/* * ld script for the x86 kernel * * Historic 32-bit version written by Martin Mares * * Modernisation, unification and other changes and fixes: * Copyright (C) 2007-2009 Sam Ravnborg * * * Don't define absolute symbols until and unless you know that symbol * value is should remain constant even if kernel image is relocated * at run time. Absolute symbols are not relocated. If symbol value should * change if kernel is relocated, make the symbol section relative and * put it inside the section definition. */ #ifdef CONFIG_X86_32 #define LOAD_OFFSET __PAGE_OFFSET #else #define LOAD_OFFSET __START_KERNEL_map #endif #include #include #include #include #include #include #undef i386 /* in case the preprocessor is a 32bit one */ OUTPUT_FORMAT(CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT, CONFIG_OUTPUT_FORMAT) #ifdef CONFIG_X86_32 OUTPUT_ARCH(i386) ENTRY(phys_startup_32) #else OUTPUT_ARCH(i386:x86-64) ENTRY(phys_startup_64) #endif #if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) /* * On 64-bit, align RODATA to 2MB so that even with CONFIG_DEBUG_RODATA * we retain large page mappings for boundaries spanning kernel text, rodata * and data sections. * * However, kernel identity mappings will have different RWX permissions * to the pages mapping to text and to the pages padding (which are freed) the * text section. Hence kernel identity mappings will be broken to smaller * pages. For 64-bit, kernel text and kernel identity mappings are different, * so we can enable protection checks that come with CONFIG_DEBUG_RODATA, * as well as retain 2MB large page mappings for kernel text. */ #define X64_ALIGN_DEBUG_RODATA_BEGIN . = ALIGN(HPAGE_SIZE); #define X64_ALIGN_DEBUG_RODATA_END \ . = ALIGN(HPAGE_SIZE); \ __end_rodata_hpage_align = .; #else #define X64_ALIGN_DEBUG_RODATA_BEGIN #define X64_ALIGN_DEBUG_RODATA_END #endif PHDRS { text PT_LOAD FLAGS(5); /* R_E */ data PT_LOAD FLAGS(6); /* RW_ */ #ifdef CONFIG_X86_64 user PT_LOAD FLAGS(5); /* R_E */ #ifdef CONFIG_SMP percpu PT_LOAD FLAGS(6); /* RW_ */ #endif init PT_LOAD FLAGS(7); /* RWE */ #endif note PT_NOTE FLAGS(0); /* ___ */ } SECTIONS { #ifdef CONFIG_X86_32 . = LOAD_OFFSET + LOAD_PHYSICAL_ADDR; phys_startup_32 = startup_32 - LOAD_OFFSET; #else . = __START_KERNEL; phys_startup_64 = startup_64 - LOAD_OFFSET; #endif /* Text and read-only data */ .text : AT(ADDR(.text) - LOAD_OFFSET) { _text = .; /* bootstrapping code */ HEAD_TEXT #ifdef CONFIG_X86_32 . = ALIGN(PAGE_SIZE); *(.text..page_aligned) #endif . = ALIGN(8); _stext = .; TEXT_TEXT SCHED_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT *(.fixup) *(.gnu.warning) /* End of text section */ _etext = .; } :text = 0x9090 NOTES :text :note EXCEPTION_TABLE(16) :text = 0x9090 #if defined(CONFIG_DEBUG_RODATA) /* .text should occupy whole number of pages */ . = ALIGN(PAGE_SIZE); #endif X64_ALIGN_DEBUG_RODATA_BEGIN RO_DATA(PAGE_SIZE) X64_ALIGN_DEBUG_RODATA_END /* Data */ .data : AT(ADDR(.data) - LOAD_OFFSET) { /* Start of data section */ _sdata = .; /* init_task */ INIT_TASK_DATA(THREAD_SIZE) #ifdef CONFIG_X86_32 /* 32 bit has nosave before _edata */ NOSAVE_DATA #endif PAGE_ALIGNED_DATA(PAGE_SIZE) CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES) DATA_DATA /* * Workaround a binutils (2.20.51.0.12 to 2.21.51.0.3) bug. * This makes jiffies relocatable in such binutils */ #ifdef CONFIG_X86_32 jiffies = jiffies_64; #else jiffies_64 = jiffies; #endif CONSTRUCTORS /* rarely changed data like cpu maps */ READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES) /* End of data section */ _edata = .; } :data #ifdef CONFIG_X86_64 #define VSYSCALL_ADDR (-10*1024*1024) #define VLOAD_OFFSET (VSYSCALL_ADDR - __vsyscall_0 + LOAD_OFFSET) #define VLOAD(x) (ADDR(x) - VLOAD_OFFSET) #define VVIRT_OFFSET (VSYSCALL_ADDR - __vsyscall_0) #define VVIRT(x) (ADDR(x) - VVIRT_OFFSET) . = ALIGN(4096); __vsyscall_0 = .; . = VSYSCALL_ADDR; .vsyscall_0 : AT(VLOAD(.vsyscall_0)) { *(.vsyscall_0) } :user . = ALIGN(L1_CACHE_BYTES); .vsyscall_fn : AT(VLOAD(.vsyscall_fn)) { *(.vsyscall_fn) } . = ALIGN(L1_CACHE_BYTES); .vsyscall_gtod_data : AT(VLOAD(.vsyscall_gtod_data)) { *(.vsyscall_gtod_data) } vsyscall_gtod_data = VVIRT(.vsyscall_gtod_data); .vsyscall_clock : AT(VLOAD(.vsyscall_clock)) { *(.vsyscall_clock) } vsyscall_clock = VVIRT(.vsyscall_clock); .vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) { *(.vsyscall_1) } .vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2)) { *(.vsyscall_2) } .vgetcpu_mode : AT(VLOAD(.vgetcpu_mode)) { *(.vgetcpu_mode) } vgetcpu_mode = VVIRT(.vgetcpu_mode); . = ALIGN(L1_CACHE_BYTES); .jiffies : AT(VLOAD(.jiffies)) { *(.jiffies) } jiffies = VVIRT(.jiffies); .vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3)) { *(.vsyscall_3) } . = __vsyscall_0 + PAGE_SIZE; #undef VSYSCALL_ADDR #undef VLOAD_OFFSET #undef VLOAD #undef VVIRT_OFFSET #undef VVIRT #endif /* CONFIG_X86_64 */ /* Init code and data - will be freed after init */ . = ALIGN(PAGE_SIZE); .init.begin : AT(ADDR(.init.begin) - LOAD_OFFSET) { __init_begin = .; /* paired with __init_end */ } #if defined(CONFIG_X86_64) && defined(CONFIG_SMP) /* * percpu offsets are zero-based on SMP. PERCPU_VADDR() changes the * output PHDR, so the next output section - .init.text - should * start another segment - init. */ PERCPU_VADDR(0, :percpu) #endif INIT_TEXT_SECTION(PAGE_SIZE) #ifdef CONFIG_X86_64 :init #endif INIT_DATA_SECTION(16) .x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) { __x86_cpu_dev_start = .; *(.x86_cpu_dev.init) __x86_cpu_dev_end = .; } /* * start address and size of operations which during runtime * can be patched with virtualization friendly instructions or * baremetal native ones. Think page table operations. * Details in paravirt_types.h */ . = ALIGN(8); .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) { __parainstructions = .; *(.parainstructions) __parainstructions_end = .; } /* * struct alt_inst entries. From the header (alternative.h): * "Alternative instructions for different CPU types or capabilities" * Think locking instructions on spinlocks. */ . = ALIGN(8); .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) { __alt_instructions = .; *(.altinstructions) __alt_instructions_end = .; } /* * And here are the replacement instructions. The linker sticks * them as binary blobs. The .altinstructions has enough data to * get the address and the length of them to patch the kernel safely. */ .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) { *(.altinstr_replacement) } /* * struct iommu_table_entry entries are injected in this section. * It is an array of IOMMUs which during run time gets sorted depending * on its dependency order. After rootfs_initcall is complete * this section can be safely removed. */ .iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) { __iommu_table = .; *(.iommu_table) __iommu_table_end = .; } . = ALIGN(8); /* * .exit.text is discard at runtime, not link time, to deal with * references from .altinstructions and .eh_frame */ .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { EXIT_TEXT } .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) { EXIT_DATA } #if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP) PERCPU(THREAD_SIZE) #endif . = ALIGN(PAGE_SIZE); /* freed after init ends here */ .init.end : AT(ADDR(.init.end) - LOAD_OFFSET) { __init_end = .; } /* * smp_locks might be freed after init * start/end must be page aligned */ . = ALIGN(PAGE_SIZE); .smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) { __smp_locks = .; *(.smp_locks) . = ALIGN(PAGE_SIZE); __smp_locks_end = .; } #ifdef CONFIG_X86_64 .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { NOSAVE_DATA } #endif /* BSS */ . = ALIGN(PAGE_SIZE); .bss : AT(ADDR(.bss) - LOAD_OFFSET) { __bss_start = .; *(.bss..page_aligned) *(.bss) . = ALIGN(PAGE_SIZE); __bss_stop = .; } . = ALIGN(PAGE_SIZE); .brk : AT(ADDR(.brk) - LOAD_OFFSET) { __brk_base = .; . += 64 * 1024; /* 64k alignment slop space */ *(.brk_reservation) /* areas brk users have reserved */ __brk_limit = .; } _end = .; STABS_DEBUG DWARF_DEBUG /* Sections to be discarded */ DISCARDS /DISCARD/ : { *(.eh_frame) } } #ifdef CONFIG_X86_32 /* * The ASSERT() sink to . is intentional, for binutils 2.14 compatibility: */ . = ASSERT((_end - LOAD_OFFSET <= KERNEL_IMAGE_SIZE), "kernel image bigger than KERNEL_IMAGE_SIZE"); #else /* * Per-cpu symbols which need to be offset from __per_cpu_load * for the boot processor. */ #define INIT_PER_CPU(x) init_per_cpu__##x = x + __per_cpu_load INIT_PER_CPU(gdt_page); INIT_PER_CPU(irq_stack_union); /* * Build-time check on the image size: */ . = ASSERT((_end - _text <= KERNEL_IMAGE_SIZE), "kernel image bigger than KERNEL_IMAGE_SIZE"); #ifdef CONFIG_SMP . = ASSERT((irq_stack_union == 0), "irq_stack_union is not at start of per-cpu area"); #endif #endif /* CONFIG_X86_32 */ #ifdef CONFIG_KEXEC #include . = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE, "kexec control code size is too big"); #endif