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Commit 0f9a4810 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/entry: Clean up the SYSENTER_stack code 



The existing code was a mess, mainly because C arrays are nasty.  Turn
SYSENTER_stack into a struct, add a helper to find it, and do all the
obvious cleanups this enables.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarBorislav Petkov <bpetkov@suse.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.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: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
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
Link: https://lkml.kernel.org/r/20171204150606.653244723@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7fbbd5cb

arch/x86/entry/entry_32.S

+2 −2
Original line number Diff line number Diff line
@@ -942,7 +942,7 @@ ENTRY(debug) 


	/* Are we currently on the SYSENTER stack? */

	movl	PER_CPU_VAR(cpu_entry_area), %ecx

	addl	$CPU_ENTRY_AREA_tss + CPU_TSS_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx

	addl	$CPU_ENTRY_AREA_tss + TSS_STRUCT_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx

	subl	%eax, %ecx	/* ecx = (end of SYSENTER_stack) - esp */

	cmpl	$SIZEOF_SYSENTER_stack, %ecx

	jb	.Ldebug_from_sysenter_stack
@@ -986,7 +986,7 @@ ENTRY(nmi) 


	/* Are we currently on the SYSENTER stack? */

	movl	PER_CPU_VAR(cpu_entry_area), %ecx

	addl	$CPU_ENTRY_AREA_tss + CPU_TSS_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx

	addl	$CPU_ENTRY_AREA_tss + TSS_STRUCT_SYSENTER_stack + SIZEOF_SYSENTER_stack, %ecx

	subl	%eax, %ecx	/* ecx = (end of SYSENTER_stack) - esp */

	cmpl	$SIZEOF_SYSENTER_stack, %ecx

	jb	.Lnmi_from_sysenter_stack

arch/x86/entry/entry_64.S

+1 −1
Original line number Diff line number Diff line
@@ -154,7 +154,7 @@ END(native_usergs_sysret64) 
	_entry_trampoline - CPU_ENTRY_AREA_entry_trampoline(%rip)



/* The top word of the SYSENTER stack is hot and is usable as scratch space. */

#define RSP_SCRATCH	CPU_ENTRY_AREA_tss + CPU_TSS_SYSENTER_stack + \

#define RSP_SCRATCH	CPU_ENTRY_AREA_tss + TSS_STRUCT_SYSENTER_stack + \

			SIZEOF_SYSENTER_stack - 8 + CPU_ENTRY_AREA



ENTRY(entry_SYSCALL_64_trampoline)

arch/x86/include/asm/fixmap.h

+5 −0
Original line number Diff line number Diff line
@@ -245,5 +245,10 @@ static inline struct cpu_entry_area *get_cpu_entry_area(int cpu) 
	return (struct cpu_entry_area *)__fix_to_virt(__get_cpu_entry_area_page_index(cpu, 0));

}



static inline struct SYSENTER_stack *cpu_SYSENTER_stack(int cpu)

{

	return &get_cpu_entry_area(cpu)->tss.SYSENTER_stack;

}



#endif /* !__ASSEMBLY__ */

#endif /* _ASM_X86_FIXMAP_H */

arch/x86/include/asm/processor.h

+5 −1
Original line number Diff line number Diff line
@@ -336,12 +336,16 @@ struct x86_hw_tss { 
#define IO_BITMAP_OFFSET		(offsetof(struct tss_struct, io_bitmap) - offsetof(struct tss_struct, x86_tss))

#define INVALID_IO_BITMAP_OFFSET	0x8000



struct SYSENTER_stack {

	unsigned long		words[64];

};



struct tss_struct {

	/*

	 * Space for the temporary SYSENTER stack, used for SYSENTER

	 * and the entry trampoline as well.

	 */

	unsigned long		SYSENTER_stack[64];

	struct SYSENTER_stack	SYSENTER_stack;



	/*

	 * The fixed hardware portion.  This must not cross a page boundary

arch/x86/kernel/asm-offsets.c

+2 −4
Original line number Diff line number Diff line
@@ -94,10 +94,8 @@ void common(void) { 
	BLANK();

	DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));



	/* Offset from cpu_tss to SYSENTER_stack */

	OFFSET(CPU_TSS_SYSENTER_stack, tss_struct, SYSENTER_stack);

	/* Size of SYSENTER_stack */

	DEFINE(SIZEOF_SYSENTER_stack, sizeof(((struct tss_struct *)0)->SYSENTER_stack));

	OFFSET(TSS_STRUCT_SYSENTER_stack, tss_struct, SYSENTER_stack);

	DEFINE(SIZEOF_SYSENTER_stack, sizeof(struct SYSENTER_stack));



	/* Layout info for cpu_entry_area */

	OFFSET(CPU_ENTRY_AREA_tss, cpu_entry_area, tss);