path: root/src/emu/x64tls.c

// Handling of TLS calls, include x86 specifi set_thread_area
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

#include "os.h"
#include "debug.h"
#include "box64context.h"
#include "x64emu.h"
#include "x64emu_private.h"
#include "x64tls.h"
#include "elfloader.h"
#ifdef BOX32
#include "box32.h"
#endif

typedef struct thread_area_s
{
             int  entry_number;
        uint64_t  base_addr;
    unsigned int  limit;
    unsigned int  seg_32bit:1;
    unsigned int  contents:2;
    unsigned int  read_exec_only:1;
    unsigned int  limit_in_pages:1;
    unsigned int  seg_not_present:1;
    unsigned int  useable:1;
    unsigned int  lm:1;
} thread_area_t;
typedef struct thread_area_32_s
{
             int  entry_number;
        uint32_t  base_addr;
    unsigned int  limit;
    unsigned int  seg_32bit:1;
    unsigned int  contents:2;
    unsigned int  read_exec_only:1;
    unsigned int  limit_in_pages:1;
    unsigned int  seg_not_present:1;
    unsigned int  useable:1;
} thread_area_32_t;

int GetTID();

uint32_t my_set_thread_area_32(x64emu_t* emu, thread_area_32_t* td)
{
    printf_log(LOG_DEBUG, "%04d| set_thread_area_32(%p[%d/base=%p/limit=%u/32bits:%u/%u/%u...])\n", GetTID(), td, td->entry_number, (void*)(uintptr_t)td->base_addr, td->limit_in_pages, td->seg_32bit, td->contents, td->read_exec_only);

    int isempty = 0;
    // first, check if the "user_desc", here td, is "empty"
    if(td->read_exec_only==1 && td->seg_not_present==1)
        if( !td->base_addr 
         && !td->limit
         && !td->seg_32bit 
         && !td->contents 
         && !td->limit_in_pages 
         && !td->useable)
            isempty = 1;
    int idx = td->entry_number;
    if(idx==-1) {
        // find a free one
        for (int i=9; i<15 && idx==-1; ++i)
            if(!my_context->seggdt[i].present)
                idx=i;
        if(idx==-1) {
            errno = ESRCH;
            return (uint32_t)-1;
        }
        td->entry_number = idx;
    }
    if(isempty && (td->entry_number<9 || td->entry_number>15)) {
        errno = EINVAL;
        return (uint32_t)-1;
    }
    if(isempty) {
        memset(&my_context->seggdt[td->entry_number], 0, sizeof(base_segment_t));
        return 0;
    }
    if((idx<9 || idx>15)) {
        errno = EINVAL;
        return (uint32_t)-1;
    }

    my_context->seggdt[idx].base = td->base_addr;
    my_context->seggdt[idx].limit = td->limit;
    my_context->seggdt[idx].present = 1;
    my_context->seggdt[idx].is32bits = 1;
    if(idx>5) {
        emu->seggdt[idx].base = td->base_addr;
        emu->seggdt[idx].limit = td->limit;
        emu->seggdt[idx].present = 1;
        emu->seggdt[idx].is32bits = 1;
    }

    ResetSegmentsCache(emu);

    return 0;
}

uint32_t my_modify_ldt(x64emu_t* emu, int op, thread_area_t* td, int size)
{
    printf_log(LOG_DEBUG, "%04d| modify_ldt(0x%x, %p[0x%x/base=%p/limit=%u/32bits:%u/%u/%u...], %d)\n", GetTID(), op, td, td->entry_number, (void*)td->base_addr, td->limit_in_pages, td->seg_32bit, td->contents, td->read_exec_only, size);
    if(!td) {
        errno = EFAULT;
        return (uint32_t)-1;
    }
    if(op!=0x11) {
        errno = ENOSYS;
        return (uint32_t)-1;
    }
    if(!td->seg_32bit) {
        // not handling 16bits segments for now
        errno = EINVAL;
        return (uint32_t)-1;
    }

    int idx = td->entry_number;
    if(idx<9 || idx>15) {
        errno = EINVAL;
        return (uint32_t)-1;
    }

    if(box64_is32bits) {
        emu->segs_serial[_GS] = 0;
        emu->segldt[idx].base = td->base_addr;
        emu->segldt[idx].limit = td->limit;
        emu->segldt[idx].present = 1;
    }

    ResetSegmentsCache(emu);

    return 0;
}

static const char* arch_prctl_param(int code)
{
    static char ret[10] = {0};
    switch (code) {
        case 0x1001: return "ARCH_SET_GS";
        case 0x1002: return "ARCH_SET_FS";
        case 0x1003: return "ARCH_GET_FS";
        case 0x1004: return "ARCH_GET_GS";
    }
    sprintf(ret, "0x%x", code);
    return ret;
}
int my_arch_prctl(x64emu_t *emu, int code, void* addr)
{
    printf_log(LOG_DEBUG, "%04d| arch_prctl(%s, %p) (RSP=%p, FS=0x%x, GS=0x%x)\n", GetTID(), arch_prctl_param(code), addr,(void*)R_RSP, emu->segs[_FS], emu->segs[_GS]);

    #define ARCH_SET_GS                 0x1001
    #define ARCH_SET_FS                 0x1002
    #define ARCH_GET_FS                 0x1003
    #define ARCH_GET_GS                 0x1004
    #define ARCH_GET_CPUID              0x1011
    #define ARCH_SET_CPUID              0x1012
    #define ARCH_GET_XCOMP_SUPP         0x1021
    #define ARCH_GET_XCOMP_PERM         0x1022
    #define ARCH_REQ_XCOMP_PERM         0x1023
    #define ARCH_GET_XCOMP_GUEST_PERM   0x1024
    #define ARCH_REQ_XCOMP_GUEST_PERM   0x1025
    int seg = 0;
    int idx = 0;
    errno = 0;
    switch(code) {
        case ARCH_GET_GS:
            *(void**)addr = GetSegmentBase(emu, emu->segs[_GS]);
            return 0;
        case ARCH_GET_FS:
            *(void**)addr = GetSegmentBase(emu, emu->segs[_FS]);
            return 0;
        case ARCH_SET_FS:
        case ARCH_SET_GS:
            seg=(code==ARCH_SET_FS)?_FS:_GS;
            int idx = -1;
            // search if it's a TLS base
            if(GetSeg43Base(emu)==addr)
                idx = 0x43>>3;
            // Is this search only occurs when seg==0?
            for (int i=9; i<15 && idx==-1; ++i)
                if(my_context->seggdt[i].present && my_context->seggdt[i].base==(uintptr_t)addr)
                    idx=i;
            // found...
            if(idx!=-1) {
               printf_log(LOG_DEBUG, "Changing segment selector from 0x%x to 0x%x\n", emu->segs[seg], (idx<<3) +3);
               emu->segs[seg]=(idx<<3) +3;
            }
            if(emu->segs[seg]==0) {
                printf_log(LOG_DEBUG, "Warning, set seg, but it's 0!\n");
                errno = EINVAL;
                return -1;
            }
            idx = emu->segs[seg] >> 3;
            if(idx<0 || idx>15) {
                errno = EINVAL;
                return -1;
            }
            emu->segs_serial[seg] = 0;
            my_context->seggdt[idx].base = (uintptr_t)addr;
            my_context->seggdt[idx].limit = 0;
            my_context->seggdt[idx].present = 1;
            if(idx>5) {
                emu->seggdt[idx].base = (uintptr_t)addr;
                emu->seggdt[idx].limit = 0;
                emu->seggdt[idx].present = 1;
            }
            ResetSegmentsCache(emu);
            return 0;
        case ARCH_GET_XCOMP_SUPP:
        case ARCH_GET_XCOMP_PERM:
        case ARCH_REQ_XCOMP_PERM:
            // unsupported, this is for AVX512...
            errno = ENOSYS;
            return -1;
    }
    // other are unsupported
    printf_log(LOG_INFO, "warning, call to unsupported arch_prctl(0x%x, %p)\n", code, addr);
    errno = ENOSYS;
    return -1;
}


#define POS_TLS     0x200
#define POS_TLS_32  0x50
/*
 tls record should looks like:
 void*      tcb             0x00
 void*      dts             0x08
 void*      self            0x10
 int        multiple        0x18
 int        gscope          0x1c
 void*      sysinfo         0x20
 uintptr_t  stack_guard     0x28
 uitnptr_t  pointer_guard   0x30
 uint64_t   vgetcpu[2]      0x38
 uint32_t   features        0x48
 int        unused          0x4c
 void*      private[4]      0x50
 void*      private_ss      0x70
 uintptr_t  ssp_base        0x78
 .... padding ....          0x200?
*/
#define NELFSIZE_MASK 0x3FF
#define NELFSIZE (NELFSIZE_MASK+1)
static int sizeDTS(box64context_t* context)
{
    return ((context->elfsize+NELFSIZE_MASK)&~NELFSIZE_MASK)*16;
}
static int sizeTLSData(int s)
{
    uint32_t mask = 0xffff/*BOX64ENV(nogtk)?0xffff:0x1fff*/;    // x86_64 does the mapping per 64K blocks, so it makes sense to have it this large
    return (s+mask)&~mask;
}

static tlsdatasize_t* setupTLSData(box64context_t* context)
{
    // Setup the GS segment:
    int dtssize = sizeDTS(context);
    int datasize = sizeTLSData(context->tlssize);
    void *ptr_oversized = (char*)actual_malloc(dtssize+(box64_is32bits?POS_TLS_32:POS_TLS)+datasize);
    void *ptr = (void*)((uintptr_t)ptr_oversized + datasize);
    memcpy((void*)((uintptr_t)ptr-context->tlssize), context->tlsdata, context->tlssize);
    tlsdatasize_t *data = (tlsdatasize_t*)actual_calloc(1, sizeof(tlsdatasize_t));
    data->data = ptr;
    data->tlssize = context->tlssize;
    data->ptr = ptr_oversized;
    data->n_elfs = context->elfsize;
    #ifdef BOX32
    if(box64_is32bits) {
        // copy canary...
        memset((void*)((uintptr_t)ptr), 0, POS_TLS_32+dtssize);        // set to 0 remining bytes
        memcpy((void*)((uintptr_t)ptr+0x14), context->canary, 4);      // put canary in place
        ptr_t tlsptr = to_ptrv(ptr);
        memcpy((void*)((uintptr_t)ptr+0x0), &tlsptr, 4);
        ptr_t dtp = to_ptrv(ptr+POS_TLS_32);
        memcpy(from_ptrv(tlsptr+0x4), &dtp, 4);
        if(dtssize) {
            for (int i=0; i<context->elfsize; ++i) {
                // set pointer
                dtp = to_ptrv(ptr + GetTLSBase(context->elfs[i]));
                memcpy((void*)((uintptr_t)ptr+POS_TLS_32+i*8), &dtp, 4);
                memcpy((void*)((uintptr_t)ptr+POS_TLS_32+i*8+4), &i, 4); // index
            }
        }
        memcpy((void*)((uintptr_t)ptr+0x10), &context->vsyscall, 4);  // address of vsyscall
    } else
    #endif
    {
        // copy canary...
        memset((void*)((uintptr_t)ptr), 0, POS_TLS+dtssize);            // set to 0 remining bytes
        memcpy((void*)((uintptr_t)ptr+0x28), context->canary, sizeof(void*));      // put canary in place
        uintptr_t tlsptr = (uintptr_t)ptr;
        memcpy((void*)((uintptr_t)ptr+0x0), &tlsptr, sizeof(void*));
        memcpy((void*)((uintptr_t)ptr+0x10), &tlsptr, sizeof(void*));  // set tcb and self same address
        uintptr_t dtp = (uintptr_t)ptr+POS_TLS;
        memcpy((void*)(tlsptr+sizeof(void*)), &dtp, sizeof(void*));
        if(dtssize) {
            for (int i=0; i<context->elfsize; ++i) {
                // set pointer
                dtp = (uintptr_t)ptr + GetTLSBase(context->elfs[i]);
                *(uint64_t*)((uintptr_t)ptr+POS_TLS+i*16) = dtp;
                *(uint64_t*)((uintptr_t)ptr+POS_TLS+i*16+8) = i; // index
            }
        }
        memcpy((void*)((uintptr_t)ptr+0x20), &context->vsyscall, sizeof(void*));  // address of vsyscall
    }
    return data;
}

static void* fillTLSData(box64context_t *context)
{
        mutex_lock(&context->mutex_tls);
        tlsdatasize_t *data = setupTLSData(context);
        mutex_unlock(&context->mutex_tls);
        return data;
}

static void* resizeTLSData(box64context_t *context, void* oldptr)
{
        mutex_lock(&context->mutex_tls);
        tlsdatasize_t* oldata = (tlsdatasize_t*)oldptr;
        if(sizeTLSData(oldata->tlssize)!=sizeTLSData(context->tlssize) || (oldata->n_elfs/NELFSIZE)!=(context->elfsize/NELFSIZE)) {
            if(sizeTLSData(oldata->tlssize)) {
                printf_log(LOG_INFO, "Warning, resizing of TLS occurred! size: %d->%d / n_elfs: %d->%d\n", sizeTLSData(oldata->tlssize), sizeTLSData(context->tlssize), 1+(oldata->n_elfs/NELFSIZE), 1+(context->elfsize/NELFSIZE));
            }
            tlsdatasize_t *data = setupTLSData(context);
            // copy the relevent old part, in case something changed
            memcpy((void*)((uintptr_t)data->data-oldata->tlssize), (void*)((uintptr_t)oldata->data-oldata->tlssize), oldata->tlssize);
            // all done, update new size, free old pointer and exit
            mutex_unlock(&context->mutex_tls);
            free_tlsdatasize(oldptr);
            return data;
        } else {
            // keep the same tlsdata, but fill in the blanks
            // adjust tlsdata
            void *ptr = oldata->data;
            if(context->tlssize!=oldata->tlssize) {
                memcpy((void*)((uintptr_t)ptr-context->tlssize), context->tlsdata, context->tlssize-oldata->tlssize);
                oldata->tlssize = context->tlssize;
            }
            // adjust DTS
            if(oldata->n_elfs!=context->elfsize) {
                uintptr_t dtp = (uintptr_t)ptr+POS_TLS;
                for (int i=oldata->n_elfs; i<context->elfsize; ++i) {
                    // set pointer
                    dtp = (uintptr_t)ptr + GetTLSBase(context->elfs[i]);
                    *(uint64_t*)((uintptr_t)ptr+POS_TLS+i*16) = dtp;
                    *(uint64_t*)((uintptr_t)ptr+POS_TLS+i*16+8) = i; // index
                }
                oldata->n_elfs = context->elfsize;
            }
            mutex_unlock(&context->mutex_tls);
            return oldata;
        }
}

tlsdatasize_t* getTLSData(x64emu_t* emu)
{
    tlsdatasize_t* ptr = NULL;
    if(!ptr)
        if ((ptr = emu->tlsdata) == NULL) {
            ptr = (tlsdatasize_t*)fillTLSData(emu->context);
        }
    if(ptr->tlssize != emu->context->tlssize)
        ptr = (tlsdatasize_t*)resizeTLSData(emu->context, ptr);
    emu->tlsdata = ptr;
    return ptr;
}