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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
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25
arch/x86/include/asm/microcode.h
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@ -9,20 +9,31 @@ struct cpu_signature {
struct device;
enum ucode_state { UCODE_ERROR, UCODE_OK, UCODE_NFOUND };
struct microcode_ops {
int (*request_microcode_user) (int cpu, const void __user *buf, size_t size);
int (*request_microcode_fw) (int cpu, struct device *device);
enum ucode_state (*request_microcode_user) (int cpu,
const void __user *buf, size_t size);
void (*apply_microcode) (int cpu);
enum ucode_state (*request_microcode_fw) (int cpu,
struct device *device);
int (*collect_cpu_info) (int cpu, struct cpu_signature *csig);
void (*microcode_fini_cpu) (int cpu);
/*
* The generic 'microcode_core' part guarantees that
* the callbacks below run on a target cpu when they
* are being called.
* See also the "Synchronization" section in microcode_core.c.
*/
int (*apply_microcode) (int cpu);
int (*collect_cpu_info) (int cpu, struct cpu_signature *csig);
};
struct ucode_cpu_info {
struct cpu_signature cpu_sig;
int valid;
void *mc;
struct cpu_signature cpu_sig;
int valid;
void *mc;
};
extern struct ucode_cpu_info ucode_cpu_info[];