linux_dsm_epyc7002/arch/x86/kernel/vmlinux.lds.S

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/*
* ld script for the x86 kernel
*
* Historic 32-bit version written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
*
* Modernisation, unification and other changes and fixes:
* Copyright (C) 2007-2009 Sam Ravnborg <sam@ravnborg.org>
*
*
* 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 <asm-generic/vmlinux.lds.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page_types.h>
#include <asm/orc_lookup.h>
#include <asm/cache.h>
#include <asm/boot.h>
#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)
jiffies = jiffies_64;
#else
OUTPUT_ARCH(i386:x86-64)
ENTRY(phys_startup_64)
jiffies_64 = jiffies;
#endif
#if defined(CONFIG_X86_64)
/*
* On 64-bit, align RODATA to 2MB so 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 as well as retain 2MB large page
* mappings for kernel text.
*/
#define X64_ALIGN_RODATA_BEGIN . = ALIGN(HPAGE_SIZE);
#define X64_ALIGN_RODATA_END \
. = ALIGN(HPAGE_SIZE); \
__end_rodata_hpage_align = .;
#else
#define X64_ALIGN_RODATA_BEGIN
#define X64_ALIGN_RODATA_END
#endif
PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
x86: Add NX protection for kernel data This patch expands functionality of CONFIG_DEBUG_RODATA to set main (static) kernel data area as NX. The following steps are taken to achieve this: 1. Linker script is adjusted so .text always starts and ends on a page bound 2. Linker script is adjusted so .rodata always start and end on a page boundary 3. NX is set for all pages from _etext through _end in mark_rodata_ro. 4. free_init_pages() sets released memory NX in arch/x86/mm/init.c 5. bios rom is set to x when pcibios is used. The results of patch application may be observed in the diff of kernel page table dumps: pcibios: -- data_nx_pt_before.txt 2009-10-13 07:48:59.000000000 -0400 ++ data_nx_pt_after.txt 2009-10-13 07:26:46.000000000 -0400 0x00000000-0xc0000000 3G pmd ---[ Kernel Mapping ]--- -0xc0000000-0xc0100000 1M RW GLB x pte +0xc0000000-0xc00a0000 640K RW GLB NX pte +0xc00a0000-0xc0100000 384K RW GLB x pte -0xc0100000-0xc03d7000 2908K ro GLB x pte +0xc0100000-0xc0318000 2144K ro GLB x pte +0xc0318000-0xc03d7000 764K ro GLB NX pte -0xc03d7000-0xc0600000 2212K RW GLB x pte +0xc03d7000-0xc0600000 2212K RW GLB NX pte 0xc0600000-0xf7a00000 884M RW PSE GLB NX pmd 0xf7a00000-0xf7bfe000 2040K RW GLB NX pte 0xf7bfe000-0xf7c00000 8K pte No pcibios: -- data_nx_pt_before.txt 2009-10-13 07:48:59.000000000 -0400 ++ data_nx_pt_after.txt 2009-10-13 07:26:46.000000000 -0400 0x00000000-0xc0000000 3G pmd ---[ Kernel Mapping ]--- -0xc0000000-0xc0100000 1M RW GLB x pte +0xc0000000-0xc0100000 1M RW GLB NX pte -0xc0100000-0xc03d7000 2908K ro GLB x pte +0xc0100000-0xc0318000 2144K ro GLB x pte +0xc0318000-0xc03d7000 764K ro GLB NX pte -0xc03d7000-0xc0600000 2212K RW GLB x pte +0xc03d7000-0xc0600000 2212K RW GLB NX pte 0xc0600000-0xf7a00000 884M RW PSE GLB NX pmd 0xf7a00000-0xf7bfe000 2040K RW GLB NX pte 0xf7bfe000-0xf7c00000 8K pte The patch has been originally developed for Linux 2.6.34-rc2 x86 by Siarhei Liakh <sliakh.lkml@gmail.com> and Xuxian Jiang <jiang@cs.ncsu.edu>. -v1: initial patch for 2.6.30 -v2: patch for 2.6.31-rc7 -v3: moved all code into arch/x86, adjusted credits -v4: fixed ifdef, removed credits from CREDITS -v5: fixed an address calculation bug in mark_nxdata_nx() -v6: added acked-by and PT dump diff to commit log -v7: minor adjustments for -tip -v8: rework with the merge of "Set first MB as RW+NX" Signed-off-by: Siarhei Liakh <sliakh.lkml@gmail.com> Signed-off-by: Xuxian Jiang <jiang@cs.ncsu.edu> Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr> Cc: Arjan van de Ven <arjan@infradead.org> Cc: James Morris <jmorris@namei.org> Cc: Andi Kleen <ak@muc.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dave Jones <davej@redhat.com> Cc: Kees Cook <kees.cook@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <4CE2F82E.60601@free.fr> [ minor cleanliness edits ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-17 04:31:26 +07:00
data PT_LOAD FLAGS(6); /* RW_ */
#ifdef CONFIG_X86_64
#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
x86/kallsyms: fix GOLD link failure with new relative kallsyms table format Commit 2213e9a66bb8 ("kallsyms: add support for relative offsets in kallsyms address table") changed the default kallsyms symbol table format to use relative references rather than absolute addresses. This reduces the size of the kallsyms symbol table by 50% on 64-bit architectures, and further reduces the size of the relocation tables used by relocatable kernels. Since the memory footprint of the static kernel image is always much smaller than 4 GB, these relative references are assumed to be representable in 32 bits, even when the native word size is 64 bits. On 64-bit architectures, this obviously only works if the distance between each relative reference and the chosen anchor point is representable in 32 bits, and so the table generation code in scripts/kallsyms.c scans the table for the lowest value that is covered by the kernel text, and selects it as the anchor point. However, when using the GOLD linker rather than the default BFD linker to build the x86_64 kernel, the symbol phys_offset_64, which is the result of arithmetic defined in the linker script, is emitted as a 'T' rather than an 'A' type symbol, resulting in scripts/kallsyms.c to mistake it for a suitable anchor point, even though it is far away from the actual kernel image in the virtual address space. This results in out-of-range warnings from scripts/kallsyms.c and a broken build. So let's align with the BFD linker, and emit the phys_offset_[32|64] symbols as absolute symbols explicitly. Note that the out of range issue does not exist on 32-bit x86, but this patch changes both symbols for symmetry. Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Kees Cook <keescook@chromium.org> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-18 16:04:37 +07:00
. = LOAD_OFFSET + LOAD_PHYSICAL_ADDR;
phys_startup_32 = ABSOLUTE(startup_32 - LOAD_OFFSET);
#else
x86/kallsyms: fix GOLD link failure with new relative kallsyms table format Commit 2213e9a66bb8 ("kallsyms: add support for relative offsets in kallsyms address table") changed the default kallsyms symbol table format to use relative references rather than absolute addresses. This reduces the size of the kallsyms symbol table by 50% on 64-bit architectures, and further reduces the size of the relocation tables used by relocatable kernels. Since the memory footprint of the static kernel image is always much smaller than 4 GB, these relative references are assumed to be representable in 32 bits, even when the native word size is 64 bits. On 64-bit architectures, this obviously only works if the distance between each relative reference and the chosen anchor point is representable in 32 bits, and so the table generation code in scripts/kallsyms.c scans the table for the lowest value that is covered by the kernel text, and selects it as the anchor point. However, when using the GOLD linker rather than the default BFD linker to build the x86_64 kernel, the symbol phys_offset_64, which is the result of arithmetic defined in the linker script, is emitted as a 'T' rather than an 'A' type symbol, resulting in scripts/kallsyms.c to mistake it for a suitable anchor point, even though it is far away from the actual kernel image in the virtual address space. This results in out-of-range warnings from scripts/kallsyms.c and a broken build. So let's align with the BFD linker, and emit the phys_offset_[32|64] symbols as absolute symbols explicitly. Note that the out of range issue does not exist on 32-bit x86, but this patch changes both symbols for symmetry. Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Kees Cook <keescook@chromium.org> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-18 16:04:37 +07:00
. = __START_KERNEL;
phys_startup_64 = ABSOLUTE(startup_64 - LOAD_OFFSET);
#endif
/* Text and read-only data */
.text : AT(ADDR(.text) - LOAD_OFFSET) {
_text = .;
_stext = .;
/* bootstrapping code */
HEAD_TEXT
. = ALIGN(8);
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
KPROBES_TEXT
x86: Separate out entry text section Put x86 entry code into a separate link section: .entry.text. Separating the entry text section seems to have performance benefits - caused by more efficient instruction cache usage. Running hackbench with perf stat --repeat showed that the change compresses the icache footprint. The icache load miss rate went down by about 15%: before patch: 19417627 L1-icache-load-misses ( +- 0.147% ) after patch: 16490788 L1-icache-load-misses ( +- 0.180% ) The motivation of the patch was to fix a particular kprobes bug that relates to the entry text section, the performance advantage was discovered accidentally. Whole perf output follows: - results for current tip tree: Performance counter stats for './hackbench/hackbench 10' (500 runs): 19417627 L1-icache-load-misses ( +- 0.147% ) 2676914223 instructions # 0.497 IPC ( +- 0.079% ) 5389516026 cycles ( +- 0.144% ) 0.206267711 seconds time elapsed ( +- 0.138% ) - results for current tip tree with the patch applied: Performance counter stats for './hackbench/hackbench 10' (500 runs): 16490788 L1-icache-load-misses ( +- 0.180% ) 2717734941 instructions # 0.502 IPC ( +- 0.079% ) 5414756975 cycles ( +- 0.148% ) 0.206747566 seconds time elapsed ( +- 0.137% ) Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: masami.hiramatsu.pt@hitachi.com Cc: ananth@in.ibm.com Cc: davem@davemloft.net Cc: 2nddept-manager@sdl.hitachi.co.jp LKML-Reference: <20110307181039.GB15197@jolsa.redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-08 01:10:39 +07:00
ENTRY_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
*(.fixup)
*(.gnu.warning)
/* End of text section */
_etext = .;
} :text = 0x9090
NOTES :text :note
EXCEPTION_TABLE(16) :text = 0x9090
x86: Add NX protection for kernel data This patch expands functionality of CONFIG_DEBUG_RODATA to set main (static) kernel data area as NX. The following steps are taken to achieve this: 1. Linker script is adjusted so .text always starts and ends on a page bound 2. Linker script is adjusted so .rodata always start and end on a page boundary 3. NX is set for all pages from _etext through _end in mark_rodata_ro. 4. free_init_pages() sets released memory NX in arch/x86/mm/init.c 5. bios rom is set to x when pcibios is used. The results of patch application may be observed in the diff of kernel page table dumps: pcibios: -- data_nx_pt_before.txt 2009-10-13 07:48:59.000000000 -0400 ++ data_nx_pt_after.txt 2009-10-13 07:26:46.000000000 -0400 0x00000000-0xc0000000 3G pmd ---[ Kernel Mapping ]--- -0xc0000000-0xc0100000 1M RW GLB x pte +0xc0000000-0xc00a0000 640K RW GLB NX pte +0xc00a0000-0xc0100000 384K RW GLB x pte -0xc0100000-0xc03d7000 2908K ro GLB x pte +0xc0100000-0xc0318000 2144K ro GLB x pte +0xc0318000-0xc03d7000 764K ro GLB NX pte -0xc03d7000-0xc0600000 2212K RW GLB x pte +0xc03d7000-0xc0600000 2212K RW GLB NX pte 0xc0600000-0xf7a00000 884M RW PSE GLB NX pmd 0xf7a00000-0xf7bfe000 2040K RW GLB NX pte 0xf7bfe000-0xf7c00000 8K pte No pcibios: -- data_nx_pt_before.txt 2009-10-13 07:48:59.000000000 -0400 ++ data_nx_pt_after.txt 2009-10-13 07:26:46.000000000 -0400 0x00000000-0xc0000000 3G pmd ---[ Kernel Mapping ]--- -0xc0000000-0xc0100000 1M RW GLB x pte +0xc0000000-0xc0100000 1M RW GLB NX pte -0xc0100000-0xc03d7000 2908K ro GLB x pte +0xc0100000-0xc0318000 2144K ro GLB x pte +0xc0318000-0xc03d7000 764K ro GLB NX pte -0xc03d7000-0xc0600000 2212K RW GLB x pte +0xc03d7000-0xc0600000 2212K RW GLB NX pte 0xc0600000-0xf7a00000 884M RW PSE GLB NX pmd 0xf7a00000-0xf7bfe000 2040K RW GLB NX pte 0xf7bfe000-0xf7c00000 8K pte The patch has been originally developed for Linux 2.6.34-rc2 x86 by Siarhei Liakh <sliakh.lkml@gmail.com> and Xuxian Jiang <jiang@cs.ncsu.edu>. -v1: initial patch for 2.6.30 -v2: patch for 2.6.31-rc7 -v3: moved all code into arch/x86, adjusted credits -v4: fixed ifdef, removed credits from CREDITS -v5: fixed an address calculation bug in mark_nxdata_nx() -v6: added acked-by and PT dump diff to commit log -v7: minor adjustments for -tip -v8: rework with the merge of "Set first MB as RW+NX" Signed-off-by: Siarhei Liakh <sliakh.lkml@gmail.com> Signed-off-by: Xuxian Jiang <jiang@cs.ncsu.edu> Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr> Cc: Arjan van de Ven <arjan@infradead.org> Cc: James Morris <jmorris@namei.org> Cc: Andi Kleen <ak@muc.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dave Jones <davej@redhat.com> Cc: Kees Cook <kees.cook@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <4CE2F82E.60601@free.fr> [ minor cleanliness edits ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-17 04:31:26 +07:00
/* .text should occupy whole number of pages */
. = ALIGN(PAGE_SIZE);
X64_ALIGN_RODATA_BEGIN
RO_DATA(PAGE_SIZE)
X64_ALIGN_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
CONSTRUCTORS
/* rarely changed data like cpu maps */
READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)
/* End of data section */
_edata = .;
} :data
BUG_TABLE
ORC_UNWIND_TABLE
. = ALIGN(PAGE_SIZE);
__vvar_page = .;
.vvar : AT(ADDR(.vvar) - LOAD_OFFSET) {
/* work around gold bug 13023 */
__vvar_beginning_hack = .;
/* Place all vvars at the offsets in asm/vvar.h. */
#define EMIT_VVAR(name, offset) \
. = __vvar_beginning_hack + offset; \
*(.vvar_ ## name)
#define __VVAR_KERNEL_LDS
#include <asm/vvar.h>
#undef __VVAR_KERNEL_LDS
#undef EMIT_VVAR
/*
* Pad the rest of the page with zeros. Otherwise the loader
* can leave garbage here.
*/
. = __vvar_beginning_hack + PAGE_SIZE;
} :data
. = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
/* 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(INTERNODE_CACHE_BYTES, 0, :percpu)
ASSERT(SIZEOF(.data..percpu) < CONFIG_PHYSICAL_START,
"per-CPU data too large - increase CONFIG_PHYSICAL_START")
#endif
INIT_TEXT_SECTION(PAGE_SIZE)
#ifdef CONFIG_X86_64
:init
#endif
/*
* Section for code used exclusively before alternatives are run. All
* references to such code must be patched out by alternatives, normally
* by using X86_FEATURE_ALWAYS CPU feature bit.
*
* See static_cpu_has() for an example.
*/
.altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) {
*(.altinstr_aux)
}
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 = .;
}
#ifdef CONFIG_X86_INTEL_MID
.x86_intel_mid_dev.init : AT(ADDR(.x86_intel_mid_dev.init) - \
LOAD_OFFSET) {
__x86_intel_mid_dev_start = .;
*(.x86_intel_mid_dev.init)
__x86_intel_mid_dev_end = .;
}
#endif
/*
* 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.
*/
x86, iommu: Add IOMMU_INIT macros, .iommu_table section, and iommu_table_entry structure This patch set adds a mechanism to "modularize" the IOMMUs we have on X86. Currently the count of IOMMUs is up to six and they have a complex relationship that requires careful execution order. 'pci_iommu_alloc' does that today, but most folks are unhappy with how it does it. This patch set addresses this and also paves a mechanism to jettison unused IOMMUs during run-time. For details that sparked this, please refer to: http://lkml.org/lkml/2010/8/2/282 The first solution that comes to mind is to convert wholesale the IOMMU detection routines to be called during initcall time frame. Unfortunately that misses the dependency relationship that some of the IOMMUs have (for example: for AMD-Vi IOMMU to work, GART detection MUST run first, and before all of that SWIOTLB MUST run). The second solution would be to introduce a registration call wherein the IOMMU would provide its detection/init routines and as well on what MUST run before it. That would work, except that the 'pci_iommu_alloc' which would run through this list, is called during mem_init. This means we don't have any memory allocator, and it is so early that we haven't yet started running through the initcall_t list. This solution borrows concepts from the 2nd idea and from how MODULE_INIT works. A macro is provided that each IOMMU uses to define it's detect function and early_init (before the memory allocate is active), and as well what other IOMMU MUST run before us. Since most IOMMUs depend on having SWIOTLB run first ("pci_swiotlb_detect") a convenience macro to depends on that is also provided. This macro is similar in design to MODULE_PARAM macro wherein we setup a .iommu_table section in which we populate it with the values that match a struct iommu_table_entry. During bootup we will sort through the array so that the IOMMUs that MUST run before us are first elements in the array. And then we just iterate through them calling the detection routine and if appropiate, the init routines. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> LKML-Reference: <1282845485-8991-2-git-send-email-konrad.wilk@oracle.com> CC: H. Peter Anvin <hpa@zytor.com> CC: Fujita Tomonori <fujita.tomonori@lab.ntt.co.jp> CC: Thomas Gleixner <tglx@linutronix.de> CC: Ingo Molnar <mingo@redhat.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-08-27 00:57:56 +07:00
.iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
__iommu_table = .;
*(.iommu_table)
__iommu_table_end = .;
}
. = ALIGN(8);
.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
__apicdrivers = .;
*(.apicdrivers);
__apicdrivers_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_SECTION(INTERNODE_CACHE_BYTES)
#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)
x86: Add NX protection for kernel data This patch expands functionality of CONFIG_DEBUG_RODATA to set main (static) kernel data area as NX. The following steps are taken to achieve this: 1. Linker script is adjusted so .text always starts and ends on a page bound 2. Linker script is adjusted so .rodata always start and end on a page boundary 3. NX is set for all pages from _etext through _end in mark_rodata_ro. 4. free_init_pages() sets released memory NX in arch/x86/mm/init.c 5. bios rom is set to x when pcibios is used. The results of patch application may be observed in the diff of kernel page table dumps: pcibios: -- data_nx_pt_before.txt 2009-10-13 07:48:59.000000000 -0400 ++ data_nx_pt_after.txt 2009-10-13 07:26:46.000000000 -0400 0x00000000-0xc0000000 3G pmd ---[ Kernel Mapping ]--- -0xc0000000-0xc0100000 1M RW GLB x pte +0xc0000000-0xc00a0000 640K RW GLB NX pte +0xc00a0000-0xc0100000 384K RW GLB x pte -0xc0100000-0xc03d7000 2908K ro GLB x pte +0xc0100000-0xc0318000 2144K ro GLB x pte +0xc0318000-0xc03d7000 764K ro GLB NX pte -0xc03d7000-0xc0600000 2212K RW GLB x pte +0xc03d7000-0xc0600000 2212K RW GLB NX pte 0xc0600000-0xf7a00000 884M RW PSE GLB NX pmd 0xf7a00000-0xf7bfe000 2040K RW GLB NX pte 0xf7bfe000-0xf7c00000 8K pte No pcibios: -- data_nx_pt_before.txt 2009-10-13 07:48:59.000000000 -0400 ++ data_nx_pt_after.txt 2009-10-13 07:26:46.000000000 -0400 0x00000000-0xc0000000 3G pmd ---[ Kernel Mapping ]--- -0xc0000000-0xc0100000 1M RW GLB x pte +0xc0000000-0xc0100000 1M RW GLB NX pte -0xc0100000-0xc03d7000 2908K ro GLB x pte +0xc0100000-0xc0318000 2144K ro GLB x pte +0xc0318000-0xc03d7000 764K ro GLB NX pte -0xc03d7000-0xc0600000 2212K RW GLB x pte +0xc03d7000-0xc0600000 2212K RW GLB NX pte 0xc0600000-0xf7a00000 884M RW PSE GLB NX pmd 0xf7a00000-0xf7bfe000 2040K RW GLB NX pte 0xf7bfe000-0xf7c00000 8K pte The patch has been originally developed for Linux 2.6.34-rc2 x86 by Siarhei Liakh <sliakh.lkml@gmail.com> and Xuxian Jiang <jiang@cs.ncsu.edu>. -v1: initial patch for 2.6.30 -v2: patch for 2.6.31-rc7 -v3: moved all code into arch/x86, adjusted credits -v4: fixed ifdef, removed credits from CREDITS -v5: fixed an address calculation bug in mark_nxdata_nx() -v6: added acked-by and PT dump diff to commit log -v7: minor adjustments for -tip -v8: rework with the merge of "Set first MB as RW+NX" Signed-off-by: Siarhei Liakh <sliakh.lkml@gmail.com> Signed-off-by: Xuxian Jiang <jiang@cs.ncsu.edu> Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr> Cc: Arjan van de Ven <arjan@infradead.org> Cc: James Morris <jmorris@namei.org> Cc: Andi Kleen <ak@muc.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dave Jones <davej@redhat.com> Cc: Kees Cook <kees.cook@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <4CE2F82E.60601@free.fr> [ minor cleanliness edits ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-17 04:31:26 +07:00
. = 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 = .;
}
x86/boot: Move compressed kernel to the end of the decompression buffer This change makes later calculations about where the kernel is located easier to reason about. To better understand this change, we must first clarify what 'VO' and 'ZO' are. These values were introduced in commits by hpa: 77d1a4999502 ("x86, boot: make symbols from the main vmlinux available") 37ba7ab5e33c ("x86, boot: make kernel_alignment adjustable; new bzImage fields") Specifically: All names prefixed with 'VO_': - relate to the uncompressed kernel image - the size of the VO image is: VO__end-VO__text ("VO_INIT_SIZE" define) All names prefixed with 'ZO_': - relate to the bootable compressed kernel image (boot/compressed/vmlinux), which is composed of the following memory areas: - head text - compressed kernel (VO image and relocs table) - decompressor code - the size of the ZO image is: ZO__end - ZO_startup_32 ("ZO_INIT_SIZE" define, though see below) The 'INIT_SIZE' value is used to find the larger of the two image sizes: #define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_extract_offset) #define VO_INIT_SIZE (VO__end - VO__text) #if ZO_INIT_SIZE > VO_INIT_SIZE # define INIT_SIZE ZO_INIT_SIZE #else # define INIT_SIZE VO_INIT_SIZE #endif The current code uses extract_offset to decide where to position the copied ZO (i.e. ZO starts at extract_offset). (This is why ZO_INIT_SIZE currently includes the extract_offset.) Why does z_extract_offset exist? It's needed because we are trying to minimize the amount of RAM used for the whole act of creating an uncompressed, executable, properly relocation-linked kernel image in system memory. We do this so that kernels can be booted on even very small systems. To achieve the goal of minimal memory consumption we have implemented an in-place decompression strategy: instead of cleanly separating the VO and ZO images and also allocating some memory for the decompression code's runtime needs, we instead create this elaborate layout of memory buffers where the output (decompressed) stream, as it progresses, overlaps with and destroys the input (compressed) stream. This can only be done safely if the ZO image is placed to the end of the VO range, plus a certain amount of safety distance to make sure that when the last bytes of the VO range are decompressed, the compressed stream pointer is safely beyond the end of the VO range. z_extract_offset is calculated in arch/x86/boot/compressed/mkpiggy.c during the build process, at a point when we know the exact compressed and uncompressed size of the kernel images and can calculate this safe minimum offset value. (Note that the mkpiggy.c calculation is not perfect, because we don't know the decompressor used at that stage, so the z_extract_offset calculation is necessarily imprecise and is mostly based on gzip internals - we'll improve that in the next patch.) When INIT_SIZE is bigger than VO_INIT_SIZE (uncommon but possible), the copied ZO occupies the memory from extract_offset to the end of decompression buffer. It overlaps with the soon-to-be-uncompressed kernel like this: |-----compressed kernel image------| V V 0 extract_offset +INIT_SIZE |-----------|---------------|-------------------------|--------| | | | | VO__text startup_32 of ZO VO__end ZO__end ^ ^ |-------uncompressed kernel image---------| When INIT_SIZE is equal to VO_INIT_SIZE (likely) there's still space left from end of ZO to the end of decompressing buffer, like below. |-compressed kernel image-| V V 0 extract_offset +INIT_SIZE |-----------|---------------|-------------------------|--------| | | | | VO__text startup_32 of ZO ZO__end VO__end ^ ^ |------------uncompressed kernel image-------------| To simplify calculations and avoid special cases, it is cleaner to always place the compressed kernel image in memory so that ZO__end is at the end of the decompression buffer, instead of placing t at the start of extract_offset as is currently done. This patch adds BP_init_size (which is the INIT_SIZE as passed in from the boot_params) into asm-offsets.c to make it visible to the assembly code. Then when moving the ZO, it calculates the starting position of the copied ZO (via BP_init_size and the ZO run size) so that the VO__end will be at the end of the decompression buffer. To make the position calculation safe, the end of ZO is page aligned (and a comment is added to the existing VO alignment for good measure). Signed-off-by: Yinghai Lu <yinghai@kernel.org> [ Rewrote changelog and comments. ] Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Young <dyoung@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: lasse.collin@tukaani.org Link: http://lkml.kernel.org/r/1461888548-32439-3-git-send-email-keescook@chromium.org [ Rewrote the changelog some more. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-29 07:09:04 +07:00
. = ALIGN(PAGE_SIZE); /* keep VO_INIT_SIZE page aligned */
_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 */
2015-09-10 05:38:55 +07:00
#ifdef CONFIG_KEXEC_CORE
#include <asm/kexec.h>
. = ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
"kexec control code size is too big");
#endif