[PATCH 1/4 linux-next] x86, msr: define msr chunksize

From: Fabian Frederick
Date: Fri Oct 17 2014 - 16:01:35 EST


define MSR_CHUNK_SIZE instead of hard-coded value (8).

Signed-off-by: Fabian Frederick <fabf@xxxxxxxxx>
---
arch/x86/include/asm/msr.h | 2 ++
arch/x86/kernel/msr.c | 18 +++++++++---------
2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index de36f22..f28a5a2 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -39,6 +39,8 @@ static inline unsigned long long native_read_tscp(unsigned int *aux)
return low | ((u64)high << 32);
}

+#define MSR_CHUNK_SIZE 8
+
/*
* both i386 and x86_64 returns 64-bit value in edx:eax, but gcc's "A"
* constraint has different meanings. For i386, "A" means exactly
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index c9603ac..f1f3ed0 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -75,19 +75,19 @@ static ssize_t msr_read(struct file *file, char __user *buf,
int err = 0;
ssize_t bytes = 0;

- if (count % 8)
+ if (count % MSR_CHUNK_SIZE)
return -EINVAL; /* Invalid chunk size */

- for (; count; count -= 8) {
+ for (; count; count -= MSR_CHUNK_SIZE) {
err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]);
if (err)
break;
- if (copy_to_user(tmp, &data, 8)) {
+ if (copy_to_user(tmp, &data, MSR_CHUNK_SIZE)) {
err = -EFAULT;
break;
}
tmp += 2;
- bytes += 8;
+ bytes += MSR_CHUNK_SIZE;
}

return bytes ? bytes : err;
@@ -103,11 +103,11 @@ static ssize_t msr_write(struct file *file, const char __user *buf,
int err = 0;
ssize_t bytes = 0;

- if (count % 8)
+ if (count % MSR_CHUNK_SIZE)
return -EINVAL; /* Invalid chunk size */

- for (; count; count -= 8) {
- if (copy_from_user(&data, tmp, 8)) {
+ for (; count; count -= MSR_CHUNK_SIZE) {
+ if (copy_from_user(&data, tmp, MSR_CHUNK_SIZE)) {
err = -EFAULT;
break;
}
@@ -115,7 +115,7 @@ static ssize_t msr_write(struct file *file, const char __user *buf,
if (err)
break;
tmp += 2;
- bytes += 8;
+ bytes += MSR_CHUNK_SIZE;
}

return bytes ? bytes : err;
@@ -124,7 +124,7 @@ static ssize_t msr_write(struct file *file, const char __user *buf,
static long msr_ioctl(struct file *file, unsigned int ioc, unsigned long arg)
{
u32 __user *uregs = (u32 __user *)arg;
- u32 regs[8];
+ u32 regs[MSR_CHUNK_SIZE];
int cpu = iminor(file_inode(file));
int err;

--
1.9.3

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