[PATCH 4/4] [V1] sparc64: convert ctx_alloc_lock raw_spinlock_t

[Allen Pais <allen.pais@oracle.com>]

This patch fixes the kernel crash faced while
trying to attempt linux-stable-rt v3.10.22-rt19
on sparc64.

[ 2317.606015]  [00000000008072f4] rt_spin_lock_slowlock+0x94/0x300
[ 2317.606020]  [0000000000451d74] get_new_mmu_context+0x14/0x160
[ 2317.606026]  [0000000000806394] switch_to_pc+0xd4/0x2a0
[ 2317.606029]  [00000000008067dc] schedule+0x1c/0xc0
[ 2317.606031]  [0000000000807364] rt_spin_lock_slowlock+0x104/0x300
[ 2317.606033]  [0000000000450284] destroy_context+0x84/0x120
[ 2317.606036]  [000000000045c788] __mmdrop+0x28/0xe0
[ 2317.606045]  [00000000004bf290] rcu_process_callbacks+0x450/0x760
[ 2317.606049]  [0000000000466d48] do_current_softirqs+0x208/0x3c0
[ 2317.606051]  [0000000000466f14] run_ksoftirqd+0x14/0x40
[ 2317.606057]  [000000000048c64c] smpboot_thread_fn+0x18c/0x2e0
[ 2317.606061]  [0000000000483b5c] kthread+0x7c/0xa0
[ 2317.606069]  [00000000004060c4] ret_from_syscall+0x1c/0x2c
[ 2317.606070]  [0000000000000000]           (null)

Signed-off-by: Allen Pais <allen.pais@oracle.com>
---
 arch/sparc/include/asm/mmu_context_64.h |    2 +-
 arch/sparc/mm/init_64.c                 |   10 +++++-----
 arch/sparc/mm/tsb.c                     |    4 ++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/sparc/include/asm/mmu_context_64.h b/arch/sparc/include/asm/mmu_context_64.h
index 3a85624..44e393b 100644
--- a/arch/sparc/include/asm/mmu_context_64.h
+++ b/arch/sparc/include/asm/mmu_context_64.h
@@ -13,7 +13,7 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 {
 }
 
-extern spinlock_t ctx_alloc_lock;
+extern raw_spinlock_t ctx_alloc_lock;
 extern unsigned long tlb_context_cache;
 extern unsigned long mmu_context_bmap[];
 
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index bd5253d..ac5ae7a 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -661,7 +661,7 @@ void __flush_dcache_range(unsigned long start, unsigned long end)
 EXPORT_SYMBOL(__flush_dcache_range);
 
 /* get_new_mmu_context() uses "cache + 1".  */
-DEFINE_SPINLOCK(ctx_alloc_lock);
+DEFINE_RAW_SPINLOCK(ctx_alloc_lock);
 unsigned long tlb_context_cache = CTX_FIRST_VERSION - 1;
 #define MAX_CTX_NR	(1UL << CTX_NR_BITS)
 #define CTX_BMAP_SLOTS	BITS_TO_LONGS(MAX_CTX_NR)
@@ -683,7 +683,7 @@ void get_new_mmu_context(struct mm_struct *mm)
 	unsigned long orig_pgsz_bits;
 	int new_version;
 
-	spin_lock(&ctx_alloc_lock);
+	raw_spin_lock(&ctx_alloc_lock);
 	orig_pgsz_bits = (mm->context.sparc64_ctx_val & CTX_PGSZ_MASK);
 	ctx = (tlb_context_cache + 1) & CTX_NR_MASK;
 	new_ctx = find_next_zero_bit(mmu_context_bmap, 1 << CTX_NR_BITS, ctx);
@@ -719,7 +719,7 @@ void get_new_mmu_context(struct mm_struct *mm)
 out:
 	tlb_context_cache = new_ctx;
 	mm->context.sparc64_ctx_val = new_ctx | orig_pgsz_bits;
-	spin_unlock(&ctx_alloc_lock);
+	raw_spin_unlock(&ctx_alloc_lock);
 
 	if (unlikely(new_version))
 		smp_new_mmu_context_version();
@@ -2739,7 +2739,7 @@ void hugetlb_setup(struct pt_regs *regs)
 	if (tlb_type == cheetah_plus) {
 		unsigned long ctx;
 
-		spin_lock(&ctx_alloc_lock);
+		raw_spin_lock(&ctx_alloc_lock);
 		ctx = mm->context.sparc64_ctx_val;
 		ctx &= ~CTX_PGSZ_MASK;
 		ctx |= CTX_PGSZ_BASE << CTX_PGSZ0_SHIFT;
@@ -2760,7 +2760,7 @@ void hugetlb_setup(struct pt_regs *regs)
 			mm->context.sparc64_ctx_val = ctx;
 			on_each_cpu(context_reload, mm, 0);
 		}
-		spin_unlock(&ctx_alloc_lock);
+		raw_spin_unlock(&ctx_alloc_lock);
 	}
 }
 #endif
diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
index d84d4ea..9eb10b4 100644
--- a/arch/sparc/mm/tsb.c
+++ b/arch/sparc/mm/tsb.c
@@ -523,12 +523,12 @@ void destroy_context(struct mm_struct *mm)
 		free_hot_cold_page(page, 0);
 	}
 
-	spin_lock_irqsave(&ctx_alloc_lock, flags);
+	raw_spin_lock_irqsave(&ctx_alloc_lock, flags);
 
 	if (CTX_VALID(mm->context)) {
 		unsigned long nr = CTX_NRBITS(mm->context);
 		mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
 	}
 
-	spin_unlock_irqrestore(&ctx_alloc_lock, flags);
+	raw_spin_unlock_irqrestore(&ctx_alloc_lock, flags);
 }
-- 
1.7.10.4