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X86: Add a vsyscall page for 32 bit processes to use.

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This commit is contained in:
Gabe Black 2009-02-27 09:25:51 -08:00
parent c3d7d7ed0e
commit db3c51d3a0
2 changed files with 66 additions and 8 deletions
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60
src/arch/x86/process.cc
View file

@ -152,12 +152,32 @@ X86_64LiveProcess::X86_64LiveProcess(LiveProcessParams *params,
mmap_start = mmap_end = (Addr)0x2aaaaaaab000ULL;
}
void
I386LiveProcess::syscall(int64_t callnum, ThreadContext *tc)
{
Addr eip = tc->readPC();
if (eip >= vsyscallPage.base &&
eip < vsyscallPage.base + vsyscallPage.size) {
tc->setNextPC(vsyscallPage.base + vsyscallPage.vsysexitOffset);
}
X86LiveProcess::syscall(callnum, tc);
}
I386LiveProcess::I386LiveProcess(LiveProcessParams *params,
ObjectFile *objFile, SyscallDesc *_syscallDescs,
int _numSyscallDescs) :
X86LiveProcess(params, objFile, _syscallDescs, _numSyscallDescs)
{
stack_base = (Addr)0xffffe000ULL;
_gdtStart = 0x100000000;
_gdtSize = VMPageSize;
vsyscallPage.base = 0xffffe000ULL;
vsyscallPage.size = VMPageSize;
vsyscallPage.vsyscallOffset = 0x400;
vsyscallPage.vsysexitOffset = 0x410;
stack_base = vsyscallPage.base;
// Set pointer for next thread stack. Reserve 8M for main stack.
next_thread_stack_base = stack_base - (8 * 1024 * 1024);
@ -255,8 +275,6 @@ I386LiveProcess::startup()
* Set up a GDT for this process. The whole GDT wouldn't really be for
* this process, but the only parts we care about are.
*/
_gdtStart = stack_base;
_gdtSize = VMPageSize;
pTable->allocate(_gdtStart, _gdtSize);
uint64_t zero = 0;
assert(_gdtSize % sizeof(zero) == 0);
@ -265,6 +283,27 @@ I386LiveProcess::startup()
initVirtMem->write(gdtCurrent, zero);
}
// Set up the vsyscall page for this process.
pTable->allocate(vsyscallPage.base, vsyscallPage.size);
uint8_t vsyscallBlob[] = {
0x51, // push %ecx
0x52, // push %edp
0x55, // push %ebp
0x89, 0xe5, // mov %esp, %ebp
0x0f, 0x34 // sysenter
};
initVirtMem->writeBlob(vsyscallPage.base + vsyscallPage.vsyscallOffset,
vsyscallBlob, sizeof(vsyscallBlob));
uint8_t vsysexitBlob[] = {
0x5d, // pop %ebp
0x5a, // pop %edx
0x59, // pop %ecx
0xc3 // ret
};
initVirtMem->writeBlob(vsyscallPage.base + vsyscallPage.vsysexitOffset,
vsysexitBlob, sizeof(vsysexitBlob));
for (int i = 0; i < contextIds.size(); i++) {
ThreadContext * tc = system->getThreadContext(contextIds[i]);
@ -332,12 +371,13 @@ I386LiveProcess::startup()
template<class IntType>
void
X86LiveProcess::argsInit(int pageSize)
X86LiveProcess::argsInit(int pageSize,
std::vector<AuxVector<IntType> > extraAuxvs)
{
int intSize = sizeof(IntType);
typedef AuxVector<IntType> auxv_t;
std::vector<auxv_t> auxv;
std::vector<auxv_t> auxv = extraAuxvs;
string filename;
if(argv.size() < 1)
@ -608,13 +648,19 @@ X86LiveProcess::argsInit(int pageSize)
void
X86_64LiveProcess::argsInit(int intSize, int pageSize)
{
X86LiveProcess::argsInit<uint64_t>(pageSize);
std::vector<AuxVector<uint64_t> > extraAuxvs;
X86LiveProcess::argsInit<uint64_t>(pageSize, extraAuxvs);
}
void
I386LiveProcess::argsInit(int intSize, int pageSize)
{
X86LiveProcess::argsInit<uint32_t>(pageSize);
std::vector<AuxVector<uint32_t> > extraAuxvs;
//Tell the binary where the vsyscall part of the vsyscall page is.
extraAuxvs.push_back(AuxVector<uint32_t>(0x20,
vsyscallPage.base + vsyscallPage.vsyscallOffset));
extraAuxvs.push_back(AuxVector<uint32_t>(0x21, vsyscallPage.base));
X86LiveProcess::argsInit<uint32_t>(pageSize, extraAuxvs);
}
void

14
src/arch/x86/process.hh
View file

@ -80,7 +80,8 @@ namespace X86ISA
SyscallDesc *_syscallDescs, int _numSyscallDescs);
template<class IntType>
void argsInit(int pageSize);
void argsInit(int pageSize,
std::vector<AuxVector<IntType> > extraAuxvs);
public:
Addr gdtStart()
@ -114,10 +115,21 @@ namespace X86ISA
I386LiveProcess(LiveProcessParams *params, ObjectFile *objFile,
SyscallDesc *_syscallDescs, int _numSyscallDescs);
class VSyscallPage
{
public:
Addr base;
Addr size;
Addr vsyscallOffset;
Addr vsysexitOffset;
};
VSyscallPage vsyscallPage;
public:
void argsInit(int intSize, int pageSize);
void startup();
void syscall(int64_t callnum, ThreadContext *tc);
X86ISA::IntReg getSyscallArg(ThreadContext *tc, int i);
void setSyscallArg(ThreadContext *tc, int i, X86ISA::IntReg val);
};