linux/arch/x86
Christian Melki 9d99c7123c swiotlb: Enable it under x86 PAE
Most distributions end up enabling SWIOTLB already with 32-bit
kernels due to the combination of CONFIG_HYPERVISOR_GUEST|CONFIG_XEN=y
as those end up requiring the SWIOTLB.

However for those that are not interested in virtualization and
run in 32-bit they will discover that: "32-bit PAE 4.2.0 kernel
(no IOMMU code) would hang when writing to my USB disk. The kernel
spews million(-ish messages per sec) to syslog, effectively
"hanging" userspace with my kernel.

Oct  2 14:33:06 voodoochild kernel: [  223.287447] nommu_map_sg:
overflow 25dcac000+1024 of device mask ffffffff
Oct  2 14:33:06 voodoochild kernel: [  223.287448] nommu_map_sg:
overflow 25dcac000+1024 of device mask ffffffff
Oct  2 14:33:06 voodoochild kernel: [  223.287449] nommu_map_sg:
overflow 25dcac000+1024 of device mask ffffffff
... etc ..."

Enabling it makes the problem go away.

N.B. With a6dfa128ce
"config: Enable NEED_DMA_MAP_STATE by default when SWIOTLB is selected"
we also have the important part of the SG macros enabled to make this
work properly - in case anybody wants to backport this patch.

Reported-and-Tested-by: Christian Melki <christian.melki@t2data.com>
Signed-off-by: Christian Melki <christian.melki@t2data.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2015-10-07 15:31:35 -04:00
..
boot lib/decompressors: use real out buf size for gunzip with kernel 2015-09-10 13:29:01 -07:00
configs Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2015-09-04 15:49:32 -07:00
crypto crypto: ghash-clmulni: specify context size for ghash async algorithm 2015-09-04 23:21:07 +08:00
entry x86/nmi/64: Fix a paravirt stack-clobbering bug in the NMI code 2015-09-22 22:40:36 +02:00
ia32 x86/compat: Move copy_siginfo_*_user32() to signal_compat.c 2015-07-06 15:28:55 +02:00
include Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-10-03 10:53:05 -04:00
kernel Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-10-03 10:53:05 -04:00
kvm Use WARN_ON_ONCE for missing X86_FEATURE_NRIPS 2015-10-01 14:59:37 +02:00
lguest genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
lib x86/asm/delay: Introduce an MWAITX-based delay with a configurable timer 2015-08-22 14:52:16 +02:00
math-emu Merge branch 'x86/urgent' into x86/asm to fix up conflicts and to pick up fixes 2015-08-18 09:39:47 +02:00
mm x86/mm: Set NX on gap between __ex_table and rodata 2015-10-02 09:21:06 +02:00
net bpf: Make the bpf_prog_array_map more generic 2015-08-09 22:50:05 -07:00
oprofile
pci PCI: Revert "PCI: Call pci_read_bridge_bases() from core instead of arch code" 2015-09-15 13:18:04 -05:00
platform x86/efi: Fix boot crash by mapping EFI memmap entries bottom-up at runtime, instead of top-down 2015-10-01 12:51:28 +02:00
power x86/ldt: Make modify_ldt synchronous 2015-07-31 10:23:23 +02:00
purgatory
ras x86/ras: Move AMD MCE injector to arch/x86/ras/ 2015-08-13 10:12:54 +02:00
realmode
tools
um x86/asm/tsc: Remove rdtsc_barrier() 2015-07-06 15:23:30 +02:00
video
xen xen: MFN/GFN/BFN terminology changes for 4.3-rc0 2015-09-10 16:21:11 -07:00
.gitignore
Kbuild x86/asm/entry, x86/vdso: Move the vDSO code to arch/x86/entry/vdso/ 2015-06-03 18:51:37 +02:00
Kconfig swiotlb: Enable it under x86 PAE 2015-10-07 15:31:35 -04:00
Kconfig.cpu
Kconfig.debug x86/entry/64, x86/nmi/64: Add CONFIG_DEBUG_ENTRY NMI testing code 2015-07-17 12:50:14 +02:00
Makefile Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-09-01 08:40:25 -07:00
Makefile_32.cpu
Makefile.um