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b2eed9b588
linux/arch/arm64/kernel
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Ard Biesheuvel b2eed9b588 arm64/kernel: kaslr: reduce module randomization range to 2 GB 
The following commit

  7290d58095 ("module: use relative references for __ksymtab entries")

updated the ksymtab handling of some KASLR capable architectures
so that ksymtab entries are emitted as pairs of 32-bit relative
references. This reduces the size of the entries, but more
importantly, it gets rid of statically assigned absolute
addresses, which require fixing up at boot time if the kernel
is self relocating (which takes a 24 byte RELA entry for each
member of the ksymtab struct).

Since ksymtab entries are always part of the same module as the
symbol they export, it was assumed at the time that a 32-bit
relative reference is always sufficient to capture the offset
between a ksymtab entry and its target symbol.

Unfortunately, this is not always true: in the case of per-CPU
variables, a per-CPU variable's base address (which usually differs
from the actual address of any of its per-CPU copies) is allocated
in the vicinity of the ..data.percpu section in the core kernel
(i.e., in the per-CPU reserved region which follows the section
containing the core kernel's statically allocated per-CPU variables).

Since we randomize the module space over a 4 GB window covering
the core kernel (based on the -/+ 4 GB range of an ADRP/ADD pair),
we may end up putting the core kernel out of the -/+ 2 GB range of
32-bit relative references of module ksymtab entries that refer to
per-CPU variables.

So reduce the module randomization range a bit further. We lose
1 bit of randomization this way, but this is something we can
tolerate.

Cc: <stable@vger.kernel.org> # v4.19+
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2019-05-23 11:38:11 +01:00
..
probes arm64: probes: Move magic BRK values into brk-imm.h 2019-04-09 11:21:13 +01:00
vdso arm64: arch_timer: Ensure counter register reads occur with seqlock held 2019-04-30 11:04:23 +01:00
.gitignore
acpi_numa.c acpi: Create subtable parsing infrastructure 2019-04-04 18:41:12 +02:00
acpi_parking_protocol.c arm64: fix endianness annotation in acpi_parking_protocol.c 2017-06-29 11:33:15 +01:00
acpi.c arm64: KVM/mm: Move SEA handling behind a single 'claim' interface 2019-02-07 23:10:45 +01:00
alternative.c arm64: alternative: Apply alternatives early in boot process 2019-02-06 10:05:20 +00:00
armv8_deprecated.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
asm-offsets.c * ARM: support for SVE and Pointer Authentication in guests, PMU improvements 2019-05-17 10:33:30 -07:00
cacheinfo.c arm64: Add support for ACPI based firmware tables 2018-05-17 17:28:09 +01:00
cpu_errata.c arm64: errata: Add workaround for Cortex-A76 erratum #1463225 2019-05-23 11:38:10 +01:00
cpu_ops.c arm64: cpu_ops: fix a leaked reference by adding missing of_node_put 2019-04-03 13:50:35 +01:00
cpu-reset.h arm64: kexec: always reset to EL2 if present 2018-07-04 18:34:24 +01:00
cpu-reset.S arm64: kexec_file: invoke the kernel without purgatory 2018-12-06 14:38:53 +00:00
cpufeature.c * ARM: support for SVE and Pointer Authentication in guests, PMU improvements 2019-05-17 10:33:30 -07:00
cpuidle.c ARM64 / cpuidle: Use new cpuidle macro for entering retention state 2018-01-02 13:50:34 +00:00
cpuinfo.c arm64: Expose SVE2 features for userspace 2019-04-23 18:02:00 +01:00
crash_core.c arm64: kernel: arch_crash_save_vmcoreinfo() should depend on CONFIG_CRASH_CORE 2018-09-11 11:08:49 +01:00
crash_dump.c arm64: kdump: fix small typo 2018-11-02 17:24:17 +00:00
debug-monitors.c arm64: Clear OSDLR_EL1 on CPU boot 2019-04-09 12:38:31 +01:00
efi-entry.S arm64: Add software workaround for Falkor erratum 1041 2018-02-06 22:53:13 +00:00
efi-header.S
efi-rt-wrapper.S efi/arm64: Check whether x18 is preserved by runtime services calls 2018-03-09 08:58:22 +01:00
efi.c efi/arm64: Check whether x18 is preserved by runtime services calls 2018-03-09 08:58:22 +01:00
entry-fpsimd.S arm64/sve: Write ZCR_EL1 on context switch only if changed 2018-05-17 18:19:53 +01:00
entry-ftrace.S arm64: frace: use asm EXPORT_SYMBOL() 2018-12-10 11:50:12 +00:00
entry.S arm64: Restrict ARM64_ERRATUM_1188873 mitigation to AArch32 2019-04-30 14:45:53 +01:00
fpsimd.c * ARM: support for SVE and Pointer Authentication in guests, PMU improvements 2019-05-17 10:33:30 -07:00
ftrace.c arm64/module: ftrace: deal with place relative nature of PLTs 2019-04-23 13:35:00 +01:00
head.S arm64: Fix size of __early_cpu_boot_status 2019-05-01 14:39:26 +01:00
hibernate-asm.S arm64: mm: Offset TTBR1 to allow 52-bit PTRS_PER_PGD 2018-12-10 18:42:17 +00:00
hibernate.c arm64: hibernate: Clean the __hyp_text to PoC after resume 2019-02-01 14:10:02 +00:00
hw_breakpoint.c perf/arch/arm64: Implement hw_breakpoint_arch_parse() 2018-06-26 09:07:56 +02:00
hyp-stub.S arm64: hyp-stub: Forbid kprobing of the hyp-stub 2019-02-01 14:10:01 +00:00
image.h Merge branch 'for-next/kexec' into aarch64/for-next/core 2018-12-10 18:57:17 +00:00
insn.c bpf, arm64: use more scalable stadd over ldxr / stxr loop in xadd 2019-04-26 18:53:40 -07:00
io.c arm64: Avoid aligning normal memory pointers in __memcpy_{to,from}io 2017-10-24 16:23:07 +01:00
irq.c arm64: Fix HCR.TGE status for NMI contexts 2019-02-06 10:05:16 +00:00
jump_label.c jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
kaslr.c arm64/kernel: kaslr: reduce module randomization range to 2 GB 2019-05-23 11:38:11 +01:00
kexec_image.c arm64: kexec_file: forbid kdump via kexec_file_load() 2018-12-07 15:28:21 +00:00
kgdb.c arm64: debug: Remove redundant user_mode(regs) checks from debug handlers 2019-04-09 11:21:13 +01:00
kuser32.S arm64: compat: Add KUSER_HELPERS config option 2019-04-23 18:01:58 +01:00
machine_kexec_file.c arm64: kexec_file: handle empty command-line 2019-02-05 09:34:49 +00:00
machine_kexec.c arm64: kdump: no need to mark crashkernel pages manually PG_reserved 2019-03-05 21:07:19 -08:00
Makefile arm64: compat: Add KUSER_HELPERS config option 2019-04-23 18:01:58 +01:00
module-plts.c arm64/module: switch to ADRP/ADD sequences for PLT entries 2018-11-27 19:00:45 +00:00
module.c arm64/kernel: kaslr: reduce module randomization range to 2 GB 2019-05-23 11:38:11 +01:00
module.lds arm64: ftrace: emit ftrace-mod.o contents through code 2017-12-01 13:04:59 +00:00
paravirt.c x86/paravirt: Use a single ops structure 2018-09-03 16:50:35 +02:00
pci.c arm64: PCI: Remove node-local allocations when initialising host controller 2018-09-17 16:33:23 -05:00
perf_callchain.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
perf_event.c * ARM: support for SVE and Pointer Authentication in guests, PMU improvements 2019-05-17 10:33:30 -07:00
perf_regs.c compat: Move compat_timespec/ timeval to compat_time.h 2018-04-19 13:29:54 +02:00
pointer_auth.c arm64: ptr auth: Move per-thread keys from thread_info to thread_struct 2018-12-13 16:42:47 +00:00
process.c arm64: Unmask PMR before going idle 2019-02-06 10:05:18 +00:00
psci.c arm64: remove unused asm/compiler.h header file 2018-10-01 11:57:04 +01:00
ptrace.c arm64 updates for 5.1: 2019-03-10 10:17:23 -07:00
reloc_test_core.c arm64: fix undefined reference to 'printk' 2018-03-19 18:14:25 +00:00
reloc_test_syms.S arm64: fix undefined reference to 'printk' 2018-03-19 18:14:25 +00:00
relocate_kernel.S arm64: kexec_file: invoke the kernel without purgatory 2018-12-06 14:38:53 +00:00
return_address.c arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack 2018-12-22 08:21:02 -05:00
sdei.c arm64: fix wrong check of on_sdei_stack in nmi context 2019-04-04 16:02:25 +01:00
setup.c arm64: replace memblock_alloc_low with memblock_alloc 2019-03-27 18:12:41 +00:00
signal32.c arm64: compat: Alloc separate pages for vectors and sigpage 2019-04-23 18:01:31 +01:00
signal.c arm64: fpsimd: Always set TIF_FOREIGN_FPSTATE on task state flush 2019-03-29 14:41:52 +00:00
sigreturn32.S arm64: compat: Split kuser32 2019-04-23 18:01:57 +01:00
sleep.S arm64/mm: Pass ttbr1 as a parameter to __enable_mmu() 2018-09-25 15:10:54 +01:00
smccc-call.S arm64: smccc: use asm EXPORT_SYMBOL() 2018-12-10 11:50:11 +00:00
smp_spin_table.c
smp.c acpi: Create subtable parsing infrastructure 2019-04-04 18:41:12 +02:00
ssbd.c arm64: ssbd: Add support for PSTATE.SSBS rather than trapping to EL3 2018-09-14 17:46:19 +01:00
stacktrace.c arm64/stacktrace: Remove the pointless ULONG_MAX marker 2019-04-14 19:58:29 +02:00
suspend.c arm64: mm: Support Common Not Private translations 2018-09-18 12:02:27 +01:00
sys32.c arm64: implement syscall wrappers 2018-07-12 14:49:48 +01:00
sys_compat.c arm64 fixes for -rc1 2019-01-05 11:28:39 -08:00
sys.c arm64: mmap: Ensure file offset is treated as unsigned 2019-04-29 15:27:41 +01:00
syscall.c arm64: errata: Add workaround for Cortex-A76 erratum #1463225 2019-05-23 11:38:10 +01:00
time.c arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack 2018-12-22 08:21:02 -05:00
topology.c arm64: topology: re-introduce numa mask check for scheduler MC selection 2018-07-06 13:18:18 +01:00
trace-events-emulation.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
traps.c arm64: Remove useless message during oops 2019-05-23 11:38:10 +01:00
vdso.c arm64: compat: Add KUSER_HELPERS config option 2019-04-23 18:01:58 +01:00
vmlinux.lds.S arm64: relocatable: fix inconsistencies in linker script and options 2018-12-04 12:48:25 +00:00