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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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f6a616800e
The powerpc kernel stacks need to be naturally aligned, as they contain the thread info at the bottom, which is obtained by clearing the low bits of the stack pointer. However, when using 64K pages, the stack is smaller than a page, so we use kmalloc to allocate it, but that doesn't provide the alignment guarantee we need. It appeared to work so far... until one enables SLUB debugging which then returns unaligned pointers. Ooops... This fixes it by using a slab cache with enforced alignment. It relies on my previous patch that adds a thread_info_cache_init() callback. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
156 lines
4.8 KiB
C
156 lines
4.8 KiB
C
/* thread_info.h: PowerPC low-level thread information
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* adapted from the i386 version by Paul Mackerras
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*
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* Copyright (C) 2002 David Howells (dhowells@redhat.com)
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* - Incorporating suggestions made by Linus Torvalds and Dave Miller
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*/
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#ifndef _ASM_POWERPC_THREAD_INFO_H
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#define _ASM_POWERPC_THREAD_INFO_H
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#ifdef __KERNEL__
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/* We have 8k stacks on ppc32 and 16k on ppc64 */
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#ifdef CONFIG_PPC64
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#define THREAD_SHIFT 14
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#else
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#define THREAD_SHIFT 13
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#endif
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#define THREAD_SIZE (1 << THREAD_SHIFT)
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#ifndef __ASSEMBLY__
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#include <linux/cache.h>
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#include <asm/processor.h>
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#include <asm/page.h>
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#include <linux/stringify.h>
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/*
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* low level task data.
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*/
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struct thread_info {
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struct task_struct *task; /* main task structure */
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struct exec_domain *exec_domain; /* execution domain */
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int cpu; /* cpu we're on */
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int preempt_count; /* 0 => preemptable,
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<0 => BUG */
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struct restart_block restart_block;
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unsigned long local_flags; /* private flags for thread */
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/* low level flags - has atomic operations done on it */
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unsigned long flags ____cacheline_aligned_in_smp;
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};
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/*
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* macros/functions for gaining access to the thread information structure
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*
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* preempt_count needs to be 1 initially, until the scheduler is functional.
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*/
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.task = &tsk, \
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.exec_domain = &default_exec_domain, \
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.cpu = 0, \
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.preempt_count = 1, \
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.restart_block = { \
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.fn = do_no_restart_syscall, \
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}, \
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.flags = 0, \
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}
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#define init_thread_info (init_thread_union.thread_info)
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#define init_stack (init_thread_union.stack)
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/* thread information allocation */
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#if THREAD_SHIFT >= PAGE_SHIFT
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#define THREAD_ORDER (THREAD_SHIFT - PAGE_SHIFT)
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#ifdef CONFIG_DEBUG_STACK_USAGE
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#define alloc_thread_info(tsk) \
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((struct thread_info *)__get_free_pages(GFP_KERNEL | \
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__GFP_ZERO, THREAD_ORDER))
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#else
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#define alloc_thread_info(tsk) \
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((struct thread_info *)__get_free_pages(GFP_KERNEL, THREAD_ORDER))
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#endif
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#define free_thread_info(ti) free_pages((unsigned long)ti, THREAD_ORDER)
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#else /* THREAD_SHIFT < PAGE_SHIFT */
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extern struct thread_info *alloc_thread_info(struct task_struct *tsk);
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extern void free_thread_info(struct thread_info *ti);
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#endif /* THREAD_SHIFT < PAGE_SHIFT */
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/* how to get the thread information struct from C */
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static inline struct thread_info *current_thread_info(void)
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{
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register unsigned long sp asm("r1");
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/* gcc4, at least, is smart enough to turn this into a single
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* rlwinm for ppc32 and clrrdi for ppc64 */
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return (struct thread_info *)(sp & ~(THREAD_SIZE-1));
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}
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#endif /* __ASSEMBLY__ */
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#define PREEMPT_ACTIVE 0x10000000
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/*
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* thread information flag bit numbers
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*/
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#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
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#define TIF_SIGPENDING 1 /* signal pending */
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#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
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#define TIF_POLLING_NRFLAG 3 /* true if poll_idle() is polling
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TIF_NEED_RESCHED */
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#define TIF_32BIT 4 /* 32 bit binary */
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#define TIF_PERFMON_WORK 5 /* work for pfm_handle_work() */
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#define TIF_PERFMON_CTXSW 6 /* perfmon needs ctxsw calls */
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#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
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#define TIF_SINGLESTEP 8 /* singlestepping active */
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#define TIF_MEMDIE 9
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#define TIF_SECCOMP 10 /* secure computing */
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#define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */
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#define TIF_NOERROR 12 /* Force successful syscall return */
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#define TIF_RESTORE_SIGMASK 13 /* Restore signal mask in do_signal */
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#define TIF_FREEZE 14 /* Freezing for suspend */
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#define TIF_RUNLATCH 15 /* Is the runlatch enabled? */
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#define TIF_ABI_PENDING 16 /* 32/64 bit switch needed */
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/* as above, but as bit values */
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#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
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#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
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#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
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#define _TIF_32BIT (1<<TIF_32BIT)
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#define _TIF_PERFMON_WORK (1<<TIF_PERFMON_WORK)
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#define _TIF_PERFMON_CTXSW (1<<TIF_PERFMON_CTXSW)
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#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
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#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP)
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#define _TIF_SECCOMP (1<<TIF_SECCOMP)
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#define _TIF_RESTOREALL (1<<TIF_RESTOREALL)
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#define _TIF_NOERROR (1<<TIF_NOERROR)
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#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
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#define _TIF_FREEZE (1<<TIF_FREEZE)
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#define _TIF_RUNLATCH (1<<TIF_RUNLATCH)
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#define _TIF_ABI_PENDING (1<<TIF_ABI_PENDING)
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#define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
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#define _TIF_USER_WORK_MASK ( _TIF_SIGPENDING | \
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_TIF_NEED_RESCHED | _TIF_RESTORE_SIGMASK)
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#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR)
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/* Bits in local_flags */
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/* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
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#define TLF_NAPPING 0 /* idle thread enabled NAP mode */
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#define _TLF_NAPPING (1 << TLF_NAPPING)
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_THREAD_INFO_H */
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