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s390: add support for transactional memory

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Allow user-space processes to use transactional execution (TX).
If the TX facility is available user space programs can use
transactions for fine-grained serialization based on the data
objects that are referenced during a transaction. This is
useful for lockless data structures and speculative compiler
optimizations.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2012-07-31 11:03:04 +02:00
parent e4b8b3f33f
commit d35339a42d
14 changed files with 151 additions and 21 deletions
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69
arch/s390/kernel/ptrace.c
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@@ -42,6 +42,7 @@ enum s390_regset {
REGSET_GENERAL,
REGSET_FP,
REGSET_LAST_BREAK,
REGSET_TDB,
REGSET_SYSTEM_CALL,
REGSET_GENERAL_EXTENDED,
};
@@ -52,6 +53,21 @@ void update_per_regs(struct task_struct *task)
struct thread_struct *thread = &task->thread;
struct per_regs old, new;
/* Take care of the enable/disable of transactional execution. */
if (MACHINE_HAS_TE) {
unsigned long cr0, cr0_new;
__ctl_store(cr0, 0, 0);
/* set or clear transaction execution bits 8 and 9. */
if (task->thread.per_flags & PER_FLAG_NO_TE)
cr0_new = cr0 & ~(3UL << 54);
else
cr0_new = cr0 | (3UL << 54);
/* Only load control register 0 if necessary. */
if (cr0 != cr0_new)
__ctl_load(cr0_new, 0, 0);
}
/* Copy user specified PER registers */
new.control = thread->per_user.control;
new.start = thread->per_user.start;
@@ -60,6 +76,10 @@ void update_per_regs(struct task_struct *task)
/* merge TIF_SINGLE_STEP into user specified PER registers. */
if (test_tsk_thread_flag(task, TIF_SINGLE_STEP)) {
new.control |= PER_EVENT_IFETCH;
#ifdef CONFIG_64BIT
new.control |= PER_CONTROL_SUSPENSION;
new.control |= PER_EVENT_TRANSACTION_END;
#endif
new.start = 0;
new.end = PSW_ADDR_INSN;
}
@@ -100,6 +120,7 @@ void ptrace_disable(struct task_struct *task)
memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
clear_tsk_thread_flag(task, TIF_PER_TRAP);
task->thread.per_flags = 0;
}
#ifndef CONFIG_64BIT
@@ -416,6 +437,16 @@ long arch_ptrace(struct task_struct *child, long request,
put_user(task_thread_info(child)->last_break,
(unsigned long __user *) data);
return 0;
case PTRACE_ENABLE_TE:
if (!MACHINE_HAS_TE)
return -EIO;
child->thread.per_flags &= ~PER_FLAG_NO_TE;
return 0;
case PTRACE_DISABLE_TE:
if (!MACHINE_HAS_TE)
return -EIO;
child->thread.per_flags |= PER_FLAG_NO_TE;
return 0;
default:
/* Removing high order bit from addr (only for 31 bit). */
addr &= PSW_ADDR_INSN;
@@ -903,6 +934,28 @@ static int s390_last_break_set(struct task_struct *target,
return 0;
}
static int s390_tdb_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
struct pt_regs *regs = task_pt_regs(target);
unsigned char *data;
if (!(regs->int_code & 0x200))
return -ENODATA;
data = target->thread.trap_tdb;
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, data, 0, 256);
}
static int s390_tdb_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
return 0;
}
#endif
static int s390_system_call_get(struct task_struct *target,
@@ -951,6 +1004,14 @@ static const struct user_regset s390_regsets[] = {
.get = s390_last_break_get,
.set = s390_last_break_set,
},
[REGSET_TDB] = {
.core_note_type = NT_S390_TDB,
.n = 1,
.size = 256,
.align = 1,
.get = s390_tdb_get,
.set = s390_tdb_set,
},
#endif
[REGSET_SYSTEM_CALL] = {
.core_note_type = NT_S390_SYSTEM_CALL,
@@ -1148,6 +1209,14 @@ static const struct user_regset s390_compat_regsets[] = {
.get = s390_compat_last_break_get,
.set = s390_compat_last_break_set,
},
[REGSET_TDB] = {
.core_note_type = NT_S390_TDB,
.n = 1,
.size = 256,
.align = 1,
.get = s390_tdb_get,
.set = s390_tdb_set,
},
[REGSET_SYSTEM_CALL] = {
.core_note_type = NT_S390_SYSTEM_CALL,
.n = 1,