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Commit 29ae8a6a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'xtensa-next-20140721' of git://github.com/czankel/xtensa-linux 

Pull Xtensa fixes from Chris Zankel:
 - resolve FIXMEs in double exception handler for window overflow. This
   fix makes native building of linux on xtensa host possible;
 - fix sysmem region removal issue introduced in 3.15.

* tag 'xtensa-next-20140721' of git://github.com/czankel/xtensa-linux:
  xtensa: fix sysmem reservation at the end of existing block
  xtensa: add fixup for double exception raised in window overflow
parents 02ec4747 4ed2ad38

arch/xtensa/kernel/vectors.S

+136 −22
Original line number Diff line number Diff line
@@ -376,38 +376,42 @@ _DoubleExceptionVector_WindowOverflow: 
	beqz	a2, 1f		# if at start of vector, don't restore



	addi	a0, a0, -128

	bbsi	a0, 8, 1f	# don't restore except for overflow 8 and 12

	bbsi	a0, 7, 2f

	bbsi.l	a0, 8, 1f	# don't restore except for overflow 8 and 12



	/*

	 * This fixup handler is for the extremely unlikely case where the

	 * overflow handler's reference thru a0 gets a hardware TLB refill

	 * that bumps out the (distinct, aliasing) TLB entry that mapped its

	 * prior references thru a9/a13, and where our reference now thru

	 * a9/a13 gets a 2nd-level miss exception (not hardware TLB refill).

	 */

	movi	a2, window_overflow_restore_a0_fixup

	s32i	a2, a3, EXC_TABLE_FIXUP

	l32i	a2, a3, EXC_TABLE_DOUBLE_SAVE

	xsr	a3, excsave1



	bbsi.l	a0, 7, 2f



	/*

	 * Restore a0 as saved by _WindowOverflow8().

	 *

	 * FIXME:  we really need a fixup handler for this L32E,

	 * for the extremely unlikely case where the overflow handler's

	 * reference thru a0 gets a hardware TLB refill that bumps out

	 * the (distinct, aliasing) TLB entry that mapped its prior

	 * references thru a9, and where our reference now thru a9

	 * gets a 2nd-level miss exception (not hardware TLB refill).

	 */



	l32e	a2, a9, -16

	wsr	a2, depc	# replace the saved a0

	j	1f

	l32e	a0, a9, -16

	wsr	a0, depc	# replace the saved a0

	j	3f



2:

	/*

	 * Restore a0 as saved by _WindowOverflow12().

	 *

	 * FIXME:  we really need a fixup handler for this L32E,

	 * for the extremely unlikely case where the overflow handler's

	 * reference thru a0 gets a hardware TLB refill that bumps out

	 * the (distinct, aliasing) TLB entry that mapped its prior

	 * references thru a13, and where our reference now thru a13

	 * gets a 2nd-level miss exception (not hardware TLB refill).

	 */



	l32e	a2, a13, -16

	wsr	a2, depc	# replace the saved a0

	l32e	a0, a13, -16

	wsr	a0, depc	# replace the saved a0

3:

	xsr	a3, excsave1

	movi	a0, 0

	s32i	a0, a3, EXC_TABLE_FIXUP

	s32i	a2, a3, EXC_TABLE_DOUBLE_SAVE

1:

	/*

	 * Restore WindowBase while leaving all address registers restored.
@@ -449,6 +453,7 @@ _DoubleExceptionVector_WindowOverflow: 


	s32i	a0, a2, PT_DEPC



_DoubleExceptionVector_handle_exception:

	addx4	a0, a0, a3

	l32i	a0, a0, EXC_TABLE_FAST_USER

	xsr	a3, excsave1
@@ -464,10 +469,119 @@ _DoubleExceptionVector_WindowOverflow: 
	rotw	-3

	j	1b



	.end literal_prefix



ENDPROC(_DoubleExceptionVector)



/*

 * Fixup handler for TLB miss in double exception handler for window owerflow.

 * We get here with windowbase set to the window that was being spilled and

 * a0 trashed. a0 bit 7 determines if this is a call8 (bit clear) or call12

 * (bit set) window.

 *

 * We do the following here:

 * - go to the original window retaining a0 value;

 * - set up exception stack to return back to appropriate a0 restore code

 *   (we'll need to rotate window back and there's no place to save this

 *    information, use different return address for that);

 * - handle the exception;

 * - go to the window that was being spilled;

 * - set up window_overflow_restore_a0_fixup as a fixup routine;

 * - reload a0;

 * - restore the original window;

 * - reset the default fixup routine;

 * - return to user. By the time we get to this fixup handler all information

 *   about the conditions of the original double exception that happened in

 *   the window overflow handler is lost, so we just return to userspace to

 *   retry overflow from start.

 *

 * a0: value of depc, original value in depc

 * a2: trashed, original value in EXC_TABLE_DOUBLE_SAVE

 * a3: exctable, original value in excsave1

 */



ENTRY(window_overflow_restore_a0_fixup)



	rsr	a0, ps

	extui	a0, a0, PS_OWB_SHIFT, PS_OWB_WIDTH

	rsr	a2, windowbase

	sub	a0, a2, a0

	extui	a0, a0, 0, 3

	l32i	a2, a3, EXC_TABLE_DOUBLE_SAVE

	xsr	a3, excsave1



	_beqi	a0, 1, .Lhandle_1

	_beqi	a0, 3, .Lhandle_3



	.macro	overflow_fixup_handle_exception_pane n



	rsr	a0, depc

	rotw	-\n



	xsr	a3, excsave1

	wsr	a2, depc

	l32i	a2, a3, EXC_TABLE_KSTK

	s32i	a0, a2, PT_AREG0



	movi	a0, .Lrestore_\n

	s32i	a0, a2, PT_DEPC

	rsr	a0, exccause

	j	_DoubleExceptionVector_handle_exception



	.endm



	overflow_fixup_handle_exception_pane 2

.Lhandle_1:

	overflow_fixup_handle_exception_pane 1

.Lhandle_3:

	overflow_fixup_handle_exception_pane 3



	.macro	overflow_fixup_restore_a0_pane n



	rotw	\n

	/* Need to preserve a0 value here to be able to handle exception

	 * that may occur on a0 reload from stack. It may occur because

	 * TLB miss handler may not be atomic and pointer to page table

	 * may be lost before we get here. There are no free registers,

	 * so we need to use EXC_TABLE_DOUBLE_SAVE area.

	 */

	xsr	a3, excsave1

	s32i	a2, a3, EXC_TABLE_DOUBLE_SAVE

	movi	a2, window_overflow_restore_a0_fixup

	s32i	a2, a3, EXC_TABLE_FIXUP

	l32i	a2, a3, EXC_TABLE_DOUBLE_SAVE

	xsr	a3, excsave1

	bbsi.l	a0, 7, 1f

	l32e	a0, a9, -16

	j	2f

1:

	l32e	a0, a13, -16

2:

	rotw	-\n



	.endm



.Lrestore_2:

	overflow_fixup_restore_a0_pane 2



.Lset_default_fixup:

	xsr	a3, excsave1

	s32i	a2, a3, EXC_TABLE_DOUBLE_SAVE

	movi	a2, 0

	s32i	a2, a3, EXC_TABLE_FIXUP

	l32i	a2, a3, EXC_TABLE_DOUBLE_SAVE

	xsr	a3, excsave1

	rfe



.Lrestore_1:

	overflow_fixup_restore_a0_pane 1

	j	.Lset_default_fixup

.Lrestore_3:

	overflow_fixup_restore_a0_pane 3

	j	.Lset_default_fixup



ENDPROC(window_overflow_restore_a0_fixup)



	.end literal_prefix

/*

 * Debug interrupt vector

 *

arch/xtensa/kernel/vmlinux.lds.S

+2 −2
Original line number Diff line number Diff line
@@ -269,13 +269,13 @@ SECTIONS 
		  .UserExceptionVector.literal)

  SECTION_VECTOR (_DoubleExceptionVector_literal,

		  .DoubleExceptionVector.literal,

		  DOUBLEEXC_VECTOR_VADDR - 16,

		  DOUBLEEXC_VECTOR_VADDR - 40,

		  SIZEOF(.UserExceptionVector.text),

		  .UserExceptionVector.text)

  SECTION_VECTOR (_DoubleExceptionVector_text,

		  .DoubleExceptionVector.text,

		  DOUBLEEXC_VECTOR_VADDR,

		  32,

		  40,

		  .DoubleExceptionVector.literal)



  . = (LOADADDR( .DoubleExceptionVector.text ) + SIZEOF( .DoubleExceptionVector.text ) + 3) & ~ 3;

arch/xtensa/mm/init.c

+1 −1
Original line number Diff line number Diff line
@@ -191,7 +191,7 @@ int __init mem_reserve(unsigned long start, unsigned long end, int must_exist) 
		return -EINVAL;

	}



	if (it && start - it->start < bank_sz) {

	if (it && start - it->start <= bank_sz) {

		if (start == it->start) {

			if (end - it->start < bank_sz) {

				it->start = end;