ppc64: remove interrupt stacks which broke when the thread info stuff went in

arch/ppc64/kernel/asm-offsets.c

@@ -83,9 +83,7 @@ int main(void)
         DEFINE(PACALPQUEUE, offsetof(struct paca_struct, lpQueuePtr));
 	DEFINE(PACATOC, offsetof(struct paca_struct, xTOC));
 	DEFINE(PACAEXCSP, offsetof(struct paca_struct, exception_sp));
-	DEFINE(PACAHRDWINTSTACK, offsetof(struct paca_struct, xHrdIntStack));
 	DEFINE(PACAPROCENABLED, offsetof(struct paca_struct, xProcEnabled));
-	DEFINE(PACAHRDWINTCOUNT, offsetof(struct paca_struct, xHrdIntCount));
 	DEFINE(PACADEFAULTDECR, offsetof(struct paca_struct, default_decr));
 	DEFINE(PACAPROFENABLED, offsetof(struct paca_struct, prof_enabled));
 	DEFINE(PACAPROFLEN, offsetof(struct paca_struct, prof_len));

arch/ppc64/kernel/head.S

@@ -705,61 +705,9 @@ HardwareInterrupt_entry:
 	li	r20,0
 	li	r6,0x500
 	bl      .save_remaining_regs
-	/* Determine if need to run do_irq on a hardware interrupt stack  */
-	/*   The first invocation of do_irq will occur on the kernel      */
-	/*   stack in the current stack                                   */
-	/*   All other invocations of do_irq will run on the hardware     */
-	/*   interrupt stack associated with the PACA of the current      */
-	/*   processor.                                                   */
-	/*                                                                */
-	/*  The call to do_irq will preserve the value of r14 - r31       */
-	/*                                                                */
-/*
- * XXX turn off interrupt stacks until the thread_info stuff is fixed.
- * Otherwise we end up setting need_resched etc bits in the interrupt
- *  stack and they never get seen when we return to the process stack - Anton
- */
-#if 0
-	lbz     r21,PACAHRDWINTCOUNT(r13)    /* get hardware interrupt cnt */
-	cmpi    0,r21,1                     /*                            */
-	addi    r21,r21,1                   /* incr hardware interrupt cnt*/
-	stb     r21,PACAHRDWINTCOUNT(r13)   /*                            */
-	bne     2f                          /*                            */
-
-	mr      r14,r1                      /* preserve current r1        */
-	ld      r1,PACAHRDWINTSTACK(r13)    /*                            */
-	std     r14,0(r1)                   /* set the back chain         */
-	bl      .do_IRQ
-	lbz     r22,PACAHRDWINTCOUNT(r13)   /* get hardware interrupt cnt */
-	cmp     0,r22,r21                   /* debug test                 */
-	bne     3f
-	subi    r21,r21,1
-	stb     r21,PACAHRDWINTCOUNT(r13)   /*                            */
-	mr      r1,r14                      /*                            */
-	b       .ret_from_except
-#endif
-
-2:
 	bl      .do_IRQ
-
-#if 0
-	lbz     r22,PACAHRDWINTCOUNT(r13)   /* get hardware interrupt cnt */
-	cmp     0,r22,r21                   /* debug test                 */
-	bne     3f                          /*                            */
-	subi    r21,r21,1                   /* decr hardware interrupt cnt*/
-	stb     r21,PACAHRDWINTCOUNT(r13)   /*                            */
-#endif
-
 	b       .ret_from_except
 
-3:
-	/* error - counts out of sync                                      */
-#ifdef CONFIG_XMON
-	bl	.xmon
-#endif
-4:	b	4b
-
-
 	.globl Alignment_common
 Alignment_common:
 	EXCEPTION_PROLOG_COMMON
@@ -1845,18 +1793,6 @@ _STATIC(start_here_common)
 	li	r5,0
 	std	r0,PACAKSAVE(r13)
 
-	/* ptr to hardware interrupt stack for boot processor */
-	LOADADDR(r3, hardware_int_paca0)
-	li      r5,PAGE_SIZE
-	sldi    r5,r5,3
-	subi    r5,r5,STACK_FRAME_OVERHEAD
-
-	add     r3,r3,r5
-	std     r3,PACAHRDWINTSTACK(r13)
-
-	li      r3,0
-	stb     r3,PACAHRDWINTCOUNT(r13)
-
 	/* Restore the parms passed in from the bootloader. */
 	mr	r3,r31
 	mr	r4,r30
@@ -1978,10 +1914,6 @@ swapper_pg_dir:
 ioremap_dir:
 	.space	4096
 
-	.globl  hardware_int_paca0
-hardware_int_paca0:
-	.space	8*PAGE_SIZE
-
 /* 1 page segment table per cpu (max 48, cpu0 allocated at STAB0_PHYS_ADDR) */
 	.globl	stab_array
 stab_array:

arch/ppc64/kernel/process.c

@@ -385,46 +385,6 @@ int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 	return error;
 }
 
-void initialize_paca_hardware_interrupt_stack(void)
-{
-	int i;
-	unsigned long stack;
-	unsigned long end_of_stack =0;
-
-	for (i=1; i < NR_CPUS; i++) {
-		if (!cpu_possible(i))
-			continue;
-		/* Carve out storage for the hardware interrupt stack */
-		stack = __get_free_pages(GFP_ATOMIC, get_order(8*PAGE_SIZE));
-
-		if ( !stack ) {     
-			printk("ERROR, cannot find space for hardware stack.\n");
-			panic(" no hardware stack ");
-		}
-
-
-		/* Store the stack value in the PACA for the processor */
-		paca[i].xHrdIntStack = stack + (8*PAGE_SIZE) - STACK_FRAME_OVERHEAD;
-		paca[i].xHrdIntCount = 0;
-
-	}
-
-	/*
-	 * __get_free_pages() might give us a page > KERNBASE+256M which
-	 * is mapped with large ptes so we can't set up the guard page.
-	 */
-	if (cur_cpu_spec->cpu_features & CPU_FTR_16M_PAGE)
-		return;
-
-	for (i=0; i < NR_CPUS; i++) {
-		if (!cpu_possible(i))
-			continue;
-		/* set page at the top of stack to be protected - prevent overflow */
-		end_of_stack = paca[i].xHrdIntStack - (8*PAGE_SIZE - STACK_FRAME_OVERHEAD);
-		ppc_md.hpte_updateboltedpp(PP_RXRX,end_of_stack);
-	}
-}
-
 char *ppc_find_proc_name(unsigned *p, char *buf, unsigned buflen)
 {
 	unsigned long tb_flags;

arch/ppc64/mm/init.c

@@ -540,8 +540,6 @@ static int __init setup_kcore(void)
 }
 module_init(setup_kcore);
 
-void initialize_paca_hardware_interrupt_stack(void);
-
 void __init mem_init(void)
 {
 #ifndef CONFIG_DISCONTIGMEM
@@ -608,9 +606,6 @@ void __init mem_init(void)
 #endif
 	mem_init_done = 1;
 
-	/* set the last page of each hardware interrupt stack to be protected */
-	initialize_paca_hardware_interrupt_stack();
-
 #ifdef CONFIG_PPC_ISERIES
 	create_virtual_bus_tce_table();
 #endif