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Subject[patch 54/55] [CPUFREQ] powernow-k8: Fix indexing issue
3.0-stable review patch.  If anyone has any objections, please let me know.

------------------
From: Andreas Herrmann <andreas.herrmann3@amd.com>

commit a8eb28480e9b637cc78b9aa5e08612ba97e1317a upstream.

The driver uses the pstate number from the status register as index in
its table of ACPI pstates (powernow_table). This is wrong as this is
not a 1-to-1 mapping.

For example we can have _PSS information to just utilize Pstate 0 and
Pstate 4, ie.

powernow-k8: Core Performance Boosting: on.
powernow-k8: 0 : pstate 0 (2200 MHz)
powernow-k8: 1 : pstate 4 (1400 MHz)

In this example the driver's powernow_table has just 2 entries. Using
the pstate number (4) as index into this table is just plain wrong.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/cpufreq/powernow-k8.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -54,6 +54,9 @@ static DEFINE_PER_CPU(struct powernow_k8

static int cpu_family = CPU_OPTERON;

+/* array to map SW pstate number to acpi state */
+static u32 ps_to_as[8];
+
/* core performance boost */
static bool cpb_capable, cpb_enabled;
static struct msr __percpu *msrs;
@@ -80,9 +83,9 @@ static u32 find_khz_freq_from_fid(u32 fi
}

static u32 find_khz_freq_from_pstate(struct cpufreq_frequency_table *data,
- u32 pstate)
+ u32 pstate)
{
- return data[pstate].frequency;
+ return data[ps_to_as[pstate]].frequency;
}

/* Return the vco fid for an input fid
@@ -926,6 +929,9 @@ static int fill_powernow_table_pstate(st
invalidate_entry(powernow_table, i);
continue;
}
+
+ ps_to_as[index] = i;
+
/* Frequency may be rounded for these */
if ((boot_cpu_data.x86 == 0x10 && boot_cpu_data.x86_model < 10)
|| boot_cpu_data.x86 == 0x11) {
@@ -1190,7 +1196,8 @@ static int powernowk8_target(struct cpuf
powernow_k8_acpi_pst_values(data, newstate);

if (cpu_family == CPU_HW_PSTATE)
- ret = transition_frequency_pstate(data, newstate);
+ ret = transition_frequency_pstate(data,
+ data->powernow_table[newstate].index);
else
ret = transition_frequency_fidvid(data, newstate);
if (ret) {
@@ -1203,7 +1210,7 @@ static int powernowk8_target(struct cpuf

if (cpu_family == CPU_HW_PSTATE)
pol->cur = find_khz_freq_from_pstate(data->powernow_table,
- newstate);
+ data->powernow_table[newstate].index);
else
pol->cur = find_khz_freq_from_fid(data->currfid);
ret = 0;



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