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57d7f939e7
Bit 0x100 of a page table, segment table of region table entry can be used to disallow code execution for the virtual addresses associated with the entry. There is one tricky bit, the system call to return from a signal is part of the signal frame written to the user stack. With a non-executable stack this would stop working. To avoid breaking things the protection fault handler checks the opcode that caused the fault for 0x0a77 (sys_sigreturn) and 0x0aad (sys_rt_sigreturn) and injects a system call. This is preferable to the alternative solution with a stub function in the vdso because it works for vdso=off and statically linked binaries as well. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
122 lines
2.4 KiB
ArmAsm
122 lines
2.4 KiB
ArmAsm
/* ld script to make s390 Linux kernel
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* Written by Martin Schwidefsky (schwidefsky@de.ibm.com)
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*/
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#include <asm/thread_info.h>
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#include <asm/page.h>
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/*
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* Put .bss..swapper_pg_dir as the first thing in .bss. This will
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* make sure it has 16k alignment.
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*/
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#define BSS_FIRST_SECTIONS *(.bss..swapper_pg_dir)
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/* Handle ro_after_init data on our own. */
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#define RO_AFTER_INIT_DATA
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#include <asm-generic/vmlinux.lds.h>
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OUTPUT_FORMAT("elf64-s390", "elf64-s390", "elf64-s390")
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OUTPUT_ARCH(s390:64-bit)
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ENTRY(startup)
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jiffies = jiffies_64;
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PHDRS {
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text PT_LOAD FLAGS(5); /* R_E */
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data PT_LOAD FLAGS(7); /* RWE */
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note PT_NOTE FLAGS(0); /* ___ */
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}
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SECTIONS
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{
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. = 0x00000000;
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.text : {
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_text = .; /* Text and read-only data */
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HEAD_TEXT
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TEXT_TEXT
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SCHED_TEXT
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CPUIDLE_TEXT
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LOCK_TEXT
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KPROBES_TEXT
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IRQENTRY_TEXT
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SOFTIRQENTRY_TEXT
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*(.fixup)
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*(.gnu.warning)
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} :text = 0x0700
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. = ALIGN(PAGE_SIZE);
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_etext = .; /* End of text section */
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NOTES :text :note
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.dummy : { *(.dummy) } :data
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RO_DATA_SECTION(PAGE_SIZE)
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#ifdef CONFIG_SHARED_KERNEL
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. = ALIGN(0x100000); /* VM shared segments are 1MB aligned */
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#endif
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. = ALIGN(PAGE_SIZE);
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_eshared = .; /* End of shareable data */
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_sdata = .; /* Start of data section */
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. = ALIGN(PAGE_SIZE);
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__start_ro_after_init = .;
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__start_data_ro_after_init = .;
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.data..ro_after_init : {
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*(.data..ro_after_init)
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}
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__end_data_ro_after_init = .;
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EXCEPTION_TABLE(16)
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. = ALIGN(PAGE_SIZE);
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__end_ro_after_init = .;
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RW_DATA_SECTION(0x100, PAGE_SIZE, THREAD_SIZE)
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_edata = .; /* End of data section */
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/* will be freed after init */
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. = ALIGN(PAGE_SIZE); /* Init code and data */
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__init_begin = .;
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. = ALIGN(PAGE_SIZE);
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.init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
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VMLINUX_SYMBOL(_sinittext) = . ;
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INIT_TEXT
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. = ALIGN(PAGE_SIZE);
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VMLINUX_SYMBOL(_einittext) = . ;
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}
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/*
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* .exit.text is discarded at runtime, not link time,
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* to deal with references from __bug_table
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*/
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.exit.text : {
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EXIT_TEXT
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}
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.exit.data : {
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EXIT_DATA
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}
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/* early.c uses stsi, which requires page aligned data. */
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. = ALIGN(PAGE_SIZE);
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INIT_DATA_SECTION(0x100)
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PERCPU_SECTION(0x100)
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. = ALIGN(PAGE_SIZE);
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__init_end = .; /* freed after init ends here */
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BSS_SECTION(PAGE_SIZE, 4 * PAGE_SIZE, PAGE_SIZE)
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_end = . ;
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/* Debugging sections. */
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STABS_DEBUG
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DWARF_DEBUG
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/* Sections to be discarded */
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DISCARDS
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}
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