commit 9a32a7e78bd0cd9a9b6332cbdc345ee5ffd0c5de upstream. IBM Power9 processors can speculatively operate on data in the L1 cache before it has been completely validated, via a way-prediction mechanism. It is not possible for an attacker to determine the contents of impermissible memory using this method, since these systems implement a combination of hardware and software security measures to prevent scenarios where protected data could be leaked. However these measures don't address the scenario where an attacker induces the operating system to speculatively execute instructions using data that the attacker controls. This can be used for example to speculatively bypass "kernel user access prevention" techniques, as discovered by Anthony Steinhauser of Google's Safeside Project. This is not an attack by itself, but there is a possibility it could be used in conjunction with side-channels or other weaknesses in the privileged code to construct an attack. This issue can be mitigated by flushing the L1 cache between privilege boundaries of concern. This patch flushes the L1 cache after user accesses. This is part of the fix for CVE-2020-4788. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
406 lines
8.9 KiB
ArmAsm
406 lines
8.9 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifdef CONFIG_PPC64
|
|
#define PROVIDE32(x) PROVIDE(__unused__##x)
|
|
#else
|
|
#define PROVIDE32(x) PROVIDE(x)
|
|
#endif
|
|
#include <asm/page.h>
|
|
#include <asm-generic/vmlinux.lds.h>
|
|
#include <asm/cache.h>
|
|
#include <asm/thread_info.h>
|
|
|
|
#if defined(CONFIG_STRICT_KERNEL_RWX) && !defined(CONFIG_PPC32)
|
|
#define STRICT_ALIGN_SIZE (1 << 24)
|
|
#else
|
|
#define STRICT_ALIGN_SIZE PAGE_SIZE
|
|
#endif
|
|
|
|
ENTRY(_stext)
|
|
|
|
PHDRS {
|
|
kernel PT_LOAD FLAGS(7); /* RWX */
|
|
notes PT_NOTE FLAGS(0);
|
|
dummy PT_NOTE FLAGS(0);
|
|
|
|
/* binutils < 2.18 has a bug that makes it misbehave when taking an
|
|
ELF file with all segments at load address 0 as input. This
|
|
happens when running "strip" on vmlinux, because of the AT() magic
|
|
in this linker script. People using GCC >= 4.2 won't run into
|
|
this problem, because the "build-id" support will put some data
|
|
into the "notes" segment (at a non-zero load address).
|
|
|
|
To work around this, we force some data into both the "dummy"
|
|
segment and the kernel segment, so the dummy segment will get a
|
|
non-zero load address. It's not enough to always create the
|
|
"notes" segment, since if nothing gets assigned to it, its load
|
|
address will be zero. */
|
|
}
|
|
|
|
#ifdef CONFIG_PPC64
|
|
OUTPUT_ARCH(powerpc:common64)
|
|
jiffies = jiffies_64;
|
|
#else
|
|
OUTPUT_ARCH(powerpc:common)
|
|
jiffies = jiffies_64 + 4;
|
|
#endif
|
|
SECTIONS
|
|
{
|
|
. = KERNELBASE;
|
|
|
|
/*
|
|
* Text, read only data and other permanent read-only sections
|
|
*/
|
|
|
|
_text = .;
|
|
_stext = .;
|
|
|
|
/*
|
|
* Head text.
|
|
* This needs to be in its own output section to avoid ld placing
|
|
* branch trampoline stubs randomly throughout the fixed sections,
|
|
* which it will do (even if the branch comes from another section)
|
|
* in order to optimize stub generation.
|
|
*/
|
|
.head.text : AT(ADDR(.head.text) - LOAD_OFFSET) {
|
|
#ifdef CONFIG_PPC64
|
|
KEEP(*(.head.text.first_256B));
|
|
#ifdef CONFIG_PPC_BOOK3E
|
|
#else
|
|
KEEP(*(.head.text.real_vectors));
|
|
*(.head.text.real_trampolines);
|
|
KEEP(*(.head.text.virt_vectors));
|
|
*(.head.text.virt_trampolines);
|
|
# if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
|
|
KEEP(*(.head.data.fwnmi_page));
|
|
# endif
|
|
#endif
|
|
#else /* !CONFIG_PPC64 */
|
|
HEAD_TEXT
|
|
#endif
|
|
} :kernel
|
|
|
|
__head_end = .;
|
|
|
|
#ifdef CONFIG_PPC64
|
|
/*
|
|
* BLOCK(0) overrides the default output section alignment because
|
|
* this needs to start right after .head.text in order for fixed
|
|
* section placement to work.
|
|
*/
|
|
.text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
|
|
#ifdef CONFIG_LD_HEAD_STUB_CATCH
|
|
*(.linker_stub_catch);
|
|
. = . ;
|
|
#endif
|
|
|
|
#else
|
|
.text : AT(ADDR(.text) - LOAD_OFFSET) {
|
|
ALIGN_FUNCTION();
|
|
#endif
|
|
/* careful! __ftr_alt_* sections need to be close to .text */
|
|
*(.text.hot .text .text.fixup .text.unlikely .fixup __ftr_alt_* .ref.text);
|
|
SCHED_TEXT
|
|
CPUIDLE_TEXT
|
|
LOCK_TEXT
|
|
KPROBES_TEXT
|
|
IRQENTRY_TEXT
|
|
SOFTIRQENTRY_TEXT
|
|
/*
|
|
* -Os builds call FP save/restore functions. The powerpc64
|
|
* linker generates those on demand in the .sfpr section.
|
|
* .sfpr gets placed at the beginning of a group of input
|
|
* sections, which can break start-of-text offset if it is
|
|
* included with the main text sections, so put it by itself.
|
|
*/
|
|
*(.sfpr);
|
|
MEM_KEEP(init.text)
|
|
MEM_KEEP(exit.text)
|
|
|
|
#ifdef CONFIG_PPC32
|
|
*(.got1)
|
|
__got2_start = .;
|
|
*(.got2)
|
|
__got2_end = .;
|
|
#endif /* CONFIG_PPC32 */
|
|
|
|
} :kernel
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
_etext = .;
|
|
PROVIDE32 (etext = .);
|
|
|
|
/* Read-only data */
|
|
RO_DATA(PAGE_SIZE)
|
|
|
|
#ifdef CONFIG_PPC64
|
|
. = ALIGN(8);
|
|
__stf_entry_barrier_fixup : AT(ADDR(__stf_entry_barrier_fixup) - LOAD_OFFSET) {
|
|
__start___stf_entry_barrier_fixup = .;
|
|
*(__stf_entry_barrier_fixup)
|
|
__stop___stf_entry_barrier_fixup = .;
|
|
}
|
|
|
|
. = ALIGN(8);
|
|
__uaccess_flush_fixup : AT(ADDR(__uaccess_flush_fixup) - LOAD_OFFSET) {
|
|
__start___uaccess_flush_fixup = .;
|
|
*(__uaccess_flush_fixup)
|
|
__stop___uaccess_flush_fixup = .;
|
|
}
|
|
|
|
. = ALIGN(8);
|
|
__entry_flush_fixup : AT(ADDR(__entry_flush_fixup) - LOAD_OFFSET) {
|
|
__start___entry_flush_fixup = .;
|
|
*(__entry_flush_fixup)
|
|
__stop___entry_flush_fixup = .;
|
|
}
|
|
|
|
. = ALIGN(8);
|
|
__stf_exit_barrier_fixup : AT(ADDR(__stf_exit_barrier_fixup) - LOAD_OFFSET) {
|
|
__start___stf_exit_barrier_fixup = .;
|
|
*(__stf_exit_barrier_fixup)
|
|
__stop___stf_exit_barrier_fixup = .;
|
|
}
|
|
|
|
. = ALIGN(8);
|
|
__rfi_flush_fixup : AT(ADDR(__rfi_flush_fixup) - LOAD_OFFSET) {
|
|
__start___rfi_flush_fixup = .;
|
|
*(__rfi_flush_fixup)
|
|
__stop___rfi_flush_fixup = .;
|
|
}
|
|
#endif /* CONFIG_PPC64 */
|
|
|
|
#ifdef CONFIG_PPC_BARRIER_NOSPEC
|
|
. = ALIGN(8);
|
|
__spec_barrier_fixup : AT(ADDR(__spec_barrier_fixup) - LOAD_OFFSET) {
|
|
__start___barrier_nospec_fixup = .;
|
|
*(__barrier_nospec_fixup)
|
|
__stop___barrier_nospec_fixup = .;
|
|
}
|
|
#endif /* CONFIG_PPC_BARRIER_NOSPEC */
|
|
|
|
#ifdef CONFIG_PPC_FSL_BOOK3E
|
|
. = ALIGN(8);
|
|
__spec_btb_flush_fixup : AT(ADDR(__spec_btb_flush_fixup) - LOAD_OFFSET) {
|
|
__start__btb_flush_fixup = .;
|
|
*(__btb_flush_fixup)
|
|
__stop__btb_flush_fixup = .;
|
|
}
|
|
#endif
|
|
EXCEPTION_TABLE(0)
|
|
|
|
NOTES :kernel :notes
|
|
|
|
/* The dummy segment contents for the bug workaround mentioned above
|
|
near PHDRS. */
|
|
.dummy : AT(ADDR(.dummy) - LOAD_OFFSET) {
|
|
LONG(0)
|
|
LONG(0)
|
|
LONG(0)
|
|
} :kernel :dummy
|
|
|
|
/*
|
|
* Init sections discarded at runtime
|
|
*/
|
|
. = ALIGN(STRICT_ALIGN_SIZE);
|
|
__init_begin = .;
|
|
INIT_TEXT_SECTION(PAGE_SIZE) :kernel
|
|
|
|
/* .exit.text is discarded at runtime, not link time,
|
|
* to deal with references from __bug_table
|
|
*/
|
|
.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
|
|
EXIT_TEXT
|
|
}
|
|
|
|
.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
|
|
INIT_DATA
|
|
__vtop_table_begin = .;
|
|
*(.vtop_fixup);
|
|
__vtop_table_end = .;
|
|
__ptov_table_begin = .;
|
|
*(.ptov_fixup);
|
|
__ptov_table_end = .;
|
|
}
|
|
|
|
.init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
|
|
INIT_SETUP(16)
|
|
}
|
|
|
|
.initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
|
|
INIT_CALLS
|
|
}
|
|
|
|
.con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
|
|
CON_INITCALL
|
|
}
|
|
|
|
SECURITY_INIT
|
|
|
|
. = ALIGN(8);
|
|
__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
|
|
__start___ftr_fixup = .;
|
|
*(__ftr_fixup)
|
|
__stop___ftr_fixup = .;
|
|
}
|
|
. = ALIGN(8);
|
|
__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
|
|
__start___mmu_ftr_fixup = .;
|
|
*(__mmu_ftr_fixup)
|
|
__stop___mmu_ftr_fixup = .;
|
|
}
|
|
. = ALIGN(8);
|
|
__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
|
|
__start___lwsync_fixup = .;
|
|
*(__lwsync_fixup)
|
|
__stop___lwsync_fixup = .;
|
|
}
|
|
#ifdef CONFIG_PPC64
|
|
. = ALIGN(8);
|
|
__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
|
|
__start___fw_ftr_fixup = .;
|
|
*(__fw_ftr_fixup)
|
|
__stop___fw_ftr_fixup = .;
|
|
}
|
|
#endif
|
|
.init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
|
|
INIT_RAM_FS
|
|
}
|
|
|
|
PERCPU_SECTION(L1_CACHE_BYTES)
|
|
|
|
. = ALIGN(8);
|
|
.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
|
|
__machine_desc_start = . ;
|
|
*(.machine.desc)
|
|
__machine_desc_end = . ;
|
|
}
|
|
#ifdef CONFIG_RELOCATABLE
|
|
. = ALIGN(8);
|
|
.dynsym : AT(ADDR(.dynsym) - LOAD_OFFSET)
|
|
{
|
|
#ifdef CONFIG_PPC32
|
|
__dynamic_symtab = .;
|
|
#endif
|
|
*(.dynsym)
|
|
}
|
|
.dynstr : AT(ADDR(.dynstr) - LOAD_OFFSET) { *(.dynstr) }
|
|
.dynamic : AT(ADDR(.dynamic) - LOAD_OFFSET)
|
|
{
|
|
__dynamic_start = .;
|
|
*(.dynamic)
|
|
}
|
|
.hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
|
|
.interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
|
|
.rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
|
|
{
|
|
__rela_dyn_start = .;
|
|
*(.rela*)
|
|
}
|
|
#endif
|
|
/* .exit.data is discarded at runtime, not link time,
|
|
* to deal with references from .exit.text
|
|
*/
|
|
.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
|
|
EXIT_DATA
|
|
}
|
|
|
|
/* freed after init ends here */
|
|
. = ALIGN(PAGE_SIZE);
|
|
__init_end = .;
|
|
|
|
/*
|
|
* And now the various read/write data
|
|
*/
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
_sdata = .;
|
|
|
|
#ifdef CONFIG_PPC32
|
|
.data : AT(ADDR(.data) - LOAD_OFFSET) {
|
|
DATA_DATA
|
|
*(.sdata)
|
|
*(.sdata2)
|
|
*(.got.plt) *(.got)
|
|
*(.plt)
|
|
}
|
|
#else
|
|
.data : AT(ADDR(.data) - LOAD_OFFSET) {
|
|
DATA_DATA
|
|
*(.data.rel*)
|
|
*(.toc1)
|
|
*(.branch_lt)
|
|
}
|
|
|
|
#ifdef CONFIG_DEBUG_INFO_BTF
|
|
.BTF : AT(ADDR(.BTF) - LOAD_OFFSET) {
|
|
*(.BTF)
|
|
}
|
|
#endif
|
|
|
|
.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
|
|
*(.opd)
|
|
}
|
|
|
|
. = ALIGN(256);
|
|
.got : AT(ADDR(.got) - LOAD_OFFSET) {
|
|
__toc_start = .;
|
|
#ifndef CONFIG_RELOCATABLE
|
|
__prom_init_toc_start = .;
|
|
arch/powerpc/kernel/prom_init.o*(.toc .got)
|
|
__prom_init_toc_end = .;
|
|
#endif
|
|
*(.got)
|
|
*(.toc)
|
|
}
|
|
#endif
|
|
|
|
/* The initial task and kernel stack */
|
|
INIT_TASK_DATA_SECTION(THREAD_SIZE)
|
|
|
|
.data..page_aligned : AT(ADDR(.data..page_aligned) - LOAD_OFFSET) {
|
|
PAGE_ALIGNED_DATA(PAGE_SIZE)
|
|
}
|
|
|
|
.data..cacheline_aligned : AT(ADDR(.data..cacheline_aligned) - LOAD_OFFSET) {
|
|
CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
|
|
}
|
|
|
|
.data..read_mostly : AT(ADDR(.data..read_mostly) - LOAD_OFFSET) {
|
|
READ_MOSTLY_DATA(L1_CACHE_BYTES)
|
|
}
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
|
|
NOSAVE_DATA
|
|
}
|
|
|
|
BUG_TABLE
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
_edata = .;
|
|
PROVIDE32 (edata = .);
|
|
|
|
/*
|
|
* And finally the bss
|
|
*/
|
|
|
|
BSS_SECTION(0, 0, 0)
|
|
|
|
. = ALIGN(PAGE_SIZE);
|
|
_end = . ;
|
|
PROVIDE32 (end = .);
|
|
|
|
STABS_DEBUG
|
|
|
|
DWARF_DEBUG
|
|
|
|
DISCARDS
|
|
/DISCARD/ : {
|
|
*(*.EMB.apuinfo)
|
|
*(.glink .iplt .plt .rela* .comment)
|
|
*(.gnu.version*)
|
|
*(.gnu.attributes)
|
|
*(.eh_frame)
|
|
}
|
|
}
|