* interrupt stacks (2/3)
- allocate per-cpu interrupt stacks. upon entry to
common_interrupt, switch to the current cpu's stack.
- inherit the interrupted task's preempt count, and pass
back relevant task flags
Depends on the previously sent thread_info cleanup
-- Dave Hansen haveblue@us.ibm.com
# This is a BitKeeper generated patch for the following project: # Project Name: Linux kernel tree # This patch format is intended for GNU patch command version 2.5 or higher. # This patch includes the following deltas: # ChangeSet 1.856 -> 1.857 # arch/i386/kernel/process.c 1.32 -> 1.32.1.1 # arch/i386/kernel/irq.c 1.21.1.2 -> 1.23.1.1 # include/asm-i386/thread_info.h 1.8 -> 1.10 # arch/i386/kernel/entry.S 1.38.2.1 -> 1.38.1.3 # arch/i386/kernel/smpboot.c 1.36 -> 1.37 # arch/i386/kernel/init_task.c 1.6 -> 1.6.1.1 # # The following is the BitKeeper ChangeSet Log # -------------------------------------------- # 02/10/31 haveblue@elm3b96.(none) 1.857 # Merge # -------------------------------------------- # diff -Nru a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S --- a/arch/i386/kernel/entry.S Thu Oct 31 11:12:05 2002 +++ b/arch/i386/kernel/entry.S Thu Oct 31 11:12:05 2002 @@ -334,7 +334,45 @@ ALIGN common_interrupt: SAVE_ALL + + + GET_THREAD_INFO(%ebx) + movl TI_IRQ_STACK(%ebx),%ecx + movl TI_TASK(%ebx),%edx + movl %esp,%eax + leal (THREAD_SIZE-4)(%ecx),%esi # %ecx+THREAD_SIZE is next stack + # -4 keeps us in the right one + testl %ecx,%ecx # is there a valid irq_stack? + + # switch to the irq stack +#ifdef CONFIG_X86_HAVE_CMOV + cmovnz %esi,%esp +#else + jz 1f + mov %esi,%esp +1: +#endif + + # update the task pointer in the irq stack + GET_THREAD_INFO(%esi) + movl %edx,TI_TASK(%esi) + + # update the preempt count in the irq stack + movl TI_PRE_COUNT(%ebx),%ecx + movl %ecx,TI_PRE_COUNT(%esi) + call do_IRQ + + movl %eax,%esp # potentially restore non-irq stack + + # copy flags from the irq stack back into the task's thread_info + # %esi is saved over the do_IRQ call and contains the irq stack + # thread_info pointer + # %ebx contains the original thread_info pointer + movl TI_FLAGS(%esi),%eax + movl $0,TI_FLAGS(%esi) + LOCK orl %eax,TI_FLAGS(%ebx) + jmp ret_from_intr #define BUILD_INTERRUPT(name, nr) \ diff -Nru a/arch/i386/kernel/init_task.c b/arch/i386/kernel/init_task.c --- a/arch/i386/kernel/init_task.c Thu Oct 31 11:12:05 2002 +++ b/arch/i386/kernel/init_task.c Thu Oct 31 11:12:05 2002 @@ -13,6 +13,10 @@ static struct signal_struct init_signals = INIT_SIGNALS(init_signals); struct mm_struct init_mm = INIT_MM(init_mm); +union thread_union init_irq_union + __attribute__((__section__(".data.init_task"))); + + /* * Initial thread structure. * diff -Nru a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c --- a/arch/i386/kernel/irq.c Thu Oct 31 11:12:05 2002 +++ b/arch/i386/kernel/irq.c Thu Oct 31 11:12:05 2002 @@ -311,7 +311,8 @@ * SMP cross-CPU interrupts have their own specific * handlers). */ -asmlinkage unsigned int do_IRQ(struct pt_regs regs) +struct pt_regs *do_IRQ(struct pt_regs *regs) __attribute__((regparm(1))); +struct pt_regs *do_IRQ(struct pt_regs *regs) { /* * We ack quickly, we don't want the irq controller @@ -323,7 +324,7 @@ * 0 return value means that this irq is already being * handled by some other CPU. (or is disabled) */ - int irq = regs.orig_eax & 0xff; /* high bits used in ret_from_ code */ + int irq = regs->orig_eax & 0xff; /* high bits used in ret_from_ code */ int cpu = smp_processor_id(); irq_desc_t *desc = irq_desc + irq; struct irqaction * action; @@ -388,7 +389,7 @@ */ for (;;) { spin_unlock(&desc->lock); - handle_IRQ_event(irq, ®s, action); + handle_IRQ_event(irq, regs, action); spin_lock(&desc->lock); if (likely(!(desc->status & IRQ_PENDING))) @@ -407,7 +408,7 @@ irq_exit(); - return 1; + return regs; } /** diff -Nru a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c --- a/arch/i386/kernel/process.c Thu Oct 31 11:12:05 2002 +++ b/arch/i386/kernel/process.c Thu Oct 31 11:12:05 2002 @@ -413,6 +413,7 @@ /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ + next_p->thread_info->irq_stack = prev_p->thread_info->irq_stack; unlazy_fpu(prev_p); /* diff -Nru a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c --- a/arch/i386/kernel/smpboot.c Thu Oct 31 11:12:05 2002 +++ b/arch/i386/kernel/smpboot.c Thu Oct 31 11:12:05 2002 @@ -70,6 +70,11 @@ /* Per CPU bogomips and other parameters */ struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned; +/* Per CPU interrupt stacks */ +extern union thread_union init_irq_union; +union thread_union *irq_stacks[NR_CPUS] __cacheline_aligned = + { &init_irq_union, }; + /* Set when the idlers are all forked */ int smp_threads_ready; @@ -764,6 +769,28 @@ return (send_status | accept_status); } +static void __init setup_irq_stack(struct task_struct *p, int cpu) +{ + unsigned long stk; + + stk = __get_free_pages(GFP_KERNEL, THREAD_ORDER+1); + if (!stk) + panic("I can't seem to allocate my irq stack. Oh well, giving up."); + + irq_stacks[cpu] = (void *)stk; + memset(irq_stacks[cpu], 0, THREAD_SIZE); + irq_stacks[cpu]->thread_info.cpu = cpu; + irq_stacks[cpu]->thread_info.preempt_count = 1; + /* interrupts are not preemptable */ + p->thread_info->irq_stack = irq_stacks[cpu]; + + /* If we want to make the irq stack more than one unit + * deep, we can chain then off of the irq_stack pointer + * here. + */ +} + + extern unsigned long cpu_initialized; static void __init do_boot_cpu (int apicid) @@ -787,6 +814,8 @@ if (IS_ERR(idle)) panic("failed fork for CPU %d", cpu); + setup_irq_stack(idle, cpu); + /* * We remove it from the pidhash and the runqueue * once we got the process: @@ -804,7 +833,13 @@ /* So we see what's up */ printk("Booting processor %d/%d eip %lx\n", cpu, apicid, start_eip); - stack_start.esp = (void *) (1024 + PAGE_SIZE + (char *)idle->thread_info); + + /* The -4 is to correct for the fact that the stack pointer + * is used to find the location of the thread_info structure + * by masking off several of the LSBs. Without the -4, esp + * is pointing to the page after the one the stack is on. + */ + stack_start.esp = (void *)(THREAD_SIZE - 4 + (char *)idle->thread_info); /* * This grunge runs the startup process for diff -Nru a/include/asm-i386/thread_info.h b/include/asm-i386/thread_info.h --- a/include/asm-i386/thread_info.h Thu Oct 31 11:12:05 2002 +++ b/include/asm-i386/thread_info.h Thu Oct 31 11:12:05 2002 @@ -29,9 +29,11 @@ __s32 preempt_count; /* 0 => preemptable, <0 => BUG */ mm_segment_t addr_limit; /* thread address space: + 0 for interrupts: illegal 0-0xBFFFFFFF for user-thead 0-0xFFFFFFFF for kernel-thread */ + struct thread_info *irq_stack; /* pointer to cpu irq stack */ __u8 supervisor_stack[0]; }; @@ -45,6 +47,7 @@ #define TI_CPU 0x0000000C #define TI_PRE_COUNT 0x00000010 #define TI_ADDR_LIMIT 0x00000014 +#define TI_IRQ_STACK 0x00000018 #endif @@ -67,6 +70,7 @@ .cpu = 0, \ .preempt_count = 1, \ .addr_limit = KERNEL_DS, \ + .irq_stack = &init_irq_union \ } #define init_thread_info (init_thread_union.thread_info)
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This archive was generated by hypermail 2b29 : Thu Oct 31 2002 - 22:00:56 EST