Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
kernel-fxtec-pro1x/arch/x86/kernel
History
Alexander van Heukelum dc4c2a0aed i386: fix/simplify espfix stack switching, move it into assembly 
The espfix code triggers if we have a protected mode userspace
application with a 16-bit stack. On returning to userspace, with iret,
the CPU doesn't restore the high word of the stack pointer. This is an
"official" bug, and the work-around used in the kernel is to temporarily
switch to a 32-bit stack segment/pointer pair where the high word of the
pointer is equal to the high word of the userspace stackpointer.

The current implementation uses THREAD_SIZE to determine the cut-off,
but there is no good reason not to use the more natural 64kb... However,
implementing this by simply substituting THREAD_SIZE with 65536 in
patch_espfix_desc crashed the test application. patch_espfix_desc tries
to do what is described above, but gets it subtly wrong if the userspace
stack pointer is just below a multiple of THREAD_SIZE: an overflow
occurs to bit 13... With a bit of luck, when the kernelspace
stackpointer is just below a 64kb-boundary, the overflow then ripples
trough to bit 16 and userspace will see its stack pointer changed by
65536.

This patch moves all espfix code into entry_32.S. Selecting a 16-bit
cut-off simplifies the code. The game with changing the limit dynamically
is removed too. It complicates matters and I see no value in it. Changing
only the top 16-bit word of ESP is one instruction and it also implies
that only two bytes of the ESPFIX GDT entry need to be changed and this
can be implemented in just a handful simple to understand instructions.
As a side effect, the operation to compute the original ESP from the
ESPFIX ESP and the GDT entry simplifies a bit too, and the remaining
three instructions have been expanded inline in entry_32.S.

impact: can now reliably run userspace with ESP=xxxxfffc on 16-bit
stack segment

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: Stas Sergeev <stsp@aknet.ru>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-17 21:35:09 -07:00
..
acpi PM/ACPI/x86: Fix sparse warning in arch/x86/kernel/acpi/sleep.c 2009-06-12 21:32:29 +02:00
apic x86, ioapic: Don't call disconnect_bsp_APIC if no APIC present 2009-06-17 20:24:39 +02:00
cpu i386: fix/simplify espfix stack switching, move it into assembly 2009-06-17 21:35:09 -07:00
.gitignore
alternative.c x86: expand irq-off region in text_poke() 2009-03-10 16:24:23 +01:00
amd_iommu.c amd-iommu: flush domain tlb when attaching a new device 2009-06-15 15:42:00 +02:00
amd_iommu_init.c amd-iommu: resume cleanup 2009-06-16 10:19:16 +02:00
aperture_64.c aperture_64.c: clarify that too small aperture is valid reason for this code 2008-11-28 15:24:39 +01:00
apm_32.c PM core: rename suspend and resume functions 2009-06-12 21:32:31 +02:00
asm-offsets.c
asm-offsets_32.c lguest: optimize by coding restore_flags and irq_enable in assembler. 2009-06-12 22:27:03 +09:30
asm-offsets_64.c x86, boot: make kernel_alignment adjustable; new bzImage fields 2009-05-11 17:44:39 -07:00
audit_64.c
bios_uv.c x86, UV: system table in bios accessed after unmap 2009-04-03 19:25:57 +02:00
bootflag.c
check.c x86: fix 64k corruption-check 2009-03-15 07:03:15 +01:00
cpuid.c Merge branch 'cpus4096-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-03 12:04:39 -08:00
crash.c x86: disable IOMMUs on kernel crash 2009-06-15 15:20:40 +02:00
crash_dump_32.c kdump: make elfcorehdr_addr independent of CONFIG_PROC_VMCORE 2008-10-20 08:52:39 -07:00
crash_dump_64.c kdump: make elfcorehdr_addr independent of CONFIG_PROC_VMCORE 2008-10-20 08:52:39 -07:00
doublefault_32.c x86: fix virt_addr_valid() with CONFIG_DEBUG_VIRTUAL=y, v2 2008-10-13 10:33:15 +02:00
ds.c x86, ds: support Core i7 2009-04-07 13:36:36 +02:00
ds_selftest.c x86, ds: fix buffer alignment in debug store selftest 2009-04-24 10:18:51 +02:00
ds_selftest.h x86, bts: cleanups 2009-03-13 11:57:22 +01:00
dumpstack.c Merge commit 'origin/master' into next 2009-03-30 14:04:53 +11:00
dumpstack.h x86: avoid multiple declaration of kstack_depth_to_print 2009-04-14 11:45:33 +02:00
dumpstack_32.c ftrace: print real return in dumpstack for function graph 2008-12-03 08:56:25 +01:00
dumpstack_64.c x86-64: Move current task from PDA to per-cpu and consolidate with 32-bit. 2009-01-19 00:38:58 +09:00
e820.c x86/pci: remove rounding quirk from e820_setup_gap() 2009-05-11 09:45:14 +02:00
early-quirks.c x86 early quirks: eliminate unused function 2009-04-08 14:16:32 +02:00
early_printk.c x86: properly __init-annotate recent early_printk additions 2009-03-13 02:37:18 +01:00
efi.c x86: correct the conversion of EFI memory types 2009-06-16 17:47:32 -07:00
efi_32.c x86: fix i486 suspend to disk CR4 oops 2008-08-18 08:50:19 +02:00
efi_64.c Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2 2009-03-27 17:28:43 +01:00
efi_stub_32.S Merge branch 'x86/asm' into x86/mm 2009-02-25 08:27:46 +01:00
efi_stub_64.S x86: efi_stub_32,64 - add missing ENDPROCs 2009-02-24 18:08:40 +01:00
entry_32.S i386: fix/simplify espfix stack switching, move it into assembly 2009-06-17 21:35:09 -07:00
entry_64.S Merge branch 'linus' into x86/mce3 2009-06-11 23:31:52 +02:00
ftrace.c x86/function-graph: fix constraint for recording old return value 2009-05-13 13:52:19 -04:00
geode_32.c
head.c x86, debug: remove EBDA debug printk 2008-12-12 11:08:42 +01:00
head32.c x86-32: use brk segment for allocating initial kernel pagetable 2009-03-14 17:23:47 -07:00
head64.c x86: add brk allocation for very, very early allocations 2009-03-14 15:37:14 -07:00
head_32.S x86, vmlinux.lds: unify .text output sections 2009-04-29 10:20:31 +02:00
head_64.S x86: head_64.S - use IDT_ENTRIES instead of hardcoded number 2009-02-24 18:08:38 +01:00
hpet.c x86: hpet: Mark per cpu interrupts IRQF_TIMER to prevent resume failure 2009-06-14 18:24:29 +02:00
i386_ksyms_32.c ftrace: rename FTRACE to FUNCTION_TRACER 2008-10-20 18:27:03 +02:00
i387.c x86, math-emu: fix init_fpu for task != current 2009-03-04 20:33:16 +01:00
i8237.c i8327: fix outb() parameter order 2009-02-10 13:13:23 +01:00
i8253.c clocksource: pass clocksource to read() callback 2009-04-21 13:41:47 -07:00
i8259.c x86: refactor x86_quirks support 2009-02-23 00:08:11 +01:00
init_task.c take init_fs to saner place 2008-12-31 18:07:42 -05:00
io_delay.c x86: io_delay.c cleanup 2009-03-21 16:57:04 +05:30
ioport.c x86-32: use non-lazy io bitmap context switching 2009-03-02 12:07:48 +01:00
irq.c Merge branch 'linus' into x86/mce3 2009-06-11 23:31:52 +02:00
irq_32.c Merge branch 'tj-percpu' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/percpu 2009-02-24 21:52:45 +01:00
irq_64.c x86: unify do_IRQ() 2009-02-09 12:16:05 +01:00
irqinit.c Merge branch 'linus' into x86/mce3 2009-06-11 23:31:52 +02:00
k8.c x86, gart: fix gart detection for Fam11h CPUs 2008-10-28 17:10:27 +01:00
kdebugfs.c x86: kdebugfs.c cleanup 2009-03-21 16:55:45 +05:30
kgdb.c Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 15:49:10 -07:00
kprobes.c Merge branch 'tracing/core-v2' into tracing-for-linus 2009-04-02 00:49:02 +02:00
kvm.c Merge branch 'kvm-updates/2.6.31' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2009-06-11 10:03:30 -07:00
kvmclock.c clocksource: pass clocksource to read() callback 2009-04-21 13:41:47 -07:00
ldt.c x86: ldt.c fix style problems 2009-01-02 17:46:24 +01:00
machine_kexec_32.c x86, kexec: fix crashdump panic with CONFIG_KEXEC_JUMP 2009-05-07 22:01:05 -07:00
machine_kexec_64.c x86, kexec: fix crashdump panic with CONFIG_KEXEC_JUMP 2009-05-07 22:01:05 -07:00
Makefile x86 module: merge the rest functions with macros 2009-06-12 21:47:01 +09:30
mca_32.c x86: refactor x86_quirks support 2009-02-23 00:08:11 +01:00
mfgpt_32.c cpumask: remove references to struct irqaction's mask field. 2009-03-30 22:05:14 +10:30
microcode_amd.c x86, microcode: Simplify vfree() use 2009-06-07 16:35:11 +02:00
microcode_core.c x86: microcode: use smp_call_function_single instead of set_cpus_allowed, cleanup of synchronization logic 2009-05-12 10:36:44 +02:00
microcode_intel.c x86: microcode: use smp_call_function_single instead of set_cpus_allowed, cleanup of synchronization logic 2009-05-12 10:36:44 +02:00
mmconf-fam10h_64.c x86: move various CPU initialization objects into .cpuinit.rodata 2009-03-12 13:13:07 +01:00
module.c module: cleanup FIXME comments about trimming exception table entries. 2009-06-12 21:47:05 +09:30
mpparse.c x86, irq: don't call mp_config_acpi_gsi() if update_mptable is not enabled 2009-05-18 09:33:29 +02:00
msr.c x86: msr.c fix style problems 2009-01-12 11:22:50 +01:00
olpc.c x86, olpc: fix model detection without OFW 2009-02-14 23:05:25 +01:00
paravirt-spinlocks.c x86: remove byte locks 2009-01-20 17:14:28 +01:00
paravirt.c Merge branch 'x86-xen-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 16:16:27 -07:00
paravirt_patch_32.c x86/pvops: add a paravirt_ident functions to allow special patching 2009-01-30 14:51:44 -08:00
paravirt_patch_64.c x86/pvops: add a paravirt_ident functions to allow special patching 2009-01-30 14:51:44 -08:00
pci-calgary_64.c x86: calgary: remove IOMMU_DEBUG 2009-04-14 13:03:36 +02:00
pci-dma.c amd-iommu: disable IOMMU hardware on shutdown 2009-06-15 15:20:40 +02:00
pci-gart_64.c x86: enable GART-IOMMU only after setting up protection methods 2009-06-06 09:42:09 +02:00
pci-nommu.c dma-mapping: replace all DMA_32BIT_MASK macro with DMA_BIT_MASK(32) 2009-04-07 08:31:11 -07:00
pci-swiotlb.c Merge commit 'v2.6.30-rc5' into core/iommu 2009-05-11 14:44:31 +02:00
pcspeaker.c x86: use platform_device_register_simple() 2008-09-22 12:58:36 +02:00
pmtimer_64.c
probe_roms_32.c x86: move mach-default/*.h files to asm/ 2009-01-29 14:16:51 +01:00
process.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 19:53:40 -07:00
process_32.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 19:53:40 -07:00
process_64.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 19:53:40 -07:00
ptrace.c x86, bts, mm: clean up buffer allocation 2009-04-24 10:18:52 +02:00
pvclock.c x86: pvclock: fix shadowed variable warning 2008-10-15 14:25:14 +02:00
quirks.c Merge branch 'linus' into x86/cpu 2009-06-07 12:22:15 +02:00
reboot.c x86: Add quirk for reboot stalls on a Dell Optiplex 360 2009-06-07 15:51:20 +02:00
reboot_fixups_32.c
relocate_kernel_32.S x86, kexec: fix kexec x86 coding style 2009-03-10 18:13:25 -07:00
relocate_kernel_64.S x86, kexec: x86_64: add kexec jump support for x86_64 2009-03-10 18:13:25 -07:00
rtc.c x86: rtc.c cleanup 2009-03-21 16:56:37 +05:30
scx200_32.c
setup.c x86: handle initrd that extends into unusable memory 2009-06-11 15:19:13 -07:00
setup_percpu.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 16:13:20 -07:00
signal.c Merge branch 'linus' into x86/mce3 2009-06-11 23:31:52 +02:00
smp.c Merge branch 'linus' into x86/mce3 2009-06-11 23:31:52 +02:00
smpboot.c x86: make zap_low_mapping could be used early 2009-06-12 13:50:24 +03:00
stacktrace.c x86/stacktrace: return 0 instead of -1 for stack ops 2009-05-14 23:19:09 -04:00
step.c
sys_i386_32.c
sys_x86_64.c Merge branches 'x86/alternatives', 'x86/cleanups', 'x86/commandline', 'x86/crashdump', 'x86/debug', 'x86/defconfig', 'x86/doc', 'x86/exports', 'x86/fpu', 'x86/gart', 'x86/idle', 'x86/mm', 'x86/mtrr', 'x86/nmi-watchdog', 'x86/oprofile', 'x86/paravirt', 'x86/reboot', 'x86/sparse-fixes', 'x86/tsc', 'x86/urgent' and 'x86/vmalloc' into x86-v28-for-linus-phase1 2008-10-06 18:17:07 +02:00
syscall_64.c x86: Fix ASM_X86__ header guards 2008-10-22 22:55:23 -07:00
syscall_table_32.S Merge branch 'core/signal' into perfcounters/core 2009-04-30 21:16:49 +02:00
tce_64.c
test_nx.c
test_rodata.c
time_32.c x86: refactor x86_quirks support 2009-02-23 00:08:11 +01:00
time_64.c cpumask: remove references to struct irqaction's mask field. 2009-03-30 22:05:14 +10:30
tlb_uv.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 16:15:14 -07:00
tls.c
tls.h
topology.c x86: topology.c cleanup 2009-03-21 16:55:24 +05:30
trampoline.c x86: change static allocation of trampoline area 2008-12-08 13:49:45 +01:00
trampoline_32.S x86: use _types.h headers in asm where available 2009-02-13 11:35:01 -08:00
trampoline_64.S x86: use _types.h headers in asm where available 2009-02-13 11:35:01 -08:00
traps.c Merge branch 'linus' into x86/mce3 2009-06-11 23:31:52 +02:00
tsc.c Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 16:15:59 -07:00
tsc_sync.c x86: clean up arch/x86/kernel/tsc_sync.c a bit 2009-05-07 09:32:10 +02:00
uv_irq.c x86, apic: remove genapic.h 2009-02-17 17:52:44 +01:00
uv_sysfs.c x86: prevent /sys/firmware/sgi_uv from being created on non-uv systems 2009-04-08 14:58:10 +02:00
uv_time.c uv_time: add parameter to uv_read_rtc() 2009-04-22 17:41:25 +02:00
verify_cpu_64.S
visws_quirks.c x86: convert obsolete irq_desc_t typedef to struct irq_desc 2009-03-11 09:49:01 +01:00
vm86_32.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-10 16:15:14 -07:00
vmi_32.c Merge commit 'origin/master' into for-linus/xen/master 2009-04-07 13:34:16 -07:00
vmiclock_32.c clocksource: pass clocksource to read() callback 2009-04-21 13:41:47 -07:00
vmlinux.lds.S x86: Provide _sdata in the vmlinux.lds.S file 2009-06-12 09:21:33 +02:00
vsmp_64.c Revert "x86: don't compile vsmp_64 for 32bit" 2009-03-25 21:34:28 +01:00
vsyscall_64.c x86: move rdtsc_barrier() into the TSC vread method 2009-05-28 14:15:54 +02:00
x8664_ksyms_64.c x86: convert pda ops to wrappers around x86 percpu accessors 2009-01-16 14:20:22 +01:00
xsave.c x86-64: fix FPU corruption with signals and preemption 2009-04-20 14:33:00 -07:00