Re: [PATCH] x86: Use wrmsrl in kprobes.c, step.c

From: H. Peter Anvin
Date: Thu Jan 10 2008 - 14:49:45 EST


Harvey Harrison wrote:
Where x86_32 passed zero in the high 32 bits, use wrmsrl which
will zero extend for us. This allows ifdefs for 32/64 bit to
be eliminated.

Eliminate ifdef in step.c. Similar cleanup was done when unifying
kprobes_32|64.c and wrmsr() was chosen there over wrmsrl(). This
patch changes these to wrmsrl.

Signed-off-by: Harvey Harrison <harvey.harrison@xxxxxxxxx>
---
arch/x86/kernel/kprobes.c | 4 ++--
arch/x86/kernel/step.c | 4 ----
2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 53ba6a5..34becd1 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -410,13 +410,13 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
static void __kprobes clear_btf(void)
{
if (test_thread_flag(TIF_DEBUGCTLMSR))
- wrmsr(MSR_IA32_DEBUGCTLMSR, 0, 0);
+ wrmsrl(MSR_IA32_DEBUGCTLMSR, 0L);
}

Drop the L. It doesn't buy you anything, and gcc will sign-extend for you anyway. It's just visual clutter.

-hpa
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