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Commit 6f66cbc6 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
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x86 microcode: revert some work_on_cpu 



Revert part of af5c820a ("x86: cpumask:
use work_on_cpu in arch/x86/kernel/microcode_core.c")

That change is causing only one Intel CPU's microcode to be updated e.g.
microcode: CPU3 updated from revision 0x9 to 0x17, date = 2005-04-22
where before it announced that also for CPU0 and CPU1 and CPU2.

We cannot use work_on_cpu() in the CONFIG_MICROCODE_OLD_INTERFACE code,
because Intel's request_microcode_user() involves a copy_from_user() from
/sbin/microcode_ctl, which therefore needs to be on that CPU at the time.

Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 610f26e7

arch/x86/kernel/microcode_core.c

+11 −22
Original line number Diff line number Diff line
@@ -108,40 +108,29 @@ struct ucode_cpu_info ucode_cpu_info[NR_CPUS]; 
EXPORT_SYMBOL_GPL(ucode_cpu_info);



#ifdef CONFIG_MICROCODE_OLD_INTERFACE

struct update_for_cpu {

	const void __user	*buf;

	size_t			size;

};



static long update_for_cpu(void *_ufc)

{

	struct update_for_cpu *ufc = _ufc;

	int error;



	error = microcode_ops->request_microcode_user(smp_processor_id(),

						      ufc->buf, ufc->size);

	if (error < 0)

		return error;

	if (!error)

		microcode_ops->apply_microcode(smp_processor_id());

	return error;

}



static int do_microcode_update(const void __user *buf, size_t size)

{

	cpumask_t old;

	int error = 0;

	int cpu;

	struct update_for_cpu ufc = { .buf = buf, .size = size };



	old = current->cpus_allowed;



	for_each_online_cpu(cpu) {

		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;



		if (!uci->valid)

			continue;

		error = work_on_cpu(cpu, update_for_cpu, &ufc);



		set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));

		error = microcode_ops->request_microcode_user(cpu, buf, size);

		if (error < 0)

			break;

			goto out;

		if (!error)

			microcode_ops->apply_microcode(cpu);

	}

out:

	set_cpus_allowed_ptr(current, &old);

	return error;

}