2002-09-11 22:57:20

by Dave Hansen

[permalink] [raw]
Subject: [PATCH] 4KB stack + irq stack for x86

# 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 1.624 -> 1.626
# arch/i386/kernel/process.c 1.40 -> 1.41
# arch/i386/kernel/irq.c 1.18 -> 1.19
# arch/i386/kernel/head.S 1.15 -> 1.16
# include/asm-i386/thread_info.h 1.7 -> 1.8
# include/asm-i386/page.h 1.16 -> 1.17
# arch/i386/kernel/entry.S 1.41 -> 1.43
# arch/i386/config.in 1.47 -> 1.48
# arch/i386/Makefile 1.17 -> 1.18
# arch/i386/kernel/i386_ksyms.c 1.30 -> 1.31
# arch/i386/kernel/smpboot.c 1.33 -> 1.34
# arch/i386/boot/compressed/misc.c 1.7 -> 1.8
# arch/i386/kernel/init_task.c 1.6 -> 1.7
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/09/09 [email protected](none) 1.625
# Import patch v2.5.20-stack-A2.diff
# --------------------------------------------
# 02/09/11 [email protected](none) 1.626
# don't fetch things out of ebx when it has garbage in it :(
# --------------------------------------------
#
diff -Nru a/arch/i386/Makefile b/arch/i386/Makefile
--- a/arch/i386/Makefile Wed Sep 11 15:30:18 2002
+++ b/arch/i386/Makefile Wed Sep 11 15:30:18 2002
@@ -85,6 +85,10 @@
CFLAGS += -march=i586
endif

+ifdef CONFIG_X86_STACK_CHECK
+CFLAGS += -p
+endif
+
HEAD := arch/i386/kernel/head.o arch/i386/kernel/init_task.o

SUBDIRS += arch/i386/kernel arch/i386/mm arch/i386/lib
diff -Nru a/arch/i386/boot/compressed/misc.c b/arch/i386/boot/compressed/misc.c
--- a/arch/i386/boot/compressed/misc.c Wed Sep 11 15:30:18 2002
+++ b/arch/i386/boot/compressed/misc.c Wed Sep 11 15:30:18 2002
@@ -377,3 +377,7 @@
if (high_loaded) close_output_buffer_if_we_run_high(mv);
return high_loaded;
}
+
+/* We don't actually check for stack overflows this early. */
+__asm__(".globl mcount ; mcount: ret\n");
+
diff -Nru a/arch/i386/config.in b/arch/i386/config.in
--- a/arch/i386/config.in Wed Sep 11 15:30:18 2002
+++ b/arch/i386/config.in Wed Sep 11 15:30:18 2002
@@ -35,6 +35,7 @@
#
# Define implied options from the CPU selection here
#
+define_bool CONFIG_X86_HAVE_CMOV n

if [ "$CONFIG_M386" = "y" ]; then
define_bool CONFIG_X86_CMPXCHG n
@@ -91,18 +92,21 @@
define_bool CONFIG_X86_GOOD_APIC y
define_bool CONFIG_X86_USE_PPRO_CHECKSUM y
define_bool CONFIG_X86_PPRO_FENCE y
+ define_bool CONFIG_X86_HAVE_CMOV y
fi
if [ "$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
@@ -116,6 +120,7 @@
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 [ "$CONFIG_MELAN" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 4
@@ -132,6 +137,7 @@
if [ "$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 [ "$CONFIG_MWINCHIPC6" = "y" ]; then
define_int CONFIG_X86_L1_CACHE_SHIFT 5
@@ -429,6 +435,7 @@
if [ "$CONFIG_HIGHMEM" = "y" ]; then
bool ' Highmem debugging' CONFIG_DEBUG_HIGHMEM
fi
+ bool ' Check for stack overflows' CONFIG_X86_STACK_CHECK
fi

endmenu
diff -Nru a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
--- a/arch/i386/kernel/entry.S Wed Sep 11 15:30:18 2002
+++ b/arch/i386/kernel/entry.S Wed Sep 11 15:30:18 2002
@@ -136,7 +136,7 @@
movl %ecx,CS(%esp) #
movl %esp, %ebx
pushl %ebx
- andl $-8192, %ebx # GET_THREAD_INFO
+ GET_THREAD_INFO_WITH_ESP(%ebx)
movl TI_EXEC_DOMAIN(%ebx), %edx # Get the execution domain
movl 4(%edx), %edx # Get the lcall7 handler for the domain
pushl $0x7
@@ -158,7 +158,7 @@
movl %ecx,CS(%esp) #
movl %esp, %ebx
pushl %ebx
- andl $-8192, %ebx # GET_THREAD_INFO
+ GET_THREAD_INFO_WITH_ESP(%ebx)
movl TI_EXEC_DOMAIN(%ebx), %edx # Get the execution domain
movl 4(%edx), %edx # Get the lcall7 handler for the domain
pushl $0x27
@@ -334,7 +334,39 @@
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
+ testl %ecx,%ecx # is there a valid irq_stack?
+
+ # switch to the irq stack
+#ifdef CONFIG_X86_HAVE_CMOV
+ cmovnz %esi,%esp
+#else
+ jnz 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) \
@@ -506,6 +538,61 @@
pushl $0
pushl $do_spurious_interrupt_bug
jmp error_code
+
+#ifdef CONFIG_X86_STACK_CHECK
+.data
+ .globl stack_overflowed
+stack_overflowed:
+ .long 0
+
+.text
+
+ENTRY(mcount)
+ push %eax
+ movl $(THREAD_SIZE - 1),%eax
+ andl %esp,%eax
+ cmpl $0x200,%eax /* 512 byte danger zone */
+ jle 1f
+2:
+ popl %eax
+ ret
+1:
+ lock; btsl $0,stack_overflowed /* Prevent reentry via printk */
+ jc 2b
+
+ # switch to overflow stack
+ movl %esp,%eax
+ movl $(stack_overflow_stack + THREAD_SIZE - 4),%esp
+
+ pushf
+ cli
+ pushl %eax
+
+ # push eip then esp of error for stack_overflow_panic
+ pushl 4(%eax)
+ pushl %eax
+
+ # update the task pointer and cpu in the overflow stack's thread_info.
+ GET_THREAD_INFO_WITH_ESP(%eax)
+ movl TI_TASK(%eax),%ebx
+ movl %ebx,stack_overflow_stack+TI_TASK
+ movl TI_CPU(%eax),%ebx
+ movl %ebx,stack_overflow_stack+TI_CPU
+
+ # never neverland
+ call stack_overflow_panic
+
+ addl $8,%esp
+
+ popf
+ popl %eax
+ movl %eax,%esp
+ popl %eax
+ movl $0,stack_overflowed
+ ret
+
+#warning stack check enabled
+#endif

.data
ENTRY(sys_call_table)
diff -Nru a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
--- a/arch/i386/kernel/head.S Wed Sep 11 15:30:18 2002
+++ b/arch/i386/kernel/head.S Wed Sep 11 15:30:18 2002
@@ -15,6 +15,7 @@
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/desc.h>
+#include <asm/thread_info.h>

#define OLD_CL_MAGIC_ADDR 0x90020
#define OLD_CL_MAGIC 0xA33F
@@ -305,7 +306,7 @@
ret

ENTRY(stack_start)
- .long init_thread_union+8192
+ .long init_thread_union+THREAD_SIZE
.long __KERNEL_DS

/* This is the default interrupt "handler" :-) */
diff -Nru a/arch/i386/kernel/i386_ksyms.c b/arch/i386/kernel/i386_ksyms.c
--- a/arch/i386/kernel/i386_ksyms.c Wed Sep 11 15:30:18 2002
+++ b/arch/i386/kernel/i386_ksyms.c Wed Sep 11 15:30:18 2002
@@ -172,3 +172,8 @@
EXPORT_SYMBOL(is_sony_vaio_laptop);

EXPORT_SYMBOL(__PAGE_KERNEL);
+
+#ifdef CONFIG_X86_STACK_CHECK
+extern void mcount(void);
+EXPORT_SYMBOL(mcount);
+#endif
diff -Nru a/arch/i386/kernel/init_task.c b/arch/i386/kernel/init_task.c
--- a/arch/i386/kernel/init_task.c Wed Sep 11 15:30:18 2002
+++ b/arch/i386/kernel/init_task.c Wed Sep 11 15:30:18 2002
@@ -13,6 +13,14 @@
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")));
+#endif
+
/*
* Initial thread structure.
*
@@ -22,7 +30,15 @@
*/
union thread_union init_thread_union
__attribute__((__section__(".data.init_task"))) =
- { INIT_THREAD_INFO(init_task) };
+ { {
+ task: &init_task,
+ exec_domain: &default_exec_domain,
+ flags: 0,
+ cpu: 0,
+ addr_limit: KERNEL_DS,
+ irq_stack: &init_irq_union,
+ } };
+

/*
* Initial task structure.
diff -Nru a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c
--- a/arch/i386/kernel/irq.c Wed Sep 11 15:30:18 2002
+++ b/arch/i386/kernel/irq.c Wed Sep 11 15:30:18 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, &regs, 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 Wed Sep 11 15:30:18 2002
+++ b/arch/i386/kernel/process.c Wed Sep 11 15:30:18 2002
@@ -438,6 +438,16 @@

extern void show_trace(unsigned long* esp);

+#ifdef CONFIG_X86_STACK_CHECK
+void stack_overflow_panic(void *esp, void *eip)
+{
+ printk("stack overflow from %p. esp: %p\n", eip, esp);
+ show_trace(esp);
+ panic("stack overflow\n");
+}
+
+#endif
+
void show_regs(struct pt_regs * regs)
{
unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
@@ -693,6 +703,7 @@

/* 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 Wed Sep 11 15:30:18 2002
+++ b/arch/i386/kernel/smpboot.c Wed Sep 11 15:30:18 2002
@@ -67,6 +67,10 @@
/* Per CPU bogomips and other parameters */
struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned;

+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;

@@ -762,6 +766,27 @@
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);
+ 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)
@@ -785,6 +810,8 @@
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:
@@ -802,7 +829,13 @@

/* 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/page.h b/include/asm-i386/page.h
--- a/include/asm-i386/page.h Wed Sep 11 15:30:18 2002
+++ b/include/asm-i386/page.h Wed Sep 11 15:30:18 2002
@@ -3,7 +3,11 @@

/* PAGE_SHIFT determines the page size */
#define PAGE_SHIFT 12
+#ifndef __ASSEMBLY__
#define PAGE_SIZE (1UL << PAGE_SHIFT)
+#else
+#define PAGE_SIZE (1 << PAGE_SHIFT)
+#endif
#define PAGE_MASK (~(PAGE_SIZE-1))

#define LARGE_PAGE_MASK (~(LARGE_PAGE_SIZE-1))
diff -Nru a/include/asm-i386/thread_info.h b/include/asm-i386/thread_info.h
--- a/include/asm-i386/thread_info.h Wed Sep 11 15:30:18 2002
+++ b/include/asm-i386/thread_info.h Wed Sep 11 15:30:18 2002
@@ -9,6 +9,7 @@

#ifdef __KERNEL__

+#include <asm/page.h>
#ifndef __ASSEMBLY__
#include <asm/processor.h>
#endif
@@ -28,9 +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];
};
@@ -44,6 +47,7 @@
#define TI_CPU 0x0000000C
#define TI_PRE_COUNT 0x00000010
#define TI_ADDR_LIMIT 0x00000014
+#define TI_IRQ_STACK 0x00000018

#endif

@@ -54,42 +58,42 @@
*
* preempt_count needs to be 1 initially, until the scheduler is functional.
*/
+#define THREAD_ORDER 0
+#define INIT_THREAD_SIZE THREAD_SIZE
+
#ifndef __ASSEMBLY__
-#define INIT_THREAD_INFO(tsk) \
-{ \
- .task = &tsk, \
- .exec_domain = &default_exec_domain, \
- .flags = 0, \
- .cpu = 0, \
- .preempt_count = 1, \
- .addr_limit = KERNEL_DS, \
-}

#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)

+/* thread information allocation */
+#define THREAD_SIZE (PAGE_SIZE << THREAD_ORDER)
+#define alloc_thread_info() ((struct thread_info *) __get_free_pages(GFP_KERNEL,THREAD_ORDER))
+#define free_thread_info(ti) free_pages((unsigned long) (ti), THREAD_ORDER)
+#define get_thread_info(ti) get_task_struct((ti)->task)
+#define put_thread_info(ti) put_task_struct((ti)->task)
+
+
/* how to get the thread information struct from C */
static inline struct thread_info *current_thread_info(void)
{
struct thread_info *ti;
- __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~8191UL));
+ __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
return ti;
}

-/* thread information allocation */
-#define THREAD_SIZE (2*PAGE_SIZE)
-#define alloc_thread_info() ((struct thread_info *) __get_free_pages(GFP_KERNEL,1))
-#define free_thread_info(ti) free_pages((unsigned long) (ti), 1)
-#define get_thread_info(ti) get_task_struct((ti)->task)
-#define put_thread_info(ti) put_task_struct((ti)->task)
-
#else /* !__ASSEMBLY__ */

+#define THREAD_SIZE (PAGE_SIZE << THREAD_ORDER)
+
/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg) \
- movl $-8192, reg; \
+ movl $-THREAD_SIZE, reg; \
andl %esp, reg
-
+/* use this one if reg already contains %esp */
+#define GET_THREAD_INFO_WITH_ESP(reg) \
+ andl $-THREAD_SIZE, reg
+
#endif

/*


Attachments:
irqstack-2.5.34-1.patch (15.27 kB)

2002-09-18 03:55:36

by Rusty Russell

[permalink] [raw]
Subject: Re: [PATCH] 4KB stack + irq stack for x86

On Wed, 11 Sep 2002 16:00:25 -0700
Dave Hansen <[email protected]> wrote:

> This is a resync of the last patch for 2.5.34 that resulted from this discussion
> (not the original patch):
> http://lwn.net/Articles/1642/
> The only change was readding the reference to task_info in the beginning of
> common_interrupt. It had been dropped when we stopped messing with
> preempt_count there.
>
> I've beaten this thing with my normal array of Specweb tests and it is behaving
> so far. I've booted on an 8-way with and without SMP.

I'd really like to see this in 2.5, if only to make massively threaded
programs using Ingo's pthreads mods even more viable, and show up those people
who think userspace threading libraries are a good idea 8)

Rusty.
--
there are those who do and those who hang on and you don't see too
many doers quoting their contemporaries. -- Larry McVoy