    segDesc.s = 1;
    segDesc.dpl = 3;
    if (!flags.seg_not_present)
        segDesc.p = 1;
    segDesc.limitHigh = bits(userDesc->limit, 19, 16);
    if (flags.useable)
        segDesc.avl = 1;
    segDesc.l = 0;
    if (flags.seg_32bit)
        segDesc.d = 1;
    if (flags.limit_in_pages)
        segDesc.g = 1;
    segDesc.baseHigh = bits(userDesc->base_addr, 31, 24);
 
    gdt[index] = (uint64_t)segDesc;
 
    if (!gdt.copyOut(tc->getVirtProxy()))
        panic("Failed to copy out GDT for %s.\n", desc->name());
 
    return 0;
}
 
} // namespace X86ISA