| From b8b7abaed7a49b350f8ba659ddc264b04931d581 Mon Sep 17 00:00:00 2001 |
| From: Andy Lutomirski <luto@kernel.org> |
| Date: Sun, 17 Sep 2017 09:03:50 -0700 |
| Subject: x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier |
| |
| From: Andy Lutomirski <luto@kernel.org> |
| |
| commit b8b7abaed7a49b350f8ba659ddc264b04931d581 upstream. |
| |
| Otherwise we might have the PCID feature bit set during cpu_init(). |
| |
| This is just for robustness. I haven't seen any actual bugs here. |
| |
| Signed-off-by: Andy Lutomirski <luto@kernel.org> |
| Cc: Borislav Petkov <bpetkov@suse.de> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Fixes: cba4671af755 ("x86/mm: Disable PCID on 32-bit kernels") |
| Link: http://lkml.kernel.org/r/b16dae9d6b0db5d9801ddbebbfd83384097c61f3.1505663533.git.luto@kernel.org |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/x86/kernel/cpu/bugs.c | 8 -------- |
| arch/x86/kernel/cpu/common.c | 8 ++++++++ |
| 2 files changed, 8 insertions(+), 8 deletions(-) |
| |
| --- a/arch/x86/kernel/cpu/bugs.c |
| +++ b/arch/x86/kernel/cpu/bugs.c |
| @@ -22,14 +22,6 @@ |
| |
| void __init check_bugs(void) |
| { |
| -#ifdef CONFIG_X86_32 |
| - /* |
| - * Regardless of whether PCID is enumerated, the SDM says |
| - * that it can't be enabled in 32-bit mode. |
| - */ |
| - setup_clear_cpu_cap(X86_FEATURE_PCID); |
| -#endif |
| - |
| identify_boot_cpu(); |
| |
| if (!IS_ENABLED(CONFIG_SMP)) { |
| --- a/arch/x86/kernel/cpu/common.c |
| +++ b/arch/x86/kernel/cpu/common.c |
| @@ -890,6 +890,14 @@ static void __init early_identify_cpu(st |
| setup_force_cpu_bug(X86_BUG_SPECTRE_V2); |
| |
| fpu__init_system(c); |
| + |
| +#ifdef CONFIG_X86_32 |
| + /* |
| + * Regardless of whether PCID is enumerated, the SDM says |
| + * that it can't be enabled in 32-bit mode. |
| + */ |
| + setup_clear_cpu_cap(X86_FEATURE_PCID); |
| +#endif |
| } |
| |
| void __init early_cpu_init(void) |
