[PATCH 2/3] [RESEND]sparc64: convert spinloc_t to raw_spinlock_t in mmu_context_t

From: Allen Pais
Date: Wed Dec 18 2013 - 00:42:37 EST


In the attempt of get PREEMPT_RT working on sparc64 using
linux-stable-rt version 3.10.22-rt19+, the kernel crash
with the following trace:

[ 1487.027884] I7: <rt_mutex_setprio+0x3c/0x2c0>
[ 1487.027885] Call Trace:
[ 1487.027887] [00000000004967dc] rt_mutex_setprio+0x3c/0x2c0
[ 1487.027892] [00000000004afe20] task_blocks_on_rt_mutex+0x180/0x200
[ 1487.027895] [0000000000819114] rt_spin_lock_slowlock+0x94/0x300
[ 1487.027897] [0000000000817ebc] __schedule+0x39c/0x53c
[ 1487.027899] [00000000008185fc] schedule+0x1c/0xc0
[ 1487.027908] [000000000048fff4] smpboot_thread_fn+0x154/0x2e0
[ 1487.027913] [000000000048753c] kthread+0x7c/0xa0
[ 1487.027920] [00000000004060c4] ret_from_syscall+0x1c/0x2c
[ 1487.027922] [0000000000000000] (null)

Thomas debugged this issue and pointed to switch_mm

spin_lock_irqsave(&mm->context.lock, flags);

context.lock needs to be a raw_spinlock.

Signed-off-by: Allen Pais <allen.pais@xxxxxxxxxx>
---
arch/sparc/Kconfig | 1 +
arch/sparc/include/asm/mmu_64.h | 2 +-
arch/sparc/include/asm/mmu_context_64.h | 8 ++++----
arch/sparc/kernel/smp_64.c | 4 ++--
arch/sparc/mm/init_64.c | 4 ++--
arch/sparc/mm/tsb.c | 16 ++++++++--------
6 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 554995d..aae5aa9 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -27,6 +27,7 @@ config SPARC
select HAVE_DMA_API_DEBUG
select HAVE_ARCH_JUMP_LABEL
select HAVE_GENERIC_HARDIRQS
+ select IRQ_FORCED_THREADING
select GENERIC_IRQ_SHOW
select ARCH_WANT_IPC_PARSE_VERSION
select USE_GENERIC_SMP_HELPERS if SMP
diff --git a/arch/sparc/include/asm/mmu_64.h b/arch/sparc/include/asm/mmu_64.h
index 76092c4..e945ddb 100644
--- a/arch/sparc/include/asm/mmu_64.h
+++ b/arch/sparc/include/asm/mmu_64.h
@@ -90,7 +90,7 @@ struct tsb_config {
#endif

typedef struct {
- spinlock_t lock;
+ raw_spinlock_t lock;
unsigned long sparc64_ctx_val;
unsigned long huge_pte_count;
struct page *pgtable_page;
diff --git a/arch/sparc/include/asm/mmu_context_64.h b/arch/sparc/include/asm/mmu_context_64.h
index 3d528f0..3a85624 100644
--- a/arch/sparc/include/asm/mmu_context_64.h
+++ b/arch/sparc/include/asm/mmu_context_64.h
@@ -77,7 +77,7 @@ static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, str
if (unlikely(mm == &init_mm))
return;

- spin_lock_irqsave(&mm->context.lock, flags);
+ raw_spin_lock_irqsave(&mm->context.lock, flags);
ctx_valid = CTX_VALID(mm->context);
if (!ctx_valid)
get_new_mmu_context(mm);
@@ -125,7 +125,7 @@ static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, str
__flush_tlb_mm(CTX_HWBITS(mm->context),
SECONDARY_CONTEXT);
}
- spin_unlock_irqrestore(&mm->context.lock, flags);
+ raw_spin_unlock_irqrestore(&mm->context.lock, flags);
}

#define deactivate_mm(tsk,mm) do { } while (0)
@@ -136,7 +136,7 @@ static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm
unsigned long flags;
int cpu;

- spin_lock_irqsave(&mm->context.lock, flags);
+ raw_spin_lock_irqsave(&mm->context.lock, flags);
if (!CTX_VALID(mm->context))
get_new_mmu_context(mm);
cpu = smp_processor_id();
@@ -146,7 +146,7 @@ static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm
load_secondary_context(mm);
__flush_tlb_mm(CTX_HWBITS(mm->context), SECONDARY_CONTEXT);
tsb_context_switch(mm);
- spin_unlock_irqrestore(&mm->context.lock, flags);
+ raw_spin_unlock_irqrestore(&mm->context.lock, flags);
}

#endif /* !(__ASSEMBLY__) */
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 77539ed..f42e1a7 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -975,12 +975,12 @@ void __irq_entry smp_new_mmu_context_version_client(int irq, struct pt_regs *reg
if (unlikely(!mm || (mm == &init_mm)))
return;

- spin_lock_irqsave(&mm->context.lock, flags);
+ raw_spin_lock_irqsave(&mm->context.lock, flags);

if (unlikely(!CTX_VALID(mm->context)))
get_new_mmu_context(mm);

- spin_unlock_irqrestore(&mm->context.lock, flags);
+ raw_spin_unlock_irqrestore(&mm->context.lock, flags);

load_secondary_context(mm);
__flush_tlb_mm(CTX_HWBITS(mm->context),
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 04fd55a..bd5253d 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -350,7 +350,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *

mm = vma->vm_mm;

- spin_lock_irqsave(&mm->context.lock, flags);
+ raw_spin_lock_irqsave(&mm->context.lock, flags);

#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
if (mm->context.huge_pte_count && is_hugetlb_pte(pte))
@@ -361,7 +361,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *
__update_mmu_tsb_insert(mm, MM_TSB_BASE, PAGE_SHIFT,
address, pte_val(pte));

- spin_unlock_irqrestore(&mm->context.lock, flags);
+ raw_spin_unlock_irqrestore(&mm->context.lock, flags);
}

void flush_dcache_page(struct page *page)
diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
index 2cc3bce..d84d4ea 100644
--- a/arch/sparc/mm/tsb.c
+++ b/arch/sparc/mm/tsb.c
@@ -73,7 +73,7 @@ void flush_tsb_user(struct tlb_batch *tb)
struct mm_struct *mm = tb->mm;
unsigned long nentries, base, flags;

- spin_lock_irqsave(&mm->context.lock, flags);
+ raw_spin_lock_irqsave(&mm->context.lock, flags);

base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
@@ -90,14 +90,14 @@ void flush_tsb_user(struct tlb_batch *tb)
__flush_tsb_one(tb, HPAGE_SHIFT, base, nentries);
}
#endif
- spin_unlock_irqrestore(&mm->context.lock, flags);
+ raw_spin_unlock_irqrestore(&mm->context.lock, flags);
}

void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr)
{
unsigned long nentries, base, flags;

- spin_lock_irqsave(&mm->context.lock, flags);
+ raw_spin_lock_irqsave(&mm->context.lock, flags);

base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
@@ -114,7 +114,7 @@ void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr)
__flush_tsb_one_entry(base, vaddr, HPAGE_SHIFT, nentries);
}
#endif
- spin_unlock_irqrestore(&mm->context.lock, flags);
+ raw_spin_unlock_irqrestore(&mm->context.lock, flags);
}

#define HV_PGSZ_IDX_BASE HV_PGSZ_IDX_8K
@@ -392,7 +392,7 @@ retry_tsb_alloc:
* the lock and ask all other cpus running this address space
* to run tsb_context_switch() to see the new TSB table.
*/
- spin_lock_irqsave(&mm->context.lock, flags);
+ raw_spin_lock_irqsave(&mm->context.lock, flags);

old_tsb = mm->context.tsb_block[tsb_index].tsb;
old_cache_index =
@@ -407,7 +407,7 @@ retry_tsb_alloc:
*/
if (unlikely(old_tsb &&
(rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
- spin_unlock_irqrestore(&mm->context.lock, flags);
+ raw_spin_unlock_irqrestore(&mm->context.lock, flags);

kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
return;
@@ -433,7 +433,7 @@ retry_tsb_alloc:
mm->context.tsb_block[tsb_index].tsb = new_tsb;
setup_tsb_params(mm, tsb_index, new_size);

- spin_unlock_irqrestore(&mm->context.lock, flags);
+ raw_spin_unlock_irqrestore(&mm->context.lock, flags);

/* If old_tsb is NULL, we're being invoked for the first time
* from init_new_context().
@@ -459,7 +459,7 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
#endif
unsigned int i;

- spin_lock_init(&mm->context.lock);
+ raw_spin_lock_init(&mm->context.lock);

mm->context.sparc64_ctx_val = 0UL;

--
1.7.10.4

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