lkml.org 
[lkml]   [2022]   [Oct]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 13/13] x86/microcode/intel: Add ability to update microcode even if rev is unchanged
Date
This comes in handy for testing without the need for a new microcode file.
It introduces a new boot parameter ucode_load_same, or it can be switched
dynamically at run time via debugfs file
/sys/kernel/debug/microcode/load_same.

NOT_FOR_INCLUSION:
Leave it to the discretion of Boris if its suitable for inclusion. It will
at least serve to validate some parts of the series without the need for a
new microcode.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
---
arch/x86/include/asm/microcode.h | 2 ++
arch/x86/kernel/cpu/microcode/amd.c | 2 +-
arch/x86/kernel/cpu/microcode/core.c | 22 +++++++++++++++++-----
arch/x86/kernel/cpu/microcode/intel.c | 4 ++--
4 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 38b501d842de..4baca634c2f7 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -43,6 +43,8 @@ struct ucode_patch {
extern struct list_head microcode_cache;
extern int ucode_updating;

+extern bool ucode_load_same;
+
struct cpu_signature {
unsigned int sig;
unsigned int pf;
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index c18d3f01a452..124461e2d7a1 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -694,7 +694,7 @@ static enum ucode_state apply_microcode_amd(int cpu)
rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);

/* need to apply patch? */
- if (rev >= mc_amd->hdr.patch_id) {
+ if (rev >= mc_amd->hdr.patch_id && !ucode_load_same) {
ret = UCODE_OK;
goto out;
}
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index eb2caa74de01..632c7a1fcffb 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -23,6 +23,7 @@
#include <linux/miscdevice.h>
#include <linux/capability.h>
#include <linux/firmware.h>
+#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/mutex.h>
@@ -46,6 +47,7 @@

static struct microcode_ops *microcode_ops;
static bool dis_ucode_ldr = true;
+bool ucode_load_same;

bool initrd_gone;

@@ -542,11 +544,12 @@ static int __reload_late(void *info)
goto wait_for_siblings;
}

- if (err >= UCODE_NFOUND) {
- if (err == UCODE_ERROR)
+ if (ret || err >= UCODE_NFOUND) {
+ if (err == UCODE_ERROR ||
+ (err == UCODE_NFOUND && !ucode_load_same)) {
pr_warn("Error reloading microcode on CPU %d\n", cpu);
-
- ret = -1;
+ ret = -1;
+ }
}

wait_for_siblings:
@@ -636,9 +639,12 @@ static ssize_t reload_store(struct device *dev,
}

tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
- if (tmp_ret != UCODE_NEW)
+ if (tmp_ret != UCODE_NEW && !ucode_load_same)
goto put;

+ if (tmp_ret != UCODE_NEW)
+ pr_info("Force loading ucode\n");
+
mutex_lock(&microcode_mutex);
ret = microcode_reload_late();
mutex_unlock(&microcode_mutex);
@@ -841,6 +847,7 @@ static const struct attribute_group cpu_root_microcode_group = {
static int __init microcode_init(void)
{
struct cpuinfo_x86 *c = &boot_cpu_data;
+ static struct dentry *dentry_ucode;
int error;

if (dis_ucode_ldr)
@@ -884,7 +891,12 @@ static int __init microcode_init(void)
cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
mc_cpu_online, mc_cpu_down_prep);

+ dentry_ucode = debugfs_create_dir("microcode", NULL);
+ debugfs_create_bool("load_same", 0644, dentry_ucode, &ucode_load_same);
+
pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
+ pr_info("ucode_load_same is %s\n",
+ ucode_load_same ? "enabled" : "disabled");

return 0;

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index c61aa661ac2f..c9f1e6f5e53b 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -763,7 +763,7 @@ static enum ucode_state apply_microcode_intel(int cpu)
* already.
*/
rev = intel_get_microcode_revision();
- if (rev >= mc->hdr.rev) {
+ if (rev >= mc->hdr.rev && !ucode_load_same) {
ret = UCODE_OK;
goto out;
}
@@ -779,7 +779,7 @@ static enum ucode_state apply_microcode_intel(int cpu)
return UCODE_ERROR;
}

- if (bsp && rev != prev_rev) {
+ if (bsp && (rev != prev_rev || ucode_load_same)) {
pr_info("updated to revision 0x%x, date = %04x-%02x-%02x\n",
rev,
mc->hdr.date & 0xffff,
--
2.34.1
\
 
 \ /
  Last update: 2022-10-14 22:11    [W:0.225 / U:0.108 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site