diff options
author | Borislav Petkov <bp@suse.de> | 2018-01-02 14:19:48 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-05 15:44:25 +0100 |
commit | e405a064bd7d6eca88935342ddb71057a9d6ceab (patch) | |
tree | 48628847f7f2b8d997decc863881cdd61513c9be /arch/x86/mm | |
parent | dea9aa9ffae11c91285335cc3215b4f0e48e8139 (diff) |
x86/kaiser: Check boottime cmdline params
AMD (and possibly other vendors) are not affected by the leak
KAISER is protecting against.
Keep the "nopti" for traditional reasons and add pti=<on|off|auto>
like upstream.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r-- | arch/x86/mm/kaiser.c | 59 |
1 files changed, 41 insertions, 18 deletions
diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c index fb812fd865d8..604aa48c8946 100644 --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -16,6 +16,7 @@ #include <asm/pgtable.h> #include <asm/pgalloc.h> #include <asm/desc.h> +#include <asm/cmdline.h> int kaiser_enabled __read_mostly = 1; EXPORT_SYMBOL(kaiser_enabled); /* for inlined TLB flush functions */ @@ -264,6 +265,43 @@ static void __init kaiser_init_all_pgds(void) WARN_ON(__ret); \ } while (0) +void __init kaiser_check_boottime_disable(void) +{ + bool enable = true; + char arg[5]; + int ret; + + ret = cmdline_find_option(boot_command_line, "pti", arg, sizeof(arg)); + if (ret > 0) { + if (!strncmp(arg, "on", 2)) + goto enable; + + if (!strncmp(arg, "off", 3)) + goto disable; + + if (!strncmp(arg, "auto", 4)) + goto skip; + } + + if (cmdline_find_option_bool(boot_command_line, "nopti")) + goto disable; + +skip: + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) + goto disable; + +enable: + if (enable) + setup_force_cpu_cap(X86_FEATURE_KAISER); + + return; + +disable: + pr_info("Kernel/User page tables isolation: disabled\n"); + kaiser_enabled = 0; + setup_clear_cpu_cap(X86_FEATURE_KAISER); +} + /* * If anything in here fails, we will likely die on one of the * first kernel->user transitions and init will die. But, we @@ -275,12 +313,10 @@ void __init kaiser_init(void) { int cpu; - if (!kaiser_enabled) { - setup_clear_cpu_cap(X86_FEATURE_KAISER); - return; - } + kaiser_check_boottime_disable(); - setup_force_cpu_cap(X86_FEATURE_KAISER); + if (!kaiser_enabled) + return; kaiser_init_all_pgds(); @@ -424,16 +460,3 @@ void kaiser_flush_tlb_on_return_to_user(void) X86_CR3_PCID_USER_FLUSH | KAISER_SHADOW_PGD_OFFSET); } EXPORT_SYMBOL(kaiser_flush_tlb_on_return_to_user); - -static int __init x86_nokaiser_setup(char *s) -{ - /* nopti doesn't accept parameters */ - if (s) - return -EINVAL; - - kaiser_enabled = 0; - pr_info("Kernel/User page tables isolation: disabled\n"); - - return 0; -} -early_param("nopti", x86_nokaiser_setup); |