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linux/arch/x86/kernel
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Andy Lutomirski 731e33e39a x86/arch_prctl/64: Remove FSBASE/GSBASE < 4G optimization 
As far as I know, the optimization doesn't work on any modern distro
because modern distros use high addresses for ASLR.  Remove it.

The ptrace code was either wrong or very strange, but the behavior
with this patch should be essentially identical to the behavior
without this patch unless user code goes out of its way to mislead
ptrace.

On newer CPUs, once the FSGSBASE instructions are enabled, we won't
want to use the optimized variant anyway.

This isn't actually much of a performance regression, it has no effect
on normal dynamically linked programs, and it's a considerably
simplification. It also removes some nasty special cases from code
that is already way too full of special cases for comfort.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/dd1599b08866961dba9d2458faa6bbd7fba471d7.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-29 11:56:41 +02:00
..
acpi x86/cpufeature: Replace cpu_has_apic with boot_cpu_has() usage 2016-04-13 11:37:41 +02:00
apic Merge branch 'x86/urgent' into x86/asm, to refresh the tree 2016-04-29 11:55:04 +02:00
cpu x86/segments/64: When loadsegment(fs, ...) fails, clear the base 2016-04-29 11:56:41 +02:00
fpu x86/fpu: Get rid of x87 math exception helpers 2016-04-13 11:37:44 +02:00
kprobes x86/asm: Stop depending on ptrace.h in alternative.h 2016-04-29 11:56:40 +02:00
.gitignore
alternative.c x86/asm: Stop depending on ptrace.h in alternative.h 2016-04-29 11:56:40 +02:00
amd_gart_64.c
amd_nb.c x86/cpu: Get rid of compute_unit_id 2016-03-29 10:45:04 +02:00
apb_timer.c x86/apb/timer: Use proper mask to modify hotplug action 2016-03-19 13:40:08 +01:00
aperture_64.c param: convert some "on"/"off" users to strtobool 2016-03-17 15:09:34 -07:00
apm_32.c x86: Fix misspellings in comments 2016-02-24 08:44:58 +01:00
asm-offsets.c x86/asm-offsets: Remove PARAVIRT_enabled 2016-03-08 14:16:44 +01:00
asm-offsets_32.c x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup 2016-03-10 09:48:14 +01:00
asm-offsets_64.c x86/syscalls: Add syscall entry qualifiers 2016-01-29 09:46:38 +01:00
audit_64.c
bootflag.c
check.c
cpuid.c new helpers: no_seek_end_llseek{,_size}() 2015-12-23 10:41:31 -05:00
crash.c x86/kexec: Remove walk_iomem_res() call with GART type 2016-01-30 09:49:59 +01:00
crash_dump_32.c
crash_dump_64.c
devicetree.c x86/cpufeature: Replace cpu_has_apic with boot_cpu_has() usage 2016-04-13 11:37:41 +02:00
doublefault.c
dumpstack.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
dumpstack_32.c
dumpstack_64.c
e820.c Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-15 09:32:27 -07:00
early-quirks.c Linux 4.4-rc2 2015-11-23 09:04:05 +01:00
early_printk.c x86: Fix misspellings in comments 2016-02-24 08:44:58 +01:00
espfix_64.c
ftrace.c Nothing major this round. Mostly small clean ups and fixes. 2016-03-24 10:52:25 -07:00
head.c
head32.c
head64.c Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-15 10:02:25 -07:00
head_32.S Merge branch 'x86/urgent' into x86/asm, to refresh the tree 2016-04-29 11:55:04 +02:00
head_64.S x86/asm: Make sure verify_cpu() has a good stack 2016-04-13 11:52:19 +02:00
hpet.c x86/vdso: Remove direct HPET access through the vDSO 2016-04-13 10:28:34 +02:00
hw_breakpoint.c x86/cpufeature: Remove unused and seldomly used cpu_has_xx macros 2015-12-19 11:49:55 +01:00
i386_ksyms_32.c
i8237.c
i8253.c
i8259.c x86/irq: Probe for PIC presence before allocating descs for legacy IRQs 2015-11-07 10:37:37 +01:00
io_delay.c
ioport.c x86/iopl: Fix iopl capability check on Xen PV 2016-03-17 09:49:27 +01:00
irq.c x86/irq: Call irq_force_move_complete with irq descriptor 2016-01-15 13:44:01 +01:00
irq_32.c
irq_64.c
irq_work.c treewide: Remove old email address 2015-11-23 09:44:58 +01:00
irqinit.c
jump_label.c x86/asm: Stop depending on ptrace.h in alternative.h 2016-04-29 11:56:40 +02:00
kdebugfs.c
kexec-bzimage64.c x86: Fix misspellings in comments 2016-02-24 08:44:58 +01:00
kgdb.c x86/asm: Stop depending on ptrace.h in alternative.h 2016-04-29 11:56:40 +02:00
ksysfs.c
kvm.c x86/cpufeature: Remove cpu_has_hypervisor 2016-03-31 13:35:07 +02:00
kvmclock.c x86: Fix misspellings in comments 2016-02-24 08:44:58 +01:00
ldt.c x86/mm: Factor out LDT init from context init 2016-02-18 19:46:31 +01:00
livepatch.c livepatch: Cleanup module page permission changes 2015-12-04 22:51:07 +01:00
machine_kexec_32.c
machine_kexec_64.c kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILE 2016-01-20 17:09:18 -08:00
Makefile mm, kasan: stackdepot implementation. Enable stackdepot for SLAB 2016-03-25 16:37:42 -07:00
mcount_64.S x86/ftrace, x86/asm: Kill ftrace_caller_end label 2016-02-17 08:47:22 +01:00
mmconf-fam10h_64.c
module.c x86/asm: Stop depending on ptrace.h in alternative.h 2016-04-29 11:56:40 +02:00
mpparse.c x86/cpufeature: Use enum cpuid_leafs instead of magic numbers 2016-02-01 10:46:48 +01:00
msr.c x86/cpufeature: Carve out X86_FEATURE_* 2016-01-30 11:22:17 +01:00
nmi.c x86/nmi: Mark 'ignore_nmis' as __read_mostly 2016-03-08 12:48:19 +01:00
nmi_selftest.c
paravirt-spinlocks.c
paravirt.c x86/paravirt: Add paravirt_{read,write}_msr() 2016-04-13 11:37:46 +02:00
paravirt_patch_32.c x86/paravirt: Remove the unused irq_enable_sysexit pv op 2015-11-23 10:48:16 +01:00
paravirt_patch_64.c x86/entry, x86/paravirt: Remove the unused usergs_sysret32 PV op 2015-11-23 10:48:16 +01:00
pci-calgary_64.c x86/platform/calgary: Constify cal_chipset_ops structures 2015-11-29 08:50:58 +01:00
pci-dma.c
pci-iommu_table.c
pci-nommu.c
pci-swiotlb.c x86/mm/64: Enable SWIOTLB if system has SRAT memory regions above MAX_DMA32_PFN 2015-12-06 12:46:31 +01:00
pcspeaker.c
perf_regs.c
pmem.c x86, kexec, nvdimm: Use walk_iomem_res_desc() for iomem search 2016-01-30 09:49:59 +01:00
probe_roms.c
process.c Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-15 09:32:27 -07:00
process_32.c
process_64.c x86/arch_prctl/64: Remove FSBASE/GSBASE < 4G optimization 2016-04-29 11:56:41 +02:00
ptrace.c x86/arch_prctl/64: Remove FSBASE/GSBASE < 4G optimization 2016-04-29 11:56:41 +02:00
pvclock.c x86/vdso: Remove pvclock fixmap machinery 2015-12-11 08:56:03 +01:00
quirks.c
reboot.c x86/reboot/quirks: Add iMac10,1 to pci_reboot_dmi_table[] 2016-01-12 12:27:36 +01:00
reboot_fixups_32.c
relocate_kernel_32.S
relocate_kernel_64.S
resource.c
rtc.c x86/paravirt: Prevent rtc_cmos platform device init on PV guests 2015-12-19 21:35:13 +01:00
setup.c Revert "x86: remove the kernel code/data/bss resources from /proc/iomem" 2016-04-14 12:55:32 -07:00
setup_percpu.c
signal.c x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall() 2016-04-19 10:44:52 +02:00
signal_compat.c
smp.c
smpboot.c x86/cpufeature: Replace cpu_has_apic with boot_cpu_has() usage 2016-04-13 11:37:41 +02:00
stacktrace.c perf: generalize perf_callchain 2016-02-20 00:21:44 -05:00
step.c
sys_x86_64.c
sysfb.c
sysfb_efi.c
sysfb_simplefb.c
tboot.c mm: cleanup *pte_alloc* interfaces 2016-03-17 15:09:34 -07:00
tce_64.c x86/cpufeature: Remove cpu_has_clflush 2016-03-31 13:35:09 +02:00
test_nx.c x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option 2016-02-22 08:51:38 +01:00
test_rodata.c x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option 2016-02-22 08:51:38 +01:00
time.c
tls.c
tls.h
topology.c
trace_clock.c
tracepoint.c
traps.c x86/asm: Stop depending on ptrace.h in alternative.h 2016-04-29 11:56:40 +02:00
tsc.c x86/tsc: Save an indentation level in recalibrate_cpu_khz() 2016-04-13 11:37:43 +02:00
tsc_msr.c
tsc_sync.c
uprobes.c x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall() 2016-04-19 10:44:52 +02:00
verify_cpu.S x86/cpufeature: Carve out X86_FEATURE_* 2016-01-30 11:22:17 +01:00
vm86_32.c x86/cpufeature: Replace the old static_cpu_has() with safe variant 2016-01-30 11:22:18 +01:00
vmlinux.lds.S arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
vsmp_64.c
x86_init.c x86/tsc: Remove unused tsc_pre_init() hook 2015-11-19 11:03:13 +01:00
x8664_ksyms_64.c x86/mm, x86/mce: Add memcpy_mcsafe() 2016-03-08 17:54:38 +01:00