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kernel-ark/arch/ppc64/kernel/process.c
Rusty Lynch 97f7943d70 [PATCH] Return probe redesign: ppc64 specific implementation 
The following is a patch provided by Ananth Mavinakayanahalli that implements
the new PPC64 specific parts of the new function return probe design.

NOTE: Since getting Ananth's patch, I changed trampoline_probe_handler()
      to consume each of the outstanding return probem instances (feedback
      on my original RFC after Ananth cut a patch), and also added the
      arch_init() function (adding arch specific initialization.) I have
      cross compiled but have not testing this on a PPC64 machine.

Changes include:
 * Addition of kretprobe_trampoline to act as a dummy function for instrumented
   functions to return to, and for the return probe infrastructure to place
   a kprobe on on, gaining control so that the return probe handler
   can be called, and so that the instruction pointer can be moved back
   to the original return address.
 * Addition of arch_init(), allowing a kprobe to be registered on
   kretprobe_trampoline
 * Addition of trampoline_probe_handler() which is used as the pre_handler
   for the kprobe inserted on kretprobe_implementation.  This is the function
   that handles the details for calling the return probe handler function
   and returning control back at the original return address
 * Addition of arch_prepare_kretprobe() which is setup as the pre_handler
   for a kprobe registered at the beginning of the target function by
   kernel/kprobes.c so that a return probe instance can be setup when
   a caller enters the target function.  (A return probe instance contains
   all the needed information for trampoline_probe_handler to do it's job.)
 * Hooks added to the exit path of a task so that we can cleanup any left-over
   return probe instances (i.e. if a task dies while inside a targeted function
   then the return probe instance was reserved at the beginning of the function
   but the function never returns so we need to mark the instance as unused.)

Signed-off-by: Rusty Lynch <rusty.lynch@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-27 15:23:53 -07:00

682 lines
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/*
* linux/arch/ppc64/kernel/process.c
*
* Derived from "arch/i386/kernel/process.c"
* Copyright (C) 1995 Linus Torvalds
*
* Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
* Paul Mackerras (paulus@cs.anu.edu.au)
*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/elf.h>
#include <linux/init.h>
#include <linux/init_task.h>
#include <linux/prctl.h>
#include <linux/ptrace.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/utsname.h>
#include <linux/kprobes.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/prom.h>
#include <asm/ppcdebug.h>
#include <asm/machdep.h>
#include <asm/iSeries/HvCallHpt.h>
#include <asm/cputable.h>
#include <asm/sections.h>
#include <asm/tlbflush.h>
#include <asm/time.h>
#ifndef CONFIG_SMP
struct task_struct *last_task_used_math = NULL;
struct task_struct *last_task_used_altivec = NULL;
#endif
/*
* Make sure the floating-point register state in the
* the thread_struct is up to date for task tsk.
*/
void flush_fp_to_thread(struct task_struct *tsk)
{
if (tsk->thread.regs) {
/*
* We need to disable preemption here because if we didn't,
* another process could get scheduled after the regs->msr
* test but before we have finished saving the FP registers
* to the thread_struct. That process could take over the
* FPU, and then when we get scheduled again we would store
* bogus values for the remaining FP registers.
*/
preempt_disable();
if (tsk->thread.regs->msr & MSR_FP) {
#ifdef CONFIG_SMP
/*
* This should only ever be called for current or
* for a stopped child process. Since we save away
* the FP register state on context switch on SMP,
* there is something wrong if a stopped child appears
* to still have its FP state in the CPU registers.
*/
BUG_ON(tsk != current);
#endif
giveup_fpu(current);
}
preempt_enable();
}
}
void enable_kernel_fp(void)
{
WARN_ON(preemptible());
#ifdef CONFIG_SMP
if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
giveup_fpu(current);
else
giveup_fpu(NULL); /* just enables FP for kernel */
#else
giveup_fpu(last_task_used_math);
#endif /* CONFIG_SMP */
}
EXPORT_SYMBOL(enable_kernel_fp);
int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
{
if (!tsk->thread.regs)
return 0;
flush_fp_to_thread(current);
memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
return 1;
}
#ifdef CONFIG_ALTIVEC
void enable_kernel_altivec(void)
{
WARN_ON(preemptible());
#ifdef CONFIG_SMP
if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
giveup_altivec(current);
else
giveup_altivec(NULL); /* just enables FP for kernel */
#else
giveup_altivec(last_task_used_altivec);
#endif /* CONFIG_SMP */
}
EXPORT_SYMBOL(enable_kernel_altivec);
/*
* Make sure the VMX/Altivec register state in the
* the thread_struct is up to date for task tsk.
*/
void flush_altivec_to_thread(struct task_struct *tsk)
{
if (tsk->thread.regs) {
preempt_disable();
if (tsk->thread.regs->msr & MSR_VEC) {
#ifdef CONFIG_SMP
BUG_ON(tsk != current);
#endif
giveup_altivec(current);
}
preempt_enable();
}
}
int dump_task_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
{
flush_altivec_to_thread(current);
memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
return 1;
}
#endif /* CONFIG_ALTIVEC */
DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *new)
{
struct thread_struct *new_thread, *old_thread;
unsigned long flags;
struct task_struct *last;
#ifdef CONFIG_SMP
/* avoid complexity of lazy save/restore of fpu
* by just saving it every time we switch out if
* this task used the fpu during the last quantum.
*
* If it tries to use the fpu again, it'll trap and
* reload its fp regs. So we don't have to do a restore
* every switch, just a save.
* -- Cort
*/
if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
giveup_fpu(prev);
#ifdef CONFIG_ALTIVEC
if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
giveup_altivec(prev);
#endif /* CONFIG_ALTIVEC */
#endif /* CONFIG_SMP */
#if defined(CONFIG_ALTIVEC) && !defined(CONFIG_SMP)
/* Avoid the trap. On smp this this never happens since
* we don't set last_task_used_altivec -- Cort
*/
if (new->thread.regs && last_task_used_altivec == new)
new->thread.regs->msr |= MSR_VEC;
#endif /* CONFIG_ALTIVEC */
flush_tlb_pending();
new_thread = &new->thread;
old_thread = &current->thread;
/* Collect purr utilization data per process and per processor wise */
/* purr is nothing but processor time base */
#if defined(CONFIG_PPC_PSERIES)
if (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR) {
struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
long unsigned start_tb, current_tb;
start_tb = old_thread->start_tb;
cu->current_tb = current_tb = mfspr(SPRN_PURR);
old_thread->accum_tb += (current_tb - start_tb);
new_thread->start_tb = current_tb;
}
#endif
local_irq_save(flags);
last = _switch(old_thread, new_thread);
local_irq_restore(flags);
return last;
}
static int instructions_to_print = 16;
static void show_instructions(struct pt_regs *regs)
{
int i;
unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
sizeof(int));
printk("Instruction dump:");
for (i = 0; i < instructions_to_print; i++) {
int instr;
if (!(i % 8))
printk("\n");
if (((REGION_ID(pc) != KERNEL_REGION_ID) &&
(REGION_ID(pc) != VMALLOC_REGION_ID)) ||
__get_user(instr, (unsigned int *)pc)) {
printk("XXXXXXXX ");
} else {
if (regs->nip == pc)
printk("<%08x> ", instr);
else
printk("%08x ", instr);
}
pc += sizeof(int);
}
printk("\n");
}
void show_regs(struct pt_regs * regs)
{
int i;
unsigned long trap;
printk("NIP: %016lX XER: %08X LR: %016lX CTR: %016lX\n",
regs->nip, (unsigned int)regs->xer, regs->link, regs->ctr);
printk("REGS: %p TRAP: %04lx %s (%s)\n",
regs, regs->trap, print_tainted(), system_utsname.release);
printk("MSR: %016lx EE: %01x PR: %01x FP: %01x ME: %01x "
"IR/DR: %01x%01x CR: %08X\n",
regs->msr, regs->msr&MSR_EE ? 1 : 0, regs->msr&MSR_PR ? 1 : 0,
regs->msr & MSR_FP ? 1 : 0,regs->msr&MSR_ME ? 1 : 0,
regs->msr&MSR_IR ? 1 : 0,
regs->msr&MSR_DR ? 1 : 0,
(unsigned int)regs->ccr);
trap = TRAP(regs);
printk("DAR: %016lx DSISR: %016lx\n", regs->dar, regs->dsisr);
printk("TASK: %p[%d] '%s' THREAD: %p",
current, current->pid, current->comm, current->thread_info);
#ifdef CONFIG_SMP
printk(" CPU: %d", smp_processor_id());
#endif /* CONFIG_SMP */
for (i = 0; i < 32; i++) {
if ((i % 4) == 0) {
printk("\n" KERN_INFO "GPR%02d: ", i);
}
printk("%016lX ", regs->gpr[i]);
if (i == 13 && !FULL_REGS(regs))
break;
}
printk("\n");
/*
* Lookup NIP late so we have the best change of getting the
* above info out without failing
*/
printk("NIP [%016lx] ", regs->nip);
print_symbol("%s\n", regs->nip);
printk("LR [%016lx] ", regs->link);
print_symbol("%s\n", regs->link);
show_stack(current, (unsigned long *)regs->gpr[1]);
if (!user_mode(regs))
show_instructions(regs);
}
void exit_thread(void)
{
kprobe_flush_task(current);
#ifndef CONFIG_SMP
if (last_task_used_math == current)
last_task_used_math = NULL;
#ifdef CONFIG_ALTIVEC
if (last_task_used_altivec == current)
last_task_used_altivec = NULL;
#endif /* CONFIG_ALTIVEC */
#endif /* CONFIG_SMP */
}
void flush_thread(void)
{
struct thread_info *t = current_thread_info();
kprobe_flush_task(current);
if (t->flags & _TIF_ABI_PENDING)
t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
#ifndef CONFIG_SMP
if (last_task_used_math == current)
last_task_used_math = NULL;
#ifdef CONFIG_ALTIVEC
if (last_task_used_altivec == current)
last_task_used_altivec = NULL;
#endif /* CONFIG_ALTIVEC */
#endif /* CONFIG_SMP */
}
void
release_thread(struct task_struct *t)
{
}
/*
* This gets called before we allocate a new thread and copy
* the current task into it.
*/
void prepare_to_copy(struct task_struct *tsk)
{
flush_fp_to_thread(current);
flush_altivec_to_thread(current);
}
/*
* Copy a thread..
*/
int
copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
unsigned long unused, struct task_struct *p, struct pt_regs *regs)
{
struct pt_regs *childregs, *kregs;
extern void ret_from_fork(void);
unsigned long sp = (unsigned long)p->thread_info + THREAD_SIZE;
/* Copy registers */
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
*childregs = *regs;
if ((childregs->msr & MSR_PR) == 0) {
/* for kernel thread, set stackptr in new task */
childregs->gpr[1] = sp + sizeof(struct pt_regs);
p->thread.regs = NULL; /* no user register state */
clear_ti_thread_flag(p->thread_info, TIF_32BIT);
} else {
childregs->gpr[1] = usp;
p->thread.regs = childregs;
if (clone_flags & CLONE_SETTLS) {
if (test_thread_flag(TIF_32BIT))
childregs->gpr[2] = childregs->gpr[6];
else
childregs->gpr[13] = childregs->gpr[6];
}
}
childregs->gpr[3] = 0; /* Result from fork() */
sp -= STACK_FRAME_OVERHEAD;
/*
* The way this works is that at some point in the future
* some task will call _switch to switch to the new task.
* That will pop off the stack frame created below and start
* the new task running at ret_from_fork. The new task will
* do some house keeping and then return from the fork or clone
* system call, using the stack frame created above.
*/
sp -= sizeof(struct pt_regs);
kregs = (struct pt_regs *) sp;
sp -= STACK_FRAME_OVERHEAD;
p->thread.ksp = sp;
if (cpu_has_feature(CPU_FTR_SLB)) {
unsigned long sp_vsid = get_kernel_vsid(sp);
sp_vsid <<= SLB_VSID_SHIFT;
sp_vsid |= SLB_VSID_KERNEL;
if (cpu_has_feature(CPU_FTR_16M_PAGE))
sp_vsid |= SLB_VSID_L;
p->thread.ksp_vsid = sp_vsid;
}
/*
* The PPC64 ABI makes use of a TOC to contain function
* pointers. The function (ret_from_except) is actually a pointer
* to the TOC entry. The first entry is a pointer to the actual
* function.
*/
kregs->nip = *((unsigned long *)ret_from_fork);
return 0;
}
/*
* Set up a thread for executing a new program
*/
void start_thread(struct pt_regs *regs, unsigned long fdptr, unsigned long sp)
{
unsigned long entry, toc, load_addr = regs->gpr[2];
/* fdptr is a relocated pointer to the function descriptor for
* the elf _start routine. The first entry in the function
* descriptor is the entry address of _start and the second
* entry is the TOC value we need to use.
*/
set_fs(USER_DS);
__get_user(entry, (unsigned long __user *)fdptr);
__get_user(toc, (unsigned long __user *)fdptr+1);
/* Check whether the e_entry function descriptor entries
* need to be relocated before we can use them.
*/
if (load_addr != 0) {
entry += load_addr;
toc += load_addr;
}
/*
* If we exec out of a kernel thread then thread.regs will not be
* set. Do it now.
*/
if (!current->thread.regs) {
unsigned long childregs = (unsigned long)current->thread_info +
THREAD_SIZE;
childregs -= sizeof(struct pt_regs);
current->thread.regs = (struct pt_regs *)childregs;
}
regs->nip = entry;
regs->gpr[1] = sp;
regs->gpr[2] = toc;
regs->msr = MSR_USER64;
#ifndef CONFIG_SMP
if (last_task_used_math == current)
last_task_used_math = 0;
#endif /* CONFIG_SMP */
memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
current->thread.fpscr = 0;
#ifdef CONFIG_ALTIVEC
#ifndef CONFIG_SMP
if (last_task_used_altivec == current)
last_task_used_altivec = 0;
#endif /* CONFIG_SMP */
memset(current->thread.vr, 0, sizeof(current->thread.vr));
current->thread.vscr.u[0] = 0;
current->thread.vscr.u[1] = 0;
current->thread.vscr.u[2] = 0;
current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
current->thread.vrsave = 0;
current->thread.used_vr = 0;
#endif /* CONFIG_ALTIVEC */
}
EXPORT_SYMBOL(start_thread);
int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
{
struct pt_regs *regs = tsk->thread.regs;
if (val > PR_FP_EXC_PRECISE)
return -EINVAL;
tsk->thread.fpexc_mode = __pack_fe01(val);
if (regs != NULL && (regs->msr & MSR_FP) != 0)
regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
| tsk->thread.fpexc_mode;
return 0;
}
int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
{
unsigned int val;
val = __unpack_fe01(tsk->thread.fpexc_mode);
return put_user(val, (unsigned int __user *) adr);
}
int sys_clone(unsigned long clone_flags, unsigned long p2, unsigned long p3,
unsigned long p4, unsigned long p5, unsigned long p6,
struct pt_regs *regs)
{
unsigned long parent_tidptr = 0;
unsigned long child_tidptr = 0;
if (p2 == 0)
p2 = regs->gpr[1]; /* stack pointer for child */
if (clone_flags & (CLONE_PARENT_SETTID | CLONE_CHILD_SETTID |
CLONE_CHILD_CLEARTID)) {
parent_tidptr = p3;
child_tidptr = p5;
if (test_thread_flag(TIF_32BIT)) {
parent_tidptr &= 0xffffffff;
child_tidptr &= 0xffffffff;
}
}
return do_fork(clone_flags, p2, regs, 0,
(int __user *)parent_tidptr, (int __user *)child_tidptr);
}
int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
unsigned long p4, unsigned long p5, unsigned long p6,
struct pt_regs *regs)
{
return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
}
int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
unsigned long p4, unsigned long p5, unsigned long p6,
struct pt_regs *regs)
{
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1], regs, 0,
NULL, NULL);
}
int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
unsigned long a3, unsigned long a4, unsigned long a5,
struct pt_regs *regs)
{
int error;
char * filename;
filename = getname((char __user *) a0);
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
flush_fp_to_thread(current);
flush_altivec_to_thread(current);
error = do_execve(filename, (char __user * __user *) a1,
(char __user * __user *) a2, regs);
if (error == 0) {
task_lock(current);
current->ptrace &= ~PT_DTRACE;
task_unlock(current);
}
putname(filename);
out:
return error;
}
static int kstack_depth_to_print = 64;
static int validate_sp(unsigned long sp, struct task_struct *p,
unsigned long nbytes)
{
unsigned long stack_page = (unsigned long)p->thread_info;
if (sp >= stack_page + sizeof(struct thread_struct)
&& sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
#ifdef CONFIG_IRQSTACKS
stack_page = (unsigned long) hardirq_ctx[task_cpu(p)];
if (sp >= stack_page + sizeof(struct thread_struct)
&& sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
stack_page = (unsigned long) softirq_ctx[task_cpu(p)];
if (sp >= stack_page + sizeof(struct thread_struct)
&& sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
#endif
return 0;
}
unsigned long get_wchan(struct task_struct *p)
{
unsigned long ip, sp;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
sp = p->thread.ksp;
if (!validate_sp(sp, p, 112))
return 0;
do {
sp = *(unsigned long *)sp;
if (!validate_sp(sp, p, 112))
return 0;
if (count > 0) {
ip = *(unsigned long *)(sp + 16);
if (!in_sched_functions(ip))
return ip;
}
} while (count++ < 16);
return 0;
}
EXPORT_SYMBOL(get_wchan);
void show_stack(struct task_struct *p, unsigned long *_sp)
{
unsigned long ip, newsp, lr;
int count = 0;
unsigned long sp = (unsigned long)_sp;
int firstframe = 1;
if (sp == 0) {
if (p) {
sp = p->thread.ksp;
} else {
sp = __get_SP();
p = current;
}
}
lr = 0;
printk("Call Trace:\n");
do {
if (!validate_sp(sp, p, 112))
return;
_sp = (unsigned long *) sp;
newsp = _sp[0];
ip = _sp[2];
if (!firstframe || ip != lr) {
printk("[%016lx] [%016lx] ", sp, ip);
print_symbol("%s", ip);
if (firstframe)
printk(" (unreliable)");
printk("\n");
}
firstframe = 0;
/*
* See if this is an exception frame.
* We look for the "regshere" marker in the current frame.
*/
if (validate_sp(sp, p, sizeof(struct pt_regs) + 400)
&& _sp[12] == 0x7265677368657265ul) {
struct pt_regs *regs = (struct pt_regs *)
(sp + STACK_FRAME_OVERHEAD);
printk("--- Exception: %lx", regs->trap);
print_symbol(" at %s\n", regs->nip);
lr = regs->link;
print_symbol(" LR = %s\n", lr);
firstframe = 1;
}
sp = newsp;
} while (count++ < kstack_depth_to_print);
}
void dump_stack(void)
{
show_stack(current, (unsigned long *)__get_SP());
}
EXPORT_SYMBOL(dump_stack);
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