diff options
Diffstat (limited to 'arch/x86/kernel/cpu/microcode/core.c')
| -rw-r--r-- | arch/x86/kernel/cpu/microcode/core.c | 75 |
1 files changed, 44 insertions, 31 deletions
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index b3658d11e7b6..b92e09a87c69 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -17,8 +17,8 @@ #define pr_fmt(fmt) "microcode: " fmt -#include <linux/platform_device.h> #include <linux/stop_machine.h> +#include <linux/device/faux.h> #include <linux/syscore_ops.h> #include <linux/miscdevice.h> #include <linux/capability.h> @@ -37,12 +37,13 @@ #include <asm/perf_event.h> #include <asm/processor.h> #include <asm/cmdline.h> +#include <asm/msr.h> #include <asm/setup.h> #include "internal.h" -static struct microcode_ops *microcode_ops; -bool dis_ucode_ldr = true; +static struct microcode_ops *microcode_ops; +static bool dis_ucode_ldr = false; bool force_minrev = IS_ENABLED(CONFIG_MICROCODE_LATE_FORCE_MINREV); module_param(force_minrev, bool, S_IRUSR | S_IWUSR); @@ -84,6 +85,9 @@ static bool amd_check_current_patch_level(void) u32 lvl, dummy, i; u32 *levels; + if (x86_cpuid_vendor() != X86_VENDOR_AMD) + return false; + native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy); levels = final_levels; @@ -95,27 +99,29 @@ static bool amd_check_current_patch_level(void) return false; } -static bool __init check_loader_disabled_bsp(void) +bool __init microcode_loader_disabled(void) { - static const char *__dis_opt_str = "dis_ucode_ldr"; - const char *cmdline = boot_command_line; - const char *option = __dis_opt_str; + if (dis_ucode_ldr) + return true; /* - * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not - * completely accurate as xen pv guests don't see that CPUID bit set but - * that's good enough as they don't land on the BSP path anyway. + * Disable when: + * + * 1) The CPU does not support CPUID. + * + * 2) Bit 31 in CPUID[1]:ECX is clear + * The bit is reserved for hypervisor use. This is still not + * completely accurate as XEN PV guests don't see that CPUID bit + * set, but that's good enough as they don't land on the BSP + * path anyway. + * + * 3) Certain AMD patch levels are not allowed to be + * overwritten. */ - if (native_cpuid_ecx(1) & BIT(31)) - return true; - - if (x86_cpuid_vendor() == X86_VENDOR_AMD) { - if (amd_check_current_patch_level()) - return true; - } - - if (cmdline_find_option_bool(cmdline, option) <= 0) - dis_ucode_ldr = false; + if (!cpuid_feature() || + native_cpuid_ecx(1) & BIT(31) || + amd_check_current_patch_level()) + dis_ucode_ldr = true; return dis_ucode_ldr; } @@ -125,7 +131,10 @@ void __init load_ucode_bsp(void) unsigned int cpuid_1_eax; bool intel = true; - if (!have_cpuid_p()) + if (cmdline_find_option_bool(boot_command_line, "dis_ucode_ldr") > 0) + dis_ucode_ldr = true; + + if (microcode_loader_disabled()) return; cpuid_1_eax = native_cpuid_eax(1); @@ -146,9 +155,6 @@ void __init load_ucode_bsp(void) return; } - if (check_loader_disabled_bsp()) - return; - if (intel) load_ucode_intel_bsp(&early_data); else @@ -159,6 +165,11 @@ void load_ucode_ap(void) { unsigned int cpuid_1_eax; + /* + * Can't use microcode_loader_disabled() here - .init section + * hell. It doesn't have to either - the BSP variant must've + * parsed cmdline already anyway. + */ if (dis_ucode_ldr) return; @@ -238,7 +249,7 @@ static void reload_early_microcode(unsigned int cpu) } /* fake device for request_firmware */ -static struct platform_device *microcode_pdev; +static struct faux_device *microcode_fdev; #ifdef CONFIG_MICROCODE_LATE_LOADING /* @@ -679,13 +690,15 @@ static int load_late_locked(void) if (!setup_cpus()) return -EBUSY; - switch (microcode_ops->request_microcode_fw(0, µcode_pdev->dev)) { + switch (microcode_ops->request_microcode_fw(0, µcode_fdev->dev)) { case UCODE_NEW: return load_late_stop_cpus(false); case UCODE_NEW_SAFE: return load_late_stop_cpus(true); case UCODE_NFOUND: return -ENOENT; + case UCODE_OK: + return 0; default: return -EBADFD; } @@ -810,7 +823,7 @@ static int __init microcode_init(void) struct cpuinfo_x86 *c = &boot_cpu_data; int error; - if (dis_ucode_ldr) + if (microcode_loader_disabled()) return -EINVAL; if (c->x86_vendor == X86_VENDOR_INTEL) @@ -828,9 +841,9 @@ static int __init microcode_init(void) if (early_data.new_rev) pr_info_once("Updated early from: 0x%08x\n", early_data.old_rev); - microcode_pdev = platform_device_register_simple("microcode", -1, NULL, 0); - if (IS_ERR(microcode_pdev)) - return PTR_ERR(microcode_pdev); + microcode_fdev = faux_device_create("microcode", NULL, NULL); + if (!microcode_fdev) + return -ENODEV; dev_root = bus_get_dev_root(&cpu_subsys); if (dev_root) { @@ -849,7 +862,7 @@ static int __init microcode_init(void) return 0; out_pdev: - platform_device_unregister(microcode_pdev); + faux_device_destroy(microcode_fdev); return error; } |