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72a671ced6
linux/arch/x86/kernel
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Suresh Siddha 72a671ced6 x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels 
Currently for x86 and x86_32 binaries, fpstate in the user sigframe is copied
to/from the fpstate in the task struct.

And in the case of signal delivery for x86_64 binaries, if the fpstate is live
in the CPU registers, then the live state is copied directly to the user
sigframe. Otherwise  fpstate in the task struct is copied to the user sigframe.
During restore, fpstate in the user sigframe is restored directly to the live
CPU registers.

Historically, different code paths led to different bugs. For example,
x86_64 code path was not preemption safe till recently. Also there is lot
of code duplication for support of new features like xsave etc.

Unify signal handling code paths for x86 and x86_64 kernels.

New strategy is as follows:

Signal delivery: Both for 32/64-bit frames, align the core math frame area to
64bytes as needed by xsave (this where the main fpu/extended state gets copied
to and excludes the legacy compatibility fsave header for the 32-bit [f]xsave
frames). If the state is live, copy the register state directly to the user
frame. If not live, copy the state in the thread struct to the user frame. And
for 32-bit [f]xsave frames, construct the fsave header separately before
the actual [f]xsave area.

Signal return: As the 32-bit frames with [f]xstate has an additional
'fsave' header, copy everything back from the user sigframe to the
fpstate in the task structure and reconstruct the fxstate from the 'fsave'
header (Also user passed pointers may not be correctly aligned for
any attempt to directly restore any partial state). At the next fpstate usage,
everything will be restored to the live CPU registers.
For all the 64-bit frames and the 32-bit fsave frame, restore the state from
the user sigframe directly to the live CPU registers. 64-bit signals always
restored the math frame directly, so we can expect the math frame pointer
to be correctly aligned. For 32-bit fsave frames, there are no alignment
requirements, so we can restore the state directly.

"lat_sig catch" microbenchmark numbers (for x86, x86_64, x86_32 binaries) are
with in the noise range with this change.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1343171129-2747-4-git-send-email-suresh.b.siddha@intel.com
[ Merged in compilation fix ]
Link: http://lkml.kernel.org/r/1344544736.8326.17.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2012-09-18 15:51:48 -07:00
..
acpi ACPI/x86: revert 'x86, acpi: Call acpi_enter_sleep_state via an asmlinkage C function from assembler' 2012-07-30 21:10:16 -04:00
apic x86, apic: fix broken legacy interrupts in the logical apic mode 2012-08-14 09:52:20 -07:00
cpu Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-08-20 10:36:18 -07:00
.gitignore
alternative.c x86/alternatives: Fix p6 nops on non-modular kernels 2012-08-22 12:09:49 +02:00
amd_gart_64.c X86 & IA64: adapt for dma_map_ops changes 2012-03-28 16:36:31 +02:00
amd_nb.c Merge branch 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-07-22 16:07:45 -07:00
apb_timer.c Merge branch 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-07-23 10:34:47 -07:00
aperture_64.c x86/gart: Fix kmemleak warning 2012-06-06 11:58:38 +02:00
apm_32.c x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level> 2012-06-06 09:17:22 +02:00
asm-offsets_32.c x86: Generate system call tables and unistd_*.h from tables 2011-11-17 13:35:37 -08:00
asm-offsets_64.c x32: If configured, add x32 system calls to system call tables 2012-02-20 12:52:06 -08:00
asm-offsets.c x86, efi: EFI boot stub support 2011-12-12 14:26:10 -08:00
audit_64.c
bootflag.c
check.c x86: kernel/check.c simple_strtoul cleanup 2012-05-15 15:36:41 -07:00
cpuid.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
crash_dump_32.c x86: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:15 +08:00
crash_dump_64.c crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn 2011-03-23 19:47:19 -07:00
crash.c x86, nmi: Wire up NMI handlers to new routines 2011-10-10 06:56:57 +02:00
devicetree.c irq_domain/x86: Convert x86 (embedded) to use common irq_domain 2012-02-23 14:37:47 -07:00
doublefault_32.c
dumpstack_32.c x86: Move call to print_modules() out of show_regs() 2012-06-20 14:33:48 +02:00
dumpstack_64.c x86: Move call to print_modules() out of show_regs() 2012-06-20 14:33:48 +02:00
dumpstack.c x86: Move call to print_modules() out of show_regs() 2012-06-20 14:33:48 +02:00
e820.c firmware_map: make firmware_map_add_early() argument consistent with firmware_map_add_hotplug() 2012-07-30 17:25:17 -07:00
early_printk.c Revert "x86/early_printk: Replace obsolete simple_strtoul() usage with kstrtoint()" 2012-07-22 15:47:52 +02:00
early-quirks.c x86, quirk: Fix SB600 revision check 2011-03-16 14:03:32 +01:00
entry_32.S x86: get rid of calling do_notify_resume() when returning to kernel mode 2012-06-01 13:01:51 -04:00
entry_64.S Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-07-26 13:17:17 -07:00
ftrace.c ftrace: Use breakpoint method to update ftrace caller 2012-05-31 23:12:19 -04:00
head32.c x86, realmode: Move ACPI wakeup to unified realmode code 2012-05-08 11:46:05 -07:00
head64.c x86, realmode: Move ACPI wakeup to unified realmode code 2012-05-08 11:46:05 -07:00
head_32.S Merge branch 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-05-29 20:14:53 -07:00
head_64.S Merge branch 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-05-29 20:14:53 -07:00
head.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
hpet.c x86: hpet: Fix copy-and-paste mistake in earlier change 2012-05-25 15:32:29 +02:00
hw_breakpoint.c
i386_ksyms_32.c
i387.c x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels 2012-09-18 15:51:48 -07:00
i8237.c x86: Use syscore_ops instead of sysdev classes and sysdevs 2011-03-23 22:15:54 +01:00
i8253.c x86: Use common i8253 clockevent 2011-07-01 10:37:14 +02:00
i8259.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
io_delay.c
ioport.c
irq_32.c x86: Use common threadinfo allocator 2012-05-08 14:08:44 +02:00
irq_64.c x86: Add stack top margin for stack overflow checking 2011-12-07 09:27:11 +01:00
irq_work.c
irq.c x86/fixup_irq: Use cpu_online_mask instead of cpu_all_mask 2012-08-22 10:36:08 +02:00
irqinit.c x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR 2012-06-27 19:29:13 -07:00
jump_label.c jump_label, x86: Fix section mismatch 2011-12-06 20:41:02 +01:00
kdebugfs.c arch/x86/kernel/kdebugfs.c: Ensure a consistent return value in error case 2012-07-26 15:07:20 +02:00
kgdb.c x86: Fix kernel-doc warnings 2012-06-18 10:53:18 +02:00
kprobes-common.h x86/kprobes: Split out optprobe related code to kprobes-opt.c 2012-03-06 09:49:49 +01:00
kprobes-opt.c x86/kprobes: Split out optprobe related code to kprobes-opt.c 2012-03-06 09:49:49 +01:00
kprobes.c x86: Avoid double stack traces with show_regs() 2012-05-09 11:44:42 +02:00
kvm.c KVM guest: switch to apic_set_eoi_write, apic_write 2012-07-16 12:51:44 +03:00
kvmclock.c x86: kvmclock: remove check_and_clear_guest_paused warning 2012-06-11 23:18:33 -03:00
ldt.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
machine_kexec_32.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
machine_kexec_64.c
Makefile Merge branch 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-05-29 20:14:53 -07:00
microcode_amd.c x86, microcode, AMD: Fix broken ucode patch size check 2012-08-22 16:10:41 -07:00
microcode_core.c Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-07-22 12:04:44 -07:00
microcode_intel.c x86/microcode: Ensure that module is only loaded on supported Intel CPUs 2012-05-07 14:37:14 +02:00
mmconf-fam10h_64.c
module.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-07-24 13:34:56 -07:00
mpparse.c Merge branch 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-05-29 20:14:53 -07:00
msr.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
nmi_selftest.c x86/nmi: Clean up register_nmi_handler() usage 2012-06-20 14:23:17 +02:00
nmi.c x86: Save cr2 in NMI in case NMIs take a page fault (for i386) 2012-06-08 18:51:12 -04:00
paravirt_patch_32.c
paravirt_patch_64.c
paravirt-spinlocks.c
paravirt.c x86, pvops: Remove hooks for {rd,wr}msr_safe_regs 2012-06-07 11:41:08 -07:00
pci-calgary_64.c x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level> 2012-06-06 09:17:22 +02:00
pci-dma.c iommu: Remove group_mf 2012-06-25 13:48:30 +02:00
pci-iommu_table.c arch/x86/kernel/pci-iommu_table.c: Convert sprintf_symbol to %pS 2011-05-10 10:21:35 +02:00
pci-nommu.c X86: integrate CMA with DMA-mapping subsystem 2012-05-21 15:09:38 +02:00
pci-swiotlb.c X86 & IA64: adapt for dma_map_ops changes 2012-03-28 16:36:31 +02:00
pcspeaker.c
probe_roms.c x86/pci/probe_roms: Add missing __iomem annotation to pci_map_biosrom() 2012-09-05 10:52:25 +02:00
process_32.c Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-05-23 10:59:07 -07:00
process_64.c Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-07-22 12:04:44 -07:00
process.c x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels 2012-09-18 15:51:48 -07:00
ptrace.c x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels 2012-09-18 15:51:48 -07:00
pvclock.c
quirks.c x86/PCI: move fixup hooks from __init to __devinit 2012-06-12 09:10:54 -06:00
reboot_fixups_32.c
reboot.c Merge branch 'x86-reboot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-07-22 12:25:47 -07:00
relocate_kernel_32.S kexec, x86: Fix incorrect jump back address if not preserving context 2011-07-21 11:19:28 +02:00
relocate_kernel_64.S kexec, x86: Fix incorrect jump back address if not preserving context 2011-07-21 11:19:28 +02:00
resource.c
rtc.c x86/rtc, mrst: Don't register a platform RTC device for for Intel MID platforms 2011-12-05 17:09:21 +01:00
setup_percpu.c x86: Add read_mostly declaration/definition to variables from smp.h 2012-06-14 12:42:11 +02:00
setup.c Merge branch 'x86/cleanups' into x86/apic 2012-06-15 14:17:01 +02:00
signal.c x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels 2012-09-18 15:51:48 -07:00
smp.c x86/reboot: Update nonmi_ipi parameter 2012-05-14 11:49:38 +02:00
smpboot.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-07-26 13:17:17 -07:00
stacktrace.c x86: Swap save_stack_trace_regs parameters 2011-06-14 22:48:51 -04:00
step.c x86-64: Add user_64bit_mode paravirt op 2011-08-04 16:13:49 -07:00
sys_i386_32.c
sys_x86_64.c Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:12:23 -07:00
syscall_32.c x86, syscall: Re-fix typo in comment 2011-11-18 16:25:07 -08:00
syscall_64.c x32: If configured, add x32 system calls to system call tables 2012-02-20 12:52:06 -08:00
tboot.c x86, realmode: fixes compilation issue in tboot.c 2012-05-08 15:04:27 -07:00
tce_64.c Disintegrate asm/system.h for X86 2012-03-28 18:11:12 +01:00
test_nx.c x86: Eliminate various 'set but not used' warnings 2011-05-21 19:10:33 +02:00
test_rodata.c x86, extable: Remove open-coded exception table entries in arch/x86/kernel/test_rodata.c 2012-04-20 13:51:38 -07:00
time.c MCA: delete all remaining traces of microchannel bus support. 2012-05-17 19:06:13 -04:00
tls.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 14:28:26 -07:00
tls.h
topology.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
traps.c x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level> 2012-06-06 09:17:22 +02:00
tsc_sync.c x86/tsc: Reduce the TSC sync check time for core-siblings 2012-02-22 11:49:40 +01:00
tsc.c x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level> 2012-06-06 09:17:22 +02:00
uprobes.c uprobes: Pass probed vaddr to arch_uprobe_analyze_insn() 2012-06-08 12:22:27 +02:00
verify_cpu.S x86: Fix common misspellings 2011-03-18 10:39:30 +01:00
vm86_32.c x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level> 2012-06-06 09:17:22 +02:00
vmlinux.lds.S x86, realmode: Move ACPI wakeup to unified realmode code 2012-05-08 11:46:05 -07:00
vsmp_64.c x86/apic/x2apic: Limit the vector reservation to the user specified mask 2012-07-06 11:00:22 +02:00
vsyscall_64.c Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-07-22 12:04:44 -07:00
vsyscall_emu_64.S x86-64: Rework vsyscall emulation and add vsyscall= parameter 2011-08-10 19:26:46 -05:00
vsyscall_trace.h x86-64: Add vsyscall:emulate_vsyscall trace event 2011-08-04 16:13:53 -07:00
x86_init.c Revert "x86/platform: Add a wallclock_init func to x86_platforms ops" 2012-05-24 23:16:14 +02:00
x8664_ksyms_64.c x86/copy_user_generic: Optimize copy_user_generic with CPU erms feature 2012-06-29 15:33:34 -07:00
xsave.c x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels 2012-09-18 15:51:48 -07:00