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x86: microcode: use smp_call_function_single instead of set_cpus_allowed, cleanup of synchronization logic

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* Solve issues described in 6f66cbc630
  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)
This commit is contained in:
Dmitry Adamushko 2009-05-11 23:48:27 +02:00 • committed by Ingo Molnar
parent a4d7749be5
commit 871b72dd1e
4 changed files with 265 additions and 243 deletions
Download patch file Download diff file Expand all files Collapse all files

92
arch/x86/kernel/microcode_intel.c
View file

@ -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 @@ struct extended_sigtable {
#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 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
csig->pf = 1 << ((val[1] >> 18) & 7);
}
/* serialize access to the physical write to MSR 0x79 */
spin_lock_irqsave(&microcode_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(&microcode_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 @@ get_matching_microcode(struct cpu_signature *cpu_sig, void *mc, int rev)
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 @@ static void apply_microcode(int cpu)
BUG_ON(cpu_num != cpu);
if (mc_intel == NULL)
return;
/* serialize access to the physical write to MSR 0x79 */
spin_lock_irqsave(&microcode_update_lock, flags);
return 0;
/* write microcode via MSR 0x79 */
wrmsr(MSR_IA32_UCODE_WRITE,
@ -351,30 +326,32 @@ static void apply_microcode(int cpu)
/* get the current revision from MSR 0x8B */
rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]);
spin_unlock_irqrestore(&microcode_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 @@ static int generic_load_microcode(int cpu, void *data, size_t size,
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 @@ static int generic_load_microcode(int cpu, void *data, size_t size,
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 @@ static int get_ucode_fw(void *to, const void *from, size_t n)
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 @@ static int get_ucode_user(void *to, const void *from, size_t n)
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);
}