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ed1cd6deb0
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>
57 lines
1.7 KiB
C
57 lines
1.7 KiB
C
/*
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* livepatch.h - powerpc-specific Kernel Live Patching Core
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*
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* Copyright (C) 2015-2016, SUSE, IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _ASM_POWERPC_LIVEPATCH_H
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#define _ASM_POWERPC_LIVEPATCH_H
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#include <linux/module.h>
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#include <linux/ftrace.h>
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#include <linux/sched/task_stack.h>
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#ifdef CONFIG_LIVEPATCH
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static inline int klp_check_compiler_support(void)
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{
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return 0;
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}
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static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
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{
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regs->nip = ip;
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}
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#define klp_get_ftrace_location klp_get_ftrace_location
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static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
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{
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/*
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* Live patch works only with -mprofile-kernel on PPC. In this case,
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* the ftrace location is always within the first 16 bytes.
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*/
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return ftrace_location_range(faddr, faddr + 16);
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}
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static inline void klp_init_thread_info(struct task_struct *p)
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{
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/* + 1 to account for STACK_END_MAGIC */
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task_thread_info(p)->livepatch_sp = end_of_stack(p) + 1;
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}
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#else
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static inline void klp_init_thread_info(struct task_struct *p) { }
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#endif /* CONFIG_LIVEPATCH */
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#endif /* _ASM_POWERPC_LIVEPATCH_H */
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