945af95f42
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>
57 lines
1.9 KiB
Text
57 lines
1.9 KiB
Text
GEN_KOBJ_LIST := $(srctree)/scripts/gen_kobject_list.py
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PROCESS_GPERF := $(srctree)/scripts/process_gperf.py
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OBJ_LIST := kobject_hash.gperf
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OUTPUT_SRC_PRE := kobject_hash_preprocessed.c
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OUTPUT_SRC := kobject_hash.c
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OUTPUT_OBJ := kobject_hash.o
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OUTPUT_OBJ_RENAMED := kobject_hash_renamed.o
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SCRIPT_EXTRA_ARGS :=
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ifeq ($(KBUILD_VERBOSE),1)
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SCRIPT_EXTRA_ARGS += --verbose
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endif
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# Scan the kernel binary's DWARF information to produce a table of
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# kernel objects which we will pass to gperf
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quiet_cmd_gen_kobj_list = KOBJ $@
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cmd_gen_kobj_list = $(GEN_KOBJ_LIST) --kernel $< --output $@ \
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$(SCRIPT_EXTRA_ARGS)
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$(OBJ_LIST): $(PREBUILT_KERNEL) $(GEN_KOBJ_LIST)
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$(call cmd,gen_kobj_list)
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# Generate C code which implements a perfect hashtable based on our
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# table of kernel objects
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quiet_cmd_gperf = GPERF $@
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cmd_gperf = gperf --output-file=$@ $<
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$(OUTPUT_SRC_PRE): $(OBJ_LIST)
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$(call cmd,gperf)
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# For our purposes, the code/data generated by gperf is not optimal.
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# This script adjusts the generated .c file to greatly reduce the amount
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# of code/data generated since we know we are always working with
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# pointer values
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quiet_cmd_process_gperf = PROCESS $@
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cmd_process_gperf = $(PROCESS_GPERF) -i $< -o $@ $(SCRIPT_EXTRA_ARGS)
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$(OUTPUT_SRC): $(OUTPUT_SRC_PRE) $(PROCESS_GPERF)
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$(call cmd,process_gperf)
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# We need precise control of where generated text/data ends up in the final
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# kernel image. Disable function/data sections and use objcopy to move
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# generated data into special section names
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$(OUTPUT_OBJ): KBUILD_CFLAGS += -fno-function-sections -fno-data-sections
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quiet_cmd_kobject_objcopy = OBJCOPY $@
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cmd_kobject_objcopy = $(OBJCOPY) \
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--rename-section .data=.kobject_data.data \
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--rename-section .rodata=.kobject_data.rodata \
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--rename-section .text=.kobject_data.text \
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$< $@
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$(OUTPUT_OBJ_RENAMED): $(OUTPUT_OBJ)
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$(call cmd,kobject_objcopy)
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GENERATED_KERNEL_OBJECT_FILES += $(OUTPUT_OBJ_RENAMED)
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