Re: [PATCH 5/7] sh64: remove the use of kernel syscalls

Paul Mundt
2006-08-28T08:06:12Z

On Mon, Aug 28, 2006 at 12:00:49AM +0200, Arnd Bergmann wrote:
> sh64 is using system call macros to call some functions
> from the kernel. Remove those so we can get rid of
> kernel syscalls.
>
It makes more sense to just rip out the old debug code, 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 <lethal@linux-sh.org>

diff --git a/arch/sh64/kernel/process.c b/arch/sh64/kernel/process.c
index dba8e14..525d0ec 100644
--- a/arch/sh64/kernel/process.c
+++ b/arch/sh64/kernel/process.c
@@ -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 @@ void cpu_idle(void)
local_irq_disable();
while (!need_resched()) {
local_irq_enable();
- idle_trace();
hlt();
local_irq_disable();
}
@@ -619,6 +376,10 @@ void free_task_struct(struct task_struct
/*
* 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 +391,17 @@ void free_task_struct(struct task_struct
*/
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);
}

/*