linux-stable/arch/x86/kernel
Andi Kleen 742c45c3ec x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2
The kernel needs to explicitly enable FSGSBASE. So, the application needs
to know if it can safely use these instructions. Just looking at the CPUID
bit is not enough because it may be running in a kernel that does not
enable the instructions.

One way for the application would be to just try and catch the SIGILL.
But that is difficult to do in libraries which may not want to overwrite
the signal handlers of the main application.

Enumerate the enabled FSGSBASE capability in bit 1 of AT_HWCAP2 in the ELF
aux vector. AT_HWCAP2 is already used by PPC for similar purposes.

The application can access it open coded or by using the getauxval()
function in newer versions of glibc.

[ tglx: Massaged changelog ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1557309753-24073-18-git-send-email-chang.seok.bae@intel.com
Link: https://lkml.kernel.org/r/20200528201402.1708239-14-sashal@kernel.org
2020-06-18 15:47:05 +02:00
..
acpi mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
apic The X86 entry, exception and interrupt code rework 2020-06-13 10:05:47 -07:00
cpu x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 2020-06-18 15:47:05 +02:00
fpu Most of the changes here related to 'XSAVES supervisor state' support, 2020-06-01 14:09:26 -07:00
kprobes x86/entry: Unbreak __irqentry_text_start/end magic 2020-06-11 15:15:29 +02:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
alternative.c x86/int3: Inline bsearch() 2020-06-11 15:14:54 +02:00
amd_gart_64.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
amd_nb.c x86/amd_nb: Add AMD family 17h model 60h PCI IDs 2020-05-22 18:24:40 +02:00
apb_timer.c x86/apb_timer: Drop unused TSC calibration 2020-05-27 13:05:59 +02:00
aperture_64.c
apm_32.c
asm-offsets.c efi/x86: Avoid using code32_start 2020-03-08 09:58:17 +01:00
asm-offsets_32.c x86 entry code updates: 2020-03-30 19:14:28 -07:00
asm-offsets_64.c x86/entry: Remove DBn stacks 2020-06-11 15:15:23 +02:00
audit_64.c x86/audit: Fix a -Wmissing-prototypes warning for ia32_classify_syscall() 2020-05-19 18:03:07 +02:00
bootflag.c
check.c
cpuid.c
crash.c x86/crash: Use resource_size() 2020-01-09 14:40:03 +01:00
crash_core_32.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
crash_core_64.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
crash_dump_32.c
crash_dump_64.c fs/core/vmcore: Move sev_active() reference to x86 arch code 2019-08-09 22:52:10 +10:00
devicetree.c
doublefault_32.c x86/entry: Convert double fault exception to IDTENTRY_DF 2020-06-11 15:15:03 +02:00
dumpstack.c kernel: rename show_stack_loglvl() => show_stack() 2020-06-09 09:39:13 -07:00
dumpstack_32.c x86/32: Remove CONFIG_DOUBLEFAULT 2020-04-14 14:24:05 +02:00
dumpstack_64.c x86/entry: Remove DBn stacks 2020-06-11 15:15:23 +02:00
e820.c Rebase locking/kcsan to locking/urgent 2020-06-11 20:02:46 +02:00
early-quirks.c x86/intel: Disable HPET on Intel Ice Lake platforms 2019-11-29 12:17:58 +01:00
early_printk.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
ebda.c
eisa.c
espfix_64.c mm: introduce include/linux/pgtable.h 2020-06-09 09:39:13 -07:00
ftrace.c Linux 5.7-rc6 2020-05-18 13:09:37 +03:00
ftrace_32.S x86: Change {JMP,CALL}_NOSPEC argument 2020-04-30 20:14:34 +02:00
ftrace_64.S x86/entry/64: Move non entry code into .text section 2020-06-11 15:14:37 +02:00
head32.c
head64.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
head_32.S x86/boot: Remove KEEP_SEGMENTS support 2020-02-22 23:37:37 +01:00
head_64.S x86/entry: Remove the apic/BUILD interrupt leftovers 2020-06-11 15:15:16 +02:00
hpet.c remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
hw_breakpoint.c x86/entry: Optimize local_db_save() for virt 2020-06-11 15:15:22 +02:00
i8237.c
i8253.c x86/timer: Skip PIT initialization on modern chipsets 2019-06-29 11:35:35 +02:00
i8259.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
idt.c x86/idt: Consolidate idt functionality 2020-06-11 15:15:26 +02:00
ima_arch.c EFI updates for v5.7: 2020-02-26 15:21:22 +01:00
io_delay.c
ioport.c x86/ioperm: Prevent a memory leak when fork fails 2020-05-28 21:36:20 +02:00
irq.c x86/entry: Convert KVM vectors to IDTENTRY_SYSVEC* 2020-06-11 15:15:15 +02:00
irq_32.c x86/irq: Rework handle_irq() for 64-bit 2020-06-11 15:15:12 +02:00
irq_64.c x86/entry/64: Move do_softirq_own_stack() to C 2020-06-11 15:15:07 +02:00
irq_work.c x86/entry: Convert various system vectors 2020-06-11 15:15:14 +02:00
irqflags.S x86/asm: Change all ENTRY+ENDPROC to SYM_FUNC_* 2019-10-18 11:58:33 +02:00
irqinit.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
itmt.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
jailhouse.c x86/jailhouse: Only enable platform UARTs if available 2019-10-10 15:43:59 +02:00
jump_label.c x86/jump_label: Move 'inline' keyword placement 2020-03-27 11:05:41 +01:00
kdebugfs.c x86/boot: Introduce setup_indirect 2019-11-12 16:21:15 +01:00
kexec-bzimage64.c efi/x86: Make fw_vendor, config_table and runtime sysfs nodes x86 specific 2020-02-23 21:59:42 +01:00
kgdb.c x86/apic: Provide and use helper for send_IPI_allbutself() 2019-07-25 16:12:00 +02:00
ksysfs.c x86/boot: Introduce setup_indirect 2019-11-12 16:21:15 +01:00
kvm.c The X86 entry, exception and interrupt code rework 2020-06-13 10:05:47 -07:00
kvmclock.c x86/vdso: Use generic VDSO clock mode storage 2020-02-17 14:40:23 +01:00
ldt.c mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
machine_kexec_32.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
machine_kexec_64.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
Makefile Rebase locking/kcsan to locking/urgent 2020-06-11 20:02:46 +02:00
mmconf-fam10h_64.c
module.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
mpparse.c x86/boot: Fix memory leak in default_get_smp_config() 2019-07-16 23:13:48 +02:00
msr.c x86/msr: Restrict MSR access when the kernel is locked down 2019-08-19 21:54:16 -07:00
nmi.c x86/entry: Make NMI use IDTENTRY_RAW 2020-06-12 14:15:48 +02:00
nmi_selftest.c
paravirt-spinlocks.c
paravirt.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
paravirt_patch.c
pci-dma.c dma-mapping updates for 5.5-rc1 2019-11-28 11:16:43 -08:00
pci-iommu_table.c
pci-swiotlb.c dma-mapping: fix filename references 2019-09-03 08:36:30 +02:00
pcspeaker.c
perf_regs.c
platform-quirks.c
pmem.c
probe_roms.c
process.c x86/process/64: Use FSGSBASE instructions on thread copy and ptrace 2020-06-18 15:47:02 +02:00
process.h x86: Use the correct SPDX License Identifier in headers 2019-10-01 20:31:35 +02:00
process_32.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
process_64.c x86/process/64: Use FSGSBASE instructions on thread copy and ptrace 2020-06-18 15:47:02 +02:00
ptrace.c x86/ptrace: Prevent ptrace from clearing the FS/GS selector 2020-06-18 15:46:59 +02:00
pvclock.c x86/vdso: Use generic VDSO clock mode storage 2020-02-17 14:40:23 +01:00
quirks.c remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
reboot.c A set of fixes and updates for x86: 2020-06-11 15:54:31 -07:00
reboot_fixups_32.c
relocate_kernel_32.S x86/asm: Annotate relocate_kernel_{32,64}.c 2019-10-18 09:53:19 +02:00
relocate_kernel_64.S x86/kexec: Make relocate_kernel_64.S objtool clean 2020-03-25 18:28:28 +01:00
resource.c
rtc.c
setup.c x86/setup: Add an initrdmem= option to specify initrd physical address 2020-04-27 09:28:16 +02:00
setup_percpu.c x86/mm: remove vmalloc faulting 2020-06-02 10:59:12 -07:00
signal.c Merge branch 'work.set_fs-exec' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-06-01 16:21:46 -07:00
signal_compat.c
smp.c x86/entry: Convert reschedule interrupt to IDTENTRY_SYSVEC_SIMPLE 2020-06-11 15:15:16 +02:00
smpboot.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
stacktrace.c x86 user stack frame reads: switch to explicit __get_user() 2020-02-15 17:26:26 -05:00
step.c
sys_ia32.c x86: switch cp_stat64() to unsafe_put_user() 2020-06-03 16:59:21 -04:00
sys_x86_64.c x86: Remove unneeded includes 2020-03-21 16:03:25 +01:00
sysfb.c
sysfb_efi.c x86/sysfb_efi: Add quirks for some devices with swapped width and height 2019-07-22 10:47:11 +02:00
sysfb_simplefb.c x86/sysfb: Fix check for bad VRAM size 2020-01-20 10:57:53 +01:00
tboot.c mmap locking API: add MMAP_LOCK_INITIALIZER 2020-06-09 09:39:14 -07:00
time.c A set of fixes and updates for x86: 2020-06-11 15:54:31 -07:00
tls.c x86/tls: Fix possible spectre-v1 in do_get_thread_area() 2019-06-27 23:48:04 +02:00
tls.h
topology.c x86/smp: Replace cpu_up/down() with add/remove_cpu() 2020-03-25 12:59:35 +01:00
trace_clock.c
tracepoint.c x86/entry: Convert reschedule interrupt to IDTENTRY_SYSVEC_SIMPLE 2020-06-11 15:15:16 +02:00
traps.c x86/entry: Treat BUG/WARN as NMI-like entries 2020-06-12 12:12:57 +02:00
tsc.c x86/tsc: Add tsc_early_khz command line parameter 2020-05-21 23:07:00 +02:00
tsc_msr.c x86 timer updates: 2020-03-30 19:55:39 -07:00
tsc_sync.c x86: Fix a handful of typos 2020-02-16 20:58:06 +01:00
umip.c x86/umip: Make umip_insns static 2020-04-15 11:13:12 +02:00
unwind_frame.c x86/entry: Unbreak __irqentry_text_start/end magic 2020-06-11 15:15:29 +02:00
unwind_guess.c
unwind_orc.c x86/unwind/orc: Fix unwind_get_return_address_ptr() for inactive tasks 2020-05-22 19:55:17 +02:00
uprobes.c x86/apic, x86/uprobes: Correct parameter names in kernel-doc comments 2019-10-27 09:00:28 +01:00
verify_cpu.S x86/asm: Annotate local pseudo-functions 2019-10-18 10:04:04 +02:00
vm86_32.c mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
vmlinux.lds.S The X86 entry, exception and interrupt code rework 2020-06-13 10:05:47 -07:00
vsmp_64.c
x86_init.c x86/kvm: Handle async page faults directly through do_page_fault() 2020-05-19 15:53:57 +02:00