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authorOlof Johansson <olof@lixom.net>2014-05-05 23:18:49 +0200
committerOlof Johansson <olof@lixom.net>2014-05-05 23:18:49 +0200
commit186a73dc9a81b087d0708f21a990615957ec9c1c (patch)
treea1db8d517665fb27f25d44eacacd4b80a0d540ed /arch/x86/lib/msr.c
parentMerge tag 'versatile-leds' of git://git.kernel.org/pub/scm/linux/kernel/git/l... (diff)
parentARM: qcom: clean-up unneeded kconfig selects (diff)
downloadlinux-186a73dc9a81b087d0708f21a990615957ec9c1c.tar.xz
linux-186a73dc9a81b087d0708f21a990615957ec9c1c.zip
Merge tag 'kconfig-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux into next/cleanup
Merge Kconfig cleanups from Rob Herring: Several mach kconfig clean-ups of redundant selects * tag 'kconfig-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: ARM: qcom: clean-up unneeded kconfig selects ARM: bcm: clean-up unneeded kconfig selects ARM: mvebu: clean-up unneeded kconfig selects + Linux 3.15-rc2 Signed-off-by: Olof Johansson <olof@lixom.net>
Diffstat (limited to 'arch/x86/lib/msr.c')
-rw-r--r--arch/x86/lib/msr.c89
1 files changed, 88 insertions, 1 deletions
diff --git a/arch/x86/lib/msr.c b/arch/x86/lib/msr.c
index 8f8eebdca7d4..db9db446b71a 100644
--- a/arch/x86/lib/msr.c
+++ b/arch/x86/lib/msr.c
@@ -8,7 +8,7 @@ struct msr *msrs_alloc(void)
msrs = alloc_percpu(struct msr);
if (!msrs) {
- pr_warning("%s: error allocating msrs\n", __func__);
+ pr_warn("%s: error allocating msrs\n", __func__);
return NULL;
}
@@ -21,3 +21,90 @@ void msrs_free(struct msr *msrs)
free_percpu(msrs);
}
EXPORT_SYMBOL(msrs_free);
+
+/**
+ * Read an MSR with error handling
+ *
+ * @msr: MSR to read
+ * @m: value to read into
+ *
+ * It returns read data only on success, otherwise it doesn't change the output
+ * argument @m.
+ *
+ */
+int msr_read(u32 msr, struct msr *m)
+{
+ int err;
+ u64 val;
+
+ err = rdmsrl_safe(msr, &val);
+ if (!err)
+ m->q = val;
+
+ return err;
+}
+
+/**
+ * Write an MSR with error handling
+ *
+ * @msr: MSR to write
+ * @m: value to write
+ */
+int msr_write(u32 msr, struct msr *m)
+{
+ return wrmsrl_safe(msr, m->q);
+}
+
+static inline int __flip_bit(u32 msr, u8 bit, bool set)
+{
+ struct msr m, m1;
+ int err = -EINVAL;
+
+ if (bit > 63)
+ return err;
+
+ err = msr_read(msr, &m);
+ if (err)
+ return err;
+
+ m1 = m;
+ if (set)
+ m1.q |= BIT_64(bit);
+ else
+ m1.q &= ~BIT_64(bit);
+
+ if (m1.q == m.q)
+ return 0;
+
+ err = msr_write(msr, &m);
+ if (err)
+ return err;
+
+ return 1;
+}
+
+/**
+ * Set @bit in a MSR @msr.
+ *
+ * Retval:
+ * < 0: An error was encountered.
+ * = 0: Bit was already set.
+ * > 0: Hardware accepted the MSR write.
+ */
+int msr_set_bit(u32 msr, u8 bit)
+{
+ return __flip_bit(msr, bit, true);
+}
+
+/**
+ * Clear @bit in a MSR @msr.
+ *
+ * Retval:
+ * < 0: An error was encountered.
+ * = 0: Bit was already cleared.
+ * > 0: Hardware accepted the MSR write.
+ */
+int msr_clear_bit(u32 msr, u8 bit)
+{
+ return __flip_bit(msr, bit, false);
+}