From f19ca27f91db6320d02ba1cd28751a217616e282 Mon Sep 17 00:00:00 2001 From: Mihai Carabas Date: Tue, 21 Apr 2020 22:28:38 +0300 Subject: [PATCH 12/36] x86/microcode: Fix return value for microcode late loading The return value from stop_machine() might not be consistent. stop_machine_cpuslocked() returns: - zero if all functions have returned 0. - a non-zero value if at least one of the functions returned a non-zero value. There is no way to know if it is negative or positive. So make __reload_late() return 0 on success or negative otherwise. [ bp: Unify ret val check and touch up. ] Signed-off-by: Mihai Carabas Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/1587497318-4438-1-git-send-email-mihai.carabas@oracle.com (cherry picked from commit 9adbf3c609af92a57a73000a3cb8f4c2d307dfa3) Signed-off-by: Mridula Shastry Reviewed-by: Todd Vierling --- arch/x86/kernel/cpu/microcode/core.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 50321a43da01..36f78ceca5f2 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -400,8 +400,7 @@ static int __wait_for_cpus(atomic_t *t, long long timeout) /* * Returns: * < 0 - on error - * 0 - no update done - * 1 - microcode was updated + * 0 - success (no update done or microcode was updated) */ static int __reload_late(void *info) { @@ -428,11 +427,11 @@ static int __reload_late(void *info) else goto wait_for_siblings; - if (err > UCODE_NFOUND) { - pr_warn("Error reloading microcode on CPU %d\n", cpu); + if (err >= UCODE_NFOUND) { + if (err == UCODE_ERROR) + pr_warn("Error reloading microcode on CPU %d\n", cpu); + ret = -1; - } else if (err == UCODE_UPDATED || err == UCODE_OK) { - ret = 1; } wait_for_siblings: @@ -466,7 +465,7 @@ static int microcode_reload_late(void) atomic_set(&late_cpus_out, 0); ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask); - if (ret > 0) + if (ret == 0) microcode_check(); pr_info("Reload completed, microcode revision: 0x%x -> 0x%x\n", @@ -508,7 +507,7 @@ static ssize_t reload_store(struct device *dev, put: put_online_cpus(); - if (ret >= 0) + if (ret == 0) ret = size; add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); -- 2.39.3