Lines Matching +full:execution +full:- +full:memory

10 x86-based platforms.
12 Virtual Memory
17 memory are identity mapped and thus giving the appearance of execution
23 is being placed in the memory, and its counterpart
29 On 32-bit x86, it is possible to have separate physical and virtual
31 but are still loaded in physical memory. However, during boot, code
34 After ``vm_enter``, code execution is done via virtual addresses
39 to the physical memory. Later in the boot process,
42 the identity mapping of physical memory. This unmapping must be done
44 restricted memory via physical addresses. Since the identity mapping
51 - Physical and virtual address spaces must be disjoint. This is
56   - If :kconfig:option:`CONFIG_X86_PAE` is enabled (``=y``), each address space
58     (Page Directory Pointer) covers 1GB of memory. For example:
60     - Assuming ``CONFIG_SRAM_OFFSET`` and ``CONFIG_KERNEL_VM_OFFSET``
63     - ``CONFIG_SRAM_BASE_ADDRESS == 0x00000000`` and
66     - ``CONFIG_SRAM_BASE_ADDRESS == 0x00000000`` and
69   - If :kconfig:option:`CONFIG_X86_PAE` is disabled (``=n``), each address space
71     (Page Directory) covers 4MB of memory.
73   - Both ``CONFIG_SRAM_BASE_ADDRESS`` and ``CONFIG_KERNEL_VM_BASE``
76 Specifying Additional Memory Mappings at Build Time
80 the necessary multi-level page tables for code execution and data access
83 memory mappings. This is useful for static mappings and/or device MMIO
88 .. code-block:: cmake
91        --map 0xA0000000,0x2000
92        --map 0x80000000,0x400000,LWUX,0xB0000000)
94 The argument ``--map`` takes the following value:
97 - ``<physical address>`` is the physical address of the mapping. (Required)
99 - ``<size>`` is the size of the region to be mapped. (Required)
101 - ``<flags>`` is the flag associated with the mapping: (Optional)
103   - ``L``: Large page at the page directory level.
105   - ``U``: Allow userspace access.
107   - ``W``: Read/write.
109   - ``X``: Allow execution.
111   - ``D``: Cache disabled.
113     - Default is small page (4KB), supervisor only, read only, and
114       execution disabled.
116 - ``<virtual address`` is the virtual address of the mapping. (Optional)
118 Note that specifying additional memory mappings requires larger storage
119 space for the pre-allocated page tables (both kernel and per-domain
121 specify how many more memory pages to be reserved for the page tables.