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Commit 3ebedbb2 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: Increase readability of entry handlers 



* use artificial PUSH/POP contructs for CORE Reg save/restore to stack
* use artificial PUSHAX/POPAX contructs for Auxiliary Space regs
* macro'ize multiple copies of callee-reg-save/restore (SAVE_R13_TO_R24)
* use BIC insn for inverse-and operation

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 16f9afe6

arch/arc/include/asm/entry.h

+182 −212
Original line number Diff line number Diff line
@@ -50,150 +50,155 @@ 
 *      Eff Addr for load = [reg2]

 */



.macro PUSH reg

	st.a	\reg, [sp, -4]

.endm



.macro PUSHAX aux

	lr	r9, [\aux]

	PUSH	r9

.endm



.macro POP reg

	ld.ab	\reg, [sp, 4]

.endm



.macro POPAX aux

	POP	r9

	sr	r9, [\aux]

.endm



/*--------------------------------------------------------------

 * Save caller saved registers (scratch registers) ( r0 - r12 )

 * Registers are pushed / popped in the order defined in struct ptregs

 * in asm/ptrace.h

 * Helpers to save/restore Scratch Regs:

 * used by Interrupt/Exception Prologue/Epilogue

 *-------------------------------------------------------------*/

.macro  SAVE_CALLER_SAVED

	st.a    r0, [sp, -4]

	st.a    r1, [sp, -4]

	st.a    r2, [sp, -4]

	st.a    r3, [sp, -4]

	st.a    r4, [sp, -4]

	st.a    r5, [sp, -4]

	st.a    r6, [sp, -4]

	st.a    r7, [sp, -4]

	st.a    r8, [sp, -4]

	st.a    r9, [sp, -4]

	st.a    r10, [sp, -4]

	st.a    r11, [sp, -4]

	st.a    r12, [sp, -4]

.macro  SAVE_R0_TO_R12

	PUSH	r0

	PUSH	r1

	PUSH	r2

	PUSH	r3

	PUSH	r4

	PUSH	r5

	PUSH	r6

	PUSH	r7

	PUSH	r8

	PUSH	r9

	PUSH	r10

	PUSH	r11

	PUSH	r12

.endm



.macro RESTORE_R12_TO_R0

	POP	r12

	POP	r11

	POP	r10

	POP	r9

	POP	r8

	POP	r7

	POP	r6

	POP	r5

	POP	r4

	POP	r3

	POP	r2

	POP	r1

	POP	r0

.endm



/*--------------------------------------------------------------

 * Restore caller saved registers (scratch registers)

 * Helpers to save/restore callee-saved regs:

 * used by several macros below

 *-------------------------------------------------------------*/

.macro RESTORE_CALLER_SAVED

	ld.ab   r12, [sp, 4]

	ld.ab   r11, [sp, 4]

	ld.ab   r10, [sp, 4]

	ld.ab   r9, [sp, 4]

	ld.ab   r8, [sp, 4]

	ld.ab   r7, [sp, 4]

	ld.ab   r6, [sp, 4]

	ld.ab   r5, [sp, 4]

	ld.ab   r4, [sp, 4]

	ld.ab   r3, [sp, 4]

	ld.ab   r2, [sp, 4]

	ld.ab   r1, [sp, 4]

	ld.ab   r0, [sp, 4]

.macro SAVE_R13_TO_R24

	PUSH	r13

	PUSH	r14

	PUSH	r15

	PUSH	r16

	PUSH	r17

	PUSH	r18

	PUSH	r19

	PUSH	r20

	PUSH	r21

	PUSH	r22

	PUSH	r23

	PUSH	r24

.endm



.macro RESTORE_R24_TO_R13

	POP	r24

	POP	r23

	POP	r22

	POP	r21

	POP	r20

	POP	r19

	POP	r18

	POP	r17

	POP	r16

	POP	r15

	POP	r14

	POP	r13

.endm





/*--------------------------------------------------------------

 * Save callee saved registers (non scratch registers) ( r13 - r25 )

 *  on kernel stack.

 * User mode callee regs need to be saved in case of

 *    -fork and friends for replicating from parent to child

 *    -before going into do_signal( ) for ptrace/core-dump

 * Special case handling is required for r25 in case it is used by kernel

 *  for caching task ptr. Low level exception/ISR save user mode r25

 *  into task->thread.user_r25. So it needs to be retrieved from there and

 *  saved into kernel stack with rest of callee reg-file

 * Collect User Mode callee regs as struct callee_regs - needed by

 * fork/do_signal/unaligned-access-emulation.

 * (By default only scratch regs are saved on entry to kernel)

 *

 * Special handling for r25 if used for caching Task Pointer.

 * It would have been saved in task->thread.user_r25 already, but to keep

 * the interface same it is copied into regular r25 placeholder in

 * struct callee_regs.

 *-------------------------------------------------------------*/

.macro SAVE_CALLEE_SAVED_USER

	st.a    r13, [sp, -4]

	st.a    r14, [sp, -4]

	st.a    r15, [sp, -4]

	st.a    r16, [sp, -4]

	st.a    r17, [sp, -4]

	st.a    r18, [sp, -4]

	st.a    r19, [sp, -4]

	st.a    r20, [sp, -4]

	st.a    r21, [sp, -4]

	st.a    r22, [sp, -4]

	st.a    r23, [sp, -4]

	st.a    r24, [sp, -4]



	SAVE_R13_TO_R24



#ifdef CONFIG_ARC_CURR_IN_REG

	; Retrieve orig r25 and save it on stack

	ld      r12, [r25, TASK_THREAD + THREAD_USER_R25]

	st.a    r12, [sp, -4]

#else

	st.a    r25, [sp, -4]

	PUSH	r25

#endif



.endm



/*--------------------------------------------------------------

 * Save callee saved registers (non scratch registers) ( r13 - r25 )

 * kernel mode callee regs needed to be saved in case of context switch

 * If r25 is used for caching task pointer then that need not be saved

 * as it can be re-created from current task global

 * Save kernel Mode callee regs at the time of Contect Switch.

 *

 * Special handling for r25 if used for caching Task Pointer.

 * Kernel simply skips saving it since it will be loaded with

 * incoming task pointer anyways

 *-------------------------------------------------------------*/

.macro SAVE_CALLEE_SAVED_KERNEL

	st.a    r13, [sp, -4]

	st.a    r14, [sp, -4]

	st.a    r15, [sp, -4]

	st.a    r16, [sp, -4]

	st.a    r17, [sp, -4]

	st.a    r18, [sp, -4]

	st.a    r19, [sp, -4]

	st.a    r20, [sp, -4]

	st.a    r21, [sp, -4]

	st.a    r22, [sp, -4]

	st.a    r23, [sp, -4]

	st.a    r24, [sp, -4]



	SAVE_R13_TO_R24



#ifdef CONFIG_ARC_CURR_IN_REG

	sub     sp, sp, 4

#else

	st.a    r25, [sp, -4]

	PUSH	r25

#endif

.endm



/*--------------------------------------------------------------

 * RESTORE_CALLEE_SAVED_KERNEL:

 * Loads callee (non scratch) Reg File by popping from Kernel mode stack.

 *  This is reverse of SAVE_CALLEE_SAVED,

 *

 * NOTE:

 * Ideally this shd only be called in switch_to for loading

 *  switched-IN task's CALLEE Reg File.

 *  For all other cases RESTORE_CALLEE_SAVED_FAST must be used

 *  which simply pops the stack w/o touching regs.

 * Opposite of SAVE_CALLEE_SAVED_KERNEL

 *-------------------------------------------------------------*/

.macro RESTORE_CALLEE_SAVED_KERNEL



#ifdef CONFIG_ARC_CURR_IN_REG

	add     sp, sp, 4  /* skip usual r25 placeholder */

#else

	ld.ab   r25, [sp, 4]

	POP	r25

#endif

	ld.ab   r24, [sp, 4]

	ld.ab   r23, [sp, 4]

	ld.ab   r22, [sp, 4]

	ld.ab   r21, [sp, 4]

	ld.ab   r20, [sp, 4]

	ld.ab   r19, [sp, 4]

	ld.ab   r18, [sp, 4]

	ld.ab   r17, [sp, 4]

	ld.ab   r16, [sp, 4]

	ld.ab   r15, [sp, 4]

	ld.ab   r14, [sp, 4]

	ld.ab   r13, [sp, 4]



	RESTORE_R24_TO_R13

.endm



/*--------------------------------------------------------------

 * RESTORE_CALLEE_SAVED_USER:

 * This is called after do_signal where tracer might have changed callee regs

 * thus we need to restore the reg file.

 * Special case handling is required for r25 in case it is used by kernel

 *  for caching task ptr. Ptrace would have modified on-kernel-stack value of

 *  r25, which needs to be shoved back into task->thread.user_r25 where from

 *  Low level exception/ISR return code will retrieve to populate with rest of

 *  callee reg-file.

 * Opposite of SAVE_CALLEE_SAVED_USER

 *

 * ptrace tracer or unaligned-access fixup might have changed a user mode

 * callee reg which is saved back to usual r25 storage location

 *-------------------------------------------------------------*/

.macro RESTORE_CALLEE_SAVED_USER
@@ -201,21 +206,9 @@ 
	ld.ab   r12, [sp, 4]

	st      r12, [r25, TASK_THREAD + THREAD_USER_R25]

#else

	ld.ab   r25, [sp, 4]

	POP	r25

#endif



	ld.ab   r24, [sp, 4]

	ld.ab   r23, [sp, 4]

	ld.ab   r22, [sp, 4]

	ld.ab   r21, [sp, 4]

	ld.ab   r20, [sp, 4]

	ld.ab   r19, [sp, 4]

	ld.ab   r18, [sp, 4]

	ld.ab   r17, [sp, 4]

	ld.ab   r16, [sp, 4]

	ld.ab   r15, [sp, 4]

	ld.ab   r14, [sp, 4]

	ld.ab   r13, [sp, 4]

	RESTORE_R24_TO_R13

.endm



/*--------------------------------------------------------------
@@ -357,7 +350,7 @@ 
 * @reg [OUT] &thread_info of "current"

 */

.macro GET_CURR_THR_INFO_FROM_SP  reg

	and \reg, sp, ~(THREAD_SIZE - 1)

	bic \reg, sp, (THREAD_SIZE - 1)

.endm



/*
@@ -409,21 +402,16 @@ 
	/* Restore r9 used to code the early prologue */

	EXCPN_PROLOG_RESTORE_REG  r9



	SAVE_CALLER_SAVED

	st.a    r26, [sp, -4]   /* gp */

	st.a    fp, [sp, -4]

	st.a    blink, [sp, -4]

	lr	r9, [eret]

	st.a    r9, [sp, -4]

	lr	r9, [erstatus]

	st.a    r9, [sp, -4]

	st.a    lp_count, [sp, -4]

	lr	r9, [lp_end]

	st.a    r9, [sp, -4]

	lr	r9, [lp_start]

	st.a    r9, [sp, -4]

	lr	r9, [erbta]

	st.a    r9, [sp, -4]

	SAVE_R0_TO_R12

	PUSH	gp

	PUSH	fp

	PUSH	blink

	PUSHAX	eret

	PUSHAX	erstatus

	PUSH	lp_count

	PUSHAX	lp_end

	PUSHAX	lp_start

	PUSHAX	erbta

.endm



/*--------------------------------------------------------------
@@ -463,22 +451,19 @@ 
 * by hardware and that is not good.

 *-------------------------------------------------------------*/

.macro RESTORE_ALL_SYS

	ld.ab   r9, [sp, 4]

	sr	r9, [erbta]

	ld.ab   r9, [sp, 4]

	sr	r9, [lp_start]

	ld.ab   r9, [sp, 4]

	sr	r9, [lp_end]

	ld.ab   r9, [sp, 4]

	mov	lp_count, r9

	ld.ab   r9, [sp, 4]

	sr	r9, [erstatus]

	ld.ab   r9, [sp, 4]

	sr	r9, [eret]

	ld.ab   blink, [sp, 4]

	ld.ab   fp, [sp, 4]

	ld.ab   r26, [sp, 4]    /* gp */

	RESTORE_CALLER_SAVED

	POPAX	erbta

	POPAX	lp_start

	POPAX	lp_end



	POP	r9

	mov	lp_count, r9	;LD to lp_count is not allowed



	POPAX	erstatus

	POPAX	eret

	POP	blink

	POP	fp

	POP	gp

	RESTORE_R12_TO_R0



	ld  sp, [sp] /* restore original sp */

	/* orig_r0 and orig_r8 skipped automatically */
@@ -490,9 +475,7 @@ 
 *-------------------------------------------------------------*/

.macro SAVE_ALL_INT1



	/* restore original r9 , saved in int1_saved_reg

	* It will be saved on stack in macro: SAVE_CALLER_SAVED

	*/

	/* restore original r9 to be saved as part of reg-file */

#ifdef CONFIG_SMP

	lr  r9, [ARC_REG_SCRATCH_DATA0]

#else
@@ -502,20 +485,17 @@ 
	/* now we are ready to save the remaining context :) */

	st      orig_r8_IS_IRQ1, [sp, 8]    /* Event Type */

	st      0, [sp, 4]    /* orig_r0 , N/A for IRQ */

	SAVE_CALLER_SAVED

	st.a    r26, [sp, -4]   /* gp */

	st.a    fp, [sp, -4]

	st.a    blink, [sp, -4]

	st.a    ilink1, [sp, -4]

	lr	r9, [status32_l1]

	st.a    r9, [sp, -4]

	st.a    lp_count, [sp, -4]

	lr	r9, [lp_end]

	st.a    r9, [sp, -4]

	lr	r9, [lp_start]

	st.a    r9, [sp, -4]

	lr	r9, [bta_l1]

	st.a    r9, [sp, -4]



	SAVE_R0_TO_R12

	PUSH	gp

	PUSH	fp

	PUSH	blink

	PUSH	ilink1

	PUSHAX	status32_l1

	PUSH	lp_count

	PUSHAX	lp_end

	PUSHAX	lp_start

	PUSHAX	bta_l1

.endm



.macro SAVE_ALL_INT2
@@ -530,20 +510,17 @@ 
	/* now we are ready to save the remaining context :) */

	st      orig_r8_IS_IRQ2, [sp, 8]    /* Event Type */

	st      0, [sp, 4]    /* orig_r0 , N/A for IRQ */

	SAVE_CALLER_SAVED

	st.a    r26, [sp, -4]   /* gp */

	st.a    fp, [sp, -4]

	st.a    blink, [sp, -4]

	st.a    ilink2, [sp, -4]

	lr	r9, [status32_l2]

	st.a    r9, [sp, -4]

	st.a    lp_count, [sp, -4]

	lr	r9, [lp_end]

	st.a    r9, [sp, -4]

	lr	r9, [lp_start]

	st.a    r9, [sp, -4]

	lr	r9, [bta_l2]

	st.a    r9, [sp, -4]



	SAVE_R0_TO_R12

	PUSH	gp

	PUSH	fp

	PUSH	blink

	PUSH	ilink2

	PUSHAX	status32_l2

	PUSH	lp_count

	PUSHAX	lp_end

	PUSHAX	lp_start

	PUSHAX	bta_l2

.endm



/*--------------------------------------------------------------
@@ -557,48 +534,41 @@ 
 *-------------------------------------------------------------*/



.macro RESTORE_ALL_INT1

	ld.ab   r9, [sp, 4] /* Actual reg file */

	sr	r9, [bta_l1]

	ld.ab   r9, [sp, 4]

	sr	r9, [lp_start]

	ld.ab   r9, [sp, 4]

	sr	r9, [lp_end]

	ld.ab   r9, [sp, 4]

	mov	lp_count, r9

	ld.ab   r9, [sp, 4]

	sr	r9, [status32_l1]

	ld.ab   r9, [sp, 4]

	mov	ilink1, r9

	ld.ab   blink, [sp, 4]

	ld.ab   fp, [sp, 4]

	ld.ab   r26, [sp, 4]    /* gp */

	RESTORE_CALLER_SAVED

	POPAX	bta_l1

	POPAX	lp_start

	POPAX	lp_end



	POP	r9

	mov	lp_count, r9	;LD to lp_count is not allowed



	POPAX	status32_l1

	POP	ilink1

	POP	blink

	POP	fp

	POP	gp

	RESTORE_R12_TO_R0



	ld  sp, [sp] /* restore original sp */

	/* orig_r0 and orig_r8 skipped automatically */

.endm



.macro RESTORE_ALL_INT2

	ld.ab   r9, [sp, 4]

	sr	r9, [bta_l2]

	ld.ab   r9, [sp, 4]

	sr	r9, [lp_start]

	ld.ab   r9, [sp, 4]

	sr	r9, [lp_end]

	ld.ab   r9, [sp, 4]

	mov	lp_count, r9

	ld.ab   r9, [sp, 4]

	sr	r9, [status32_l2]

	ld.ab   r9, [sp, 4]

	mov	ilink2, r9

	ld.ab   blink, [sp, 4]

	ld.ab   fp, [sp, 4]

	ld.ab   r26, [sp, 4]    /* gp */

	RESTORE_CALLER_SAVED

	POPAX	bta_l2

	POPAX	lp_start

	POPAX	lp_end



	POP	r9

	mov	lp_count, r9	;LD to lp_count is not allowed



	POPAX	status32_l2

	POP	ilink2

	POP	blink

	POP	fp

	POP	gp

	RESTORE_R12_TO_R0



	ld  sp, [sp] /* restore original sp */

	/* orig_r0 and orig_r8 skipped automatically */



.endm

arch/arc/kernel/process.c

+4 −0
Original line number Diff line number Diff line
@@ -73,6 +73,10 @@ asmlinkage void ret_from_fork(void); 
 * ~                ~

 * |    --to--      |   (scratch Regs of user mode)

 * |     r0         |

 * ------------------

 * |      SP        |

 * |    orig_r0     |

 * |    orig_r8     |

 * ------------------  <===== END of PAGE

 */

int copy_thread(unsigned long clone_flags,