[v6][PATCH 4/5] powerpc/kgdb: use DEFINE_PER_CPU to allocate kgdb's thread_info

From: Tiejun Chen
Date: Wed Oct 23 2013 - 05:31:48 EST


Use DEFINE_PER_CPU to allocate thread_info statically instead of kmalloc().
This can avoid introducing more memory check codes.

Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxxxxxx>
---
arch/powerpc/kernel/kgdb.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index c1eef24..447c14b 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -151,15 +151,15 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs)
return 1;
}

+static DEFINE_PER_CPU(struct thread_info, kgdb_thread_info);
static int kgdb_singlestep(struct pt_regs *regs)
{
struct thread_info *thread_info, *exception_thread_info;
- struct thread_info *backup_current_thread_info;
+ struct thread_info *backup_current_thread_info = &__get_cpu_var(kgdb_thread_info);

if (user_mode(regs))
return 0;

- backup_current_thread_info = kmalloc(sizeof(struct thread_info), GFP_KERNEL);
/*
* On Book E and perhaps other processors, singlestep is handled on
* the critical exception stack. This causes current_thread_info()
@@ -185,7 +185,6 @@ static int kgdb_singlestep(struct pt_regs *regs)
/* Restore current_thread_info lastly. */
memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info);

- kfree(backup_current_thread_info);
return 1;
}

--
1.7.9.5

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