zephyr/include/linker/kobject-text.ld

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/* SPDX-License-Identifier: Apache-2.0 */
kernel: introduce object validation mechanism All system calls made from userspace which involve pointers to kernel objects (including device drivers) will need to have those pointers validated; userspace should never be able to crash the kernel by passing it garbage. The actual validation with _k_object_validate() will be in the system call receiver code, which doesn't exist yet. - CONFIG_USERSPACE introduced. We are somewhat far away from having an end-to-end implementation, but at least need a Kconfig symbol to guard the incoming code with. Formal documentation doesn't exist yet either, but will appear later down the road once the implementation is mostly finalized. - In the memory region for RAM, the data section has been moved last, past bss and noinit. This ensures that inserting generated tables with addresses of kernel objects does not change the addresses of those objects (which would make the table invalid) - The DWARF debug information in the generated ELF binary is parsed to fetch the locations of all kernel objects and pass this to gperf to create a perfect hash table of their memory addresses. - The generated gperf code doesn't know that we are exclusively working with memory addresses and uses memory inefficently. A post-processing script process_gperf.py adjusts the generated code before it is compiled to work with pointer values directly and not strings containing them. - _k_object_init() calls inserted into the init functions for the set of kernel object types we are going to support so far Issue: ZEP-2187 Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2017-08-23 04:15:23 +08:00
#ifdef CONFIG_USERSPACE
/* We need to reserve room for the gperf generated hash functions.
* Fortunately, unlike the data tables, the size of the code is
* reasonably predictable.
kernel: introduce object validation mechanism All system calls made from userspace which involve pointers to kernel objects (including device drivers) will need to have those pointers validated; userspace should never be able to crash the kernel by passing it garbage. The actual validation with _k_object_validate() will be in the system call receiver code, which doesn't exist yet. - CONFIG_USERSPACE introduced. We are somewhat far away from having an end-to-end implementation, but at least need a Kconfig symbol to guard the incoming code with. Formal documentation doesn't exist yet either, but will appear later down the road once the implementation is mostly finalized. - In the memory region for RAM, the data section has been moved last, past bss and noinit. This ensures that inserting generated tables with addresses of kernel objects does not change the addresses of those objects (which would make the table invalid) - The DWARF debug information in the generated ELF binary is parsed to fetch the locations of all kernel objects and pass this to gperf to create a perfect hash table of their memory addresses. - The generated gperf code doesn't know that we are exclusively working with memory addresses and uses memory inefficently. A post-processing script process_gperf.py adjusts the generated code before it is compiled to work with pointer values directly and not strings containing them. - _k_object_init() calls inserted into the init functions for the set of kernel object types we are going to support so far Issue: ZEP-2187 Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2017-08-23 04:15:23 +08:00
*
* The linker will error out complaining that the location pointer
* is moving backwards if the reserved room isn't large enough.
*/
_kobject_text_area_start = .;
*(".kobject_data.text*")
_kobject_text_area_end = .;
_kobject_text_area_used = _kobject_text_area_end - _kobject_text_area_start;
kernel: introduce object validation mechanism All system calls made from userspace which involve pointers to kernel objects (including device drivers) will need to have those pointers validated; userspace should never be able to crash the kernel by passing it garbage. The actual validation with _k_object_validate() will be in the system call receiver code, which doesn't exist yet. - CONFIG_USERSPACE introduced. We are somewhat far away from having an end-to-end implementation, but at least need a Kconfig symbol to guard the incoming code with. Formal documentation doesn't exist yet either, but will appear later down the road once the implementation is mostly finalized. - In the memory region for RAM, the data section has been moved last, past bss and noinit. This ensures that inserting generated tables with addresses of kernel objects does not change the addresses of those objects (which would make the table invalid) - The DWARF debug information in the generated ELF binary is parsed to fetch the locations of all kernel objects and pass this to gperf to create a perfect hash table of their memory addresses. - The generated gperf code doesn't know that we are exclusively working with memory addresses and uses memory inefficently. A post-processing script process_gperf.py adjusts the generated code before it is compiled to work with pointer values directly and not strings containing them. - _k_object_init() calls inserted into the init functions for the set of kernel object types we are going to support so far Issue: ZEP-2187 Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2017-08-23 04:15:23 +08:00
#ifndef LINKER_PASS2
#ifdef CONFIG_DYNAMIC_OBJECTS
PROVIDE(z_object_gperf_find = .);
PROVIDE(z_object_gperf_wordlist_foreach = .);
#else
PROVIDE(z_object_find = .);
PROVIDE(z_object_wordlist_foreach = .);
#endif
kernel: introduce object validation mechanism All system calls made from userspace which involve pointers to kernel objects (including device drivers) will need to have those pointers validated; userspace should never be able to crash the kernel by passing it garbage. The actual validation with _k_object_validate() will be in the system call receiver code, which doesn't exist yet. - CONFIG_USERSPACE introduced. We are somewhat far away from having an end-to-end implementation, but at least need a Kconfig symbol to guard the incoming code with. Formal documentation doesn't exist yet either, but will appear later down the road once the implementation is mostly finalized. - In the memory region for RAM, the data section has been moved last, past bss and noinit. This ensures that inserting generated tables with addresses of kernel objects does not change the addresses of those objects (which would make the table invalid) - The DWARF debug information in the generated ELF binary is parsed to fetch the locations of all kernel objects and pass this to gperf to create a perfect hash table of their memory addresses. - The generated gperf code doesn't know that we are exclusively working with memory addresses and uses memory inefficently. A post-processing script process_gperf.py adjusts the generated code before it is compiled to work with pointer values directly and not strings containing them. - _k_object_init() calls inserted into the init functions for the set of kernel object types we are going to support so far Issue: ZEP-2187 Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2017-08-23 04:15:23 +08:00
#endif
/* In a valid build the MAX function will always evaluate to the
second argument below, but to give the user a good error message
when the area overflows we need to temporarily corrupt the
location counter, and then detect the overflow with an assertion
later on. */
. = MAX(., _kobject_text_area_start + CONFIG_KOBJECT_TEXT_AREA);
ASSERT(
CONFIG_KOBJECT_TEXT_AREA >= _kobject_text_area_used,
"The configuration system has incorrectly set
'CONFIG_KOBJECT_TEXT_AREA' to
CONFIG_KOBJECT_TEXT_AREA, which is not big enough. You must
through Kconfig either disable 'CONFIG_USERSPACE', or set
'CONFIG_KOBJECT_TEXT_AREA' to a value larger than
CONFIG_KOBJECT_TEXT_AREA."
);
kernel: introduce object validation mechanism All system calls made from userspace which involve pointers to kernel objects (including device drivers) will need to have those pointers validated; userspace should never be able to crash the kernel by passing it garbage. The actual validation with _k_object_validate() will be in the system call receiver code, which doesn't exist yet. - CONFIG_USERSPACE introduced. We are somewhat far away from having an end-to-end implementation, but at least need a Kconfig symbol to guard the incoming code with. Formal documentation doesn't exist yet either, but will appear later down the road once the implementation is mostly finalized. - In the memory region for RAM, the data section has been moved last, past bss and noinit. This ensures that inserting generated tables with addresses of kernel objects does not change the addresses of those objects (which would make the table invalid) - The DWARF debug information in the generated ELF binary is parsed to fetch the locations of all kernel objects and pass this to gperf to create a perfect hash table of their memory addresses. - The generated gperf code doesn't know that we are exclusively working with memory addresses and uses memory inefficently. A post-processing script process_gperf.py adjusts the generated code before it is compiled to work with pointer values directly and not strings containing them. - _k_object_init() calls inserted into the init functions for the set of kernel object types we are going to support so far Issue: ZEP-2187 Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2017-08-23 04:15:23 +08:00
#endif /* CONFIG_USERSPACE */