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Subject[: [PATCH] take 2 of the tr-based current]
Arrgh, forgot to cc l-k.

----- Forwarded message from Benjamin LaHaise <bcrl@redhat.com> -----

Date: Thu, 8 Nov 2001 19:05:46 -0500
From: Benjamin LaHaise <bcrl@redhat.com>
To: Linus Torvalds <torvalds@transmeta.com>,
Manfred Spraul <manfred@colorfullife.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Arjan Van de Ven <arjanv@redhat.com>
Subject: [PATCH] take 2 of the tr-based current

Hey folks,

Here's another take of the current-from-TR patch against 2.4.13-ac8. This
fixes the per_cpu_data array madness by taking schedule's per cpu array
and moving it into linux/per_cpu.h. The LOG2_PER_CPU_SIZE macro should
probably be automatically generated, but I'm lazy and someone else can do
that. Also, I removed the assembly GET_CURRENT macro from get_user.S and
put it into C code as a parameter to the __asm__ magic. That part could
just use the current_asm.h macro, but I'd rather let the compiler take care
of it as optimizations across multiple calls would be nice.

If other people could bang on this a bit and post any problems, I'd
appreciate it. tia,

-ben
--
Fish.


diff -urN kernels/2.4/v2.4.13-ac8/arch/i386/kernel/entry.S v2.4.13-ac8+tr.2/arch/i386/kernel/entry.S
--- kernels/2.4/v2.4.13-ac8/arch/i386/kernel/entry.S Tue Nov 6 20:43:22 2001
+++ v2.4.13-ac8+tr.2/arch/i386/kernel/entry.S Wed Nov 7 02:58:41 2001
@@ -45,6 +45,7 @@
#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/smp.h>
+#include <asm/current_asm.h>

EBX = 0x00
ECX = 0x04
@@ -134,9 +135,6 @@
.long 3b,6b; \
.previous

-#define GET_CURRENT(reg) \
- movl %cr2, reg
-
ENTRY(lcall7)
pushfl # We get a different stack layout with call gates,
pushl %eax # which has to be cleaned up later..
@@ -149,7 +147,7 @@
movl %ecx,CS(%esp) #
movl %esp,%ebx
pushl %ebx
- GET_CURRENT(%ebx)
+ GET_CURRENT(%ebx,%bx)
movl exec_domain(%ebx),%edx # Get the execution domain
movl 4(%edx),%edx # Get the lcall7 handler for the domain
pushl $0x7
@@ -170,7 +168,7 @@
movl %ecx,CS(%esp) #
movl %esp,%ebx
pushl %ebx
- GET_CURRENT(%ebx)
+ GET_CURRENT(%ebx,%bx)
movl exec_domain(%ebx),%edx # Get the execution domain
movl 4(%edx),%edx # Get the lcall7 handler for the domain
pushl $0x27
@@ -184,7 +182,7 @@
pushl %ebx
call SYMBOL_NAME(schedule_tail)
addl $4, %esp
- GET_CURRENT(%ebx)
+ GET_CURRENT(%ebx,%bx)
testb $0x02,tsk_ptrace(%ebx) # PT_TRACESYS
jne tracesys_exit
jmp ret_from_sys_call
@@ -199,7 +197,7 @@
ENTRY(system_call)
pushl %eax # save orig_eax
SAVE_ALL
- GET_CURRENT(%ebx)
+ GET_CURRENT(%ebx,%bx)
cmpl $(NR_syscalls),%eax
jae badsys
testb $0x02,tsk_ptrace(%ebx) # PT_TRACESYS
@@ -251,7 +249,7 @@

ALIGN
ENTRY(ret_from_intr)
- GET_CURRENT(%ebx)
+ GET_CURRENT(%ebx,%bx)
ret_from_exception:
movl EFLAGS(%esp),%eax # mix EFLAGS and CS
movb CS(%esp),%al
@@ -297,7 +295,7 @@
movl %edx,%ds
2: call *%edi
addl $8,%esp
- GET_CURRENT(%ebx)
+ GET_CURRENT(%ebx,%bx)
jmp ret_from_exception

ENTRY(coprocessor_error)
@@ -313,7 +311,7 @@
ENTRY(device_not_available)
pushl $-1 # mark this as an int
SAVE_ALL
- GET_CURRENT(%ebx)
+ GET_CURRENT(%ebx,%bx)
movl %cr0,%eax
testl $0x4,%eax # EM (math emulation bit)
jne device_not_available_emulate
diff -urN kernels/2.4/v2.4.13-ac8/arch/i386/kernel/ldt.c v2.4.13-ac8+tr.2/arch/i386/kernel/ldt.c
--- kernels/2.4/v2.4.13-ac8/arch/i386/kernel/ldt.c Thu Nov 1 16:39:57 2001
+++ v2.4.13-ac8+tr.2/arch/i386/kernel/ldt.c Thu Nov 8 18:25:56 2001
@@ -12,11 +12,13 @@
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/vmalloc.h>
+#include <linux/per_cpu.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/ldt.h>
#include <asm/desc.h>
+#include <asm/descfn.h>

/*
* read_ldt() is not really atomic - this is not a problem since
diff -urN kernels/2.4/v2.4.13-ac8/arch/i386/kernel/nmi.c v2.4.13-ac8+tr.2/arch/i386/kernel/nmi.c
--- kernels/2.4/v2.4.13-ac8/arch/i386/kernel/nmi.c Tue Nov 6 20:43:22 2001
+++ v2.4.13-ac8+tr.2/arch/i386/kernel/nmi.c Tue Nov 6 23:13:03 2001
@@ -264,7 +264,7 @@
/*
* NMI can interrupt page faults, use hard_get_current.
*/
- int sum, cpu = hard_get_current()->processor;
+ int sum, cpu = smp_processor_id();

sum = apic_timer_irqs[cpu];

@@ -280,7 +280,6 @@
* We are in trouble anyway, lets at least try
* to get a message out.
*/
- set_current(hard_get_current());
bust_spinlocks(1);
printk("NMI Watchdog detected LOCKUP on CPU%d, registers:\n", cpu);
show_registers(regs);
diff -urN kernels/2.4/v2.4.13-ac8/arch/i386/kernel/setup.c v2.4.13-ac8+tr.2/arch/i386/kernel/setup.c
--- kernels/2.4/v2.4.13-ac8/arch/i386/kernel/setup.c Tue Nov 6 20:43:22 2001
+++ v2.4.13-ac8+tr.2/arch/i386/kernel/setup.c Wed Nov 7 00:49:49 2001
@@ -108,6 +108,7 @@
#include <asm/cobalt.h>
#include <asm/msr.h>
#include <asm/desc.h>
+#include <asm/descfn.h>
#include <asm/e820.h>
#include <asm/dma.h>
#include <asm/mpspec.h>
@@ -2852,8 +2853,9 @@
*/
void __init cpu_init (void)
{
- int nr = smp_processor_id();
+ int nr = hard_smp_processor_id();
struct tss_struct * t = &init_tss[nr];
+ struct task_struct *cur;

if (test_and_set_bit(nr, &cpu_initialized)) {
printk(KERN_WARNING "CPU#%d already initialized!\n", nr);
@@ -2884,17 +2886,19 @@
* set up and load the per-CPU TSS and LDT
*/
atomic_inc(&init_mm.mm_count);
- current->active_mm = &init_mm;
- if(current->mm)
- BUG();
- enter_lazy_tlb(&init_mm, current, nr);
+ cur = hard_get_current();

- t->esp0 = current->thread.esp0;
+ t->esp0 = cur->thread.esp0;
set_tss_desc(nr,t);
gdt_table[__TSS(nr)].b &= 0xfffffdff;
load_TR(nr);
load_LDT(&init_mm);

+ cur->active_mm = &init_mm;
+ if(cur->mm)
+ BUG();
+ enter_lazy_tlb(&init_mm, cur, nr);
+
/*
* Clear all 6 debug registers:
*/
diff -urN kernels/2.4/v2.4.13-ac8/arch/i386/lib/getuser.S v2.4.13-ac8+tr.2/arch/i386/lib/getuser.S
--- kernels/2.4/v2.4.13-ac8/arch/i386/lib/getuser.S Tue Nov 6 20:43:22 2001
+++ v2.4.13-ac8+tr.2/arch/i386/lib/getuser.S Wed Nov 7 22:33:07 2001
@@ -8,6 +8,7 @@
* return an error value in addition to the "real"
* return value.
*/
+#include <asm/current_asm.h>

/*
* __get_user_X
@@ -27,7 +28,6 @@
.align 4
.globl __get_user_1
__get_user_1:
- movl %cr2,%edx
cmpl addr_limit(%edx),%eax
jae bad_get_user
1: movzbl (%eax),%edx
@@ -39,7 +39,6 @@
__get_user_2:
addl $1,%eax
jc bad_get_user
- movl %cr2,%edx
cmpl addr_limit(%edx),%eax
jae bad_get_user
2: movzwl -1(%eax),%edx
@@ -51,7 +50,6 @@
__get_user_4:
addl $3,%eax
jc bad_get_user
- movl %cr2,%edx
cmpl addr_limit(%edx),%eax
jae bad_get_user
3: movl -3(%eax),%edx
diff -urN kernels/2.4/v2.4.13-ac8/arch/i386/mm/fault.c v2.4.13-ac8+tr.2/arch/i386/mm/fault.c
--- kernels/2.4/v2.4.13-ac8/arch/i386/mm/fault.c Tue Nov 6 20:43:22 2001
+++ v2.4.13-ac8+tr.2/arch/i386/mm/fault.c Wed Nov 7 15:56:01 2001
@@ -25,6 +25,7 @@
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/hardirq.h>
+#include <asm/desc.h>

extern void die(const char *,struct pt_regs *,long);

@@ -148,7 +149,6 @@
}

asmlinkage void do_invalid_op(struct pt_regs *, unsigned long);
-extern unsigned long idt;

/*
* This routine handles page faults. It determines the address,
@@ -173,14 +173,13 @@

/* get the address */
__asm__("movl %%cr2,%0":"=r" (address));
- /* and restore current */
- tsk = hard_get_current();
- set_current(tsk);

/* It's safe to allow irq's after cr2 has been saved */
if (regs->eflags & X86_EFLAGS_IF)
local_irq_enable();

+ tsk = current;
+
/*
* We fault-in kernel-space virtual memory on-demand. The
* 'reference' page table is init_mm.pgd.
@@ -309,7 +308,7 @@
if (boot_cpu_data.f00f_bug) {
unsigned long nr;

- nr = (address - idt) >> 3;
+ nr = (address - (unsigned long)idt) >> 3;

if (nr == 6) {
do_invalid_op(regs, 0);
diff -urN kernels/2.4/v2.4.13-ac8/include/asm-i386/current.h v2.4.13-ac8+tr.2/include/asm-i386/current.h
--- kernels/2.4/v2.4.13-ac8/include/asm-i386/current.h Tue Nov 6 20:43:27 2001
+++ v2.4.13-ac8+tr.2/include/asm-i386/current.h Wed Nov 7 17:58:08 2001
@@ -1,28 +1,22 @@
#ifndef _I386_CURRENT_H
#define _I386_CURRENT_H

-struct task_struct;
+#include <linux/per_cpu.h>

static inline struct task_struct * get_current(void)
{
- struct task_struct *tsk;
- __asm__("movl %%cr2,%0;": "=r" (tsk));
- return tsk;
+ return per_data(smp_processor_id())->curr;
}

/* for within NMI, do_page_fault, cpu_init */
static inline struct task_struct * hard_get_current(void)
{
- struct task_struct **ptsk;
- __asm__("andl %%esp,%0; ":"=r" (ptsk) : "0" (~8191UL));
- return *ptsk;
+ return per_data(hard_smp_processor_id())->curr;
}

static inline void set_current(struct task_struct *tsk)
{
- __asm__("movl %0,%%cr2;"
- : /* no output */
- :"r" (tsk));
+ per_data(hard_smp_processor_id())->curr = tsk;
}

/* Note: the implementation is hardcoded into arch/i386/lib/getuser.S */
diff -urN kernels/2.4/v2.4.13-ac8/include/asm-i386/current_asm.h v2.4.13-ac8+tr.2/include/asm-i386/current_asm.h
--- kernels/2.4/v2.4.13-ac8/include/asm-i386/current_asm.h Wed Dec 31 19:00:00 1969
+++ v2.4.13-ac8+tr.2/include/asm-i386/current_asm.h Thu Nov 8 18:26:14 2001
@@ -0,0 +1,15 @@
+/* asm/current_asm.h
+ */
+#include <asm/desc.h>
+#include <linux/per_cpu.h>
+
+/* Pass in the long and word versions of the registers.
+ * eg GET_CURRENT(%ebx,%bx)
+ * Note: str does clear the high 16 bits of the register.
+ */
+#define GET_CURRENT(reg, regw) \
+ str regw \
+ ; shll $LOG2_PER_CPU_SIZE-2,reg \
+ ; aligned_data_adjusted = aligned_data-(__FIRST_TSS_ENTRY << (3 + LOG2_PER_CPU_SIZE - 2)) \
+ ; movl aligned_data_adjusted(reg),reg
+
diff -urN kernels/2.4/v2.4.13-ac8/include/asm-i386/desc.h v2.4.13-ac8+tr.2/include/asm-i386/desc.h
--- kernels/2.4/v2.4.13-ac8/include/asm-i386/desc.h Tue Nov 6 20:43:27 2001
+++ v2.4.13-ac8+tr.2/include/asm-i386/desc.h Tue Nov 6 21:21:32 2001
@@ -68,40 +68,6 @@

#define __load_LDT(n) __asm__ __volatile__("lldt %%ax"::"a" (__LDT(n)<<3))

-/*
- * This is the ldt that every process will get unless we need
- * something other than this.
- */
-extern struct desc_struct default_ldt[];
-extern void set_intr_gate(unsigned int irq, void * addr);
-extern void set_ldt_desc(unsigned int n, void *addr, unsigned int size);
-extern void set_tss_desc(unsigned int n, void *addr);
-
-static inline void clear_LDT(void)
-{
- int cpu = smp_processor_id();
- set_ldt_desc(cpu, &default_ldt[0], 5);
- __load_LDT(cpu);
-}
-
-/*
- * load one particular LDT into the current CPU
- */
-static inline void load_LDT (struct mm_struct *mm)
-{
- int cpu = smp_processor_id();
- void *segments = mm->context.segments;
- int count = LDT_ENTRIES;
-
- if (!segments) {
- segments = &default_ldt[0];
- count = 5;
- }
-
- set_ldt_desc(cpu, segments, count);
- __load_LDT(cpu);
-}
-
#endif /* !__ASSEMBLY__ */

#endif
diff -urN kernels/2.4/v2.4.13-ac8/include/asm-i386/descfn.h v2.4.13-ac8+tr.2/include/asm-i386/descfn.h
--- kernels/2.4/v2.4.13-ac8/include/asm-i386/descfn.h Wed Dec 31 19:00:00 1969
+++ v2.4.13-ac8+tr.2/include/asm-i386/descfn.h Tue Nov 6 21:23:59 2001
@@ -0,0 +1,42 @@
+#ifndef __ARCH_DESCFN_H
+#define __ARCH_DESCFN_H
+
+#ifndef __ARCH_DESC_H
+#include <asm/desc.h>
+#endif
+
+/*
+ * This is the ldt that every process will get unless we need
+ * something other than this.
+ */
+extern struct desc_struct default_ldt[];
+extern void set_intr_gate(unsigned int irq, void * addr);
+extern void set_ldt_desc(unsigned int n, void *addr, unsigned int size);
+extern void set_tss_desc(unsigned int n, void *addr);
+
+static inline void clear_LDT(void)
+{
+ int cpu = smp_processor_id();
+ set_ldt_desc(cpu, &default_ldt[0], 5);
+ __load_LDT(cpu);
+}
+
+/*
+ * load one particular LDT into the current CPU
+ */
+static inline void load_LDT (struct mm_struct *mm)
+{
+ int cpu = smp_processor_id();
+ void *segments = mm->context.segments;
+ int count = LDT_ENTRIES;
+
+ if (!segments) {
+ segments = &default_ldt[0];
+ count = 5;
+ }
+
+ set_ldt_desc(cpu, segments, count);
+ __load_LDT(cpu);
+}
+
+#endif /* __ARCH_DESCFN_H */
diff -urN kernels/2.4/v2.4.13-ac8/include/asm-i386/mmu_context.h v2.4.13-ac8+tr.2/include/asm-i386/mmu_context.h
--- kernels/2.4/v2.4.13-ac8/include/asm-i386/mmu_context.h Tue Nov 6 21:23:24 2001
+++ v2.4.13-ac8+tr.2/include/asm-i386/mmu_context.h Thu Nov 8 18:57:00 2001
@@ -5,6 +5,7 @@
#include <asm/desc.h>
#include <asm/atomic.h>
#include <asm/pgalloc.h>
+#include <asm/descfn.h>

/*
* possibly do the LDT unload here?
diff -urN kernels/2.4/v2.4.13-ac8/include/asm-i386/smp.h v2.4.13-ac8+tr.2/include/asm-i386/smp.h
--- kernels/2.4/v2.4.13-ac8/include/asm-i386/smp.h Tue Nov 6 21:00:35 2001
+++ v2.4.13-ac8+tr.2/include/asm-i386/smp.h Thu Nov 8 18:56:50 2001
@@ -8,6 +8,7 @@
#include <linux/config.h>
#include <linux/threads.h>
#include <linux/ptrace.h>
+#include <asm/desc.h>
#endif

#ifdef CONFIG_X86_LOCAL_APIC
@@ -101,7 +102,14 @@
* so this is correct in the x86 case.
*/

-#define smp_processor_id() (current->processor)
+static unsigned get_TR(void) __attribute__ ((pure))
+{
+ unsigned tr;
+ __asm__("str %w0" : "=g" (tr));
+ return tr;
+}
+
+#define smp_processor_id() ( ((get_TR() >> 3) - __FIRST_TSS_ENTRY) >> 2 )

static __inline int hard_smp_processor_id(void)
{
diff -urN kernels/2.4/v2.4.13-ac8/include/asm-i386/uaccess.h v2.4.13-ac8+tr.2/include/asm-i386/uaccess.h
--- kernels/2.4/v2.4.13-ac8/include/asm-i386/uaccess.h Wed Nov 7 18:09:12 2001
+++ v2.4.13-ac8+tr.2/include/asm-i386/uaccess.h Thu Nov 8 18:59:41 2001
@@ -109,7 +109,7 @@
#define __get_user_x(size,ret,x,ptr) \
__asm__ __volatile__("call __get_user_" #size \
:"=a" (ret),"=d" (x) \
- :"0" (ptr))
+ :"0" (ptr), "1" (current))

/* Careful: we have to cast the result to the type of the pointer for sign reasons */
#define get_user(x,ptr) \
diff -urN kernels/2.4/v2.4.13-ac8/include/linux/per_cpu.h v2.4.13-ac8+tr.2/include/linux/per_cpu.h
--- kernels/2.4/v2.4.13-ac8/include/linux/per_cpu.h Wed Dec 31 19:00:00 1969
+++ v2.4.13-ac8+tr.2/include/linux/per_cpu.h Thu Nov 8 18:27:10 2001
@@ -0,0 +1,26 @@
+#ifndef __LINUX__PER_CPU__H
+#define __LINUX__PER_CPU__H
+
+#define LOG2_PER_CPU_SIZE 8
+
+#ifndef __ASSEMBLY__
+struct task_struct;
+
+struct per_cpu_data {
+ struct task_struct *curr;
+ cycles_t last_schedule;
+};
+
+union aligned_data {
+ struct per_cpu_data data;
+ char __pad [1 << LOG2_PER_CPU_SIZE];
+
+ /* Make sure the padding is large enough */
+ char __pad2 [(1 << LOG2_PER_CPU_SIZE) - sizeof(struct per_cpu_data)];
+};
+
+extern union aligned_data aligned_data[];
+
+#define per_data(nr) (&aligned_data[nr].data)
+#endif
+#endif
diff -urN kernels/2.4/v2.4.13-ac8/kernel/sched.c v2.4.13-ac8+tr.2/kernel/sched.c
--- kernels/2.4/v2.4.13-ac8/kernel/sched.c Tue Nov 6 20:43:28 2001
+++ v2.4.13-ac8+tr.2/kernel/sched.c Wed Nov 7 17:49:00 2001
@@ -28,6 +28,7 @@
#include <linux/kernel_stat.h>
#include <linux/completion.h>
#include <linux/prefetch.h>
+#include <linux/per_cpu.h>

#include <asm/uaccess.h>
#include <asm/mmu_context.h>
@@ -97,16 +98,12 @@
* We align per-CPU scheduling data on cacheline boundaries,
* to prevent cacheline ping-pong.
*/
-static union {
- struct schedule_data {
- struct task_struct * curr;
- cycles_t last_schedule;
- } schedule_data;
- char __pad [SMP_CACHE_BYTES];
-} aligned_data [NR_CPUS] __cacheline_aligned = { {{&init_task,0}}};
+union aligned_data aligned_data[NR_CPUS] __cacheline_aligned = {
+ {{&init_task,0}}
+};

-#define cpu_curr(cpu) aligned_data[(cpu)].schedule_data.curr
-#define last_schedule(cpu) aligned_data[(cpu)].schedule_data.last_schedule
+#define cpu_curr(cpu) per_data(cpu)->curr
+#define last_schedule(cpu) per_data(cpu)->last_schedule

struct kernel_stat kstat;
extern struct task_struct *child_reaper;
@@ -532,7 +529,7 @@
*/
asmlinkage void schedule(void)
{
- struct schedule_data * sched_data;
+ struct per_cpu_data * sched_data;
struct task_struct *prev, *next, *p;
struct list_head *tmp;
int this_cpu, c;
@@ -543,7 +540,7 @@
if (!current->active_mm) BUG();
need_resched_back:
prev = current;
- this_cpu = prev->processor;
+ this_cpu = smp_processor_id(); /* This better than current->processor on up */

if (in_interrupt())
goto scheduling_in_interrupt;
@@ -554,7 +551,7 @@
* 'sched_data' is protected by the fact that we can run
* only one process per CPU.
*/
- sched_data = & aligned_data[this_cpu].schedule_data;
+ sched_data = per_data(this_cpu);

spin_lock_irq(&runqueue_lock);

@@ -1057,7 +1054,7 @@
// Subtract non-idle processes running on other CPUs.
for (i = 0; i < smp_num_cpus; i++) {
int cpu = cpu_logical_map(i);
- if (aligned_data[cpu].schedule_data.curr != idle_task(cpu))
+ if (per_data(cpu)->curr != idle_task(cpu))
nr_pending--;
}
#else
@@ -1309,17 +1306,18 @@

void __init init_idle(void)
{
- struct schedule_data * sched_data;
- sched_data = &aligned_data[smp_processor_id()].schedule_data;
+ struct per_cpu_data * sched_data;
+ int cpu = smp_processor_id();
+ sched_data = per_data(cpu);

if (current != &init_task && task_on_runqueue(current)) {
printk("UGH! (%d:%d) was on the runqueue, removing.\n",
- smp_processor_id(), current->pid);
+ cpu, current->pid);
del_from_runqueue(current);
}
sched_data->curr = current;
sched_data->last_schedule = get_cycles();
- clear_bit(current->processor, &wait_init_idle);
+ clear_bit(cpu, &wait_init_idle);
}

extern void init_timervecs (void);
----- End forwarded message -----
--
Fish.
-
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