linux_dsm_epyc7002/Documentation/x86/x86_64
Andy Lutomirski 48e08d0fb2 x86, entry: Switch stacks on a paranoid entry from userspace
This causes all non-NMI, non-double-fault kernel entries from
userspace to run on the normal kernel stack.  Double-fault is
exempt to minimize confusion if we double-fault directly from
userspace due to a bad kernel stack.

This is, suprisingly, simpler and shorter than the current code.  It
removes the IMO rather frightening paranoid_userspace path, and it
make sync_regs much simpler.

There is no risk of stack overflow due to this change -- the kernel
stack that we switch to is empty.

This will also enable us to create non-atomic sections within
machine checks from userspace, which will simplify memory failure
handling.  It will also allow the upcoming fsgsbase code to be
simplified, because it doesn't need to worry about usergs when
scheduling in paranoid_exit, as that code no longer exists.

Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tony Luck <tony.luck@intel.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
2015-01-02 10:22:45 -08:00
..
00-INDEX
boot-options.txt Documentation: Update x86_64/boot-options.txt 2013-12-02 14:47:44 +01:00
cpu-hotplug-spec
fake-numa-for-cpusets trivial: fix where cgroup documentation is not correctly referred to 2009-03-30 15:22:02 +02:00
kernel-stacks x86, entry: Switch stacks on a paranoid entry from userspace 2015-01-02 10:22:45 -08:00
machinecheck x86, mce: switch x86 machine check handler to Monarch election. 2009-06-03 14:45:12 -07:00
mm.txt x86/mm: Update memory map description to list hypervisor-reserved area 2014-09-19 12:48:02 +02:00
uefi.txt x86 boot: only pick up additional EFI memmap if add_efi_memmap flag 2008-07-08 13:10:41 +02:00