linux_dsm_epyc7002/arch/powerpc/include/asm/livepatch.h
Christophe Leroy ed1cd6deb0 powerpc: Activate CONFIG_THREAD_INFO_IN_TASK
This patch activates CONFIG_THREAD_INFO_IN_TASK which
moves the thread_info into task_struct.

Moving thread_info into task_struct has the following advantages:
  - It protects thread_info from corruption in the case of stack
    overflows.
  - Its address is harder to determine if stack addresses are leaked,
    making a number of attacks more difficult.

This has the following consequences:
  - thread_info is now located at the beginning of task_struct.
  - The 'cpu' field is now in task_struct, and only exists when
    CONFIG_SMP is active.
  - thread_info doesn't have anymore the 'task' field.

This patch:
  - Removes all recopy of thread_info struct when the stack changes.
  - Changes the CURRENT_THREAD_INFO() macro to point to current.
  - Selects CONFIG_THREAD_INFO_IN_TASK.
  - Modifies raw_smp_processor_id() to get ->cpu from current without
    including linux/sched.h to avoid circular inclusion and without
    including asm/asm-offsets.h to avoid symbol names duplication
    between ASM constants and C constants.
  - Modifies klp_init_thread_info() to take a task_struct pointer
    argument.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add task_stack.h to livepatch.h to fix build fails]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-02-23 22:31:40 +11:00

57 lines
1.7 KiB
C

/*
* livepatch.h - powerpc-specific Kernel Live Patching Core
*
* Copyright (C) 2015-2016, SUSE, IBM Corp.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _ASM_POWERPC_LIVEPATCH_H
#define _ASM_POWERPC_LIVEPATCH_H
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/sched/task_stack.h>
#ifdef CONFIG_LIVEPATCH
static inline int klp_check_compiler_support(void)
{
return 0;
}
static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
{
regs->nip = ip;
}
#define klp_get_ftrace_location klp_get_ftrace_location
static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
{
/*
* Live patch works only with -mprofile-kernel on PPC. In this case,
* the ftrace location is always within the first 16 bytes.
*/
return ftrace_location_range(faddr, faddr + 16);
}
static inline void klp_init_thread_info(struct task_struct *p)
{
/* + 1 to account for STACK_END_MAGIC */
task_thread_info(p)->livepatch_sp = end_of_stack(p) + 1;
}
#else
static inline void klp_init_thread_info(struct task_struct *p) { }
#endif /* CONFIG_LIVEPATCH */
#endif /* _ASM_POWERPC_LIVEPATCH_H */