From: Ingo Molnar <mingo@elte.hu>
To: Zwane Mwaikambo <zwane@linuxpower.ca>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>, Matt Mackall <mpm@selenic.com>
Subject: Re: [PATCH][2.6-mm] Fix 4G/4G w/ 8k+ stacks
Date: Tue, 16 Mar 2004 08:16:02 +0100 [thread overview]
Message-ID: <20040316071601.GA2560@elte.hu> (raw)
In-Reply-To: <Pine.LNX.4.58.0403150401310.28447@montezuma.fsmlabs.com>
looks good to me!
Ingo
* Zwane Mwaikambo <zwane@linuxpower.ca> wrote:
> The 4/4 code right now is setup for 8k stacks, this patch should allow for
> arbitrary stack sizes. Some parts are rather ugly (e.g. STACK_PAGE_COUNT)
> so (abusive too) comments are welcome.
>
> I've tested it with 4k,8k and 16k stacks on UP and SMP, but i believe it
> breaks with CONFIG_DEBUG_PAGEALLOC
>
> Index: linux-2.6.4-mm2/include/asm-i386/fixmap.h
> ===================================================================
> RCS file: /home/cvsroot/linux-2.6.4-mm2/include/asm-i386/fixmap.h,v
> retrieving revision 1.1.1.1
> diff -u -p -B -r1.1.1.1 fixmap.h
> --- linux-2.6.4-mm2/include/asm-i386/fixmap.h 15 Mar 2004 05:53:41 -0000 1.1.1.1
> +++ linux-2.6.4-mm2/include/asm-i386/fixmap.h 15 Mar 2004 16:01:20 -0000
> @@ -115,10 +115,10 @@ extern void __set_fixmap (enum fixed_add
> * Leave one empty page between vmalloc'ed areas and
> * the start of the fixmap.
> *
> - * IMPORTANT: dont change FIXADDR_TOP without adjusting KM_VSTACK0
> - * and KM_VSTACK1 so that the virtual stack is 8K aligned.
> + * IMPORTANT: we have to align FIXADDR_TOP so that the virtual stack
> + * is THREAD_SIZE aligned.
> */
> -#define FIXADDR_TOP (0xffffe000UL)
> +#define FIXADDR_TOP (0xffffe000UL & ~(THREAD_SIZE-1))
> #define __FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
> #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
>
> Index: linux-2.6.4-mm2/include/asm-i386/kmap_types.h
> ===================================================================
> RCS file: /home/cvsroot/linux-2.6.4-mm2/include/asm-i386/kmap_types.h,v
> retrieving revision 1.1.1.1
> diff -u -p -B -r1.1.1.1 kmap_types.h
> --- linux-2.6.4-mm2/include/asm-i386/kmap_types.h 15 Mar 2004 05:53:41 -0000 1.1.1.1
> +++ linux-2.6.4-mm2/include/asm-i386/kmap_types.h 15 Mar 2004 23:09:53 -0000
> @@ -2,15 +2,16 @@
> #define _ASM_KMAP_TYPES_H
>
> #include <linux/config.h>
> +#include <linux/thread_info.h>
>
> enum km_type {
> /*
> - * IMPORTANT: don't move these 3 entries, and only add entries in
> - * pairs: the 4G/4G virtual stack must be 8K aligned on each cpu.
> + * IMPORTANT: don't move these 3 entries, be wary when adding entries,
> + * the 4G/4G virtual stack must be THREAD_SIZE aligned on each cpu.
> */
> KM_BOUNCE_READ,
> - KM_VSTACK1,
> - KM_VSTACK0,
> + KM_VSTACK_BASE,
> + KM_VSTACK_TOP = KM_VSTACK_BASE + STACK_PAGE_COUNT-1,
>
> KM_LDT_PAGE15,
> KM_LDT_PAGE0 = KM_LDT_PAGE15 + 16-1,
> @@ -30,8 +31,8 @@ enum km_type {
> KM_SOFTIRQ0,
> KM_SOFTIRQ1,
> /*
> - * Add new entries in pairs:
> - * the 4G/4G virtual stack must be 8K aligned on each cpu.
> + * Be wary when adding entries:
> + * the 4G/4G virtual stack must be THREAD_SIZE aligned on each cpu.
> */
> KM_TYPE_NR
> };
> Index: linux-2.6.4-mm2/include/asm-i386/processor.h
> ===================================================================
> RCS file: /home/cvsroot/linux-2.6.4-mm2/include/asm-i386/processor.h,v
> retrieving revision 1.1.1.1
> diff -u -p -B -r1.1.1.1 processor.h
> --- linux-2.6.4-mm2/include/asm-i386/processor.h 15 Mar 2004 05:53:41 -0000 1.1.1.1
> +++ linux-2.6.4-mm2/include/asm-i386/processor.h 15 Mar 2004 15:44:57 -0000
> @@ -401,10 +401,16 @@ struct tss_struct {
>
> #define ARCH_MIN_TASKALIGN 16
>
> +#ifdef CONFIG_4KSTACKS
> +#define STACK_PAGE_COUNT (4096/PAGE_SIZE)
> +#else
> +#define STACK_PAGE_COUNT (8192/PAGE_SIZE) /* THREAD_SIZE/PAGE_SIZE */
> +#endif
> +
> struct thread_struct {
> /* cached TLS descriptors. */
> struct desc_struct tls_array[GDT_ENTRY_TLS_ENTRIES];
> - void *stack_page0, *stack_page1;
> + void *stack_page[STACK_PAGE_COUNT];
> unsigned long esp0;
> unsigned long sysenter_cs;
> unsigned long eip;
> Index: linux-2.6.4-mm2/include/asm-i386/thread_info.h
> ===================================================================
> RCS file: /home/cvsroot/linux-2.6.4-mm2/include/asm-i386/thread_info.h,v
> retrieving revision 1.1.1.1
> diff -u -p -B -r1.1.1.1 thread_info.h
> --- linux-2.6.4-mm2/include/asm-i386/thread_info.h 15 Mar 2004 05:53:41 -0000 1.1.1.1
> +++ linux-2.6.4-mm2/include/asm-i386/thread_info.h 15 Mar 2004 15:49:56 -0000
> @@ -49,8 +49,10 @@ struct thread_info {
> #endif
>
> #define PREEMPT_ACTIVE 0x4000000
> +
> +/* if you change THREAD_SIZE here, don't forget to change STACK_PAGE_COUNT */
> #ifdef CONFIG_4KSTACKS
> -#define THREAD_SIZE (4096)
> +#define THREAD_SIZE (4096)
> #else
> #define THREAD_SIZE (8192)
> #endif
> Index: linux-2.6.4-mm2/arch/i386/kernel/entry_trampoline.c
> ===================================================================
> RCS file: /home/cvsroot/linux-2.6.4-mm2/arch/i386/kernel/entry_trampoline.c,v
> retrieving revision 1.1.1.1
> diff -u -p -B -r1.1.1.1 entry_trampoline.c
> --- linux-2.6.4-mm2/arch/i386/kernel/entry_trampoline.c 15 Mar 2004 05:53:30 -0000 1.1.1.1
> +++ linux-2.6.4-mm2/arch/i386/kernel/entry_trampoline.c 15 Mar 2004 08:52:48 -0000
> @@ -21,7 +21,9 @@ extern char __entry_tramp_start, __entry
> void __init init_entry_mappings(void)
> {
> #ifdef CONFIG_X86_HIGH_ENTRY
> +
> void *tramp;
> + int p;
>
> /*
> * We need a high IDT and GDT for the 4G/4G split:
> @@ -37,7 +39,7 @@ void __init init_entry_mappings(void)
> /*
> * Virtual kernel stack:
> */
> - BUG_ON(__kmap_atomic_vaddr(KM_VSTACK0) & (THREAD_SIZE-1));
> + BUG_ON(__kmap_atomic_vaddr(KM_VSTACK_TOP) & (THREAD_SIZE-1));
> BUG_ON(sizeof(struct desc_struct)*NR_CPUS*GDT_ENTRIES > 2*PAGE_SIZE);
> BUG_ON((unsigned int)&__entry_tramp_end - (unsigned int)&__entry_tramp_start > 2*PAGE_SIZE);
>
> @@ -45,15 +47,15 @@ void __init init_entry_mappings(void)
> * set up the initial thread's virtual stack related
> * fields:
> */
> - current->thread.stack_page0 = virt_to_page((char *)current->thread_info);
> - current->thread.stack_page1 = virt_to_page((char *)current->thread_info + PAGE_SIZE);
> - current->thread_info->virtual_stack = (void *)__kmap_atomic_vaddr(KM_VSTACK0);
> -
> - __kunmap_atomic_type(KM_VSTACK0);
> - __kunmap_atomic_type(KM_VSTACK1);
> - __kmap_atomic(current->thread.stack_page0, KM_VSTACK0);
> - __kmap_atomic(current->thread.stack_page1, KM_VSTACK1);
> + for (p = 0; p < ARRAY_SIZE(current->thread.stack_page); p++)
> + current->thread.stack_page[p] = virt_to_page((char *)current->thread_info + (p*PAGE_SIZE));
> +
> + current->thread_info->virtual_stack = (void *)__kmap_atomic_vaddr(KM_VSTACK_TOP);
>
> + for (p = 0; p < ARRAY_SIZE(current->thread.stack_page); p++) {
> + __kunmap_atomic_type(KM_VSTACK_TOP-p);
> + __kmap_atomic(current->thread.stack_page[p], KM_VSTACK_TOP-p);
> + }
> #endif
> current->thread_info->real_stack = (void *)current->thread_info;
> current->thread_info->user_pgd = NULL;
> Index: linux-2.6.4-mm2/arch/i386/kernel/process.c
> ===================================================================
> RCS file: /home/cvsroot/linux-2.6.4-mm2/arch/i386/kernel/process.c,v
> retrieving revision 1.1.1.1
> diff -u -p -B -r1.1.1.1 process.c
> --- linux-2.6.4-mm2/arch/i386/kernel/process.c 15 Mar 2004 05:53:30 -0000 1.1.1.1
> +++ linux-2.6.4-mm2/arch/i386/kernel/process.c 15 Mar 2004 08:08:42 -0000
> @@ -345,7 +345,7 @@ int copy_thread(int nr, unsigned long cl
> {
> struct pt_regs * childregs;
> struct task_struct *tsk;
> - int err;
> + int err, i;
>
> childregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
> struct_cpy(childregs, regs);
> @@ -360,10 +360,11 @@ int copy_thread(int nr, unsigned long cl
> * get the two stack pages, for the virtual stack.
> *
> * IMPORTANT: this code relies on the fact that the task
> - * structure is an 8K aligned piece of physical memory.
> + * structure is an THREAD_SIZE aligned piece of physical memory.
> */
> - p->thread.stack_page0 = virt_to_page((unsigned long)p->thread_info);
> - p->thread.stack_page1 = virt_to_page((unsigned long)p->thread_info + PAGE_SIZE);
> + for (i = 0; i < ARRAY_SIZE(p->thread.stack_page); i++)
> + p->thread.stack_page[i] =
> + virt_to_page((unsigned long)p->thread_info + (i*PAGE_SIZE));
>
> p->thread.eip = (unsigned long) ret_from_fork;
> p->thread_info->real_stack = p->thread_info;
> @@ -519,22 +520,23 @@ struct task_struct fastcall * __switch_t
> __unlazy_fpu(prev_p);
>
> #ifdef CONFIG_X86_HIGH_ENTRY
> +{
> + int i;
> /*
> * Set the ptes of the virtual stack. (NOTE: a one-page TLB flush is
> * needed because otherwise NMIs could interrupt the
> * user-return code with a virtual stack and stale TLBs.)
> */
> - __kunmap_atomic_type(KM_VSTACK0);
> - __kunmap_atomic_type(KM_VSTACK1);
> - __kmap_atomic(next->stack_page0, KM_VSTACK0);
> - __kmap_atomic(next->stack_page1, KM_VSTACK1);
> -
> + for (i = 0; i < ARRAY_SIZE(next->stack_page); i++) {
> + __kunmap_atomic_type(KM_VSTACK_TOP-i);
> + __kmap_atomic(next->stack_page[i], KM_VSTACK_TOP-i);
> + }
> /*
> * NOTE: here we rely on the task being the stack as well
> */
> next_p->thread_info->virtual_stack =
> - (void *)__kmap_atomic_vaddr(KM_VSTACK0);
> -
> + (void *)__kmap_atomic_vaddr(KM_VSTACK_TOP);
> +}
> #if defined(CONFIG_PREEMPT) && defined(CONFIG_SMP)
> /*
> * If next was preempted on entry from userspace to kernel,
next prev parent reply other threads:[~2004-03-16 10:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-16 6:35 [PATCH][2.6-mm] Fix 4G/4G w/ 8k+ stacks Zwane Mwaikambo
2004-03-16 7:16 ` Ingo Molnar [this message]
2004-03-16 10:40 ` William Lee Irwin III
2004-03-16 17:08 ` Zwane Mwaikambo
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