x86: microcode: use smp_call_function_single instead of set_cpus_allowed, cleanup of synchronization logic
* Solve issues described in 6f66cbc63081fd70e3191b4dbb796746780e5ae1
in a way that doesn't resort to set_cpus_allowed();
* in fact, only collect_cpu_info and apply_microcode callbacks
must run on a target cpu, others will do just fine on any other.
smp_call_function_single() (as suggested by Ingo) is used to run
these callbacks on a target cpu.
* cleanup of synchronization logic of the 'microcode_core' part
The generic 'microcode_core' part guarantees that only a single cpu
(be it a full-fledged cpu, one of the cores or HT)
is being updated at any particular moment of time.
In general, there is no need for any additional sync. mechanism in
arch-specific parts (the patch removes existing spinlocks).
See also the "Synchronization" section in microcode_core.c.
* return -EINVAL instead of -1 (which is translated into -EPERM) in
microcode_write(), reload_cpu() and mc_sysdev_add(). Other suggestions
for an error code?
* use 'enum ucode_state' as return value of request_microcode_{fw, user}
to gain more flexibility by distinguishing between real error cases
and situations when an appropriate ucode was not found (which is not an
error per-se).
* some minor cleanups
Thanks a lot to Hugh Dickins for review/suggestions/testing!
Reference: http://marc.info/?l=linux-kernel&m=124025889012541&w=2
[ Impact: refactor and clean up microcode driver locking code ]
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Peter Oruba <peter.oruba@amd.com>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <1242078507.5560.9.camel@earth>
[ did some more cleanups ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/include/asm/microcode.h | 25 ++
arch/x86/kernel/microcode_amd.c | 58 ++----
arch/x86/kernel/microcode_core.c | 326 +++++++++++++++++++++-----------------
arch/x86/kernel/microcode_intel.c | 92 +++-------
4 files changed, 261 insertions(+), 240 deletions(-)
(~20 new comment lines)
diff --git a/arch/x86/kernel/microcode_intel.c b/arch/x86/kernel/microcode_intel.c
index 149b9ec..0d334dd 100644
--- a/arch/x86/kernel/microcode_intel.c
+++ b/arch/x86/kernel/microcode_intel.c
@@ -70,24 +70,11 @@
* Fix sigmatch() macro to handle old CPUs with pf == 0.
* Thanks to Stuart Swales for pointing out this bug.
*/
-#include <linux/platform_device.h>
-#include <linux/capability.h>
-#include <linux/miscdevice.h>
#include <linux/firmware.h>
-#include <linux/smp_lock.h>
-#include <linux/spinlock.h>
-#include <linux/cpumask.h>
#include <linux/uaccess.h>
-#include <linux/vmalloc.h>
#include <linux/kernel.h>
#include <linux/module.h>
-#include <linux/mutex.h>
-#include <linux/sched.h>
-#include <linux/init.h>
-#include <linux/slab.h>
-#include <linux/cpu.h>
-#include <linux/fs.h>
-#include <linux/mm.h>
+#include <linux/vmalloc.h>
#include <asm/microcode.h>
#include <asm/processor.h>
@@ -150,13 +137,9 @@
#define exttable_size(et) ((et)->count * EXT_SIGNATURE_SIZE + EXT_HEADER_SIZE)
-/* serialize access to the physical write to MSR 0x79 */
-static DEFINE_SPINLOCK(microcode_update_lock);
-
static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
{
struct cpuinfo_x86 *c = &cpu_data(cpu_num);
- unsigned long flags;
unsigned int val[2];
memset(csig, 0, sizeof(*csig));
@@ -176,18 +159,14 @@
csig->pf = 1 << ((val[1] >> 18) & 7);
}
- /* serialize access to the physical write to MSR 0x79 */
- spin_lock_irqsave(µcode_update_lock, flags);
-
wrmsr(MSR_IA32_UCODE_REV, 0, 0);
/* see notes above for revision 1.07. Apparent chip bug */
sync_core();
/* get the current revision from MSR 0x8B */
rdmsr(MSR_IA32_UCODE_REV, val[0], csig->rev);
- spin_unlock_irqrestore(µcode_update_lock, flags);
- pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n",
- csig->sig, csig->pf, csig->rev);
+ printk(KERN_INFO "microcode: CPU%d sig=0x%x, pf=0x%x, revision=0x%x\n",
+ cpu_num, csig->sig, csig->pf, csig->rev);
return 0;
}
@@ -318,11 +297,10 @@
return 0;
}
-static void apply_microcode(int cpu)
+static int apply_microcode(int cpu)
{
struct microcode_intel *mc_intel;
struct ucode_cpu_info *uci;
- unsigned long flags;
unsigned int val[2];
int cpu_num;
@@ -334,10 +312,7 @@
BUG_ON(cpu_num != cpu);
if (mc_intel == NULL)
- return;
-
- /* serialize access to the physical write to MSR 0x79 */
- spin_lock_irqsave(µcode_update_lock, flags);
+ return 0;
/* write microcode via MSR 0x79 */
wrmsr(MSR_IA32_UCODE_WRITE,
@@ -351,30 +326,32 @@
/* get the current revision from MSR 0x8B */
rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]);
- spin_unlock_irqrestore(µcode_update_lock, flags);
if (val[1] != mc_intel->hdr.rev) {
- printk(KERN_ERR "microcode: CPU%d update from revision "
- "0x%x to 0x%x failed\n",
- cpu_num, uci->cpu_sig.rev, val[1]);
- return;
+ printk(KERN_ERR "microcode: CPU%d update "
+ "to revision 0x%x failed\n",
+ cpu_num, mc_intel->hdr.rev);
+ return -1;
}
- printk(KERN_INFO "microcode: CPU%d updated from revision "
- "0x%x to 0x%x, date = %04x-%02x-%02x \n",
- cpu_num, uci->cpu_sig.rev, val[1],
+ printk(KERN_INFO "microcode: CPU%d updated to revision "
+ "0x%x, date = %04x-%02x-%02x \n",
+ cpu_num, val[1],
mc_intel->hdr.date & 0xffff,
mc_intel->hdr.date >> 24,
(mc_intel->hdr.date >> 16) & 0xff);
uci->cpu_sig.rev = val[1];
+
+ return 0;
}
-static int generic_load_microcode(int cpu, void *data, size_t size,
- int (*get_ucode_data)(void *, const void *, size_t))
+static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
+ int (*get_ucode_data)(void *, const void *, size_t))
{
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
u8 *ucode_ptr = data, *new_mc = NULL, *mc;
int new_rev = uci->cpu_sig.rev;
unsigned int leftover = size;
+ enum ucode_state state = UCODE_OK;
while (leftover) {
struct microcode_header_intel mc_header;
@@ -412,11 +389,15 @@
leftover -= mc_size;
}
- if (!new_mc)
- goto out;
-
if (leftover) {
- vfree(new_mc);
+ if (new_mc)
+ vfree(new_mc);
+ state = UCODE_ERROR;
+ goto out;
+ }
+
+ if (!new_mc) {
+ state = UCODE_NFOUND;
goto out;
}
@@ -427,9 +408,8 @@
pr_debug("microcode: CPU%d found a matching microcode update with"
" version 0x%x (current=0x%x)\n",
cpu, new_rev, uci->cpu_sig.rev);
-
- out:
- return (int)leftover;
+out:
+ return state;
}
static int get_ucode_fw(void *to, const void *from, size_t n)
@@ -438,21 +418,19 @@
return 0;
}
-static int request_microcode_fw(int cpu, struct device *device)
+static enum ucode_state request_microcode_fw(int cpu, struct device *device)
{
char name[30];
struct cpuinfo_x86 *c = &cpu_data(cpu);
const struct firmware *firmware;
- int ret;
+ enum ucode_state ret;
- /* We should bind the task to the CPU */
- BUG_ON(cpu != raw_smp_processor_id());
sprintf(name, "intel-ucode/%02x-%02x-%02x",
c->x86, c->x86_model, c->x86_mask);
- ret = request_firmware(&firmware, name, device);
- if (ret) {
+
+ if (request_firmware(&firmware, name, device)) {
pr_debug("microcode: data file %s load failed\n", name);
- return ret;
+ return UCODE_NFOUND;
}
ret = generic_load_microcode(cpu, (void *)firmware->data,
@@ -468,11 +446,9 @@
return copy_from_user(to, from, n);
}
-static int request_microcode_user(int cpu, const void __user *buf, size_t size)
+static enum ucode_state
+request_microcode_user(int cpu, const void __user *buf, size_t size)
{
- /* We should bind the task to the CPU */
- BUG_ON(cpu != raw_smp_processor_id());
-
return generic_load_microcode(cpu, (void *)buf, size, &get_ucode_user);
}
