5.4-stable review patch. If anyone has any objections, please let me know.
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From: Breno Leitao leitao@debian.org
This reverts commit a8c22ec36cdd99c1002d7152f859798fef7c4d58 which is commit 98fdaeb296f51ef08e727a7cc72e5b5c864c4f4d upstream.
commit 7adb96687ce8 ("x86/bugs: Make spectre user default depend on MITIGATION_SPECTRE_V2") depends on commit 72c70f480a70 ("x86/bugs: Add a separate config for Spectre V2"), which introduced MITIGATION_SPECTRE_V2.
commit 72c70f480a70 ("x86/bugs: Add a separate config for Spectre V2") never landed in stable tree, thus, stable tree doesn't have MITIGATION_SPECTRE_V2, that said, commit 7adb96687ce8 ("x86/bugs: Make spectre user default depend on MITIGATION_SPECTRE_V2") has no value if the dependecy was not applied.
Revert commit 7adb96687ce8 ("x86/bugs: Make spectre user default depend on MITIGATION_SPECTRE_V2") in stable kernel which landed in in 5.4.294, 5.10.238, 5.15.185, 6.1.141 and 6.6.93 stable versions.
Cc: David.Kaplan@amd.com Cc: peterz@infradead.org Cc: pawan.kumar.gupta@linux.intel.com Cc: mingo@kernel.org Cc: brad.spengler@opensrcsec.com Cc: stable@vger.kernel.org # 6.6 6.1 5.15 5.10 5.4 Reported-by: Brad Spengler brad.spengler@opensrcsec.com Reported-by: Salvatore Bonaccorso carnil@debian.org Signed-off-by: Breno Leitao leitao@debian.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Documentation/admin-guide/kernel-parameters.txt | 2 -- arch/x86/kernel/cpu/bugs.c | 10 +++------- 2 files changed, 3 insertions(+), 9 deletions(-)
--- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4600,8 +4600,6 @@
Selecting 'on' will also enable the mitigation against user space to user space task attacks. - Selecting specific mitigation does not force enable - user mitigations.
Selecting 'off' will disable both the kernel and the user space protections. --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1050,13 +1050,9 @@ static __ro_after_init enum spectre_v2_m static enum spectre_v2_user_cmd __init spectre_v2_parse_user_cmdline(void) { - enum spectre_v2_user_cmd mode; char arg[20]; int ret, i;
- mode = IS_ENABLED(CONFIG_MITIGATION_SPECTRE_V2) ? - SPECTRE_V2_USER_CMD_AUTO : SPECTRE_V2_USER_CMD_NONE; - switch (spectre_v2_cmd) { case SPECTRE_V2_CMD_NONE: return SPECTRE_V2_USER_CMD_NONE; @@ -1069,7 +1065,7 @@ spectre_v2_parse_user_cmdline(void) ret = cmdline_find_option(boot_command_line, "spectre_v2_user", arg, sizeof(arg)); if (ret < 0) - return mode; + return SPECTRE_V2_USER_CMD_AUTO;
for (i = 0; i < ARRAY_SIZE(v2_user_options); i++) { if (match_option(arg, ret, v2_user_options[i].option)) { @@ -1079,8 +1075,8 @@ spectre_v2_parse_user_cmdline(void) } }
- pr_err("Unknown user space protection option (%s). Switching to default\n", arg); - return mode; + pr_err("Unknown user space protection option (%s). Switching to AUTO select\n", arg); + return SPECTRE_V2_USER_CMD_AUTO; }
static inline bool spectre_v2_in_eibrs_mode(enum spectre_v2_mitigation mode)