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linux/arch/x86/power
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Andy Lutomirski 7ee18d6779 x86/power: Make restore_processor_context() sane 
My previous attempt to fix a couple of bugs in __restore_processor_context():

  5b06bbcfc2 ("x86/power: Fix some ordering bugs in __restore_processor_context()")

... introduced yet another bug, breaking suspend-resume.

Rather than trying to come up with a minimal fix, let's try to clean it up
for real.  This patch fixes quite a few things:

 - The old code saved a nonsensical subset of segment registers.
   The only registers that need to be saved are those that contain
   userspace state or those that can't be trivially restored without
   percpu access working.  (On x86_32, we can restore percpu access
   by writing __KERNEL_PERCPU to %fs.  On x86_64, it's easier to
   save and restore the kernel's GSBASE.)  With this patch, we
   restore hardcoded values to the kernel state where applicable and
   explicitly restore the user state after fixing all the descriptor
   tables.

 - We used to use an unholy mix of inline asm and C helpers for
   segment register access.  Let's get rid of the inline asm.

This fixes the reported s2ram hangs and make the code all around
more logical.

Analyzed-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reported-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Fixes: 5b06bbcfc2 ("x86/power: Fix some ordering bugs in __restore_processor_context()")
Link: http://lkml.kernel.org/r/398ee68e5c0f766425a7b746becfc810840770ff.1513286253.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-12-15 12:21:38 +01:00
..
cpu.c x86/power: Make restore_processor_context() sane 2017-12-15 12:21:38 +01:00
hibernate_32.c x86/mm: Convert trivial cases of page table walk to 5-level paging 2017-03-14 08:45:08 +01:00
hibernate_64.c x86/hibernate/64: Mask off CR3's PCID bits in the saved CR3 2017-09-13 09:52:37 +02:00
hibernate_asm_32.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hibernate_asm_64.S x86/power/64: Do not refer to __PAGE_OFFSET from assembly code 2016-08-03 01:35:38 +02:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00