[RFC 0/3] Baby steps toward cleaning up KERNEL_STACK_OFFSET

[Andy Lutomirski]

Denys is right that KERNEL_STACK_OFFSET is a mess.  Let's start fixing
it.

This removes all C code that *reads* kernel_stack.  It also fixes the
KERNEL_STACK_OFFSET abomination in ia32_sysenter_target.

It does not fix the KERNEL_STACK_OFFSET abomination in GET_THREAD_INFO
and THREAD_INFO.  I think that should be its own patch.

It also doesn't change the two syscall targets.  To fix them, we should
make a decision.  Either we should make KERNEL_STACK_OFFSET have the
correct nonzero value to save an instruction or we should get rid of
kernel_stack entirely.

Andy Lutomirski (3):
  x86: Add this_cpu_sp0() to read sp0 for the current cpu
  x86: Switch all C consumers of kernel_stack to this_cpu_sp0
  x86, asm: Change the 32-bit sysenter code to use sp0

 arch/x86/ia32/ia32entry.S          | 3 +--
 arch/x86/include/asm/processor.h   | 5 +++++
 arch/x86/include/asm/thread_info.h | 3 +--
 arch/x86/kernel/asm-offsets_64.c   | 1 +
 arch/x86/kernel/traps.c            | 2 +-
 arch/x86/lguest/boot.c             | 1 +
 arch/x86/xen/enlighten.c           | 1 +
 7 files changed, 11 insertions(+), 5 deletions(-)

-- 
2.1.0

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