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_amd.c b/arch/x86/kernel/microcode_amd.c
index 453b579..c8be20f 100644
--- a/arch/x86/kernel/microcode_amd.c
+++ b/arch/x86/kernel/microcode_amd.c
@@ -13,25 +13,13 @@
* Licensed under the terms of the GNU General Public
* License version 2. See file COPYING for details.
*/
-#include <linux/platform_device.h>
-#include <linux/capability.h>
-#include <linux/miscdevice.h>
#include <linux/firmware.h>
-#include <linux/spinlock.h>
-#include <linux/cpumask.h>
#include <linux/pci_ids.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/pci.h>
-#include <linux/fs.h>
-#include <linux/mm.h>
#include <asm/microcode.h>
#include <asm/processor.h>
@@ -79,9 +67,6 @@
#define UCODE_CONTAINER_SECTION_HDR 8
#define UCODE_CONTAINER_HEADER_SIZE 12
-/* serialize access to the physical write */
-static DEFINE_SPINLOCK(microcode_update_lock);
-
static struct equiv_cpu_entry *equiv_cpu_table;
static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
@@ -144,9 +129,8 @@
return 1;
}
-static void apply_microcode_amd(int cpu)
+static int apply_microcode_amd(int cpu)
{
- unsigned long flags;
u32 rev, dummy;
int cpu_num = raw_smp_processor_id();
struct ucode_cpu_info *uci = ucode_cpu_info + cpu_num;
@@ -156,25 +140,25 @@
BUG_ON(cpu_num != cpu);
if (mc_amd == NULL)
- return;
+ return 0;
- spin_lock_irqsave(µcode_update_lock, flags);
wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code);
/* get patch id after patching */
rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
- spin_unlock_irqrestore(µcode_update_lock, flags);
/* check current patch id and patch's id for match */
if (rev != mc_amd->hdr.patch_id) {
printk(KERN_ERR "microcode: CPU%d: update failed "
"(for patch_level=0x%x)\n", cpu, mc_amd->hdr.patch_id);
- return;
+ return -1;
}
printk(KERN_INFO "microcode: CPU%d: updated (new patch_level=0x%x)\n",
cpu, rev);
uci->cpu_sig.rev = rev;
+
+ return 0;
}
static int get_ucode_data(void *to, const u8 *from, size_t n)
@@ -263,7 +247,8 @@
}
}
-static int generic_load_microcode(int cpu, const u8 *data, size_t size)
+static enum ucode_state
+generic_load_microcode(int cpu, const u8 *data, size_t size)
{
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
const u8 *ucode_ptr = data;
@@ -272,12 +257,13 @@
int new_rev = uci->cpu_sig.rev;
unsigned int leftover;
unsigned long offset;
+ enum ucode_state state = UCODE_OK;
offset = install_equiv_cpu_table(ucode_ptr);
if (!offset) {
printk(KERN_ERR "microcode: failed to create "
"equivalent cpu table\n");
- return -EINVAL;
+ return UCODE_ERROR;
}
ucode_ptr += offset;
@@ -312,28 +298,27 @@
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);
- } else
+ } else {
vfree(new_mc);
- }
+ state = UCODE_ERROR;
+ }
+ } else
+ state = UCODE_NFOUND;
free_equiv_cpu_table();
- return (int)leftover;
+ return state;
}
-static int request_microcode_fw(int cpu, struct device *device)
+static enum ucode_state request_microcode_fw(int cpu, struct device *device)
{
const char *fw_name = "amd-ucode/microcode_amd.bin";
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());
-
- ret = request_firmware(&firmware, fw_name, device);
- if (ret) {
+ if (request_firmware(&firmware, fw_name, device)) {
printk(KERN_ERR "microcode: failed to load file %s\n", fw_name);
- return ret;
+ return UCODE_NFOUND;
}
ret = generic_load_microcode(cpu, firmware->data, firmware->size);
@@ -343,11 +328,12 @@
return ret;
}
-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)
{
printk(KERN_INFO "microcode: AMD microcode update via "
"/dev/cpu/microcode not supported\n");
- return -1;
+ return UCODE_ERROR;
}
static void microcode_fini_cpu_amd(int cpu)