check_bugs() is a dump ground for finalizing the CPU bringup. Only parts of
it has to do with actual CPU bugs.
Split it apart into arch_cpu_finalize_init() and cpu_select_mitigations().
Fixup the bogus 32bit comments while at it.
No functional change.
Signed-off-by: Thomas Gleixner <[email protected]>
---
arch/x86/Kconfig | 1
arch/x86/include/asm/bugs.h | 2 -
arch/x86/kernel/cpu/bugs.c | 51 -----------------------------------------
arch/x86/kernel/cpu/common.c | 53 +++++++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/cpu.h | 1
5 files changed, 56 insertions(+), 52 deletions(-)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -71,6 +71,7 @@ config X86
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
select ARCH_HAS_CACHE_LINE_SIZE
select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
+ select ARCH_HAS_CPU_FINALIZE_INIT
select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
--- a/arch/x86/include/asm/bugs.h
+++ b/arch/x86/include/asm/bugs.h
@@ -4,8 +4,6 @@
#include <asm/processor.h>
-extern void check_bugs(void);
-
#if defined(CONFIG_CPU_SUP_INTEL) && defined(CONFIG_X86_32)
int ppro_with_ram_bug(void);
#else
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -9,7 +9,6 @@
* - Andrew D. Balsa (code cleanup).
*/
#include <linux/init.h>
-#include <linux/utsname.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/nospec.h>
@@ -27,8 +26,6 @@
#include <asm/msr.h>
#include <asm/vmx.h>
#include <asm/paravirt.h>
-#include <asm/alternative.h>
-#include <asm/set_memory.h>
#include <asm/intel-family.h>
#include <asm/e820/api.h>
#include <asm/hypervisor.h>
@@ -125,21 +122,8 @@ DEFINE_STATIC_KEY_FALSE(switch_mm_cond_l
DEFINE_STATIC_KEY_FALSE(mmio_stale_data_clear);
EXPORT_SYMBOL_GPL(mmio_stale_data_clear);
-void __init check_bugs(void)
+void __init cpu_select_mitigations(void)
{
- identify_boot_cpu();
-
- /*
- * identify_boot_cpu() initialized SMT support information, let the
- * core code know.
- */
- cpu_smt_check_topology();
-
- if (!IS_ENABLED(CONFIG_SMP)) {
- pr_info("CPU: ");
- print_cpu_info(&boot_cpu_data);
- }
-
/*
* Read the SPEC_CTRL MSR to account for reserved bits which may
* have unknown values. AMD64_LS_CFG MSR is cached in the early AMD
@@ -176,39 +160,6 @@ void __init check_bugs(void)
md_clear_select_mitigation();
srbds_select_mitigation();
l1d_flush_select_mitigation();
-
- arch_smt_update();
-
-#ifdef CONFIG_X86_32
- /*
- * Check whether we are able to run this kernel safely on SMP.
- *
- * - i386 is no longer supported.
- * - In order to run on anything without a TSC, we need to be
- * compiled for a i486.
- */
- if (boot_cpu_data.x86 < 4)
- panic("Kernel requires i486+ for 'invlpg' and other features");
-
- init_utsname()->machine[1] =
- '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
- alternative_instructions();
-
- fpu__init_check_bugs();
-#else /* CONFIG_X86_64 */
- alternative_instructions();
-
- /*
- * Make sure the first 2MB area is not mapped by huge pages
- * There are typically fixed size MTRRs in there and overlapping
- * MTRRs into large pages causes slow downs.
- *
- * Right now we don't do that with gbpages because there seems
- * very little benefit for that case.
- */
- if (!direct_gbpages)
- set_memory_4k((unsigned long)__va(0), 1);
-#endif
}
/*
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -19,11 +19,14 @@
#include <linux/kprobes.h>
#include <linux/kgdb.h>
#include <linux/smp.h>
+#include <linux/cpu.h>
#include <linux/io.h>
#include <linux/syscore_ops.h>
#include <linux/pgtable.h>
#include <linux/stackprotector.h>
+#include <linux/utsname.h>
+#include <asm/alternative.h>
#include <asm/cmdline.h>
#include <asm/perf_event.h>
#include <asm/mmu_context.h>
@@ -59,6 +62,7 @@
#include <asm/intel-family.h>
#include <asm/cpu_device_id.h>
#include <asm/uv/uv.h>
+#include <asm/set_memory.h>
#include <asm/sigframe.h>
#include <asm/traps.h>
#include <asm/sev.h>
@@ -2362,3 +2366,52 @@ void arch_smt_update(void)
/* Check whether IPI broadcasting can be enabled */
apic_smt_update();
}
+
+void __init arch_cpu_finalize_init(void)
+{
+ identify_boot_cpu();
+
+ /*
+ * identify_boot_cpu() initialized SMT support information, let the
+ * core code know.
+ */
+ cpu_smt_check_topology();
+
+ if (!IS_ENABLED(CONFIG_SMP)) {
+ pr_info("CPU: ");
+ print_cpu_info(&boot_cpu_data);
+ }
+
+ arch_smt_update();
+
+ cpu_select_mitigations();
+
+ if (IS_ENABLED(CONFIG_X86_32)) {
+ /*
+ * Check whether this is a real i386 which is not longer
+ * supported and fixup the utsname.
+ */
+ if (boot_cpu_data.x86 < 4)
+ panic("Kernel requires i486+ for 'invlpg' and other features");
+
+ init_utsname()->machine[1] =
+ '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
+ }
+
+ alternative_instructions();
+
+ if (IS_ENABLED(CONFIG_X86_64)) {
+ /*
+ * Make sure the first 2MB area is not mapped by huge pages
+ * There are typically fixed size MTRRs in there and overlapping
+ * MTRRs into large pages causes slow downs.
+ *
+ * Right now we don't do that with gbpages because there seems
+ * very little benefit for that case.
+ */
+ if (!direct_gbpages)
+ set_memory_4k((unsigned long)__va(0), 1);
+ } else {
+ fpu__init_check_bugs();
+ }
+}
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -79,6 +79,7 @@ extern void detect_ht(struct cpuinfo_x86
extern void check_null_seg_clears_base(struct cpuinfo_x86 *c);
unsigned int aperfmperf_get_khz(int cpu);
+void cpu_select_mitigations(void);
extern void x86_spec_ctrl_setup_ap(void);
extern void update_srbds_msr(void);
On Wed, Jun 14 2023 at 01:39, Thomas Gleixner wrote:
> + /*
> + * identify_boot_cpu() initialized SMT support information, let the
> + * core code know.
> + */
> + cpu_smt_check_topology();
> +
> + if (!IS_ENABLED(CONFIG_SMP)) {
> + pr_info("CPU: ");
> + print_cpu_info(&boot_cpu_data);
> + }
> +
> + arch_smt_update();
> +
> + cpu_select_mitigations();
That's the wrong order. mitigations must come before the smt
update. Thanks to Boris for spotting it.
On Wed, Jun 14, 2023 at 11:53:50AM +0200, Thomas Gleixner wrote:
> That's the wrong order. mitigations must come before the smt
> update. Thanks to Boris for spotting it.
Right, with that fixed the ordering looks good now.
Reviewed-by: Borislav Petkov (AMD) <[email protected]>
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
The following commit has been merged into the x86/boot branch of tip:
Commit-ID: 7c7077a72674402654f3291354720cd73cdf649e
Gitweb: https://git.kernel.org/tip/7c7077a72674402654f3291354720cd73cdf649e
Author: Thomas Gleixner <[email protected]>
AuthorDate: Wed, 14 Jun 2023 01:39:24 +02:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Fri, 16 Jun 2023 10:15:59 +02:00
x86/cpu: Switch to arch_cpu_finalize_init()
check_bugs() is a dumping ground for finalizing the CPU bringup. Only parts of
it has to do with actual CPU bugs.
Split it apart into arch_cpu_finalize_init() and cpu_select_mitigations().
Fixup the bogus 32bit comments while at it.
No functional change.
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Borislav Petkov (AMD) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/Kconfig | 1 +-
arch/x86/include/asm/bugs.h | 2 +-
arch/x86/kernel/cpu/bugs.c | 51 +----------------------------------
arch/x86/kernel/cpu/common.c | 53 +++++++++++++++++++++++++++++++++++-
arch/x86/kernel/cpu/cpu.h | 1 +-
5 files changed, 56 insertions(+), 52 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 53bab12..e8ebafa 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -71,6 +71,7 @@ config X86
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
select ARCH_HAS_CACHE_LINE_SIZE
select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
+ select ARCH_HAS_CPU_FINALIZE_INIT
select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
diff --git a/arch/x86/include/asm/bugs.h b/arch/x86/include/asm/bugs.h
index 92ae283..f25ca2d 100644
--- a/arch/x86/include/asm/bugs.h
+++ b/arch/x86/include/asm/bugs.h
@@ -4,8 +4,6 @@
#include <asm/processor.h>
-extern void check_bugs(void);
-
#if defined(CONFIG_CPU_SUP_INTEL) && defined(CONFIG_X86_32)
int ppro_with_ram_bug(void);
#else
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 182af64..9e2a918 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -9,7 +9,6 @@
* - Andrew D. Balsa (code cleanup).
*/
#include <linux/init.h>
-#include <linux/utsname.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/nospec.h>
@@ -27,8 +26,6 @@
#include <asm/msr.h>
#include <asm/vmx.h>
#include <asm/paravirt.h>
-#include <asm/alternative.h>
-#include <asm/set_memory.h>
#include <asm/intel-family.h>
#include <asm/e820/api.h>
#include <asm/hypervisor.h>
@@ -125,21 +122,8 @@ DEFINE_STATIC_KEY_FALSE(switch_mm_cond_l1d_flush);
DEFINE_STATIC_KEY_FALSE(mmio_stale_data_clear);
EXPORT_SYMBOL_GPL(mmio_stale_data_clear);
-void __init check_bugs(void)
+void __init cpu_select_mitigations(void)
{
- identify_boot_cpu();
-
- /*
- * identify_boot_cpu() initialized SMT support information, let the
- * core code know.
- */
- cpu_smt_check_topology();
-
- if (!IS_ENABLED(CONFIG_SMP)) {
- pr_info("CPU: ");
- print_cpu_info(&boot_cpu_data);
- }
-
/*
* Read the SPEC_CTRL MSR to account for reserved bits which may
* have unknown values. AMD64_LS_CFG MSR is cached in the early AMD
@@ -176,39 +160,6 @@ void __init check_bugs(void)
md_clear_select_mitigation();
srbds_select_mitigation();
l1d_flush_select_mitigation();
-
- arch_smt_update();
-
-#ifdef CONFIG_X86_32
- /*
- * Check whether we are able to run this kernel safely on SMP.
- *
- * - i386 is no longer supported.
- * - In order to run on anything without a TSC, we need to be
- * compiled for a i486.
- */
- if (boot_cpu_data.x86 < 4)
- panic("Kernel requires i486+ for 'invlpg' and other features");
-
- init_utsname()->machine[1] =
- '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
- alternative_instructions();
-
- fpu__init_check_bugs();
-#else /* CONFIG_X86_64 */
- alternative_instructions();
-
- /*
- * Make sure the first 2MB area is not mapped by huge pages
- * There are typically fixed size MTRRs in there and overlapping
- * MTRRs into large pages causes slow downs.
- *
- * Right now we don't do that with gbpages because there seems
- * very little benefit for that case.
- */
- if (!direct_gbpages)
- set_memory_4k((unsigned long)__va(0), 1);
-#endif
}
/*
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 80710a6..18612e5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -19,11 +19,14 @@
#include <linux/kprobes.h>
#include <linux/kgdb.h>
#include <linux/smp.h>
+#include <linux/cpu.h>
#include <linux/io.h>
#include <linux/syscore_ops.h>
#include <linux/pgtable.h>
#include <linux/stackprotector.h>
+#include <linux/utsname.h>
+#include <asm/alternative.h>
#include <asm/cmdline.h>
#include <asm/perf_event.h>
#include <asm/mmu_context.h>
@@ -59,6 +62,7 @@
#include <asm/intel-family.h>
#include <asm/cpu_device_id.h>
#include <asm/uv/uv.h>
+#include <asm/set_memory.h>
#include <asm/sigframe.h>
#include <asm/traps.h>
#include <asm/sev.h>
@@ -2362,3 +2366,52 @@ void arch_smt_update(void)
/* Check whether IPI broadcasting can be enabled */
apic_smt_update();
}
+
+void __init arch_cpu_finalize_init(void)
+{
+ identify_boot_cpu();
+
+ /*
+ * identify_boot_cpu() initialized SMT support information, let the
+ * core code know.
+ */
+ cpu_smt_check_topology();
+
+ if (!IS_ENABLED(CONFIG_SMP)) {
+ pr_info("CPU: ");
+ print_cpu_info(&boot_cpu_data);
+ }
+
+ cpu_select_mitigations();
+
+ arch_smt_update();
+
+ if (IS_ENABLED(CONFIG_X86_32)) {
+ /*
+ * Check whether this is a real i386 which is not longer
+ * supported and fixup the utsname.
+ */
+ if (boot_cpu_data.x86 < 4)
+ panic("Kernel requires i486+ for 'invlpg' and other features");
+
+ init_utsname()->machine[1] =
+ '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
+ }
+
+ alternative_instructions();
+
+ if (IS_ENABLED(CONFIG_X86_64)) {
+ /*
+ * Make sure the first 2MB area is not mapped by huge pages
+ * There are typically fixed size MTRRs in there and overlapping
+ * MTRRs into large pages causes slow downs.
+ *
+ * Right now we don't do that with gbpages because there seems
+ * very little benefit for that case.
+ */
+ if (!direct_gbpages)
+ set_memory_4k((unsigned long)__va(0), 1);
+ } else {
+ fpu__init_check_bugs();
+ }
+}
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index f97b0fe..1c44630 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -79,6 +79,7 @@ extern void detect_ht(struct cpuinfo_x86 *c);
extern void check_null_seg_clears_base(struct cpuinfo_x86 *c);
unsigned int aperfmperf_get_khz(int cpu);
+void cpu_select_mitigations(void);
extern void x86_spec_ctrl_setup_ap(void);
extern void update_srbds_msr(void);