* [RFC][PATCH] x86 transition to 4k stacks (3/3)
@ 2002-10-15 6:00 Dave Hansen
[not found] ` <20021015173740.A3955@dikhow>
0 siblings, 1 reply; 2+ messages in thread
From: Dave Hansen @ 2002-10-15 6:00 UTC (permalink / raw)
To: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 229 bytes --]
* interrupt stacks (3/3)
- allocate per-cpu interrupt stacks. upon entry to
common_interrupt, switch to the current cpu's stack.
- inherit the interrupted task's preempt count
--
Dave Hansen
haveblue@us.ibm.com
[-- Attachment #2: interrupt_stacks-2.5.42+bk-6.patch --]
[-- Type: text/plain, Size: 9866 bytes --]
# 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 1.852 -> 1.855
# arch/i386/kernel/process.c 1.33 -> 1.34
# arch/i386/kernel/irq.c 1.21 -> 1.23
# include/asm-i386/thread_info.h 1.8 -> 1.9
# arch/i386/kernel/entry.S 1.39 -> 1.40
# arch/i386/config.in 1.57 -> 1.58
# arch/i386/kernel/smpboot.c 1.35 -> 1.36
# arch/i386/kernel/init_task.c 1.7 -> 1.8
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/14 haveblue@elm3b96.(none) 1.851.1.1
# interrupt_stacks-tmp.patch
# --------------------------------------------
# 02/10/14 haveblue@elm3b96.(none) 1.853
# Merge elm3b96.(none):/work/dave/bk/linux-2.5-irq-stack
# into elm3b96.(none):/work/dave/bk/linux-2.5-overflow-detect+irq-stack
# --------------------------------------------
# 02/10/14 haveblue@elm3b96.(none) 1.854
# merge problem
# --------------------------------------------
# 02/10/14 haveblue@elm3b96.(none) 1.855
# irq.c:
# add correct preempt_count handling
# --------------------------------------------
#
diff -Nru a/arch/i386/config.in b/arch/i386/config.in
--- a/arch/i386/config.in Mon Oct 14 22:31:41 2002
+++ b/arch/i386/config.in Mon Oct 14 22:31:41 2002
@@ -34,6 +34,7 @@
#
# Define implied options from the CPU selection here
#
+define_bool CONFIG_X86_HAVE_CMOV n
if [ "$CONFIG_M386" = "y" ]; then
define_bool CONFIG_X86_CMPXCHG n
@@ -90,18 +91,21 @@
define_bool CONFIG_X86_GOOD_APIC y
define_bool CONFIG_X86_USE_PPRO_CHECKSUM y
define_bool CONFIG_X86_PPRO_FENCE y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MPENTIUMIII" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 5
define_bool CONFIG_X86_TSC y
define_bool CONFIG_X86_GOOD_APIC y
define_bool CONFIG_X86_USE_PPRO_CHECKSUM y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MPENTIUM4" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 7
define_bool CONFIG_X86_TSC y
define_bool CONFIG_X86_GOOD_APIC y
define_bool CONFIG_X86_USE_PPRO_CHECKSUM y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MK6" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 5
@@ -115,6 +119,7 @@
define_bool CONFIG_X86_GOOD_APIC y
define_bool CONFIG_X86_USE_3DNOW y
define_bool CONFIG_X86_USE_PPRO_CHECKSUM y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MELAN" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 4
@@ -131,6 +136,7 @@
if [ "$CONFIG_MCRUSOE" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 5
define_bool CONFIG_X86_TSC y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MWINCHIPC6" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 5
diff -Nru a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
--- a/arch/i386/kernel/entry.S Mon Oct 14 22:31:41 2002
+++ b/arch/i386/kernel/entry.S Mon Oct 14 22:31:41 2002
@@ -334,7 +334,41 @@
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)
+
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 Mon Oct 14 22:31:41 2002
+++ b/arch/i386/kernel/init_task.c Mon Oct 14 22:31:41 2002
@@ -13,6 +13,9 @@
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")));
+
#ifdef CONFIG_X86_STACK_CHECK
union thread_union stack_overflow_stack
__attribute__((__section__(".data.init_task")));
diff -Nru a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c
--- a/arch/i386/kernel/irq.c Mon Oct 14 22:31:41 2002
+++ b/arch/i386/kernel/irq.c Mon Oct 14 22:31:41 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
@@ -323,12 +324,19 @@
* 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;
unsigned int status;
+ /*
+ * get the preempt count from the thread that was interrupted
+ * preempt_count() is the interrupt stack's thread_info
+ * current->thread_info is the interrupted task
+ */
+ preempt_count() += current->thread_info->preempt_count;
+
irq_enter();
kstat.irqs[cpu][irq]++;
spin_lock(&desc->lock);
@@ -373,7 +381,7 @@
*/
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)))
@@ -391,8 +399,9 @@
spin_unlock(&desc->lock);
irq_exit();
+ preempt_count() += current->thread_info->preempt_count;
- return 1;
+ return regs;
}
/**
diff -Nru a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
--- a/arch/i386/kernel/process.c Mon Oct 14 22:31:41 2002
+++ b/arch/i386/kernel/process.c Mon Oct 14 22:31:41 2002
@@ -427,6 +427,7 @@
/* 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 Mon Oct 14 22:31:41 2002
+++ b/arch/i386/kernel/smpboot.c Mon Oct 14 22:31:41 2002
@@ -69,6 +69,11 @@
/* 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;
@@ -763,6 +768,28 @@
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)
@@ -786,6 +813,8 @@
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:
@@ -803,7 +832,13 @@
/* 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 Mon Oct 14 22:31:41 2002
+++ b/include/asm-i386/thread_info.h Mon Oct 14 22:31:41 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
@@ -59,6 +62,7 @@
#define INIT_THREAD_SIZE THREAD_SIZE
#ifndef __ASSEMBLY__
+
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
@@ -67,8 +71,9 @@
.cpu = 0, \
.preempt_count = 1, \
.addr_limit = KERNEL_DS, \
+ .irq_stack = &init_irq_union \
}
-
+
#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [RFC][PATCH] x86 transition to 4k stacks (3/3)
[not found] ` <20021015173740.A3955@dikhow>
@ 2002-10-15 18:59 ` Dave Hansen
0 siblings, 0 replies; 2+ messages in thread
From: Dave Hansen @ 2002-10-15 18:59 UTC (permalink / raw)
To: dipankar, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 855 bytes --]
Dipankar Sarma wrote:
> On Tue, Oct 15, 2002 at 08:10:08AM +0200, Dave Hansen wrote:
>
>>* interrupt stacks (3/3)
>> - allocate per-cpu interrupt stacks. upon entry to
>> common_interrupt, switch to the current cpu's stack.
>> - inherit the interrupted task's preempt count
>
> Adding current->thread_info->preempt_count doesn't make sense. What
> you need to do is to copy the old thread_info->preempt_count to
> new thread_info->preempt_count. If you aren't switching stack
> this has no effect.
Right you are.
> movl TI_PRE_COUNT(%ebx),%ecx
> movl %ecx,TI_PRE_COUNT(%esi)
>
> So if you are not switching stack, %ebx == %esi and this has no effect.
> The preempt_count() manipulation in do_IRQ() should be deleted.
>
> And, no you can't weasel out of x86 assembly :)
Updated patch is attached.
--
Dave Hansen
haveblue@us.ibm.com
[-- Attachment #2: interrupt_stacks-2.5.42+bk-7.patch --]
[-- Type: text/plain, Size: 9093 bytes --]
# 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 1.852 -> 1.856
# arch/i386/kernel/process.c 1.33 -> 1.34
# arch/i386/kernel/irq.c 1.21 -> 1.25
# include/asm-i386/thread_info.h 1.8 -> 1.9
# arch/i386/kernel/entry.S 1.39 -> 1.41
# arch/i386/config.in 1.57 -> 1.58
# arch/i386/kernel/smpboot.c 1.35 -> 1.36
# arch/i386/kernel/init_task.c 1.7 -> 1.8
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/14 haveblue@elm3b96.(none) 1.851.1.1
# interrupt_stacks-tmp.patch
# --------------------------------------------
#
diff -Nru a/arch/i386/config.in b/arch/i386/config.in
--- a/arch/i386/config.in Tue Oct 15 11:13:17 2002
+++ b/arch/i386/config.in Tue Oct 15 11:13:17 2002
@@ -34,6 +34,7 @@
#
# Define implied options from the CPU selection here
#
+define_bool CONFIG_X86_HAVE_CMOV n
if [ "$CONFIG_M386" = "y" ]; then
define_bool CONFIG_X86_CMPXCHG n
@@ -90,18 +91,21 @@
define_bool CONFIG_X86_GOOD_APIC y
define_bool CONFIG_X86_USE_PPRO_CHECKSUM y
define_bool CONFIG_X86_PPRO_FENCE y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MPENTIUMIII" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 5
define_bool CONFIG_X86_TSC y
define_bool CONFIG_X86_GOOD_APIC y
define_bool CONFIG_X86_USE_PPRO_CHECKSUM y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MPENTIUM4" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 7
define_bool CONFIG_X86_TSC y
define_bool CONFIG_X86_GOOD_APIC y
define_bool CONFIG_X86_USE_PPRO_CHECKSUM y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MK6" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 5
@@ -115,6 +119,7 @@
define_bool CONFIG_X86_GOOD_APIC y
define_bool CONFIG_X86_USE_3DNOW y
define_bool CONFIG_X86_USE_PPRO_CHECKSUM y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MELAN" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 4
@@ -131,6 +136,7 @@
if [ "$CONFIG_MCRUSOE" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 5
define_bool CONFIG_X86_TSC y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$CONFIG_MWINCHIPC6" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 5
diff -Nru a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
--- a/arch/i386/kernel/entry.S Tue Oct 15 11:13:17 2002
+++ b/arch/i386/kernel/entry.S Tue Oct 15 11:13:17 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 Tue Oct 15 11:13:17 2002
+++ b/arch/i386/kernel/init_task.c Tue Oct 15 11:13:17 2002
@@ -13,6 +13,9 @@
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")));
+
#ifdef CONFIG_X86_STACK_CHECK
union thread_union stack_overflow_stack
__attribute__((__section__(".data.init_task")));
diff -Nru a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c
--- a/arch/i386/kernel/irq.c Tue Oct 15 11:13:17 2002
+++ b/arch/i386/kernel/irq.c Tue Oct 15 11:13:17 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;
@@ -373,7 +374,7 @@
*/
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)))
@@ -392,7 +393,7 @@
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 Tue Oct 15 11:13:17 2002
+++ b/arch/i386/kernel/process.c Tue Oct 15 11:13:17 2002
@@ -427,6 +427,7 @@
/* 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 Tue Oct 15 11:13:17 2002
+++ b/arch/i386/kernel/smpboot.c Tue Oct 15 11:13:17 2002
@@ -69,6 +69,11 @@
/* 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;
@@ -763,6 +768,28 @@
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)
@@ -786,6 +813,8 @@
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:
@@ -803,7 +832,13 @@
/* 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 Tue Oct 15 11:13:17 2002
+++ b/include/asm-i386/thread_info.h Tue Oct 15 11:13:17 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
@@ -59,6 +62,7 @@
#define INIT_THREAD_SIZE THREAD_SIZE
#ifndef __ASSEMBLY__
+
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
@@ -67,8 +71,9 @@
.cpu = 0, \
.preempt_count = 1, \
.addr_limit = KERNEL_DS, \
+ .irq_stack = &init_irq_union \
}
-
+
#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2002-10-15 18:56 UTC | newest]
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2002-10-15 6:00 [RFC][PATCH] x86 transition to 4k stacks (3/3) Dave Hansen
[not found] ` <20021015173740.A3955@dikhow>
2002-10-15 18:59 ` Dave Hansen
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