From 3f1f576a195aa266813cbd4ca70291deb61e0129 Mon Sep 17 00:00:00 2001

From: Borislav Petkov <bp@suse.de>

Date: Fri, 16 Feb 2018 12:26:38 +0100

Subject: x86/microcode: Propagate return value from updating functions

... so that callers can know when microcode was updated and act

accordingly.

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

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

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

Cc: Andy Lutomirski <luto@kernel.org>

Cc: Arjan van de Ven <arjan@linux.intel.com>

Cc: Borislav Petkov <bp@alien8.de>

Cc: Dan Williams <dan.j.williams@intel.com>

Cc: Dave Hansen <dave.hansen@linux.intel.com>

Cc: David Woodhouse <dwmw2@infradead.org>

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Cc: Josh Poimboeuf <jpoimboe@redhat.com>

Cc: Linus Torvalds <torvalds@linux-foundation.org>

Cc: Peter Zijlstra <peterz@infradead.org>

Cc: Thomas Gleixner <tglx@linutronix.de>

Link: http://lkml.kernel.org/r/20180216112640.11554-2-bp@alien8.de

Signed-off-by: Ingo Molnar <mingo@kernel.org>

---

 arch/x86/include/asm/microcode.h      |  9 +++++++--

 arch/x86/kernel/cpu/microcode/amd.c   | 10 +++++-----

 arch/x86/kernel/cpu/microcode/core.c  | 33 +++++++++++++++++----------------

 arch/x86/kernel/cpu/microcode/intel.c | 10 +++++-----

 4 files changed, 34 insertions(+), 28 deletions(-)

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h

index 55520cec..7fb1047 100644

--- a/arch/x86/include/asm/microcode.h

+++ b/arch/x86/include/asm/microcode.h

@@ -37,7 +37,12 @@ struct cpu_signature {

 struct device;

-enum ucode_state { UCODE_ERROR, UCODE_OK, UCODE_NFOUND };

+enum ucode_state {

+	UCODE_OK	= 0,

+	UCODE_UPDATED,

+	UCODE_NFOUND,

+	UCODE_ERROR,

+};

 struct microcode_ops {

 	enum ucode_state (*request_microcode_user) (int cpu,

@@ -54,7 +59,7 @@ struct microcode_ops {

 	 * are being called.

 	 * See also the "Synchronization" section in microcode_core.c.

 	 */

-	int (*apply_microcode) (int cpu);

+	enum ucode_state (*apply_microcode) (int cpu);

 	int (*collect_cpu_info) (int cpu, struct cpu_signature *csig);

 };

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c

index 330b846..a998e1a 100644

--- a/arch/x86/kernel/cpu/microcode/amd.c

+++ b/arch/x86/kernel/cpu/microcode/amd.c

@@ -498,7 +498,7 @@ static unsigned int verify_patch_size(u8 family, u32 patch_size,

 	return patch_size;

 }

-static int apply_microcode_amd(int cpu)

+static enum ucode_state apply_microcode_amd(int cpu)

 {

 	struct cpuinfo_x86 *c = &cpu_data(cpu);

 	struct microcode_amd *mc_amd;

@@ -512,7 +512,7 @@ static int apply_microcode_amd(int cpu)

 	p = find_patch(cpu);

 	if (!p)

-		return 0;

+		return UCODE_NFOUND;

 	mc_amd  = p->data;

 	uci->mc = p->data;

@@ -523,13 +523,13 @@ static int apply_microcode_amd(int cpu)

 	if (rev >= mc_amd->hdr.patch_id) {

 		c->microcode = rev;

 		uci->cpu_sig.rev = rev;

-		return 0;

+		return UCODE_OK;

 	}

 	if (__apply_microcode_amd(mc_amd)) {

 		pr_err("CPU%d: update failed for patch_level=0x%08x\n",

 			cpu, mc_amd->hdr.patch_id);

-		return -1;

+		return UCODE_ERROR;

 	}

 	pr_info("CPU%d: new patch_level=0x%08x\n", cpu,

 		mc_amd->hdr.patch_id);

@@ -537,7 +537,7 @@ static int apply_microcode_amd(int cpu)

 	uci->cpu_sig.rev = mc_amd->hdr.patch_id;

 	c->microcode = mc_amd->hdr.patch_id;

-	return 0;

+	return UCODE_UPDATED;

 }

 static int install_equiv_cpu_table(const u8 *buf)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c

index 319dd65..6fdaf7c 100644

--- a/arch/x86/kernel/cpu/microcode/core.c

+++ b/arch/x86/kernel/cpu/microcode/core.c

@@ -374,7 +374,7 @@ static int collect_cpu_info(int cpu)

 }

 struct apply_microcode_ctx {

-	int err;

+	enum ucode_state err;

 };

 static void apply_microcode_local(void *arg)

@@ -489,31 +489,29 @@ static void __exit microcode_dev_exit(void)

 /* fake device for request_firmware */

 static struct platform_device	*microcode_pdev;

-static int reload_for_cpu(int cpu)

+static enum ucode_state reload_for_cpu(int cpu)

 {

 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

 	enum ucode_state ustate;

-	int err = 0;

 	if (!uci->valid)

-		return err;

+		return UCODE_OK;

 	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, true);

-	if (ustate == UCODE_OK)

-		apply_microcode_on_target(cpu);

-	else

-		if (ustate == UCODE_ERROR)

-			err = -EINVAL;

-	return err;

+	if (ustate != UCODE_OK)

+		return ustate;

+

+	return apply_microcode_on_target(cpu);

 }

 static ssize_t reload_store(struct device *dev,

 			    struct device_attribute *attr,

 			    const char *buf, size_t size)

 {

+	enum ucode_state tmp_ret = UCODE_OK;

 	unsigned long val;

+	ssize_t ret = 0;

 	int cpu;

-	ssize_t ret = 0, tmp_ret;

 	ret = kstrtoul(buf, 0, &val;;

 	if (ret)

@@ -526,15 +524,18 @@ static ssize_t reload_store(struct device *dev,

 	mutex_lock(&microcode_mutex);

 	for_each_online_cpu(cpu) {

 		tmp_ret = reload_for_cpu(cpu);

-		if (tmp_ret != 0)

+		if (tmp_ret > UCODE_NFOUND) {

 			pr_warn("Error reloading microcode on CPU %d\n", cpu);

-		/* save retval of the first encountered reload error */

-		if (!ret)

-			ret = tmp_ret;

+			/* set retval for the first encountered reload error */

+			if (!ret)

+				ret = -EINVAL;

+		}

 	}

-	if (!ret)

+

+	if (!ret && tmp_ret == UCODE_UPDATED)

 		perf_check_microcode();

+

 	mutex_unlock(&microcode_mutex);

 	put_online_cpus();

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c

index a15db2b..923054a 100644

--- a/arch/x86/kernel/cpu/microcode/intel.c

+++ b/arch/x86/kernel/cpu/microcode/intel.c

@@ -772,7 +772,7 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)

 	return 0;

 }

-static int apply_microcode_intel(int cpu)

+static enum ucode_state apply_microcode_intel(int cpu)

 {

 	struct microcode_intel *mc;

 	struct ucode_cpu_info *uci;

@@ -782,7 +782,7 @@ static int apply_microcode_intel(int cpu)

 	/* We should bind the task to the CPU */

 	if (WARN_ON(raw_smp_processor_id() != cpu))

-		return -1;

+		return UCODE_ERROR;

 	uci = ucode_cpu_info + cpu;

 	mc = uci->mc;

@@ -790,7 +790,7 @@ static int apply_microcode_intel(int cpu)

 		/* Look for a newer patch in our cache: */

 		mc = find_patch(uci);

 		if (!mc)

-			return 0;

+			return UCODE_NFOUND;

 	}

 	/* write microcode via MSR 0x79 */

@@ -801,7 +801,7 @@ static int apply_microcode_intel(int cpu)

 	if (rev != mc->hdr.rev) {

 		pr_err("CPU%d update to revision 0x%x failed\n",

 		       cpu, mc->hdr.rev);

-		return -1;

+		return UCODE_ERROR;

 	}

 	if (rev != prev_rev) {

@@ -818,7 +818,7 @@ static int apply_microcode_intel(int cpu)

 	uci->cpu_sig.rev = rev;

 	c->microcode = rev;

-	return 0;

+	return UCODE_UPDATED;

 }

 static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,

-- 

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