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da141706ae
Add page protections for arm64 similar to those in arm. This is for security reasons to prevent certain classes of exploits. The current method: - Map all memory as either RWX or RW. We round to the nearest section to avoid creating page tables before everything is mapped - Once everything is mapped, if either end of the RWX section should not be X, we split the PMD and remap as necessary - When initmem is to be freed, we change the permissions back to RW (using stop machine if necessary to flush the TLB) - If CONFIG_DEBUG_RODATA is set, the read only sections are set read only. Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Kees Cook <keescook@chromium.org> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Laura Abbott <lauraa@codeaurora.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
175 lines
3.6 KiB
ArmAsm
175 lines
3.6 KiB
ArmAsm
/*
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* ld script to make ARM Linux kernel
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* taken from the i386 version by Russell King
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* Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
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*/
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#include <asm-generic/vmlinux.lds.h>
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#include <asm/thread_info.h>
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#include <asm/memory.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include "image.h"
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/* .exit.text needed in case of alternative patching */
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#define ARM_EXIT_KEEP(x) x
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#define ARM_EXIT_DISCARD(x)
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OUTPUT_ARCH(aarch64)
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ENTRY(_text)
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jiffies = jiffies_64;
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#define HYPERVISOR_TEXT \
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/* \
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* Force the alignment to be compatible with \
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* the vectors requirements \
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*/ \
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. = ALIGN(2048); \
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VMLINUX_SYMBOL(__hyp_idmap_text_start) = .; \
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*(.hyp.idmap.text) \
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VMLINUX_SYMBOL(__hyp_idmap_text_end) = .; \
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VMLINUX_SYMBOL(__hyp_text_start) = .; \
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*(.hyp.text) \
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VMLINUX_SYMBOL(__hyp_text_end) = .;
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/*
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* The size of the PE/COFF section that covers the kernel image, which
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* runs from stext to _edata, must be a round multiple of the PE/COFF
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* FileAlignment, which we set to its minimum value of 0x200. 'stext'
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* itself is 4 KB aligned, so padding out _edata to a 0x200 aligned
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* boundary should be sufficient.
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*/
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PECOFF_FILE_ALIGNMENT = 0x200;
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#ifdef CONFIG_EFI
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#define PECOFF_EDATA_PADDING \
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.pecoff_edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGNMENT); }
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#else
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#define PECOFF_EDATA_PADDING
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#endif
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#ifdef CONFIG_DEBUG_ALIGN_RODATA
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#define ALIGN_DEBUG_RO . = ALIGN(1<<SECTION_SHIFT);
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#define ALIGN_DEBUG_RO_MIN(min) ALIGN_DEBUG_RO
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#else
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#define ALIGN_DEBUG_RO
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#define ALIGN_DEBUG_RO_MIN(min) . = ALIGN(min);
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#endif
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SECTIONS
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{
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/*
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* XXX: The linker does not define how output sections are
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* assigned to input sections when there are multiple statements
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* matching the same input section name. There is no documented
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* order of matching.
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*/
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/DISCARD/ : {
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ARM_EXIT_DISCARD(EXIT_TEXT)
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ARM_EXIT_DISCARD(EXIT_DATA)
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EXIT_CALL
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*(.discard)
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*(.discard.*)
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}
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. = PAGE_OFFSET + TEXT_OFFSET;
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.head.text : {
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_text = .;
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HEAD_TEXT
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}
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ALIGN_DEBUG_RO
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.text : { /* Real text segment */
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_stext = .; /* Text and read-only data */
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__exception_text_start = .;
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*(.exception.text)
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__exception_text_end = .;
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IRQENTRY_TEXT
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TEXT_TEXT
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SCHED_TEXT
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LOCK_TEXT
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HYPERVISOR_TEXT
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*(.fixup)
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*(.gnu.warning)
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. = ALIGN(16);
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*(.got) /* Global offset table */
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}
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ALIGN_DEBUG_RO
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RO_DATA(PAGE_SIZE)
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EXCEPTION_TABLE(8)
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NOTES
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ALIGN_DEBUG_RO
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_etext = .; /* End of text and rodata section */
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ALIGN_DEBUG_RO_MIN(PAGE_SIZE)
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__init_begin = .;
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INIT_TEXT_SECTION(8)
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.exit.text : {
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ARM_EXIT_KEEP(EXIT_TEXT)
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}
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ALIGN_DEBUG_RO_MIN(16)
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.init.data : {
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INIT_DATA
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INIT_SETUP(16)
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INIT_CALLS
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CON_INITCALL
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SECURITY_INITCALL
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INIT_RAM_FS
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}
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.exit.data : {
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ARM_EXIT_KEEP(EXIT_DATA)
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}
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PERCPU_SECTION(64)
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. = ALIGN(PAGE_SIZE);
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__init_end = .;
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. = ALIGN(4);
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.altinstructions : {
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__alt_instructions = .;
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*(.altinstructions)
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__alt_instructions_end = .;
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}
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.altinstr_replacement : {
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*(.altinstr_replacement)
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}
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. = ALIGN(PAGE_SIZE);
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_data = .;
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_sdata = .;
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RW_DATA_SECTION(64, PAGE_SIZE, THREAD_SIZE)
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PECOFF_EDATA_PADDING
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_edata = .;
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BSS_SECTION(0, 0, 0)
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. = ALIGN(PAGE_SIZE);
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idmap_pg_dir = .;
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. += IDMAP_DIR_SIZE;
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swapper_pg_dir = .;
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. += SWAPPER_DIR_SIZE;
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_end = .;
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STABS_DEBUG
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HEAD_SYMBOLS
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}
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/*
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* The HYP init code can't be more than a page long.
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*/
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ASSERT(((__hyp_idmap_text_start + PAGE_SIZE) > __hyp_idmap_text_end),
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"HYP init code too big")
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/*
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* If padding is applied before .head.text, virt<->phys conversions will fail.
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*/
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ASSERT(_text == (PAGE_OFFSET + TEXT_OFFSET), "HEAD is misaligned")
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