[POWERPC] Add IRQSTACKS support on ppc32
This makes it possible to use separate stacks for hard and soft IRQs on 32-bit powerpc as well as on 64-bit. The code for 32-bit is just the 32-bit analog of the 64-bit code. * Added allocation and initialization of the irq stacks. We limit the stacks to be in lowmem for ppc32. * Implemented ppc32 versions of call_do_softirq() and call_handle_irq() to switch the stack pointers * Reworked how we do stack overflow detection. We now keep around the limit of the stack in the thread_struct and compare against the limit to see if we've overflowed. We can now use this on ppc64 if desired. [ paulus@samba.org: Fixed bug on 6xx where we need to reload r9 with the thread_info pointer. ] Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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@ -118,7 +118,6 @@ config XMON_DISASSEMBLY
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config IRQSTACKS
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config IRQSTACKS
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bool "Use separate kernel stacks when processing interrupts"
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bool "Use separate kernel stacks when processing interrupts"
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depends on PPC64
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help
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help
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If you say Y here the kernel will use separate kernel stacks
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If you say Y here the kernel will use separate kernel stacks
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for handling hard and soft interrupts. This can help avoid
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for handling hard and soft interrupts. This can help avoid
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@ -67,6 +67,7 @@ int main(void)
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#endif /* CONFIG_PPC64 */
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#endif /* CONFIG_PPC64 */
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DEFINE(KSP, offsetof(struct thread_struct, ksp));
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DEFINE(KSP, offsetof(struct thread_struct, ksp));
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DEFINE(KSP_LIMIT, offsetof(struct thread_struct, ksp_limit));
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DEFINE(PT_REGS, offsetof(struct thread_struct, regs));
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DEFINE(PT_REGS, offsetof(struct thread_struct, regs));
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DEFINE(THREAD_FPEXC_MODE, offsetof(struct thread_struct, fpexc_mode));
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DEFINE(THREAD_FPEXC_MODE, offsetof(struct thread_struct, fpexc_mode));
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DEFINE(THREAD_FPR0, offsetof(struct thread_struct, fpr[0]));
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DEFINE(THREAD_FPR0, offsetof(struct thread_struct, fpr[0]));
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@ -137,11 +137,12 @@ transfer_to_handler:
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2: /* if from kernel, check interrupted DOZE/NAP mode and
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2: /* if from kernel, check interrupted DOZE/NAP mode and
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* check for stack overflow
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* check for stack overflow
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*/
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*/
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lwz r9,THREAD_INFO-THREAD(r12)
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lwz r9,KSP_LIMIT(r12)
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cmplw r1,r9 /* if r1 <= current->thread_info */
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cmplw r1,r9 /* if r1 <= ksp_limit */
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ble- stack_ovf /* then the kernel stack overflowed */
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ble- stack_ovf /* then the kernel stack overflowed */
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5:
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5:
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#ifdef CONFIG_6xx
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#ifdef CONFIG_6xx
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rlwinm r9,r1,0,0,31-THREAD_SHIFT
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tophys(r9,r9) /* check local flags */
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tophys(r9,r9) /* check local flags */
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lwz r12,TI_LOCAL_FLAGS(r9)
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lwz r12,TI_LOCAL_FLAGS(r9)
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mtcrf 0x01,r12
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mtcrf 0x01,r12
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@ -307,6 +307,7 @@ void do_IRQ(struct pt_regs *regs)
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if (curtp != irqtp) {
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if (curtp != irqtp) {
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struct irq_desc *desc = irq_desc + irq;
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struct irq_desc *desc = irq_desc + irq;
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void *handler = desc->handle_irq;
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void *handler = desc->handle_irq;
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unsigned long saved_sp_limit = current->thread.ksp_limit;
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if (handler == NULL)
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if (handler == NULL)
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handler = &__do_IRQ;
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handler = &__do_IRQ;
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irqtp->task = curtp->task;
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irqtp->task = curtp->task;
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@ -319,7 +320,10 @@ void do_IRQ(struct pt_regs *regs)
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(irqtp->preempt_count & ~SOFTIRQ_MASK) |
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(irqtp->preempt_count & ~SOFTIRQ_MASK) |
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(curtp->preempt_count & SOFTIRQ_MASK);
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(curtp->preempt_count & SOFTIRQ_MASK);
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current->thread.ksp_limit = (unsigned long)irqtp +
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_ALIGN_UP(sizeof(struct thread_info), 16);
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call_handle_irq(irq, desc, irqtp, handler);
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call_handle_irq(irq, desc, irqtp, handler);
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current->thread.ksp_limit = saved_sp_limit;
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irqtp->task = NULL;
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irqtp->task = NULL;
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@ -352,9 +356,7 @@ void __init init_IRQ(void)
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{
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{
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if (ppc_md.init_IRQ)
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if (ppc_md.init_IRQ)
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ppc_md.init_IRQ();
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ppc_md.init_IRQ();
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#ifdef CONFIG_PPC64
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irq_ctx_init();
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irq_ctx_init();
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#endif
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}
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}
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@ -383,11 +385,15 @@ void irq_ctx_init(void)
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static inline void do_softirq_onstack(void)
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static inline void do_softirq_onstack(void)
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{
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{
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struct thread_info *curtp, *irqtp;
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struct thread_info *curtp, *irqtp;
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unsigned long saved_sp_limit = current->thread.ksp_limit;
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curtp = current_thread_info();
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curtp = current_thread_info();
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irqtp = softirq_ctx[smp_processor_id()];
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irqtp = softirq_ctx[smp_processor_id()];
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irqtp->task = curtp->task;
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irqtp->task = curtp->task;
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current->thread.ksp_limit = (unsigned long)irqtp +
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_ALIGN_UP(sizeof(struct thread_info), 16);
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call_do_softirq(irqtp);
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call_do_softirq(irqtp);
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current->thread.ksp_limit = saved_sp_limit;
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irqtp->task = NULL;
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irqtp->task = NULL;
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}
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}
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@ -32,6 +32,31 @@
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.text
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.text
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#ifdef CONFIG_IRQSTACKS
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_GLOBAL(call_do_softirq)
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mflr r0
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stw r0,4(r1)
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stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r3)
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mr r1,r3
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bl __do_softirq
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lwz r1,0(r1)
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lwz r0,4(r1)
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mtlr r0
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blr
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_GLOBAL(call_handle_irq)
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mflr r0
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stw r0,4(r1)
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mtctr r6
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stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r5)
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mr r1,r5
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bctrl
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lwz r1,0(r1)
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lwz r0,4(r1)
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mtlr r0
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blr
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#endif /* CONFIG_IRQSTACKS */
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/*
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/*
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* This returns the high 64 bits of the product of two 64-bit numbers.
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* This returns the high 64 bits of the product of two 64-bit numbers.
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*/
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*/
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@ -589,6 +589,8 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
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kregs = (struct pt_regs *) sp;
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kregs = (struct pt_regs *) sp;
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sp -= STACK_FRAME_OVERHEAD;
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sp -= STACK_FRAME_OVERHEAD;
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p->thread.ksp = sp;
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p->thread.ksp = sp;
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p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
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_ALIGN_UP(sizeof(struct thread_info), 16);
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#ifdef CONFIG_PPC64
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#ifdef CONFIG_PPC64
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if (cpu_has_feature(CPU_FTR_SLB)) {
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if (cpu_has_feature(CPU_FTR_SLB)) {
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@ -16,6 +16,7 @@
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#include <linux/root_dev.h>
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#include <linux/root_dev.h>
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#include <linux/cpu.h>
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#include <linux/cpu.h>
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#include <linux/console.h>
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#include <linux/console.h>
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#include <linux/lmb.h>
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#include <asm/io.h>
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#include <asm/io.h>
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#include <asm/prom.h>
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#include <asm/prom.h>
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@ -229,6 +230,24 @@ int __init ppc_init(void)
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arch_initcall(ppc_init);
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arch_initcall(ppc_init);
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#ifdef CONFIG_IRQSTACKS
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static void __init irqstack_early_init(void)
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{
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unsigned int i;
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/* interrupt stacks must be in lowmem, we get that for free on ppc32
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* as the lmb is limited to lowmem by LMB_REAL_LIMIT */
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for_each_possible_cpu(i) {
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softirq_ctx[i] = (struct thread_info *)
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__va(lmb_alloc(THREAD_SIZE, THREAD_SIZE));
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hardirq_ctx[i] = (struct thread_info *)
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__va(lmb_alloc(THREAD_SIZE, THREAD_SIZE));
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}
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}
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#else
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#define irqstack_early_init()
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#endif
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/* Warning, IO base is not yet inited */
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/* Warning, IO base is not yet inited */
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void __init setup_arch(char **cmdline_p)
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void __init setup_arch(char **cmdline_p)
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{
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{
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@ -286,6 +305,8 @@ void __init setup_arch(char **cmdline_p)
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init_mm.end_data = (unsigned long) _edata;
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init_mm.end_data = (unsigned long) _edata;
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init_mm.brk = klimit;
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init_mm.brk = klimit;
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irqstack_early_init();
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/* set up the bootmem stuff with available memory */
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/* set up the bootmem stuff with available memory */
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do_init_bootmem();
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do_init_bootmem();
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if ( ppc_md.progress ) ppc_md.progress("setup_arch: bootmem", 0x3eab);
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if ( ppc_md.progress ) ppc_md.progress("setup_arch: bootmem", 0x3eab);
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@ -138,6 +138,8 @@ typedef struct {
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struct thread_struct {
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struct thread_struct {
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unsigned long ksp; /* Kernel stack pointer */
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unsigned long ksp; /* Kernel stack pointer */
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unsigned long ksp_limit; /* if ksp <= ksp_limit stack overflow */
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#ifdef CONFIG_PPC64
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#ifdef CONFIG_PPC64
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unsigned long ksp_vsid;
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unsigned long ksp_vsid;
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#endif
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#endif
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@ -182,11 +184,14 @@ struct thread_struct {
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#define ARCH_MIN_TASKALIGN 16
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#define ARCH_MIN_TASKALIGN 16
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#define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack)
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#define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack)
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#define INIT_SP_LIMIT \
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(_ALIGN_UP(sizeof(init_thread_info), 16) + (unsigned long) &init_stack)
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#ifdef CONFIG_PPC32
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#ifdef CONFIG_PPC32
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#define INIT_THREAD { \
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#define INIT_THREAD { \
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.ksp = INIT_SP, \
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.ksp = INIT_SP, \
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.ksp_limit = INIT_SP_LIMIT, \
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.fs = KERNEL_DS, \
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.fs = KERNEL_DS, \
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.pgdir = swapper_pg_dir, \
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.pgdir = swapper_pg_dir, \
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.fpexc_mode = MSR_FE0 | MSR_FE1, \
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.fpexc_mode = MSR_FE0 | MSR_FE1, \
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@ -194,6 +199,7 @@ struct thread_struct {
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#else
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#else
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#define INIT_THREAD { \
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#define INIT_THREAD { \
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.ksp = INIT_SP, \
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.ksp = INIT_SP, \
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.ksp_limit = INIT_SP_LIMIT, \
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.regs = (struct pt_regs *)INIT_SP - 1, /* XXX bogus, I think */ \
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.regs = (struct pt_regs *)INIT_SP - 1, /* XXX bogus, I think */ \
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.fs = KERNEL_DS, \
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.fs = KERNEL_DS, \
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.fpr = {0}, \
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.fpr = {0}, \
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