mirror of
https://github.com/brain-hackers/linux-brain.git
synced 2024-06-09 23:36:23 +09:00
4f5416710e
[ Upstream commit 6553896666433e7efec589838b400a2a652b3ffa ] Some code pathes, especially the low level entry code, must be protected against instrumentation for various reasons: - Low level entry code can be a fragile beast, especially on x86. - With NO_HZ_FULL RCU state needs to be established before using it. Having a dedicated section for such code allows to validate with tooling that no unsafe functions are invoked. Add the .noinstr.text section and the noinstr attribute to mark functions. noinstr implies notrace. Kprobes will gain a section check later. Provide also a set of markers: instrumentation_begin()/end() These are used to mark code inside a noinstr function which calls into regular instrumentable text section as safe. The instrumentation markers are only active when CONFIG_DEBUG_ENTRY is enabled as the end marker emits a NOP to prevent the compiler from merging the annotation points. This means the objtool verification requires a kernel compiled with this option. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200505134100.075416272@linutronix.de Signed-off-by: Sasha Levin <sashal@kernel.org>
403 lines
8.9 KiB
ArmAsm
403 lines
8.9 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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#ifdef CONFIG_PPC64
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#define PROVIDE32(x) PROVIDE(__unused__##x)
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#else
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#define PROVIDE32(x) PROVIDE(x)
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#endif
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#define BSS_FIRST_SECTIONS *(.bss.prominit)
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#include <asm/page.h>
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#include <asm-generic/vmlinux.lds.h>
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#include <asm/cache.h>
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#include <asm/thread_info.h>
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#define STRICT_ALIGN_SIZE (1 << CONFIG_DATA_SHIFT)
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#define ETEXT_ALIGN_SIZE (1 << CONFIG_ETEXT_SHIFT)
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ENTRY(_stext)
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PHDRS {
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kernel PT_LOAD FLAGS(7); /* RWX */
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notes PT_NOTE FLAGS(0);
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dummy PT_NOTE FLAGS(0);
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/* binutils < 2.18 has a bug that makes it misbehave when taking an
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ELF file with all segments at load address 0 as input. This
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happens when running "strip" on vmlinux, because of the AT() magic
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in this linker script. People using GCC >= 4.2 won't run into
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this problem, because the "build-id" support will put some data
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into the "notes" segment (at a non-zero load address).
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To work around this, we force some data into both the "dummy"
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segment and the kernel segment, so the dummy segment will get a
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non-zero load address. It's not enough to always create the
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"notes" segment, since if nothing gets assigned to it, its load
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address will be zero. */
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}
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#ifdef CONFIG_PPC64
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OUTPUT_ARCH(powerpc:common64)
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jiffies = jiffies_64;
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#else
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OUTPUT_ARCH(powerpc:common)
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jiffies = jiffies_64 + 4;
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#endif
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SECTIONS
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{
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. = KERNELBASE;
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/*
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* Text, read only data and other permanent read-only sections
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*/
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_text = .;
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_stext = .;
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/*
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* Head text.
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* This needs to be in its own output section to avoid ld placing
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* branch trampoline stubs randomly throughout the fixed sections,
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* which it will do (even if the branch comes from another section)
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* in order to optimize stub generation.
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*/
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.head.text : AT(ADDR(.head.text) - LOAD_OFFSET) {
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#ifdef CONFIG_PPC64
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KEEP(*(.head.text.first_256B));
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#ifdef CONFIG_PPC_BOOK3E
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#else
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KEEP(*(.head.text.real_vectors));
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*(.head.text.real_trampolines);
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KEEP(*(.head.text.virt_vectors));
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*(.head.text.virt_trampolines);
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# if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
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KEEP(*(.head.data.fwnmi_page));
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# endif
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#endif
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#else /* !CONFIG_PPC64 */
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HEAD_TEXT
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#endif
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} :kernel
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__head_end = .;
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#ifdef CONFIG_PPC64
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/*
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* ALIGN(0) overrides the default output section alignment because
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* this needs to start right after .head.text in order for fixed
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* section placement to work.
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*/
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.text ALIGN(0) : AT(ADDR(.text) - LOAD_OFFSET) {
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#ifdef CONFIG_LD_HEAD_STUB_CATCH
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KEEP(*(.linker_stub_catch));
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. = . ;
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#endif
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#else
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.text : AT(ADDR(.text) - LOAD_OFFSET) {
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ALIGN_FUNCTION();
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#endif
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/* careful! __ftr_alt_* sections need to be close to .text */
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*(.text.hot .text.hot.* TEXT_MAIN .text.fixup .text.unlikely .text.unlikely.* .fixup __ftr_alt_* .ref.text);
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#ifdef CONFIG_PPC64
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*(.tramp.ftrace.text);
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#endif
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NOINSTR_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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/*
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* -Os builds call FP save/restore functions. The powerpc64
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* linker generates those on demand in the .sfpr section.
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* .sfpr gets placed at the beginning of a group of input
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* sections, which can break start-of-text offset if it is
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* included with the main text sections, so put it by itself.
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*/
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*(.sfpr);
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MEM_KEEP(init.text)
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MEM_KEEP(exit.text)
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#ifdef CONFIG_PPC32
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*(.got1)
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__got2_start = .;
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*(.got2)
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__got2_end = .;
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#endif /* CONFIG_PPC32 */
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} :kernel
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. = ALIGN(ETEXT_ALIGN_SIZE);
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_etext = .;
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PROVIDE32 (etext = .);
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/* Read-only data */
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RO_DATA(PAGE_SIZE)
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#ifdef CONFIG_PPC64
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. = ALIGN(8);
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__stf_entry_barrier_fixup : AT(ADDR(__stf_entry_barrier_fixup) - LOAD_OFFSET) {
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__start___stf_entry_barrier_fixup = .;
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*(__stf_entry_barrier_fixup)
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__stop___stf_entry_barrier_fixup = .;
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}
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. = ALIGN(8);
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__uaccess_flush_fixup : AT(ADDR(__uaccess_flush_fixup) - LOAD_OFFSET) {
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__start___uaccess_flush_fixup = .;
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*(__uaccess_flush_fixup)
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__stop___uaccess_flush_fixup = .;
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}
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. = ALIGN(8);
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__entry_flush_fixup : AT(ADDR(__entry_flush_fixup) - LOAD_OFFSET) {
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__start___entry_flush_fixup = .;
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*(__entry_flush_fixup)
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__stop___entry_flush_fixup = .;
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}
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. = ALIGN(8);
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__stf_exit_barrier_fixup : AT(ADDR(__stf_exit_barrier_fixup) - LOAD_OFFSET) {
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__start___stf_exit_barrier_fixup = .;
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*(__stf_exit_barrier_fixup)
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__stop___stf_exit_barrier_fixup = .;
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}
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. = ALIGN(8);
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__rfi_flush_fixup : AT(ADDR(__rfi_flush_fixup) - LOAD_OFFSET) {
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__start___rfi_flush_fixup = .;
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*(__rfi_flush_fixup)
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__stop___rfi_flush_fixup = .;
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}
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#endif /* CONFIG_PPC64 */
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#ifdef CONFIG_PPC_BARRIER_NOSPEC
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. = ALIGN(8);
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__spec_barrier_fixup : AT(ADDR(__spec_barrier_fixup) - LOAD_OFFSET) {
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__start___barrier_nospec_fixup = .;
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*(__barrier_nospec_fixup)
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__stop___barrier_nospec_fixup = .;
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}
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#endif /* CONFIG_PPC_BARRIER_NOSPEC */
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#ifdef CONFIG_PPC_FSL_BOOK3E
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. = ALIGN(8);
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__spec_btb_flush_fixup : AT(ADDR(__spec_btb_flush_fixup) - LOAD_OFFSET) {
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__start__btb_flush_fixup = .;
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*(__btb_flush_fixup)
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__stop__btb_flush_fixup = .;
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}
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#endif
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EXCEPTION_TABLE(0)
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NOTES :kernel :notes
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/* The dummy segment contents for the bug workaround mentioned above
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near PHDRS. */
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.dummy : AT(ADDR(.dummy) - LOAD_OFFSET) {
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LONG(0)
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LONG(0)
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LONG(0)
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} :kernel :dummy
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/*
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* Init sections discarded at runtime
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*/
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. = ALIGN(STRICT_ALIGN_SIZE);
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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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_sinittext = .;
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INIT_TEXT
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/*
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*.init.text might be RO so we must ensure this section ends on
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* a page boundary.
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*/
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. = ALIGN(PAGE_SIZE);
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_einittext = .;
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#ifdef CONFIG_PPC64
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*(.tramp.ftrace.init);
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#endif
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} :kernel
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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 : AT(ADDR(.exit.text) - LOAD_OFFSET) {
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EXIT_TEXT
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}
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. = ALIGN(PAGE_SIZE);
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INIT_DATA_SECTION(16)
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. = ALIGN(8);
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__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
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__start___ftr_fixup = .;
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KEEP(*(__ftr_fixup))
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__stop___ftr_fixup = .;
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}
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. = ALIGN(8);
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__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
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__start___mmu_ftr_fixup = .;
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KEEP(*(__mmu_ftr_fixup))
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__stop___mmu_ftr_fixup = .;
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}
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. = ALIGN(8);
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__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
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__start___lwsync_fixup = .;
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KEEP(*(__lwsync_fixup))
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__stop___lwsync_fixup = .;
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}
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#ifdef CONFIG_PPC64
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. = ALIGN(8);
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__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
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__start___fw_ftr_fixup = .;
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KEEP(*(__fw_ftr_fixup))
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__stop___fw_ftr_fixup = .;
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}
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#endif
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PERCPU_SECTION(L1_CACHE_BYTES)
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. = ALIGN(8);
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.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
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__machine_desc_start = . ;
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KEEP(*(.machine.desc))
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__machine_desc_end = . ;
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}
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#ifdef CONFIG_RELOCATABLE
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. = ALIGN(8);
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.dynsym : AT(ADDR(.dynsym) - LOAD_OFFSET)
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{
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#ifdef CONFIG_PPC32
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__dynamic_symtab = .;
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#endif
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*(.dynsym)
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}
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.dynstr : AT(ADDR(.dynstr) - LOAD_OFFSET) { *(.dynstr) }
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.dynamic : AT(ADDR(.dynamic) - LOAD_OFFSET)
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{
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__dynamic_start = .;
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*(.dynamic)
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}
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.hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
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.interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
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.rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
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{
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__rela_dyn_start = .;
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*(.rela*)
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}
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#endif
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/* .exit.data is discarded at runtime, not link time,
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* to deal with references from .exit.text
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*/
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.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
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EXIT_DATA
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}
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/* freed after init ends here */
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. = ALIGN(PAGE_SIZE);
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__init_end = .;
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/*
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* And now the various read/write data
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*/
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. = ALIGN(PAGE_SIZE);
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_sdata = .;
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#ifdef CONFIG_PPC32
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.data : AT(ADDR(.data) - LOAD_OFFSET) {
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DATA_DATA
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#ifdef CONFIG_UBSAN
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*(.data..Lubsan_data*)
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*(.data..Lubsan_type*)
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#endif
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*(.data.rel*)
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*(SDATA_MAIN)
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*(.sdata2)
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*(.got.plt) *(.got)
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*(.plt)
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*(.branch_lt)
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}
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#else
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.data : AT(ADDR(.data) - LOAD_OFFSET) {
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DATA_DATA
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*(.data.rel*)
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*(.toc1)
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*(.branch_lt)
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}
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.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
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__start_opd = .;
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KEEP(*(.opd))
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__end_opd = .;
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}
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. = ALIGN(256);
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.got : AT(ADDR(.got) - LOAD_OFFSET) {
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__toc_start = .;
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#ifndef CONFIG_RELOCATABLE
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__prom_init_toc_start = .;
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arch/powerpc/kernel/prom_init.o*(.toc .got)
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__prom_init_toc_end = .;
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#endif
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*(.got)
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*(.toc)
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}
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#endif
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/* The initial task and kernel stack */
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INIT_TASK_DATA_SECTION(THREAD_SIZE)
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.data..page_aligned : AT(ADDR(.data..page_aligned) - LOAD_OFFSET) {
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PAGE_ALIGNED_DATA(PAGE_SIZE)
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}
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.data..cacheline_aligned : AT(ADDR(.data..cacheline_aligned) - LOAD_OFFSET) {
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CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
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}
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.data..read_mostly : AT(ADDR(.data..read_mostly) - LOAD_OFFSET) {
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READ_MOSTLY_DATA(L1_CACHE_BYTES)
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}
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. = ALIGN(PAGE_SIZE);
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.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
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NOSAVE_DATA
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}
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BUG_TABLE
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. = ALIGN(PAGE_SIZE);
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_edata = .;
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PROVIDE32 (edata = .);
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/*
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* And finally the bss
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*/
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BSS_SECTION(0, 0, 0)
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. = ALIGN(PAGE_SIZE);
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_end = . ;
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PROVIDE32 (end = .);
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STABS_DEBUG
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DWARF_DEBUG
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DISCARDS
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/DISCARD/ : {
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*(*.EMB.apuinfo)
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*(.glink .iplt .plt .rela* .comment)
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*(.gnu.version*)
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*(.gnu.attributes)
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*(.eh_frame)
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}
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}
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