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x86/entry/32: Split off return-to-kernel path

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Use a separate return path when returning to the kernel.

This allows to put the PTI cr3-switch and the switch to the entry-stack
into the return-to-user path without further checking.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-7-git-send-email-joro@8bytes.org
This commit is contained in:
Joerg Roedel 2018-07-18 11:40:43 +02:00 committed by Thomas Gleixner
parent 8e676ced31
commit 0d2eb73b29
1 changed files with 8 additions and 3 deletions
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11
arch/x86/entry/entry_32.S
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@ -65,7 +65,7 @@
# define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
#else
# define preempt_stop(clobbers)
# define resume_kernel restore_all
# define resume_kernel restore_all_kernel
#endif
.macro TRACE_IRQS_IRET
@ -399,9 +399,9 @@ ENTRY(resume_kernel)
DISABLE_INTERRUPTS(CLBR_ANY)
.Lneed_resched:
cmpl $0, PER_CPU_VAR(__preempt_count)
jnz restore_all
jnz restore_all_kernel
testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ?
jz restore_all
jz restore_all_kernel
call preempt_schedule_irq
jmp .Lneed_resched
END(resume_kernel)
@ -606,6 +606,11 @@ restore_all:
*/
INTERRUPT_RETURN
restore_all_kernel:
TRACE_IRQS_IRET
RESTORE_REGS 4
jmp .Lirq_return
.section .fixup, "ax"
ENTRY(iret_exc )
pushl $0 # no error code