linux/arch/arm64/kernel
Will Deacon 1c5b51dfb7 arm64: swp emulation: bound LL/SC retries before rescheduling
If a CPU does not implement a global monitor for certain memory types,
then userspace can attempt a kernel DoS by issuing SWP instructions
targetting the problematic memory (for example, a framebuffer mapped
with non-cacheable attributes).

The SWP emulation code protects against these sorts of attacks by
checking for pending signals and potentially rescheduling when the STXR
instruction fails during the emulation. Whilst this is good for avoiding
livelock, it harms emulation of legitimate SWP instructions on CPUs
where forward progress is not guaranteed if there are memory accesses to
the same reservation granule (up to 2k) between the failing STXR and
the retry of the LDXR.

This patch solves the problem by retrying the STXR a bounded number of
times (4) before breaking out of the LL/SC loop and looking for
something else to do.

Cc: <stable@vger.kernel.org>
Fixes: bd35a4adc4 ("arm64: Port SWP/SWPB emulation support from arm")
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-10-19 15:37:23 +01:00
..
probes arm64: migrate exception table users off module.h and onto extable.h 2016-09-20 09:36:21 +01:00
vdso arm64: Add support for CLOCK_MONOTONIC_RAW in clock_gettime() vDSO 2016-07-12 16:06:32 +01:00
.gitignore
acpi.c ARM64: ACPI: enable ACPI_SPCR_TABLE 2016-09-28 17:46:57 +02:00
acpi_numa.c arm64/numa: avoid inconsistent information to be printed 2016-09-09 14:59:08 +01:00
acpi_parking_protocol.c arm64: kernel: acpi: fix ioremap in ACPI parking protocol cpu_postboot 2016-02-26 15:39:52 +00:00
alternative.c arm64: alternative: Add support for patching adrp instructions 2016-09-09 15:03:28 +01:00
arm64ksyms.c Merge branch 'for-next/kprobes' into for-next/core 2016-07-21 18:20:41 +01:00
armv8_deprecated.c arm64: swp emulation: bound LL/SC retries before rescheduling 2016-10-19 15:37:23 +01:00
asm-offsets.c arm64: Work around systems with mismatched cache line sizes 2016-09-09 15:03:29 +01:00
cacheinfo.c arm64: simplify sysreg manipulation 2016-09-09 11:43:50 +01:00
cpu-reset.h arm64: Add back cpu reset routines 2016-06-27 16:31:25 +01:00
cpu-reset.S arm64: Add back cpu reset routines 2016-06-27 16:31:25 +01:00
cpu_errata.c arm64: Work around systems with mismatched cache line sizes 2016-09-09 15:03:29 +01:00
cpu_ops.c arm64: apply __ro_after_init to some objects 2016-08-22 12:32:29 +01:00
cpufeature.c arm64: Rearrange CPU errata workaround checks 2016-09-09 15:03:28 +01:00
cpuidle.c arm64: add support for ACPI Low Power Idle(LPI) 2016-07-21 23:29:38 +02:00
cpuinfo.c arm64: Rearrange CPU errata workaround checks 2016-09-09 15:03:28 +01:00
debug-monitors.c arm64: simplify sysreg manipulation 2016-09-09 11:43:50 +01:00
efi-entry.S arm64: move early boot code to the .init segment 2016-04-14 18:11:30 +01:00
efi.c arm64: efi: avoid block mappings for unaligned UEFI memory regions 2016-07-01 11:56:26 +01:00
entry-fpsimd.S
entry-ftrace.S ftrace: Remove CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST from config 2016-08-24 12:15:13 +02:00
entry.S arm64: use alternative auto-nop 2016-09-12 10:46:07 +01:00
entry32.S arm64: entry32: remove pointless register assignment 2015-07-10 16:47:13 +01:00
fpsimd.c arm64/FP/SIMD: Convert to hotplug state machine 2016-09-19 21:44:25 +02:00
ftrace.c ftrace: Add return address pointer to ftrace_ret_stack 2016-08-24 12:15:14 +02:00
head.S arm64: kernel: Init MDCR_EL2 even in the absence of a PMU 2016-10-17 15:54:30 +01:00
hibernate-asm.S arm64: Introduce raw_{d,i}cache_line_size 2016-09-09 15:03:29 +01:00
hibernate.c Revert "arm64: hibernate: Refuse to hibernate if the boot cpu is offline" 2016-08-26 11:21:25 +01:00
hw_breakpoint.c arm64: hw_breakpoint: convert CPU hotplug notifier to new infrastructure 2016-09-01 13:45:51 +01:00
hyp-stub.S arm64: Add back cpu reset routines 2016-06-27 16:31:25 +01:00
image.h arm64 updates for 4.7: 2016-05-16 17:17:24 -07:00
insn.c arm64: insn: Add helpers for adrp offsets 2016-09-09 15:03:28 +01:00
io.c
irq.c arm64: remove irq_count and do_softirq_own_stack() 2015-12-21 17:26:01 +00:00
jump_label.c jump_label: Rename JUMP_LABEL_{EN,DIS}ABLE to JUMP_LABEL_{JMP,NOP} 2015-08-03 11:34:12 +02:00
kaslr.c arm64: apply __ro_after_init to some objects 2016-08-22 12:32:29 +01:00
kgdb.c arm64: kgdb: handle read-only text / modules 2016-09-23 11:25:01 +01:00
kuser32.S
machine_kexec.c arm64/kexec: Add pr_debug output 2016-06-27 16:31:26 +01:00
Makefile arm64: Set UTS_MACHINE in the Makefile 2016-08-31 12:31:38 +01:00
module-plts.c arm64: add support for module PLTs 2016-02-24 14:57:24 +00:00
module.c arm64: add support for kernel ASLR 2016-02-24 14:57:27 +00:00
module.lds arm64: add support for module PLTs 2016-02-24 14:57:24 +00:00
paravirt.c arm64: introduce CONFIG_PARAVIRT, PARAVIRT_TIME_ACCOUNTING and pv_time_ops 2015-12-21 14:40:54 +00:00
pci.c Merge branch 'pci/resource' into next 2016-08-01 12:23:44 -05:00
perf_callchain.c perf core: Add a 'nr' field to perf_event_callchain_context 2016-05-16 23:11:51 -03:00
perf_event.c arm64: pmu: Hoist pmu platform device name 2016-09-16 17:11:34 +01:00
perf_regs.c
process.c arm64: use simpler API for random address requests 2016-10-11 15:06:32 -07:00
psci.c ARM: 8511/1: ARM64: kernel: PSCI: move PSCI idle management code to drivers/firmware 2016-02-11 15:33:38 +00:00
ptrace.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2016-07-29 17:38:46 -07:00
relocate_kernel.S arm64: Introduce raw_{d,i}cache_line_size 2016-09-09 15:03:29 +01:00
return_address.c arm64: ftrace: fix a stack tracer's output under function graph tracer 2015-12-21 17:26:02 +00:00
setup.c arm64: Set UTS_MACHINE in the Makefile 2016-08-31 12:31:38 +01:00
signal.c arm64: factor work_pending state machine to C 2016-08-22 10:00:48 +01:00
signal32.c arm64: Fix misspellings in comments. 2016-03-04 18:19:17 +00:00
sleep.S arm64: kernel: re-export _cpu_resume() from sleep.S 2016-09-05 10:24:55 +01:00
smccc-call.S ARM: 8480/2: arm64: add implementation for arm-smccc 2016-01-04 16:24:45 +00:00
smp.c arm64: kernel: numa: fix ACPI boot cpu numa node mapping 2016-10-17 15:49:23 +01:00
smp_spin_table.c arm64: vmlinux.ld: Add mmuoff data sections and move mmuoff text into idmap 2016-08-25 18:00:30 +01:00
stacktrace.c arm64: fix dump_backtrace/unwind_frame with NULL tsk 2016-09-26 14:24:01 +01:00
suspend.c arm64: hw_breakpoint: convert CPU hotplug notifier to new infrastructure 2016-09-01 13:45:51 +01:00
sys.c arm64: compat: Check for AArch32 state 2016-04-20 12:22:42 +01:00
sys32.c arm64: fix implementation of mmap2 compat syscall 2015-03-19 10:43:51 +00:00
sys_compat.c arm64: simplify sysreg manipulation 2016-09-09 11:43:50 +01:00
time.c arm64: ftrace: fix a stack tracer's output under function graph tracer 2015-12-21 17:26:02 +00:00
topology.c arm64: kernel: remove non-legit DT warnings when booting using ACPI 2015-07-27 11:08:41 +01:00
trace-events-emulation.h
traps.c arm64: fix dump_backtrace/unwind_frame with NULL tsk 2016-09-26 14:24:01 +01:00
vdso.c arm/arm64: arch_timer: Use archdata to indicate vdso suitability 2016-09-23 17:19:25 +01:00
vmlinux.lds.S nmi_backtrace: generate one-line reports for idle cpus 2016-10-07 18:46:30 -07:00