| Date | Mon, 09 Oct 2023 12:29:48 -0000 | From | "tip-bot2 for Thomas Gleixner" <> | Subject | [tip: x86/microcode] x86/microcode: Clarify the late load logic |
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The following commit has been merged into the x86/microcode branch of tip:
Commit-ID: f696f2fbae3dd52a4e79f0a02b8cb31fe0dc69ce Gitweb: https://git.kernel.org/tip/f696f2fbae3dd52a4e79f0a02b8cb31fe0dc69ce Author: Thomas Gleixner <tglx@linutronix.de> AuthorDate: Mon, 02 Oct 2023 13:59:57 +02:00 Committer: Borislav Petkov (AMD) <bp@alien8.de> CommitterDate: Fri, 06 Oct 2023 15:12:23 +02:00
x86/microcode: Clarify the late load logic
reload_store() is way too complicated. Split the inner workings out and make the following enhancements:
- Taint the kernel only when the microcode was actually updated. If. e.g. the rendezvous fails, then nothing happened and there is no reason for tainting.
- Return useful error codes
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Nikolay Borisov <nik.borisov@suse.com> Link: https://lore.kernel.org/r/20231002115903.145048840@linutronix.de --- arch/x86/kernel/cpu/microcode/core.c | 41 ++++++++++++--------------- 1 file changed, 19 insertions(+), 22 deletions(-)
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 02e9e5d..d82d763 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -391,11 +391,11 @@ static int microcode_reload_late(void) pr_info("Reload succeeded, microcode revision: 0x%x -> 0x%x\n", old, boot_cpu_data.microcode); microcode_check(&prev_info); + add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); } else { pr_info("Reload failed, current microcode revision: 0x%x\n", boot_cpu_data.microcode); } - return ret; } @@ -428,40 +428,37 @@ static bool ensure_cpus_are_online(void) return true; } +static int ucode_load_late_locked(void) +{ + if (!ensure_cpus_are_online()) + return -EBUSY; + + switch (microcode_ops->request_microcode_fw(0, µcode_pdev->dev)) { + case UCODE_NEW: + return microcode_reload_late(); + case UCODE_NFOUND: + return -ENOENT; + default: + return -EBADFD; + } +} + 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; - int bsp = boot_cpu_data.cpu_index; unsigned long val; - ssize_t ret = 0; + ssize_t ret; ret = kstrtoul(buf, 0, &val); if (ret || val != 1) return -EINVAL; cpus_read_lock(); - - if (!ensure_cpus_are_online()) { - ret = -EBUSY; - goto put; - } - - tmp_ret = microcode_ops->request_microcode_fw(bsp, µcode_pdev->dev); - if (tmp_ret != UCODE_NEW) - goto put; - - ret = microcode_reload_late(); -put: + ret = ucode_load_late_locked(); cpus_read_unlock(); - if (ret == 0) - ret = size; - - add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); - - return ret; + return ret ? : size; } static DEVICE_ATTR_WO(reload);
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