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Message-ID: <169815365668.3135.6098105876703309302.tip-bot2@tip-bot2>
Date: Tue, 24 Oct 2023 13:20:56 -0000
From: "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
"Borislav Petkov (AMD)" <bp@...en8.de>,
Nikolay Borisov <nik.borisov@...e.com>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [tip: x86/microcode] x86/microcode: Clarify the late load logic
The following commit has been merged into the x86/microcode branch of tip:
Commit-ID: 6f059e634dcd0d725854514c94c114bbdd83950d
Gitweb: https://git.kernel.org/tip/6f059e634dcd0d725854514c94c114bbdd83950d
Author: Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Mon, 02 Oct 2023 13:59:57 +02:00
Committer: Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Tue, 24 Oct 2023 15:05:54 +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@...utronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@...e.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 7af1b60..63c4e12 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -362,11 +362,11 @@ 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;
}
@@ -399,40 +399,37 @@ 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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