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102 lines
2.2 KiB
102 lines
2.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright IBM Corp. 2012 |
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* Author(s): Jan Glauber <[email protected]> |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/syscalls.h> |
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#include <linux/signal.h> |
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#include <linux/mm.h> |
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#include <linux/slab.h> |
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#include <linux/init.h> |
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#include <linux/errno.h> |
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#include <linux/kernel_stat.h> |
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#include <linux/sched/task_stack.h> |
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#include <asm/runtime_instr.h> |
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#include <asm/cpu_mf.h> |
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#include <asm/irq.h> |
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#include "entry.h" |
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/* empty control block to disable RI by loading it */ |
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struct runtime_instr_cb runtime_instr_empty_cb; |
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void runtime_instr_release(struct task_struct *tsk) |
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{ |
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kfree(tsk->thread.ri_cb); |
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} |
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static void disable_runtime_instr(void) |
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{ |
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struct task_struct *task = current; |
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struct pt_regs *regs; |
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if (!task->thread.ri_cb) |
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return; |
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regs = task_pt_regs(task); |
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preempt_disable(); |
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load_runtime_instr_cb(&runtime_instr_empty_cb); |
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kfree(task->thread.ri_cb); |
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task->thread.ri_cb = NULL; |
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preempt_enable(); |
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/* |
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* Make sure the RI bit is deleted from the PSW. If the user did not |
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* switch off RI before the system call the process will get a |
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* specification exception otherwise. |
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*/ |
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regs->psw.mask &= ~PSW_MASK_RI; |
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} |
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static void init_runtime_instr_cb(struct runtime_instr_cb *cb) |
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{ |
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cb->rla = 0xfff; |
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cb->s = 1; |
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cb->k = 1; |
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cb->ps = 1; |
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cb->pc = 1; |
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cb->key = PAGE_DEFAULT_KEY >> 4; |
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cb->v = 1; |
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} |
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/* |
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* The signum argument is unused. In older kernels it was used to |
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* specify a real-time signal. For backwards compatibility user space |
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* should pass a valid real-time signal number (the signum argument |
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* was checked in older kernels). |
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*/ |
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SYSCALL_DEFINE2(s390_runtime_instr, int, command, int, signum) |
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{ |
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struct runtime_instr_cb *cb; |
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if (!test_facility(64)) |
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return -EOPNOTSUPP; |
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if (command == S390_RUNTIME_INSTR_STOP) { |
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disable_runtime_instr(); |
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return 0; |
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} |
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if (command != S390_RUNTIME_INSTR_START) |
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return -EINVAL; |
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if (!current->thread.ri_cb) { |
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cb = kzalloc(sizeof(*cb), GFP_KERNEL); |
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if (!cb) |
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return -ENOMEM; |
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} else { |
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cb = current->thread.ri_cb; |
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memset(cb, 0, sizeof(*cb)); |
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} |
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init_runtime_instr_cb(cb); |
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/* now load the control block to make it available */ |
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preempt_disable(); |
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current->thread.ri_cb = cb; |
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load_runtime_instr_cb(cb); |
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preempt_enable(); |
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return 0; |
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}
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