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d91460f2d0
commit 76a5eaa38b upstream.
In order to protect against speculation attacks (Spectre
variant 2) on NXP PowerPC platforms, the branch predictor
should be flushed when the privillege level is changed.
This patch is adding the infrastructure to fixup at runtime
the code sections that are performing the branch predictor flush
depending on a boot arg parameter which is added later in a
separate patch.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
372 lines
8.6 KiB
ArmAsm
372 lines
8.6 KiB
ArmAsm
#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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#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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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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# define END_FIXED 0x100
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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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# define END_FIXED 0x8000
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# else
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# define END_FIXED 0x7000
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# endif
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#endif
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ASSERT((. == END_FIXED), "vmlinux.lds.S: fixed section overflow error");
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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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/*
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* If the build dies here, it's likely code in head_64.S is referencing
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* labels it can't reach, and the linker inserting stubs without the
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* assembler's knowledge. To debug, remove the above assert and
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* rebuild. Look for branch stubs in the fixed section region.
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*
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* Linker stub generation could be allowed in "trampoline"
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* sections if absolutely necessary, but this would require
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* some rework of the fixed sections. Before resorting to this,
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* consider references that have sufficient addressing range,
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* (e.g., hand coded trampolines) so the linker does not have
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* to add stubs.
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*
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* Linker stubs at the top of the main text section are currently not
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* detected, and will result in a crash at boot due to offsets being
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* wrong.
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*/
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#ifdef CONFIG_PPC64
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/*
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* BLOCK(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 BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
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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 .fixup __ftr_alt_* .ref.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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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(PAGE_SIZE);
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_etext = .;
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PROVIDE32 (etext = .);
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/* Read-only data */
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RODATA
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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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__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(PAGE_SIZE);
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__init_begin = .;
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INIT_TEXT_SECTION(PAGE_SIZE) :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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.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
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INIT_DATA
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__vtop_table_begin = .;
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*(.vtop_fixup);
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__vtop_table_end = .;
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__ptov_table_begin = .;
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*(.ptov_fixup);
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__ptov_table_end = .;
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}
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.init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
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INIT_SETUP(16)
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}
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.initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
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INIT_CALLS
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}
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.con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
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CON_INITCALL
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}
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SECURITY_INIT
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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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*(__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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*(__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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*(__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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*(__fw_ftr_fixup)
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__stop___fw_ftr_fixup = .;
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}
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#endif
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.init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
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INIT_RAM_FS
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}
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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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*(.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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*(.sdata)
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*(.got.plt) *(.got)
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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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*(.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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. = 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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/* Sections to be discarded. */
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DISCARDS
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}
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