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sh: Add support for 4K stacks.

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This enables support for 4K stacks on SH.

Currently this depends on DEBUG_KERNEL, but likely all boards
will switch to this as the default in the future.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2006-09-27 18:22:14 +09:00
parent 2cb7ce3bb3
commit a6a3113989
9 changed files with 190 additions and 24 deletions
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10
arch/sh/Kconfig.debug
View File

@ -46,6 +46,16 @@ config DEBUG_STACK_USAGE
This option will slow down process creation somewhat.
config 4KSTACKS
bool "Use 4Kb for kernel stacks instead of 8Kb"
depends on DEBUG_KERNEL
help
If you say Y here the kernel will use a 4Kb stacksize for the
kernel stack attached to each process/thread. This facilitates
running more threads on a system and also reduces the pressure
on the VM subsystem for higher order allocations. This option
will also use IRQ stacks to compensate for the reduced stackspace.
config KGDB
bool "Include KGDB kernel debugger"
select FRAME_POINTER

2
arch/sh/kernel/cpu/irq/ipr.c
View File

@ -190,6 +190,8 @@ void __init init_IRQ(void)
/* Perform the machine specific initialisation */
if (sh_mv.mv_init_irq != NULL)
sh_mv.mv_init_irq();
irq_ctx_init(smp_processor_id());
}
#if !defined(CONFIG_CPU_HAS_PINT_IRQ)

4
arch/sh/kernel/entry.S
View File

@ -716,8 +716,8 @@ ENTRY(handle_exception)
bt/s 1f ! It's a kernel to kernel transition.
mov r15, k0 ! save original stack to k0
/* User space to kernel */
mov #0x20, k1
shll8 k1 ! k1 := 8192 (== THREAD_SIZE)
mov #(THREAD_SIZE >> 8), k1
shll8 k1 ! k1 := THREAD_SIZE
add current, k1
mov k1, r15 ! change to kernel stack
!

5
arch/sh/kernel/head.S
View File

@ -12,7 +12,6 @@
*/
#include <linux/linkage.h>
#include <asm/thread_info.h>
#include <asm/page.h>
#ifdef CONFIG_CPU_SH4A
#define SYNCO() synco
@ -69,8 +68,8 @@ ENTRY(_stext)
!
mov.l 2f, r0
mov r0, r15 ! Set initial r15 (stack pointer)
mov #0x20, r1 !
shll8 r1 ! r1 = 8192
mov #(THREAD_SIZE >> 8), r1
shll8 r1 ! r1 = THREAD_SIZE
sub r1, r0 !
ldc r0, r7_bank ! ... and initial thread_info

153
arch/sh/kernel/irq.c
View File

@ -1,5 +1,4 @@
/* $Id: irq.c,v 1.20 2004/01/13 05:52:11 kkojima Exp $
*
/*
* linux/arch/sh/kernel/irq.c
*
* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
@ -7,13 +6,15 @@
*
* SuperH version: Copyright (C) 1999 Niibe Yutaka
*/
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/kernel_stat.h>
#include <linux/seq_file.h>
#include <asm/irq.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/thread_info.h>
#include <asm/cpu/mmu_context.h>
/*
@ -60,11 +61,27 @@ int show_interrupts(struct seq_file *p, void *v)
}
#endif
#ifdef CONFIG_4KSTACKS
/*
* per-CPU IRQ handling contexts (thread information and stack)
*/
union irq_ctx {
struct thread_info tinfo;
u32 stack[THREAD_SIZE/sizeof(u32)];
};
static union irq_ctx *hardirq_ctx[NR_CPUS];
static union irq_ctx *softirq_ctx[NR_CPUS];
#endif
asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs regs)
{
int irq = r4;
#ifdef CONFIG_4KSTACKS
union irq_ctx *curctx, *irqctx;
#endif
irq_enter();
@ -102,7 +119,135 @@ asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
#endif
irq = irq_demux(irq);
__do_IRQ(irq, &regs);
#ifdef CONFIG_4KSTACKS
curctx = (union irq_ctx *)current_thread_info();
irqctx = hardirq_ctx[smp_processor_id()];
/*
* this is where we switch to the IRQ stack. However, if we are
* already using the IRQ stack (because we interrupted a hardirq
* handler) we can't do that and just have to keep using the
* current stack (which is the irq stack already after all)
*/
if (curctx != irqctx) {
u32 *isp;
isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
irqctx->tinfo.task = curctx->tinfo.task;
irqctx->tinfo.previous_sp = current_stack_pointer;
__asm__ __volatile__ (
"mov %0, r4 \n"
"mov %1, r5 \n"
"mov r15, r9 \n"
"jsr @%2 \n"
/* swith to the irq stack */
" mov %3, r15 \n"
/* restore the stack (ring zero) */
"mov r9, r15 \n"
: /* no outputs */
: "r" (irq), "r" (&regs), "r" (__do_IRQ), "r" (isp)
/* XXX: A somewhat excessive clobber list? -PFM */
: "memory", "r0", "r1", "r2", "r3", "r4",
"r5", "r6", "r7", "r8", "t", "pr"
);
} else
#endif
__do_IRQ(irq, &regs);
irq_exit();
return 1;
}
#ifdef CONFIG_4KSTACKS
/*
* These should really be __section__(".bss.page_aligned") as well, but
* gcc's 3.0 and earlier don't handle that correctly.
*/
static char softirq_stack[NR_CPUS * THREAD_SIZE]
__attribute__((__aligned__(THREAD_SIZE)));
static char hardirq_stack[NR_CPUS * THREAD_SIZE]
__attribute__((__aligned__(THREAD_SIZE)));
/*
* allocate per-cpu stacks for hardirq and for softirq processing
*/
void irq_ctx_init(int cpu)
{
union irq_ctx *irqctx;
if (hardirq_ctx[cpu])
return;
irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
irqctx->tinfo.task = NULL;
irqctx->tinfo.exec_domain = NULL;
irqctx->tinfo.cpu = cpu;
irqctx->tinfo.preempt_count = HARDIRQ_OFFSET;
irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
hardirq_ctx[cpu] = irqctx;
irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
irqctx->tinfo.task = NULL;
irqctx->tinfo.exec_domain = NULL;
irqctx->tinfo.cpu = cpu;
irqctx->tinfo.preempt_count = SOFTIRQ_OFFSET;
irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
softirq_ctx[cpu] = irqctx;
printk("CPU %u irqstacks, hard=%p soft=%p\n",
cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
}
void irq_ctx_exit(int cpu)
{
hardirq_ctx[cpu] = NULL;
}
extern asmlinkage void __do_softirq(void);
asmlinkage void do_softirq(void)
{
unsigned long flags;
struct thread_info *curctx;
union irq_ctx *irqctx;
u32 *isp;
if (in_interrupt())
return;
local_irq_save(flags);
if (local_softirq_pending()) {
curctx = current_thread_info();
irqctx = softirq_ctx[smp_processor_id()];
irqctx->tinfo.task = curctx->task;
irqctx->tinfo.previous_sp = current_stack_pointer;
/* build the stack frame on the softirq stack */
isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
__asm__ __volatile__ (
"mov r15, r9 \n"
"jsr @%0 \n"
/* switch to the softirq stack */
" mov %1, r15 \n"
/* restore the thread stack */
"mov r9, r15 \n"
: /* no outputs */
: "r" (__do_softirq), "r" (isp)
/* XXX: A somewhat excessive clobber list? -PFM */
: "memory", "r0", "r1", "r2", "r3", "r4",
"r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
);
}
local_irq_restore(flags);
}
EXPORT_SYMBOL(do_softirq);
#endif

18
arch/sh/kernel/traps.c
View File

@ -741,20 +741,12 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
unsigned long module_end = VMALLOC_END;
int i = 1;
if (tsk && !sp) {
if (!tsk)
tsk = current;
if (tsk == current)
sp = (unsigned long *)current_stack_pointer;
else
sp = (unsigned long *)tsk->thread.sp;
}
if (!sp) {
__asm__ __volatile__ (
"mov r15, %0\n\t"
"stc r7_bank, %1\n\t"
: "=r" (module_start),
"=r" (module_end)
);
sp = (unsigned long *)module_start;
}
stack = sp;

1
arch/sh/kernel/vmlinux.lds.S
View File

@ -3,7 +3,6 @@
* Written by Niibe Yutaka
*/
#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm-generic/vmlinux.lds.h>
#ifdef CONFIG_CPU_LITTLE_ENDIAN

9
include/asm-sh/irq.h
View File

@ -719,6 +719,15 @@ static inline int generic_irq_demux(int irq)
#define irq_canonicalize(irq) (irq)
#define irq_demux(irq) __irq_demux(sh_mv.mv_irq_demux(irq))
#ifdef CONFIG_4KSTACKS
extern void irq_ctx_init(int cpu);
extern void irq_ctx_exit(int cpu);
# define __ARCH_HAS_DO_SOFTIRQ
#else
# define irq_ctx_init(cpu) do { } while (0)
# define irq_ctx_exit(cpu) do { } while (0)
#endif
#if defined(CONFIG_CPU_SUBTYPE_SH73180)
#include <asm/irq-sh73180.h>
#endif

12
include/asm-sh/thread_info.h
View File

@ -9,8 +9,8 @@
* Copyright (C) 2002 David Howells (dhowells@redhat.com)
* - Incorporating suggestions made by Linus Torvalds and Dave Miller
*/
#ifdef __KERNEL__
#include <asm/page.h>
#ifndef __ASSEMBLY__
#include <asm/processor.h>
@ -23,13 +23,20 @@ struct thread_info {
int preempt_count; /* 0 => preemptable, <0 => BUG */
mm_segment_t addr_limit; /* thread address space */
struct restart_block restart_block;
unsigned long previous_sp; /* sp of previous stack in case
of nested IRQ stacks */
__u8 supervisor_stack[0];
};
#endif
#define PREEMPT_ACTIVE 0x10000000
#ifdef CONFIG_4KSTACKS
#define THREAD_SIZE (PAGE_SIZE)
#else
#define THREAD_SIZE (PAGE_SIZE * 2)
#endif
#define STACK_WARN (THREAD_SIZE / 8)
/*
@ -52,6 +59,9 @@ struct thread_info {
#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)
/* how to get the current stack pointer from C */
register unsigned long current_stack_pointer asm("r15") __attribute_used__;
/* how to get the thread information struct from C */
static inline struct thread_info *current_thread_info(void)
{