2006-08-30 12:54:08

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH 5/6] sh64: remove the use of kernel syscalls

sh64 is using system call macros to call some functions from the
kernel.

The old debug code can simply be removed, since we don't really have
that much of a need for it anymore, it was mostly something
that was handy during the initial bringup. This also brings us closer to
something that looks like readable code again..

I also added a sane kernel_thread() implementation that gets away from
this, so that should take care of sh64 at least.

Signed-off-by: Paul Mundt <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Index: linux-cg/arch/sh64/kernel/process.c
===================================================================
--- linux-cg.orig/arch/sh64/kernel/process.c 2006-08-29 20:01:54.000000000 +0200
+++ linux-cg/arch/sh64/kernel/process.c 2006-08-29 20:04:13.000000000 +0200
@@ -20,261 +20,16 @@
/*
* This file handles the architecture-dependent parts of process handling..
*/
-
-/* Temporary flags/tests. All to be removed/undefined. BEGIN */
-#define IDLE_TRACE
-#define VM_SHOW_TABLES
-#define VM_TEST_FAULT
-#define VM_TEST_RTLBMISS
-#define VM_TEST_WTLBMISS
-
-#undef VM_SHOW_TABLES
-#undef IDLE_TRACE
-/* Temporary flags/tests. All to be removed/undefined. END */
-
-#define __KERNEL_SYSCALLS__
-#include <stdarg.h>
-
-#include <linux/kernel.h>
-#include <linux/rwsem.h>
#include <linux/mm.h>
-#include <linux/smp.h>
-#include <linux/smp_lock.h>
#include <linux/ptrace.h>
-#include <linux/slab.h>
-#include <linux/vmalloc.h>
-#include <linux/user.h>
-#include <linux/a.out.h>
-#include <linux/interrupt.h>
-#include <linux/unistd.h>
-#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/init.h>
-
+#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
-#include <asm/system.h>
-#include <asm/io.h>
-#include <asm/processor.h> /* includes also <asm/registers.h> */
-#include <asm/mmu_context.h>
-#include <asm/elf.h>
-#include <asm/page.h>
-
-#include <linux/irq.h>

struct task_struct *last_task_used_math = NULL;

-#ifdef IDLE_TRACE
-#ifdef VM_SHOW_TABLES
-/* For testing */
-static void print_PTE(long base)
-{
- int i, skip=0;
- long long x, y, *p = (long long *) base;
-
- for (i=0; i< 512; i++, p++){
- if (*p == 0) {
- if (!skip) {
- skip++;
- printk("(0s) ");
- }
- } else {
- skip=0;
- x = (*p) >> 32;
- y = (*p) & 0xffffffff;
- printk("%08Lx%08Lx ", x, y);
- if (!((i+1)&0x3)) printk("\n");
- }
- }
-}
-
-/* For testing */
-static void print_DIR(long base)
-{
- int i, skip=0;
- long *p = (long *) base;
-
- for (i=0; i< 512; i++, p++){
- if (*p == 0) {
- if (!skip) {
- skip++;
- printk("(0s) ");
- }
- } else {
- skip=0;
- printk("%08lx ", *p);
- if (!((i+1)&0x7)) printk("\n");
- }
- }
-}
-
-/* For testing */
-static void print_vmalloc_first_tables(void)
-{
-
-#define PRESENT 0x800 /* Bit 11 */
-
- /*
- * Do it really dirty by looking at raw addresses,
- * raw offsets, no types. If we used pgtable/pgalloc
- * macros/definitions we could hide potential bugs.
- *
- * Note that pointers are 32-bit for CDC.
- */
- long pgdt, pmdt, ptet;
-
- pgdt = (long) &swapper_pg_dir;
- printk("-->PGD (0x%08lx):\n", pgdt);
- print_DIR(pgdt);
- printk("\n");
-
- /* VMALLOC pool is mapped at 0xc0000000, second (pointer) entry in PGD */
- pgdt += 4;
- pmdt = (long) (* (long *) pgdt);
- if (!(pmdt & PRESENT)) {
- printk("No PMD\n");
- return;
- } else pmdt &= 0xfffff000;
-
- printk("-->PMD (0x%08lx):\n", pmdt);
- print_DIR(pmdt);
- printk("\n");
-
- /* Get the pmdt displacement for 0xc0000000 */
- pmdt += 2048;
-
- /* just look at first two address ranges ... */
- /* ... 0xc0000000 ... */
- ptet = (long) (* (long *) pmdt);
- if (!(ptet & PRESENT)) {
- printk("No PTE0\n");
- return;
- } else ptet &= 0xfffff000;
-
- printk("-->PTE0 (0x%08lx):\n", ptet);
- print_PTE(ptet);
- printk("\n");
-
- /* ... 0xc0001000 ... */
- ptet += 4;
- if (!(ptet & PRESENT)) {
- printk("No PTE1\n");
- return;
- } else ptet &= 0xfffff000;
- printk("-->PTE1 (0x%08lx):\n", ptet);
- print_PTE(ptet);
- printk("\n");
-}
-#else
-#define print_vmalloc_first_tables()
-#endif /* VM_SHOW_TABLES */
-
-static void test_VM(void)
-{
- void *a, *b, *c;
-
-#ifdef VM_SHOW_TABLES
- printk("Initial PGD/PMD/PTE\n");
-#endif
- print_vmalloc_first_tables();
-
- printk("Allocating 2 bytes\n");
- a = vmalloc(2);
- print_vmalloc_first_tables();
-
- printk("Allocating 4100 bytes\n");
- b = vmalloc(4100);
- print_vmalloc_first_tables();
-
- printk("Allocating 20234 bytes\n");
- c = vmalloc(20234);
- print_vmalloc_first_tables();
-
-#ifdef VM_TEST_FAULT
- /* Here you may want to fault ! */
-
-#ifdef VM_TEST_RTLBMISS
- printk("Ready to fault upon read.\n");
- if (* (char *) a) {
- printk("RTLBMISSed on area a !\n");
- }
- printk("RTLBMISSed on area a !\n");
-#endif
-
-#ifdef VM_TEST_WTLBMISS
- printk("Ready to fault upon write.\n");
- *((char *) b) = 'L';
- printk("WTLBMISSed on area b !\n");
-#endif
-
-#endif /* VM_TEST_FAULT */
-
- printk("Deallocating the 4100 byte chunk\n");
- vfree(b);
- print_vmalloc_first_tables();
-
- printk("Deallocating the 2 byte chunk\n");
- vfree(a);
- print_vmalloc_first_tables();
-
- printk("Deallocating the last chunk\n");
- vfree(c);
- print_vmalloc_first_tables();
-}
-
-extern unsigned long volatile jiffies;
-int once = 0;
-unsigned long old_jiffies;
-int pid = -1, pgid = -1;
-
-void idle_trace(void)
-{
-
- _syscall0(int, getpid)
- _syscall1(int, getpgid, int, pid)
-
- if (!once) {
- /* VM allocation/deallocation simple test */
- test_VM();
- pid = getpid();
-
- printk("Got all through to Idle !!\n");
- printk("I'm now going to loop forever ...\n");
- printk("Any ! below is a timer tick.\n");
- printk("Any . below is a getpgid system call from pid = %d.\n", pid);
-
-
- old_jiffies = jiffies;
- once++;
- }
-
- if (old_jiffies != jiffies) {
- old_jiffies = jiffies - old_jiffies;
- switch (old_jiffies) {
- case 1:
- printk("!");
- break;
- case 2:
- printk("!!");
- break;
- case 3:
- printk("!!!");
- break;
- case 4:
- printk("!!!!");
- break;
- default:
- printk("(%d!)", (int) old_jiffies);
- }
- old_jiffies = jiffies;
- }
- pgid = getpgid(pid);
- printk(".");
-}
-#else
-#define idle_trace() do { } while (0)
-#endif /* IDLE_TRACE */
-
static int hlt_counter = 1;

#define HARD_IDLE_TIMEOUT (HZ / 3)
@@ -323,7 +78,6 @@
local_irq_disable();
while (!need_resched()) {
local_irq_enable();
- idle_trace();
hlt();
local_irq_disable();
}
@@ -619,6 +373,10 @@
/*
* Create a kernel thread
*/
+ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
+{
+ do_exit(fn(arg));
+}

/*
* This is the mechanism for creating a new kernel thread.
@@ -630,19 +388,17 @@
*/
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
- /* A bit less processor dependent than older sh ... */
- unsigned int reply;
+ struct pt_regs regs;

-static __inline__ _syscall2(int,clone,unsigned long,flags,unsigned long,newsp)
-static __inline__ _syscall1(int,exit,int,ret)
+ memset(&regs, 0, sizeof(regs));
+ regs.regs[2] = (unsigned long)arg;
+ regs.regs[3] = (unsigned long)fn;

- reply = clone(flags | CLONE_VM, 0);
- if (!reply) {
- /* Child */
- reply = exit(fn(arg));
- }
+ regs.pc = (unsigned long)kernel_thread_helper;
+ regs.sr = (1 << 30);

- return reply;
+ return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
+ &regs, 0, NULL, NULL);
}

/*

--


2006-08-30 13:11:36

by Arnd Bergmann

[permalink] [raw]
Subject: Re: [PATCH 5/6] sh64: remove the use of kernel syscalls

Hm, script error. This mail was sent by me, but the copy I
received was attributed to Paul my kmail instead of starting
with 'From: Paul Mundt <[email protected]>' as intended.

Arnd <><