bdcf81b658
Inconsistently, the raw_* IRQ routines do not interact with and update the irqflags tracing and lockdep state, whereas the raw_* spinlock interfaces do. This causes problems in p1275_cmd_direct() because we disable hardirqs by hand using raw_local_irq_restore() and then do a raw_spin_lock() which triggers a lockdep trace because the CPU's hw IRQ state doesn't match IRQ tracing's internal software copy of that state. The CPU's irqs are disabled, yet current->hardirqs_enabled is true. ==================== reboot: Restarting system ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3536 check_flags+0x7c/0x240() DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled) Modules linked in: openpromfs CPU: 0 PID: 1 Comm: systemd-shutdow Tainted: G W 3.17.0-dirty #145 Call Trace: [000000000045919c] warn_slowpath_common+0x5c/0xa0 [0000000000459210] warn_slowpath_fmt+0x30/0x40 [000000000048f41c] check_flags+0x7c/0x240 [0000000000493280] lock_acquire+0x20/0x1c0 [0000000000832b70] _raw_spin_lock+0x30/0x60 [000000000068f2fc] p1275_cmd_direct+0x1c/0x60 [000000000068ed28] prom_reboot+0x28/0x40 [000000000043610c] machine_restart+0x4c/0x80 [000000000047d2d4] kernel_restart+0x54/0x80 [000000000047d618] SyS_reboot+0x138/0x200 [00000000004060b4] linux_sparc_syscall32+0x34/0x60 ---[ end trace 5c439fe81c05a100 ]--- possible reason: unannotated irqs-off. irq event stamp: 2010267 hardirqs last enabled at (2010267): [<000000000049a358>] vprintk_emit+0x4b8/0x580 hardirqs last disabled at (2010266): [<0000000000499f08>] vprintk_emit+0x68/0x580 softirqs last enabled at (2010046): [<000000000045d278>] __do_softirq+0x378/0x4a0 softirqs last disabled at (2010039): [<000000000042bf08>] do_softirq_own_stack+0x28/0x40 Resetting ... ==================== Use local_* variables of the hw IRQ interfaces so that IRQ tracing sees all of our changes. Reported-by: Meelis Roos <mroos@linux.ee> Tested-by: Meelis Roos <mroos@linux.ee> Signed-off-by: David S. Miller <davem@davemloft.net>
57 lines
1.2 KiB
C
57 lines
1.2 KiB
C
/*
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* p1275.c: Sun IEEE 1275 PROM low level interface routines
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*
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* Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/smp.h>
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#include <linux/string.h>
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#include <linux/spinlock.h>
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#include <linux/irqflags.h>
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#include <asm/openprom.h>
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#include <asm/oplib.h>
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#include <asm/spitfire.h>
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#include <asm/pstate.h>
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#include <asm/ldc.h>
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struct {
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long prom_callback; /* 0x00 */
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void (*prom_cif_handler)(long *); /* 0x08 */
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unsigned long prom_cif_stack; /* 0x10 */
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} p1275buf;
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extern void prom_world(int);
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extern void prom_cif_direct(unsigned long *args);
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extern void prom_cif_callback(void);
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/*
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* This provides SMP safety on the p1275buf.
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*/
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DEFINE_RAW_SPINLOCK(prom_entry_lock);
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void p1275_cmd_direct(unsigned long *args)
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{
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unsigned long flags;
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local_save_flags(flags);
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local_irq_restore((unsigned long)PIL_NMI);
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raw_spin_lock(&prom_entry_lock);
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prom_world(1);
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prom_cif_direct(args);
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prom_world(0);
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raw_spin_unlock(&prom_entry_lock);
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local_irq_restore(flags);
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}
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void prom_cif_init(void *cif_handler, void *cif_stack)
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{
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p1275buf.prom_cif_handler = (void (*)(long *))cif_handler;
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p1275buf.prom_cif_stack = (unsigned long)cif_stack;
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}
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