[PATCH 0/5] x86/microcode: Clean up the init path

[PATCH 0/5] x86/microcode: Clean up the init path

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

The microcode loader init path had a lot of old and unnecessary gunk.
Rip it out.

No functional changes.

Borislav Petkov (5):
  x86/microcode: Rip out the subsys interface gunk
  x86/microcode: Simplify init path even more
  x86/microcode: Kill refresh_fw
  x86/microcode: Do some minor fixups
  x86/microcode: Drop struct ucode_cpu_info.valid

 arch/x86/include/asm/microcode.h      |   4 +-
 arch/x86/kernel/cpu/intel.c           |   1 -
 arch/x86/kernel/cpu/microcode/amd.c   |   5 +-
 arch/x86/kernel/cpu/microcode/core.c  | 205 +++++---------------------
 arch/x86/kernel/cpu/microcode/intel.c |   3 +-
 5 files changed, 43 insertions(+), 175 deletions(-)

-- 
2.35.1

[PATCH 1/5] x86/microcode: Rip out the subsys interface gunk

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

This is a left-over from the old days when CPU hotplug wasn't as robust
as it is now. Currently, microcode gets loaded early on the CPU init
path and there's no need to attempt to load it again, which that subsys
interface callback is doing.

The only other thing that the subsys interface init path was doing is
adding the

  /sys/devices/system/cpu/cpu*/microcode/

hierarchy.

So add a function which gets called on each CPU after all the necessary
driver setup has happened. Use schedule_on_each_cpu() which can block
because the sysfs creating code does kmem_cache_zalloc() which can block
too and the initial version of this where it did that setup in an IPI
handler of on_each_cpu() can cause a deadlock of the sort:

  lock(fs_reclaim);
  <Interrupt>
    lock(fs_reclaim);

as the IPI handler runs in IRQ context.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/kernel/cpu/microcode/core.c | 78 +++++++---------------------
 1 file changed, 20 insertions(+), 58 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 6a41cee242f6..4c222e667567 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -601,8 +601,8 @@ static enum ucode_state microcode_resume_cpu(int cpu)
 
 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
 {
-	enum ucode_state ustate;
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+	enum ucode_state ustate;
 
 	if (uci->valid)
 		return UCODE_OK;
@@ -636,44 +636,6 @@ static enum ucode_state microcode_update_cpu(int cpu)
 	return microcode_init_cpu(cpu, false);
 }
 
-static int mc_device_add(struct device *dev, struct subsys_interface *sif)
-{
-	int err, cpu = dev->id;
-
-	if (!cpu_online(cpu))
-		return 0;
-
-	pr_debug("CPU%d added\n", cpu);
-
-	err = sysfs_create_group(&dev->kobj, &mc_attr_group);
-	if (err)
-		return err;
-
-	if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
-		return -EINVAL;
-
-	return err;
-}
-
-static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
-{
-	int cpu = dev->id;
-
-	if (!cpu_online(cpu))
-		return;
-
-	pr_debug("CPU%d removed\n", cpu);
-	microcode_fini_cpu(cpu);
-	sysfs_remove_group(&dev->kobj, &mc_attr_group);
-}
-
-static struct subsys_interface mc_cpu_interface = {
-	.name			= "microcode",
-	.subsys			= &cpu_subsys,
-	.add_dev		= mc_device_add,
-	.remove_dev		= mc_device_remove,
-};
-
 /**
  * microcode_bsp_resume - Update boot CPU microcode during resume.
  */
@@ -713,6 +675,9 @@ static int mc_cpu_down_prep(unsigned int cpu)
 	struct device *dev;
 
 	dev = get_cpu_device(cpu);
+
+	microcode_fini_cpu(cpu);
+
 	/* Suspend is in progress, only remove the interface */
 	sysfs_remove_group(&dev->kobj, &mc_attr_group);
 	pr_debug("CPU%d removed\n", cpu);
@@ -720,6 +685,18 @@ static int mc_cpu_down_prep(unsigned int cpu)
 	return 0;
 }
 
+static void setup_online_cpu(struct work_struct *work)
+{
+	int cpu = smp_processor_id();
+	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+	memset(uci, 0, sizeof(*uci));
+
+	microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
+
+	mc_cpu_online(cpu);
+}
+
 static struct attribute *cpu_root_microcode_attrs[] = {
 #ifdef CONFIG_MICROCODE_LATE_LOADING
 	&dev_attr_reload.attr,
@@ -755,23 +732,17 @@ static int __init microcode_init(void)
 	if (IS_ERR(microcode_pdev))
 		return PTR_ERR(microcode_pdev);
 
-	cpus_read_lock();
-	mutex_lock(&microcode_mutex);
-	error = subsys_interface_register(&mc_cpu_interface);
-	mutex_unlock(&microcode_mutex);
-	cpus_read_unlock();
-
-	if (error)
-		goto out_pdev;
-
 	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
 				   &cpu_root_microcode_group);
 
 	if (error) {
 		pr_err("Error creating microcode group!\n");
-		goto out_driver;
+		goto out_pdev;
 	}
 
+	/* Do per-CPU setup */
+	schedule_on_each_cpu(setup_online_cpu);
+
 	register_syscore_ops(&mc_syscore_ops);
 	cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
 				  mc_cpu_starting, NULL);
@@ -782,15 +753,6 @@ static int __init microcode_init(void)
 
 	return 0;
 
- out_driver:
-	cpus_read_lock();
-	mutex_lock(&microcode_mutex);
-
-	subsys_interface_unregister(&mc_cpu_interface);
-
-	mutex_unlock(&microcode_mutex);
-	cpus_read_unlock();
-
  out_pdev:
 	platform_device_unregister(microcode_pdev);
 	return error;
-- 
2.35.1

[PATCH 2/5] x86/microcode: Simplify init path even more

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

Get rid of all the IPI-sending functions and their wrappers and use
those which are supposed to be called on each CPU.

Thus:

- microcode_init_cpu() gets called on each CPU on init, applying any new
  microcode that the driver might've found on the filesystem.

- mc_cpu_starting() simply tries to apply cached microcode as this is
  the cpuhp starting callback which gets called on CPU resume too.

Even if the driver init function is a late initcall, there is no
filesystem by then (not even a hdd driver has been loaded yet) so a new
firmware load attempt cannot simply be done.

It is pointless anyway - for that there's late loading if one really
needs it.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/kernel/cpu/microcode/core.c | 120 ++++-----------------------
 1 file changed, 16 insertions(+), 104 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 4c222e667567..63f7678743be 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -319,60 +319,6 @@ void reload_early_microcode(void)
 	}
 }
 
-static void collect_cpu_info_local(void *arg)
-{
-	struct cpu_info_ctx *ctx = arg;
-
-	ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
-						   ctx->cpu_sig);
-}
-
-static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
-{
-	struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
-	int ret;
-
-	ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
-	if (!ret)
-		ret = ctx.err;
-
-	return ret;
-}
-
-static int collect_cpu_info(int cpu)
-{
-	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-	int ret;
-
-	memset(uci, 0, sizeof(*uci));
-
-	ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
-	if (!ret)
-		uci->valid = 1;
-
-	return ret;
-}
-
-static void apply_microcode_local(void *arg)
-{
-	enum ucode_state *err = arg;
-
-	*err = microcode_ops->apply_microcode(smp_processor_id());
-}
-
-static int apply_microcode_on_target(int cpu)
-{
-	enum ucode_state err;
-	int ret;
-
-	ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
-	if (!ret) {
-		if (err == UCODE_ERROR)
-			ret = 1;
-	}
-	return ret;
-}
-
 /* fake device for request_firmware */
 static struct platform_device	*microcode_pdev;
 
@@ -458,7 +404,7 @@ static int __reload_late(void *info)
 	 * below.
 	 */
 	if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu)
-		apply_microcode_local(&err);
+		err = microcode_ops->apply_microcode(cpu);
 	else
 		goto wait_for_siblings;
 
@@ -480,7 +426,7 @@ static int __reload_late(void *info)
 	 * revision.
 	 */
 	if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu)
-		apply_microcode_local(&err);
+		err = microcode_ops->apply_microcode(cpu);
 
 	return ret;
 }
@@ -589,51 +535,15 @@ static void microcode_fini_cpu(int cpu)
 		microcode_ops->microcode_fini_cpu(cpu);
 }
 
-static enum ucode_state microcode_resume_cpu(int cpu)
-{
-	if (apply_microcode_on_target(cpu))
-		return UCODE_ERROR;
-
-	pr_debug("CPU%d updated upon resume\n", cpu);
-
-	return UCODE_OK;
-}
-
-static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
-{
-	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-	enum ucode_state ustate;
-
-	if (uci->valid)
-		return UCODE_OK;
-
-	if (collect_cpu_info(cpu))
-		return UCODE_ERROR;
-
-	/* --dimm. Trigger a delayed update? */
-	if (system_state != SYSTEM_RUNNING)
-		return UCODE_NFOUND;
-
-	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, refresh_fw);
-	if (ustate == UCODE_NEW) {
-		pr_debug("CPU%d updated upon init\n", cpu);
-		apply_microcode_on_target(cpu);
-	}
-
-	return ustate;
-}
-
-static enum ucode_state microcode_update_cpu(int cpu)
+static enum ucode_state microcode_init_cpu(int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 
-	/* Refresh CPU microcode revision after resume. */
-	collect_cpu_info(cpu);
+	memset(uci, 0, sizeof(*uci));
 
-	if (uci->valid)
-		return microcode_resume_cpu(cpu);
+	microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
 
-	return microcode_init_cpu(cpu, false);
+	return microcode_ops->apply_microcode(cpu);
 }
 
 /**
@@ -651,14 +561,14 @@ void microcode_bsp_resume(void)
 }
 
 static struct syscore_ops mc_syscore_ops = {
-	.resume			= microcode_bsp_resume,
+	.resume	= microcode_bsp_resume,
 };
 
 static int mc_cpu_starting(unsigned int cpu)
 {
-	microcode_update_cpu(cpu);
-	pr_debug("CPU%d added\n", cpu);
-	return 0;
+	enum ucode_state err = microcode_ops->apply_microcode(cpu);
+
+	return err == UCODE_ERROR;
 }
 
 static int mc_cpu_online(unsigned int cpu)
@@ -688,11 +598,13 @@ static int mc_cpu_down_prep(unsigned int cpu)
 static void setup_online_cpu(struct work_struct *work)
 {
 	int cpu = smp_processor_id();
-	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-
-	memset(uci, 0, sizeof(*uci));
+	enum ucode_state err;
 
-	microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
+	err = microcode_init_cpu(cpu);
+	if (err == UCODE_ERROR) {
+		pr_err("Error applying microcode on CPU%d\n", cpu);
+		return;
+	}
 
 	mc_cpu_online(cpu);
 }
-- 
2.35.1

[PATCH 3/5] x86/microcode: Kill refresh_fw

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

request_microcode_fw() can always request firmware now so drop this
superfluous argument.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/include/asm/microcode.h      | 3 +--
 arch/x86/kernel/cpu/microcode/amd.c   | 5 ++---
 arch/x86/kernel/cpu/microcode/core.c  | 2 +-
 arch/x86/kernel/cpu/microcode/intel.c | 3 +--
 4 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 74ecc2bd6cd0..d4c36fbd1d39 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -33,8 +33,7 @@ enum ucode_state {
 };
 
 struct microcode_ops {
-	enum ucode_state (*request_microcode_fw) (int cpu, struct device *,
-						  bool refresh_fw);
+	enum ucode_state (*request_microcode_fw) (int cpu, struct device *);
 
 	void (*microcode_fini_cpu) (int cpu);
 
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index e7410e98fc1f..b103d5e5f447 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -891,8 +891,7 @@ load_microcode_amd(bool save, u8 family, const u8 *data, size_t size)
  *
  * These might be larger than 2K.
  */
-static enum ucode_state request_microcode_amd(int cpu, struct device *device,
-					      bool refresh_fw)
+static enum ucode_state request_microcode_amd(int cpu, struct device *device)
 {
 	char fw_name[36] = "amd-ucode/microcode_amd.bin";
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
@@ -901,7 +900,7 @@ static enum ucode_state request_microcode_amd(int cpu, struct device *device,
 	const struct firmware *fw;
 
 	/* reload ucode container only on the boot cpu */
-	if (!refresh_fw || !bsp)
+	if (!bsp)
 		return UCODE_OK;
 
 	if (c->x86 >= 0x15)
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 63f7678743be..7c41e0132fa1 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -477,7 +477,7 @@ static ssize_t reload_store(struct device *dev,
 	if (ret)
 		goto put;
 
-	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
+	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev);
 	if (tmp_ret != UCODE_NEW)
 		goto put;
 
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 1fcbd671f1df..8c35c70029bf 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -885,8 +885,7 @@ static bool is_blacklisted(unsigned int cpu)
 	return false;
 }
 
-static enum ucode_state request_microcode_fw(int cpu, struct device *device,
-					     bool refresh_fw)
+static enum ucode_state request_microcode_fw(int cpu, struct device *device)
 {
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
 	const struct firmware *firmware;
-- 
2.35.1

[PATCH 4/5] x86/microcode: Do some minor fixups

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

Improve debugging printks and fixup formatting.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/kernel/cpu/microcode/core.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 7c41e0132fa1..ffb249c29f30 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -568,6 +568,8 @@ static int mc_cpu_starting(unsigned int cpu)
 {
 	enum ucode_state err = microcode_ops->apply_microcode(cpu);
 
+	pr_debug("%s: CPU%d, err: %d\n", __func__, cpu, err);
+
 	return err == UCODE_ERROR;
 }
 
@@ -590,7 +592,7 @@ static int mc_cpu_down_prep(unsigned int cpu)
 
 	/* Suspend is in progress, only remove the interface */
 	sysfs_remove_group(&dev->kobj, &mc_attr_group);
-	pr_debug("CPU%d removed\n", cpu);
+	pr_debug("%s: CPU%d\n", __func__, cpu);
 
 	return 0;
 }
@@ -639,14 +641,11 @@ static int __init microcode_init(void)
 	if (!microcode_ops)
 		return -ENODEV;
 
-	microcode_pdev = platform_device_register_simple("microcode", -1,
-							 NULL, 0);
+	microcode_pdev = platform_device_register_simple("microcode", -1, NULL, 0);
 	if (IS_ERR(microcode_pdev))
 		return PTR_ERR(microcode_pdev);
 
-	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
-				   &cpu_root_microcode_group);
-
+	error = sysfs_create_group(&cpu_subsys.dev_root->kobj, &cpu_root_microcode_group);
 	if (error) {
 		pr_err("Error creating microcode group!\n");
 		goto out_pdev;
-- 
2.35.1

[PATCH 5/5] x86/microcode: Drop struct ucode_cpu_info.valid

[Borislav Petkov]

From: Borislav Petkov <bp@suse.de>

It is not needed anymore.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/include/asm/microcode.h     | 1 -
 arch/x86/kernel/cpu/intel.c          | 1 -
 arch/x86/kernel/cpu/microcode/core.c | 4 ++--
 3 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index d4c36fbd1d39..d5a58bde091c 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -49,7 +49,6 @@ struct microcode_ops {
 
 struct ucode_cpu_info {
 	struct cpu_signature	cpu_sig;
-	int			valid;
 	void			*mc;
 };
 extern struct ucode_cpu_info ucode_cpu_info[];
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 2d7ea5480ec3..beb8ca596784 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -210,7 +210,6 @@ int intel_cpu_collect_info(struct ucode_cpu_info *uci)
 	csig.rev = intel_get_microcode_revision();
 
 	uci->cpu_sig = csig;
-	uci->valid = 1;
 
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index ffb249c29f30..712aafff96e0 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -554,9 +554,9 @@ void microcode_bsp_resume(void)
 	int cpu = smp_processor_id();
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 
-	if (uci->valid && uci->mc)
+	if (uci->mc)
 		microcode_ops->apply_microcode(cpu);
-	else if (!uci->mc)
+	else
 		reload_early_microcode();
 }
 
-- 
2.35.1

Re: [PATCH 5/5] x86/microcode: Drop struct ucode_cpu_info.valid

[Ashok Raj]

Hi Boris

On Fri, Oct 28, 2022 at 04:26:38PM +0200, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
> 
> It is not needed anymore.

Reviewed and Tested this series. Everything looks good.

> 
> Signed-off-by: Borislav Petkov <bp@suse.de>

Reviewed-by: Ashok Raj <ashok.raj@intel.com>

Re: [PATCH 5/5] x86/microcode: Drop struct ucode_cpu_info.valid

[Borislav Petkov]

On Fri, Oct 28, 2022 at 12:03:00PM -0700, Ashok Raj wrote:
> Reviewed and Tested this series. Everything looks good.

Thanks!

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

[tip: x86/microcode] x86/microcode: Drop struct ucode_cpu_info.valid

[tip-bot2 for Borislav Petkov]

The following commit has been merged into the x86/microcode branch of tip:

Commit-ID:     254ed7cf4dd79a18bbc496ab53f6c82d45431c78
Gitweb:        https://git.kernel.org/tip/254ed7cf4dd79a18bbc496ab53f6c82d45431c78
Author:        Borislav Petkov <bp@suse.de>
AuthorDate:    Wed, 19 Oct 2022 19:25:27 +02:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 02 Nov 2022 16:45:46 +01:00

x86/microcode: Drop struct ucode_cpu_info.valid

It is not needed anymore.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221028142638.28498-6-bp@alien8.de
---
 arch/x86/include/asm/microcode.h     | 1 -
 arch/x86/kernel/cpu/intel.c          | 1 -
 arch/x86/kernel/cpu/microcode/core.c | 4 ++--
 3 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index d4c36fb..d5a58bd 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -49,7 +49,6 @@ struct microcode_ops {
 
 struct ucode_cpu_info {
 	struct cpu_signature	cpu_sig;
-	int			valid;
 	void			*mc;
 };
 extern struct ucode_cpu_info ucode_cpu_info[];
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 2d7ea54..beb8ca5 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -210,7 +210,6 @@ int intel_cpu_collect_info(struct ucode_cpu_info *uci)
 	csig.rev = intel_get_microcode_revision();
 
 	uci->cpu_sig = csig;
-	uci->valid = 1;
 
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index ffb249c..712aaff 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -554,9 +554,9 @@ void microcode_bsp_resume(void)
 	int cpu = smp_processor_id();
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 
-	if (uci->valid && uci->mc)
+	if (uci->mc)
 		microcode_ops->apply_microcode(cpu);
-	else if (!uci->mc)
+	else
 		reload_early_microcode();
 }
 

[tip: x86/microcode] x86/microcode: Do some minor fixups

[tip-bot2 for Borislav Petkov]

The following commit has been merged into the x86/microcode branch of tip:

Commit-ID:     2e6ff4052d89ff9eeaddece14ba88c40bf8b2721
Gitweb:        https://git.kernel.org/tip/2e6ff4052d89ff9eeaddece14ba88c40bf8b2721
Author:        Borislav Petkov <bp@suse.de>
AuthorDate:    Wed, 19 Oct 2022 19:20:47 +02:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 02 Nov 2022 16:45:46 +01:00

x86/microcode: Do some minor fixups

Improve debugging printks and fixup formatting.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221028142638.28498-5-bp@alien8.de
---
 arch/x86/kernel/cpu/microcode/core.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 7c41e01..ffb249c 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -568,6 +568,8 @@ static int mc_cpu_starting(unsigned int cpu)
 {
 	enum ucode_state err = microcode_ops->apply_microcode(cpu);
 
+	pr_debug("%s: CPU%d, err: %d\n", __func__, cpu, err);
+
 	return err == UCODE_ERROR;
 }
 
@@ -590,7 +592,7 @@ static int mc_cpu_down_prep(unsigned int cpu)
 
 	/* Suspend is in progress, only remove the interface */
 	sysfs_remove_group(&dev->kobj, &mc_attr_group);
-	pr_debug("CPU%d removed\n", cpu);
+	pr_debug("%s: CPU%d\n", __func__, cpu);
 
 	return 0;
 }
@@ -639,14 +641,11 @@ static int __init microcode_init(void)
 	if (!microcode_ops)
 		return -ENODEV;
 
-	microcode_pdev = platform_device_register_simple("microcode", -1,
-							 NULL, 0);
+	microcode_pdev = platform_device_register_simple("microcode", -1, NULL, 0);
 	if (IS_ERR(microcode_pdev))
 		return PTR_ERR(microcode_pdev);
 
-	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
-				   &cpu_root_microcode_group);
-
+	error = sysfs_create_group(&cpu_subsys.dev_root->kobj, &cpu_root_microcode_group);
 	if (error) {
 		pr_err("Error creating microcode group!\n");
 		goto out_pdev;

[tip: x86/microcode] x86/microcode: Kill refresh_fw

[tip-bot2 for Borislav Petkov]

The following commit has been merged into the x86/microcode branch of tip:

Commit-ID:     a61ac80ae52ea349416472cd52005f9988537208
Gitweb:        https://git.kernel.org/tip/a61ac80ae52ea349416472cd52005f9988537208
Author:        Borislav Petkov <bp@suse.de>
AuthorDate:    Wed, 19 Oct 2022 19:16:20 +02:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 02 Nov 2022 16:45:46 +01:00

x86/microcode: Kill refresh_fw

request_microcode_fw() can always request firmware now so drop this
superfluous argument.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221028142638.28498-4-bp@alien8.de
---
 arch/x86/include/asm/microcode.h      | 3 +--
 arch/x86/kernel/cpu/microcode/amd.c   | 5 ++---
 arch/x86/kernel/cpu/microcode/core.c  | 2 +-
 arch/x86/kernel/cpu/microcode/intel.c | 3 +--
 4 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 74ecc2b..d4c36fb 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -33,8 +33,7 @@ enum ucode_state {
 };
 
 struct microcode_ops {
-	enum ucode_state (*request_microcode_fw) (int cpu, struct device *,
-						  bool refresh_fw);
+	enum ucode_state (*request_microcode_fw) (int cpu, struct device *);
 
 	void (*microcode_fini_cpu) (int cpu);
 
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index e7410e9..b103d5e 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -891,8 +891,7 @@ load_microcode_amd(bool save, u8 family, const u8 *data, size_t size)
  *
  * These might be larger than 2K.
  */
-static enum ucode_state request_microcode_amd(int cpu, struct device *device,
-					      bool refresh_fw)
+static enum ucode_state request_microcode_amd(int cpu, struct device *device)
 {
 	char fw_name[36] = "amd-ucode/microcode_amd.bin";
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
@@ -901,7 +900,7 @@ static enum ucode_state request_microcode_amd(int cpu, struct device *device,
 	const struct firmware *fw;
 
 	/* reload ucode container only on the boot cpu */
-	if (!refresh_fw || !bsp)
+	if (!bsp)
 		return UCODE_OK;
 
 	if (c->x86 >= 0x15)
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 63f7678..7c41e01 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -477,7 +477,7 @@ static ssize_t reload_store(struct device *dev,
 	if (ret)
 		goto put;
 
-	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
+	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev);
 	if (tmp_ret != UCODE_NEW)
 		goto put;
 
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 1fcbd67..8c35c70 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -885,8 +885,7 @@ static bool is_blacklisted(unsigned int cpu)
 	return false;
 }
 
-static enum ucode_state request_microcode_fw(int cpu, struct device *device,
-					     bool refresh_fw)
+static enum ucode_state request_microcode_fw(int cpu, struct device *device)
 {
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
 	const struct firmware *firmware;

[tip: x86/microcode] x86/microcode: Simplify init path even more

[tip-bot2 for Borislav Petkov]

The following commit has been merged into the x86/microcode branch of tip:

Commit-ID:     2071c0aeda228107bf1b9e870b6187c90fbeef1d
Gitweb:        https://git.kernel.org/tip/2071c0aeda228107bf1b9e870b6187c90fbeef1d
Author:        Borislav Petkov <bp@suse.de>
AuthorDate:    Wed, 19 Oct 2022 19:07:30 +02:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 02 Nov 2022 16:45:46 +01:00

x86/microcode: Simplify init path even more

Get rid of all the IPI-sending functions and their wrappers and use
those which are supposed to be called on each CPU.

Thus:

- microcode_init_cpu() gets called on each CPU on init, applying any new
  microcode that the driver might've found on the filesystem.

- mc_cpu_starting() simply tries to apply cached microcode as this is
  the cpuhp starting callback which gets called on CPU resume too.

Even if the driver init function is a late initcall, there is no
filesystem by then (not even a hdd driver has been loaded yet) so a new
firmware load attempt cannot simply be done.

It is pointless anyway - for that there's late loading if one really
needs it.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221028142638.28498-3-bp@alien8.de
---
 arch/x86/kernel/cpu/microcode/core.c | 120 +++-----------------------
 1 file changed, 16 insertions(+), 104 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 4c222e6..63f7678 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -319,60 +319,6 @@ void reload_early_microcode(void)
 	}
 }
 
-static void collect_cpu_info_local(void *arg)
-{
-	struct cpu_info_ctx *ctx = arg;
-
-	ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
-						   ctx->cpu_sig);
-}
-
-static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
-{
-	struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
-	int ret;
-
-	ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
-	if (!ret)
-		ret = ctx.err;
-
-	return ret;
-}
-
-static int collect_cpu_info(int cpu)
-{
-	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-	int ret;
-
-	memset(uci, 0, sizeof(*uci));
-
-	ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
-	if (!ret)
-		uci->valid = 1;
-
-	return ret;
-}
-
-static void apply_microcode_local(void *arg)
-{
-	enum ucode_state *err = arg;
-
-	*err = microcode_ops->apply_microcode(smp_processor_id());
-}
-
-static int apply_microcode_on_target(int cpu)
-{
-	enum ucode_state err;
-	int ret;
-
-	ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
-	if (!ret) {
-		if (err == UCODE_ERROR)
-			ret = 1;
-	}
-	return ret;
-}
-
 /* fake device for request_firmware */
 static struct platform_device	*microcode_pdev;
 
@@ -458,7 +404,7 @@ static int __reload_late(void *info)
 	 * below.
 	 */
 	if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu)
-		apply_microcode_local(&err);
+		err = microcode_ops->apply_microcode(cpu);
 	else
 		goto wait_for_siblings;
 
@@ -480,7 +426,7 @@ wait_for_siblings:
 	 * revision.
 	 */
 	if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu)
-		apply_microcode_local(&err);
+		err = microcode_ops->apply_microcode(cpu);
 
 	return ret;
 }
@@ -589,51 +535,15 @@ static void microcode_fini_cpu(int cpu)
 		microcode_ops->microcode_fini_cpu(cpu);
 }
 
-static enum ucode_state microcode_resume_cpu(int cpu)
-{
-	if (apply_microcode_on_target(cpu))
-		return UCODE_ERROR;
-
-	pr_debug("CPU%d updated upon resume\n", cpu);
-
-	return UCODE_OK;
-}
-
-static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
-{
-	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-	enum ucode_state ustate;
-
-	if (uci->valid)
-		return UCODE_OK;
-
-	if (collect_cpu_info(cpu))
-		return UCODE_ERROR;
-
-	/* --dimm. Trigger a delayed update? */
-	if (system_state != SYSTEM_RUNNING)
-		return UCODE_NFOUND;
-
-	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, refresh_fw);
-	if (ustate == UCODE_NEW) {
-		pr_debug("CPU%d updated upon init\n", cpu);
-		apply_microcode_on_target(cpu);
-	}
-
-	return ustate;
-}
-
-static enum ucode_state microcode_update_cpu(int cpu)
+static enum ucode_state microcode_init_cpu(int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 
-	/* Refresh CPU microcode revision after resume. */
-	collect_cpu_info(cpu);
+	memset(uci, 0, sizeof(*uci));
 
-	if (uci->valid)
-		return microcode_resume_cpu(cpu);
+	microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
 
-	return microcode_init_cpu(cpu, false);
+	return microcode_ops->apply_microcode(cpu);
 }
 
 /**
@@ -651,14 +561,14 @@ void microcode_bsp_resume(void)
 }
 
 static struct syscore_ops mc_syscore_ops = {
-	.resume			= microcode_bsp_resume,
+	.resume	= microcode_bsp_resume,
 };
 
 static int mc_cpu_starting(unsigned int cpu)
 {
-	microcode_update_cpu(cpu);
-	pr_debug("CPU%d added\n", cpu);
-	return 0;
+	enum ucode_state err = microcode_ops->apply_microcode(cpu);
+
+	return err == UCODE_ERROR;
 }
 
 static int mc_cpu_online(unsigned int cpu)
@@ -688,11 +598,13 @@ static int mc_cpu_down_prep(unsigned int cpu)
 static void setup_online_cpu(struct work_struct *work)
 {
 	int cpu = smp_processor_id();
-	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-
-	memset(uci, 0, sizeof(*uci));
+	enum ucode_state err;
 
-	microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
+	err = microcode_init_cpu(cpu);
+	if (err == UCODE_ERROR) {
+		pr_err("Error applying microcode on CPU%d\n", cpu);
+		return;
+	}
 
 	mc_cpu_online(cpu);
 }

[tip: x86/microcode] x86/microcode: Rip out the subsys interface gunk

[tip-bot2 for Borislav Petkov]

The following commit has been merged into the x86/microcode branch of tip:

Commit-ID:     b6f86689d5b740f2cc3ac3a1032c7374b24381cc
Gitweb:        https://git.kernel.org/tip/b6f86689d5b740f2cc3ac3a1032c7374b24381cc
Author:        Borislav Petkov <bp@suse.de>
AuthorDate:    Wed, 19 Oct 2022 18:13:06 +02:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 02 Nov 2022 16:45:46 +01:00

x86/microcode: Rip out the subsys interface gunk

This is a left-over from the old days when CPU hotplug wasn't as robust
as it is now. Currently, microcode gets loaded early on the CPU init
path and there's no need to attempt to load it again, which that subsys
interface callback is doing.

The only other thing that the subsys interface init path was doing is
adding the

  /sys/devices/system/cpu/cpu*/microcode/

hierarchy.

So add a function which gets called on each CPU after all the necessary
driver setup has happened. Use schedule_on_each_cpu() which can block
because the sysfs creating code does kmem_cache_zalloc() which can block
too and the initial version of this where it did that setup in an IPI
handler of on_each_cpu() can cause a deadlock of the sort:

  lock(fs_reclaim);
  <Interrupt>
    lock(fs_reclaim);

as the IPI handler runs in IRQ context.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221028142638.28498-2-bp@alien8.de
---
 arch/x86/kernel/cpu/microcode/core.c | 78 ++++++---------------------
 1 file changed, 20 insertions(+), 58 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 6a41cee..4c222e6 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -601,8 +601,8 @@ static enum ucode_state microcode_resume_cpu(int cpu)
 
 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
 {
-	enum ucode_state ustate;
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+	enum ucode_state ustate;
 
 	if (uci->valid)
 		return UCODE_OK;
@@ -636,44 +636,6 @@ static enum ucode_state microcode_update_cpu(int cpu)
 	return microcode_init_cpu(cpu, false);
 }
 
-static int mc_device_add(struct device *dev, struct subsys_interface *sif)
-{
-	int err, cpu = dev->id;
-
-	if (!cpu_online(cpu))
-		return 0;
-
-	pr_debug("CPU%d added\n", cpu);
-
-	err = sysfs_create_group(&dev->kobj, &mc_attr_group);
-	if (err)
-		return err;
-
-	if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
-		return -EINVAL;
-
-	return err;
-}
-
-static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
-{
-	int cpu = dev->id;
-
-	if (!cpu_online(cpu))
-		return;
-
-	pr_debug("CPU%d removed\n", cpu);
-	microcode_fini_cpu(cpu);
-	sysfs_remove_group(&dev->kobj, &mc_attr_group);
-}
-
-static struct subsys_interface mc_cpu_interface = {
-	.name			= "microcode",
-	.subsys			= &cpu_subsys,
-	.add_dev		= mc_device_add,
-	.remove_dev		= mc_device_remove,
-};
-
 /**
  * microcode_bsp_resume - Update boot CPU microcode during resume.
  */
@@ -713,6 +675,9 @@ static int mc_cpu_down_prep(unsigned int cpu)
 	struct device *dev;
 
 	dev = get_cpu_device(cpu);
+
+	microcode_fini_cpu(cpu);
+
 	/* Suspend is in progress, only remove the interface */
 	sysfs_remove_group(&dev->kobj, &mc_attr_group);
 	pr_debug("CPU%d removed\n", cpu);
@@ -720,6 +685,18 @@ static int mc_cpu_down_prep(unsigned int cpu)
 	return 0;
 }
 
+static void setup_online_cpu(struct work_struct *work)
+{
+	int cpu = smp_processor_id();
+	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+	memset(uci, 0, sizeof(*uci));
+
+	microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
+
+	mc_cpu_online(cpu);
+}
+
 static struct attribute *cpu_root_microcode_attrs[] = {
 #ifdef CONFIG_MICROCODE_LATE_LOADING
 	&dev_attr_reload.attr,
@@ -755,23 +732,17 @@ static int __init microcode_init(void)
 	if (IS_ERR(microcode_pdev))
 		return PTR_ERR(microcode_pdev);
 
-	cpus_read_lock();
-	mutex_lock(&microcode_mutex);
-	error = subsys_interface_register(&mc_cpu_interface);
-	mutex_unlock(&microcode_mutex);
-	cpus_read_unlock();
-
-	if (error)
-		goto out_pdev;
-
 	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
 				   &cpu_root_microcode_group);
 
 	if (error) {
 		pr_err("Error creating microcode group!\n");
-		goto out_driver;
+		goto out_pdev;
 	}
 
+	/* Do per-CPU setup */
+	schedule_on_each_cpu(setup_online_cpu);
+
 	register_syscore_ops(&mc_syscore_ops);
 	cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
 				  mc_cpu_starting, NULL);
@@ -782,15 +753,6 @@ static int __init microcode_init(void)
 
 	return 0;
 
- out_driver:
-	cpus_read_lock();
-	mutex_lock(&microcode_mutex);
-
-	subsys_interface_unregister(&mc_cpu_interface);
-
-	mutex_unlock(&microcode_mutex);
-	cpus_read_unlock();
-
  out_pdev:
 	platform_device_unregister(microcode_pdev);
 	return error;