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>

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 55520ce..7fb1047 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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,