Re: [git-pull -tip] x86: cpu_debug support read-write opertaionsfor PMC
From: Jaswinder Singh Rajput
Date: Thu Mar 12 2009 - 03:47:39 EST
On Thu, 2009-03-12 at 12:44 +0530, Jaswinder Singh Rajput wrote:
> On Thu, 2009-03-12 at 03:04 +0530, Jaswinder Singh Rajput wrote:
> > Currently I added read-write operations for PMC MSRs for cpu_debug:
>
> Now I made generic write support by adding write flag for registers.
> currently write is enabled only for PMC MSR but we can also support
> another MSRs just changing the write flag.
Here some more cleanups and comment to avoid confusions, and then new
request pull:
Log is available at:
http://git.kernel.org/?p=linux/kernel/git/jaswinder/linux-2.6-cpu.git;a=commit;h=1fdb3c7038d8bde067f56d43705ea24e866c9673
The following changes since commit 8851485ba842e892adfa343463ce6b74550bb8b1:
Ingo Molnar (1):
Merge branch 'x86/urgent'
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/jaswinder/linux-2.6-cpu.git master
Jaswinder Singh Rajput (1):
x86: cpu_debug add write support for MSRs
arch/x86/include/asm/cpu_debug.h | 16 ++++--
arch/x86/kernel/cpu/cpu_debug.c | 118 +++++++++++++++++++++++++++----------
2 files changed, 97 insertions(+), 37 deletions(-)
Complete diff:
diff --git a/arch/x86/include/asm/cpu_debug.h b/arch/x86/include/asm/cpu_debug.h
index d24d64f..56f1635 100755
--- a/arch/x86/include/asm/cpu_debug.h
+++ b/arch/x86/include/asm/cpu_debug.h
@@ -171,16 +171,22 @@ struct cpu_private {
struct cpu_debug_base {
char *name; /* Register name */
unsigned flag; /* Register flag */
+ unsigned write; /* Register write flag */
};
-struct cpu_cpuX_base {
- struct dentry *dentry; /* Register dentry */
- int init; /* Register index file */
-};
-
+/*
+ * Currently it looks similar to cpu_debug_base but once we add more files
+ * cpu_file_base will go in different direction
+ */
struct cpu_file_base {
char *name; /* Register file name */
unsigned flag; /* Register file flag */
+ unsigned write; /* Register write flag */
+};
+
+struct cpu_cpuX_base {
+ struct dentry *dentry; /* Register dentry */
+ int init; /* Register index file */
};
struct cpu_debug_range {
diff --git a/arch/x86/kernel/cpu/cpu_debug.c b/arch/x86/kernel/cpu/cpu_debug.c
index 9abbcbd..21c0cf8 100755
--- a/arch/x86/kernel/cpu/cpu_debug.c
+++ b/arch/x86/kernel/cpu/cpu_debug.c
@@ -11,6 +11,7 @@
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/kprobes.h>
+#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/percpu.h>
@@ -40,41 +41,41 @@ static DEFINE_MUTEX(cpu_debug_lock);
static struct dentry *cpu_debugfs_dir;
static struct cpu_debug_base cpu_base[] = {
- { "mc", CPU_MC }, /* Machine Check */
- { "monitor", CPU_MONITOR }, /* Monitor */
- { "time", CPU_TIME }, /* Time */
- { "pmc", CPU_PMC }, /* Performance Monitor */
- { "platform", CPU_PLATFORM }, /* Platform */
- { "apic", CPU_APIC }, /* APIC */
- { "poweron", CPU_POWERON }, /* Power-on */
- { "control", CPU_CONTROL }, /* Control */
- { "features", CPU_FEATURES }, /* Features control */
- { "lastbranch", CPU_LBRANCH }, /* Last Branch */
- { "bios", CPU_BIOS }, /* BIOS */
- { "freq", CPU_FREQ }, /* Frequency */
- { "mtrr", CPU_MTRR }, /* MTRR */
- { "perf", CPU_PERF }, /* Performance */
- { "cache", CPU_CACHE }, /* Cache */
- { "sysenter", CPU_SYSENTER }, /* Sysenter */
- { "therm", CPU_THERM }, /* Thermal */
- { "misc", CPU_MISC }, /* Miscellaneous */
- { "debug", CPU_DEBUG }, /* Debug */
- { "pat", CPU_PAT }, /* PAT */
- { "vmx", CPU_VMX }, /* VMX */
- { "call", CPU_CALL }, /* System Call */
- { "base", CPU_BASE }, /* BASE Address */
- { "smm", CPU_SMM }, /* System mgmt mode */
- { "svm", CPU_SVM }, /*Secure Virtial Machine*/
- { "osvm", CPU_OSVM }, /* OS-Visible Workaround*/
- { "tss", CPU_TSS }, /* Task Stack Segment */
- { "cr", CPU_CR }, /* Control Registers */
- { "dt", CPU_DT }, /* Descriptor Table */
- { "registers", CPU_REG_ALL }, /* Select all Registers */
+ { "mc", CPU_MC, 0 },
+ { "monitor", CPU_MONITOR, 0 },
+ { "time", CPU_TIME, 0 },
+ { "pmc", CPU_PMC, 1 },
+ { "platform", CPU_PLATFORM, 0 },
+ { "apic", CPU_APIC, 0 },
+ { "poweron", CPU_POWERON, 0 },
+ { "control", CPU_CONTROL, 0 },
+ { "features", CPU_FEATURES, 0 },
+ { "lastbranch", CPU_LBRANCH, 0 },
+ { "bios", CPU_BIOS, 0 },
+ { "freq", CPU_FREQ, 0 },
+ { "mtrr", CPU_MTRR, 0 },
+ { "perf", CPU_PERF, 0 },
+ { "cache", CPU_CACHE, 0 },
+ { "sysenter", CPU_SYSENTER, 0 },
+ { "therm", CPU_THERM, 0 },
+ { "misc", CPU_MISC, 0 },
+ { "debug", CPU_DEBUG, 0 },
+ { "pat", CPU_PAT, 0 },
+ { "vmx", CPU_VMX, 0 },
+ { "call", CPU_CALL, 0 },
+ { "base", CPU_BASE, 0 },
+ { "smm", CPU_SMM, 0 },
+ { "svm", CPU_SVM, 0 },
+ { "osvm", CPU_OSVM, 0 },
+ { "tss", CPU_TSS, 0 },
+ { "cr", CPU_CR, 0 },
+ { "dt", CPU_DT, 0 },
+ { "registers", CPU_REG_ALL, 0 },
};
static struct cpu_file_base cpu_file[] = {
- { "index", CPU_REG_ALL }, /* index */
- { "value", CPU_REG_ALL }, /* value */
+ { "index", CPU_REG_ALL, 0 },
+ { "value", CPU_REG_ALL, 1 },
};
/* Intel Registers Range */
@@ -608,9 +609,62 @@ static int cpu_seq_open(struct inode *inode, struct file *file)
return err;
}
+static int write_msr(struct cpu_private *priv, u64 val)
+{
+ u32 low, high;
+
+ high = (val >> 32) & 0xffffffff;
+ low = val & 0xffffffff;
+
+ if (!wrmsr_safe_on_cpu(priv->cpu, priv->reg, low, high))
+ return 0;
+
+ return -EPERM;
+}
+
+static int write_cpu_register(struct cpu_private *priv, const char *buf)
+{
+ int ret = -EPERM;
+ u64 val;
+
+ ret = strict_strtoull(buf, 0, &val);
+ if (ret < 0)
+ return ret;
+
+ /* Supporting only MSRs */
+ if (priv->type < CPU_TSS_BIT)
+ return write_msr(priv, val);
+
+ return ret;
+}
+
+static ssize_t cpu_write(struct file *file, const char __user *ubuf,
+ size_t count, loff_t *off)
+{
+ struct seq_file *seq = file->private_data;
+ struct cpu_private *priv = seq->private;
+ char buf[19];
+
+ if ((priv == NULL) || (count >= sizeof(buf)))
+ return -EINVAL;
+
+ if (copy_from_user(&buf, ubuf, count))
+ return -EFAULT;
+
+ buf[count] = 0;
+
+ if ((cpu_base[priv->type].write) && (cpu_file[priv->file].write))
+ if (!write_cpu_register(priv, buf))
+ return count;
+
+ return -EACCES;
+}
+
static const struct file_operations cpu_fops = {
+ .owner = THIS_MODULE,
.open = cpu_seq_open,
.read = seq_read,
+ .write = cpu_write,
.llseek = seq_lseek,
.release = seq_release,
};
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