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c8b06e3fdd
linux/arch/arm64/kernel
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James Morse c8b06e3fdd arm64: Remove useless UAO IPI and describe how this gets enabled 
Since its introduction, the UAO enable call was broken, and useless.
commit 2a6dcb2b5f ("arm64: cpufeature: Schedule enable() calls instead
of calling them via IPI"), fixed the framework so that these calls
are scheduled, so that they can modify PSTATE.

Now it is just useless. Remove it. UAO is enabled by the code patching
which causes get_user() and friends to use the 'ldtr' family of
instructions. This relies on the PSTATE.UAO bit being set to match
addr_limit, which we do in uao_thread_switch() called via __switch_to().

All that is needed to enable UAO is patch the code, and call schedule().
__apply_alternatives_multi_stop() calls stop_machine() when it modifies
the kernel text to enable the alternatives, (including the UAO code in
uao_thread_switch()). Once stop_machine() has finished __switch_to() is
called to reschedule the original task, this causes PSTATE.UAO to be set
appropriately. An explicit enable() call is not needed.

Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
2017-01-10 12:38:06 +00:00
..
probes Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
vdso arm64: Add support for CLOCK_MONOTONIC_RAW in clock_gettime() vDSO 2016-07-12 16:06:32 +01:00
.gitignore
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
acpi.c ACPI / osl: Remove acpi_get_table_with_size()/early_acpi_os_unmap_memory() users 2016-12-21 02:36:38 +01:00
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: add missing printk newlines 2017-01-10 12:35:27 +00:00
asm-offsets.c arm64: Introduce uaccess_{disable,enable} functionality based on TTBR0_EL1 2016-11-21 18:48:53 +00:00
cacheinfo.c arm64: simplify sysreg manipulation 2016-09-09 11:43:50 +01:00
cpu_errata.c arm64: cpufeature: Schedule enable() calls instead of calling them via IPI 2016-10-20 09:50:53 +01:00
cpu_ops.c arm64: apply __ro_after_init to some objects 2016-08-22 12:32:29 +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
cpufeature.c arm64: Remove useless UAO IPI and describe how this gets enabled 2017-01-10 12:38:06 +00:00
cpuidle.c arm64: add support for ACPI Low Power Idle(LPI) 2016-07-21 23:29:38 +02:00
cpuinfo.c arm64/cpuinfo: Convert to hotplug state machine 2016-12-02 00:52:38 +01:00
debug-monitors.c cpu/hotplug: Cleanup state names 2016-12-25 10:47:44 +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: mm: replace 'block_mappings_allowed' with 'page_mappings_only' 2016-11-07 18:15:04 +00:00
entry32.S arm64: entry32: remove pointless register assignment 2015-07-10 16:47:13 +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: don't pull uaccess.h into *.S 2016-12-26 13:05:17 -05:00
fpsimd.c arm64: Support systems without FP/ASIMD 2016-11-16 18:05:10 +00:00
ftrace.c ftrace: Add return address pointer to ftrace_ret_stack 2016-08-24 12:15:14 +02:00
head.S arm64: head.S: fix up stale comments 2017-01-10 12:36:22 +00:00
hibernate-asm.S arm64: Introduce raw_{d,i}cache_line_size 2016-09-09 15:03:29 +01:00
hibernate.c arm64: add missing printk newlines 2017-01-10 12:35:27 +00:00
hw_breakpoint.c cpu/hotplug: Cleanup state names 2016-12-25 10:47:44 +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: Get rid of asm/opcodes.h 2016-12-02 10:56:21 +00:00
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_step_brk_fn: ignore other's exception 2016-11-07 18:15:20 +00:00
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 PCI/ACPI: Extend pci_mcfg_lookup() to return ECAM config accessors 2016-12-06 13:45:48 -06:00
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 KVM: arm64: Fix the issues when guest PMCCFILTR is configured 2016-11-18 09:06:58 +00:00
perf_regs.c perf: Move task_pt_regs sampling into arch code 2015-01-09 11:12:28 +01:00
process.c arm64: Don't trace __switch_to if function graph tracer is enabled 2017-01-10 11:05:08 +00:00
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 arm64: Allow hw watchpoint at varied offset from base address 2016-11-18 17:23:17 +00:00
relocate_kernel.S arm64: Introduce raw_{d,i}cache_line_size 2016-09-09 15:03:29 +01:00
return_address.c arm64: factor out current_stack_pointer 2016-11-11 18:25:43 +00:00
setup.c arm64: setup: introduce kaslr_offset() 2016-12-20 09:48:46 -08:00
signal32.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
signal.c arm64: Add uprobe support 2016-11-07 18:15:21 +00:00
sleep.S arm64: move sp_el0 and tpidr_el1 into cpu_suspend_ctx 2016-11-11 18:25:44 +00:00
smccc-call.S ARM: 8480/2: arm64: add implementation for arm-smccc 2016-01-04 16:24:45 +00:00
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
smp.c arm64: split thread_info from task stack 2016-11-11 18:25:46 +00:00
stacktrace.c arm64: prep stack walkers for THREAD_INFO_IN_TASK 2016-11-11 18:25:44 +00:00
suspend.c arm64: move sp_el0 and tpidr_el1 into cpu_suspend_ctx 2016-11-11 18:25:44 +00:00
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
sys.c arm64: compat: Check for AArch32 state 2016-04-20 12:22:42 +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: add sysfs cpu_capacity attribute 2016-11-07 18:15:03 +00:00
trace-events-emulation.h arm64: Trace emulation of AArch32 legacy instructions 2014-11-20 16:35:02 +00:00
traps.c arm64: Disable TTBR0_EL1 during normal kernel execution 2016-11-21 18:48:54 +00:00
vdso.c arm/arm64: arch_timer: Use archdata to indicate vdso suitability 2016-09-23 17:19:25 +01:00
vmlinux.lds.S arm64: Introduce uaccess_{disable,enable} functionality based on TTBR0_EL1 2016-11-21 18:48:53 +00:00