C++ (Cpp) mmap_reserve Examples

Example #1

File: mmap.c Project: mickael-guene/qemu

int target_munmap(abi_ulong start, abi_ulong len)
{
    abi_ulong end, real_start, real_end, addr;
    int prot, ret;

#ifdef DEBUG_MMAP
    printf("munmap: start=0x" TARGET_ABI_FMT_lx " len=0x"
           TARGET_ABI_FMT_lx "\n",
           start, len);
#endif
    if (start & ~TARGET_PAGE_MASK)
        return -EINVAL;
    len = TARGET_PAGE_ALIGN(len);
    if (len == 0)
        return -EINVAL;
    mmap_lock();
    end = start + len;
    real_start = start & qemu_host_page_mask;
    real_end = HOST_PAGE_ALIGN(end);

    if (start > real_start) {
        /* handle host page containing start */
        prot = 0;
        for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
            prot |= page_get_flags(addr);
        }
        if (real_end == real_start + qemu_host_page_size) {
            for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
                prot |= page_get_flags(addr);
            }
            end = real_end;
        }
        if (prot != 0)
            real_start += qemu_host_page_size;
    }
    if (end < real_end) {
        prot = 0;
        for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
            prot |= page_get_flags(addr);
        }
        if (prot != 0)
            real_end -= qemu_host_page_size;
    }

    ret = 0;
    /* unmap what we can */
    if (real_start < real_end) {
        if (RESERVED_VA) {
            mmap_reserve(real_start, real_end - real_start);
        } else {
            ret = munmap(g2h(real_start), real_end - real_start);
        }
    }

    if (ret == 0)
        page_set_flags(start, start + len, 0);
    mmap_unlock();
    return ret;
}

Example #2

File: mmap.c Project: LingxiaoJIA/qemu

abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
                       abi_ulong new_size, unsigned long flags,
                       abi_ulong new_addr)
{
    int prot;
    void *host_addr;

    mmap_lock();

    if (flags & MREMAP_FIXED) {
        host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
                                     old_size, new_size,
                                     flags,
                                     g2h(new_addr));

        if (RESERVED_VA && host_addr != MAP_FAILED) {
            /* If new and old addresses overlap then the above mremap will
               already have failed with EINVAL.  */
            mmap_reserve(old_addr, old_size);
        }
    } else if (flags & MREMAP_MAYMOVE) {
        abi_ulong mmap_start;

        mmap_start = mmap_find_vma(0, new_size);

        if (mmap_start == -1) {
            errno = ENOMEM;
            host_addr = MAP_FAILED;
        } else {
            host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
                                         old_size, new_size,
                                         flags | MREMAP_FIXED,
                                         g2h(mmap_start));
            if ( RESERVED_VA ) {
                mmap_reserve(old_addr, old_size);
            }
        }
    } else {
        int prot = 0;
        if (RESERVED_VA && old_size < new_size) {
            abi_ulong addr;
            for (addr = old_addr + old_size;
                 addr < old_addr + new_size;
                 addr++) {
                prot |= page_get_flags(addr);
            }
        }
        if (prot == 0) {
            host_addr = mremap(g2h(old_addr), old_size, new_size, flags);
            if (host_addr != MAP_FAILED && RESERVED_VA && old_size > new_size) {
                mmap_reserve(old_addr + old_size, new_size - old_size);
            }
        } else {
            errno = ENOMEM;
            host_addr = MAP_FAILED;
        }
        /* Check if address fits target address space */
        if ((unsigned long)host_addr + new_size > (abi_ulong)-1) {
            /* Revert mremap() changes */
            host_addr = mremap(g2h(old_addr), new_size, old_size, flags);
            errno = ENOMEM;
            host_addr = MAP_FAILED;
        }
    }

    if (host_addr == MAP_FAILED) {
        new_addr = -1;
    } else {
        new_addr = h2g(host_addr);
        prot = page_get_flags(old_addr);
        page_set_flags(old_addr, old_addr + old_size, 0);
        page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
    }
    tb_invalidate_phys_range(new_addr, new_addr + new_size);
    mmap_unlock();
    return new_addr;
}