[tip:,x86/bugs] x86/pti: Fix kernel warnings for pti= and nopti cmdline options
Commit Message
The following commit has been merged into the x86/bugs branch of tip:
Commit-ID: f75a0e70ed379019b209cdb591ffbfe2fbf4342f
Gitweb: https://git.kernel.org/tip/f75a0e70ed379019b209cdb591ffbfe2fbf4342f
Author: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
AuthorDate: Sat, 19 Aug 2023 10:09:21 +02:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 19 Sep 2023 11:42:48 +02:00
x86/pti: Fix kernel warnings for pti= and nopti cmdline options
Parse the pti= and nopti cmdline options using early_param to fix 'Unknown
kernel command line parameters "nopti", will be passed to user space'
warnings in the kernel log when nopti or pti= are passed to the kernel
cmdline on x86 platforms.
Additionally allow the kernel to warn for malformed pti= options.
Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20230819080921.5324-2-jo.vanbulck@cs.kuleuven.be
---
arch/x86/mm/pti.c | 58 +++++++++++++++++++++++-----------------------
1 file changed, 29 insertions(+), 29 deletions(-)
@@ -69,6 +69,7 @@ static void __init pti_print_if_secure(const char *reason)
pr_info("%s\n", reason);
}
+/* Assume mode is auto unless overridden via cmdline below. */
static enum pti_mode {
PTI_AUTO = 0,
PTI_FORCE_OFF,
@@ -77,50 +78,49 @@ static enum pti_mode {
void __init pti_check_boottime_disable(void)
{
- char arg[5];
- int ret;
-
- /* Assume mode is auto unless overridden. */
- pti_mode = PTI_AUTO;
-
if (hypervisor_is_type(X86_HYPER_XEN_PV)) {
pti_mode = PTI_FORCE_OFF;
pti_print_if_insecure("disabled on XEN PV.");
return;
}
- ret = cmdline_find_option(boot_command_line, "pti", arg, sizeof(arg));
- if (ret > 0) {
- if (ret == 3 && !strncmp(arg, "off", 3)) {
- pti_mode = PTI_FORCE_OFF;
- pti_print_if_insecure("disabled on command line.");
- return;
- }
- if (ret == 2 && !strncmp(arg, "on", 2)) {
- pti_mode = PTI_FORCE_ON;
- pti_print_if_secure("force enabled on command line.");
- goto enable;
- }
- if (ret == 4 && !strncmp(arg, "auto", 4)) {
- pti_mode = PTI_AUTO;
- goto autosel;
- }
- }
-
- if (cmdline_find_option_bool(boot_command_line, "nopti") ||
- cpu_mitigations_off()) {
+ if (cpu_mitigations_off())
pti_mode = PTI_FORCE_OFF;
+ if (pti_mode == PTI_FORCE_OFF) {
pti_print_if_insecure("disabled on command line.");
return;
}
-autosel:
- if (!boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN))
+ if (pti_mode == PTI_FORCE_ON)
+ pti_print_if_secure("force enabled on command line.");
+
+ if (pti_mode == PTI_AUTO && !boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN))
return;
-enable:
+
setup_force_cpu_cap(X86_FEATURE_PTI);
}
+static int __init pti_parse_cmdline(char *arg)
+{
+ if (!strcmp(arg, "off"))
+ pti_mode = PTI_FORCE_OFF;
+ else if (!strcmp(arg, "on"))
+ pti_mode = PTI_FORCE_ON;
+ else if (!strcmp(arg, "auto"))
+ pti_mode = PTI_AUTO;
+ else
+ return -EINVAL;
+ return 0;
+}
+early_param("pti", pti_parse_cmdline);
+
+static int __init pti_parse_cmdline_nopti(char *arg)
+{
+ pti_mode = PTI_FORCE_OFF;
+ return 0;
+}
+early_param("nopti", pti_parse_cmdline_nopti);
+
pgd_t __pti_set_user_pgtbl(pgd_t *pgdp, pgd_t pgd)
{
/*