sh: Add support for 4K stacks.
This enables support for 4K stacks on SH. Currently this depends on DEBUG_KERNEL, but likely all boards will switch to this as the default in the future. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt
parent
2cb7ce3bb3
commit
a6a3113989
9 changed files with 190 additions and 24 deletions
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@ -46,6 +46,16 @@ config DEBUG_STACK_USAGE
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This option will slow down process creation somewhat.
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config 4KSTACKS
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bool "Use 4Kb for kernel stacks instead of 8Kb"
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depends on DEBUG_KERNEL
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help
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If you say Y here the kernel will use a 4Kb stacksize for the
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kernel stack attached to each process/thread. This facilitates
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running more threads on a system and also reduces the pressure
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on the VM subsystem for higher order allocations. This option
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will also use IRQ stacks to compensate for the reduced stackspace.
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config KGDB
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bool "Include KGDB kernel debugger"
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select FRAME_POINTER
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@ -190,6 +190,8 @@ void __init init_IRQ(void)
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/* Perform the machine specific initialisation */
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if (sh_mv.mv_init_irq != NULL)
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sh_mv.mv_init_irq();
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irq_ctx_init(smp_processor_id());
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}
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#if !defined(CONFIG_CPU_HAS_PINT_IRQ)
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@ -716,8 +716,8 @@ ENTRY(handle_exception)
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bt/s 1f ! It's a kernel to kernel transition.
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mov r15, k0 ! save original stack to k0
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/* User space to kernel */
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mov #0x20, k1
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shll8 k1 ! k1 := 8192 (== THREAD_SIZE)
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mov #(THREAD_SIZE >> 8), k1
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shll8 k1 ! k1 := THREAD_SIZE
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add current, k1
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mov k1, r15 ! change to kernel stack
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!
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@ -12,7 +12,6 @@
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*/
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#include <linux/linkage.h>
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#include <asm/thread_info.h>
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#include <asm/page.h>
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#ifdef CONFIG_CPU_SH4A
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#define SYNCO() synco
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@ -69,8 +68,8 @@ ENTRY(_stext)
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!
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mov.l 2f, r0
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mov r0, r15 ! Set initial r15 (stack pointer)
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mov #0x20, r1 !
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shll8 r1 ! r1 = 8192
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mov #(THREAD_SIZE >> 8), r1
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shll8 r1 ! r1 = THREAD_SIZE
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sub r1, r0 !
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ldc r0, r7_bank ! ... and initial thread_info
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@ -1,5 +1,4 @@
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/* $Id: irq.c,v 1.20 2004/01/13 05:52:11 kkojima Exp $
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*
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/*
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* linux/arch/sh/kernel/irq.c
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*
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* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
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@ -7,13 +6,15 @@
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*
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* SuperH version: Copyright (C) 1999 Niibe Yutaka
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*/
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#include <linux/irq.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/kernel_stat.h>
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#include <linux/seq_file.h>
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#include <asm/irq.h>
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#include <asm/processor.h>
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#include <asm/uaccess.h>
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#include <asm/thread_info.h>
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#include <asm/cpu/mmu_context.h>
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/*
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@ -60,11 +61,27 @@ unlock:
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}
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#endif
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#ifdef CONFIG_4KSTACKS
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/*
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* per-CPU IRQ handling contexts (thread information and stack)
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*/
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union irq_ctx {
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struct thread_info tinfo;
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u32 stack[THREAD_SIZE/sizeof(u32)];
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};
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static union irq_ctx *hardirq_ctx[NR_CPUS];
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static union irq_ctx *softirq_ctx[NR_CPUS];
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#endif
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asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
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unsigned long r6, unsigned long r7,
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struct pt_regs regs)
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{
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int irq = r4;
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#ifdef CONFIG_4KSTACKS
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union irq_ctx *curctx, *irqctx;
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#endif
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irq_enter();
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@ -102,7 +119,135 @@ asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
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#endif
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irq = irq_demux(irq);
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__do_IRQ(irq, ®s);
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#ifdef CONFIG_4KSTACKS
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curctx = (union irq_ctx *)current_thread_info();
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irqctx = hardirq_ctx[smp_processor_id()];
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/*
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* this is where we switch to the IRQ stack. However, if we are
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* already using the IRQ stack (because we interrupted a hardirq
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* handler) we can't do that and just have to keep using the
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* current stack (which is the irq stack already after all)
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*/
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if (curctx != irqctx) {
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u32 *isp;
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isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
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irqctx->tinfo.task = curctx->tinfo.task;
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irqctx->tinfo.previous_sp = current_stack_pointer;
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__asm__ __volatile__ (
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"mov %0, r4 \n"
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"mov %1, r5 \n"
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"mov r15, r9 \n"
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"jsr @%2 \n"
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/* swith to the irq stack */
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" mov %3, r15 \n"
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/* restore the stack (ring zero) */
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"mov r9, r15 \n"
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: /* no outputs */
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: "r" (irq), "r" (®s), "r" (__do_IRQ), "r" (isp)
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/* XXX: A somewhat excessive clobber list? -PFM */
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: "memory", "r0", "r1", "r2", "r3", "r4",
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"r5", "r6", "r7", "r8", "t", "pr"
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);
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} else
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#endif
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__do_IRQ(irq, ®s);
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irq_exit();
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return 1;
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}
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#ifdef CONFIG_4KSTACKS
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/*
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* These should really be __section__(".bss.page_aligned") as well, but
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* gcc's 3.0 and earlier don't handle that correctly.
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*/
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static char softirq_stack[NR_CPUS * THREAD_SIZE]
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__attribute__((__aligned__(THREAD_SIZE)));
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static char hardirq_stack[NR_CPUS * THREAD_SIZE]
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__attribute__((__aligned__(THREAD_SIZE)));
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/*
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* allocate per-cpu stacks for hardirq and for softirq processing
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*/
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void irq_ctx_init(int cpu)
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{
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union irq_ctx *irqctx;
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if (hardirq_ctx[cpu])
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return;
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irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
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irqctx->tinfo.task = NULL;
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irqctx->tinfo.exec_domain = NULL;
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irqctx->tinfo.cpu = cpu;
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irqctx->tinfo.preempt_count = HARDIRQ_OFFSET;
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irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
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hardirq_ctx[cpu] = irqctx;
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irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
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irqctx->tinfo.task = NULL;
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irqctx->tinfo.exec_domain = NULL;
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irqctx->tinfo.cpu = cpu;
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irqctx->tinfo.preempt_count = SOFTIRQ_OFFSET;
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irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
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softirq_ctx[cpu] = irqctx;
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printk("CPU %u irqstacks, hard=%p soft=%p\n",
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cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
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}
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void irq_ctx_exit(int cpu)
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{
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hardirq_ctx[cpu] = NULL;
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}
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extern asmlinkage void __do_softirq(void);
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asmlinkage void do_softirq(void)
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{
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unsigned long flags;
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struct thread_info *curctx;
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union irq_ctx *irqctx;
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u32 *isp;
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if (in_interrupt())
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return;
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local_irq_save(flags);
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if (local_softirq_pending()) {
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curctx = current_thread_info();
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irqctx = softirq_ctx[smp_processor_id()];
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irqctx->tinfo.task = curctx->task;
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irqctx->tinfo.previous_sp = current_stack_pointer;
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/* build the stack frame on the softirq stack */
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isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
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__asm__ __volatile__ (
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"mov r15, r9 \n"
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"jsr @%0 \n"
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/* switch to the softirq stack */
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" mov %1, r15 \n"
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/* restore the thread stack */
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"mov r9, r15 \n"
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: /* no outputs */
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: "r" (__do_softirq), "r" (isp)
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/* XXX: A somewhat excessive clobber list? -PFM */
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: "memory", "r0", "r1", "r2", "r3", "r4",
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"r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
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);
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}
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local_irq_restore(flags);
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}
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EXPORT_SYMBOL(do_softirq);
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#endif
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@ -741,20 +741,12 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
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unsigned long module_end = VMALLOC_END;
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int i = 1;
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if (tsk && !sp) {
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if (!tsk)
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tsk = current;
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if (tsk == current)
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sp = (unsigned long *)current_stack_pointer;
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else
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sp = (unsigned long *)tsk->thread.sp;
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}
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if (!sp) {
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__asm__ __volatile__ (
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"mov r15, %0\n\t"
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"stc r7_bank, %1\n\t"
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: "=r" (module_start),
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"=r" (module_end)
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);
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sp = (unsigned long *)module_start;
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}
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stack = sp;
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@ -3,7 +3,6 @@
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* Written by Niibe Yutaka
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*/
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#include <asm/thread_info.h>
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#include <asm/page.h>
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#include <asm-generic/vmlinux.lds.h>
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#ifdef CONFIG_CPU_LITTLE_ENDIAN
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@ -719,6 +719,15 @@ static inline int generic_irq_demux(int irq)
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#define irq_canonicalize(irq) (irq)
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#define irq_demux(irq) __irq_demux(sh_mv.mv_irq_demux(irq))
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#ifdef CONFIG_4KSTACKS
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extern void irq_ctx_init(int cpu);
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extern void irq_ctx_exit(int cpu);
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# define __ARCH_HAS_DO_SOFTIRQ
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#else
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# define irq_ctx_init(cpu) do { } while (0)
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# define irq_ctx_exit(cpu) do { } while (0)
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#endif
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#if defined(CONFIG_CPU_SUBTYPE_SH73180)
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#include <asm/irq-sh73180.h>
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#endif
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@ -9,8 +9,8 @@
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* Copyright (C) 2002 David Howells (dhowells@redhat.com)
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* - Incorporating suggestions made by Linus Torvalds and Dave Miller
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*/
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#ifdef __KERNEL__
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#include <asm/page.h>
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#ifndef __ASSEMBLY__
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#include <asm/processor.h>
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@ -23,13 +23,20 @@ struct thread_info {
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int preempt_count; /* 0 => preemptable, <0 => BUG */
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mm_segment_t addr_limit; /* thread address space */
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struct restart_block restart_block;
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unsigned long previous_sp; /* sp of previous stack in case
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of nested IRQ stacks */
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__u8 supervisor_stack[0];
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};
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#endif
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#define PREEMPT_ACTIVE 0x10000000
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#ifdef CONFIG_4KSTACKS
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#define THREAD_SIZE (PAGE_SIZE)
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#else
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#define THREAD_SIZE (PAGE_SIZE * 2)
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#endif
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#define STACK_WARN (THREAD_SIZE / 8)
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/*
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@ -52,6 +59,9 @@ struct thread_info {
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#define init_thread_info (init_thread_union.thread_info)
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#define init_stack (init_thread_union.stack)
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/* how to get the current stack pointer from C */
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register unsigned long current_stack_pointer asm("r15") __attribute_used__;
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/* how to get the thread information struct from C */
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static inline struct thread_info *current_thread_info(void)
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{
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