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x86/speculation: Add a common function for MD_CLEAR mitigation update

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commit f52ea6c26953fed339aa4eae717ee5c2133c7ff2 upstream

Processor MMIO Stale Data mitigation uses similar mitigation as MDS and
TAA. In preparation for adding its mitigation, add a common function to
update all mitigations that depend on MD_CLEAR.

  [ bp: Add a newline in md_clear_update_mitigation() to separate
    statements better. ]

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Pawan Gupta 2022-05-19 20:28:10 -07:00 committed by Greg Kroah-Hartman
parent e66310bc96
commit f83d4e5be4
1 changed files with 33 additions and 26 deletions
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59
arch/x86/kernel/cpu/bugs.c
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@ -41,7 +41,7 @@ static void __init spectre_v2_select_mitigation(void);
static void __init ssb_select_mitigation(void);
static void __init l1tf_select_mitigation(void);
static void __init mds_select_mitigation(void);
static void __init mds_print_mitigation(void);
static void __init md_clear_update_mitigation(void);
static void __init taa_select_mitigation(void);
static void __init srbds_select_mitigation(void);
@ -114,10 +114,10 @@ void __init check_bugs(void)
srbds_select_mitigation();
/*
* As MDS and TAA mitigations are inter-related, print MDS
* mitigation until after TAA mitigation selection is done.
* As MDS and TAA mitigations are inter-related, update and print their
* mitigation after TAA mitigation selection is done.
*/
mds_print_mitigation();
md_clear_update_mitigation();
arch_smt_update();
@ -258,14 +258,6 @@ static void __init mds_select_mitigation(void)
}
}
static void __init mds_print_mitigation(void)
{
if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off())
return;
pr_info("%s\n", mds_strings[mds_mitigation]);
}
static int __init mds_cmdline(char *str)
{
if (!boot_cpu_has_bug(X86_BUG_MDS))
@ -320,7 +312,7 @@ static void __init taa_select_mitigation(void)
/* TSX previously disabled by tsx=off */
if (!boot_cpu_has(X86_FEATURE_RTM)) {
taa_mitigation = TAA_MITIGATION_TSX_DISABLED;
goto out;
return;
}
if (cpu_mitigations_off()) {
@ -334,7 +326,7 @@ static void __init taa_select_mitigation(void)
*/
if (taa_mitigation == TAA_MITIGATION_OFF &&
mds_mitigation == MDS_MITIGATION_OFF)
goto out;
return;
if (boot_cpu_has(X86_FEATURE_MD_CLEAR))
taa_mitigation = TAA_MITIGATION_VERW;
@ -366,18 +358,6 @@ static void __init taa_select_mitigation(void)
if (taa_nosmt || cpu_mitigations_auto_nosmt())
cpu_smt_disable(false);
/*
* Update MDS mitigation, if necessary, as the mds_user_clear is
* now enabled for TAA mitigation.
*/
if (mds_mitigation == MDS_MITIGATION_OFF &&
boot_cpu_has_bug(X86_BUG_MDS)) {
mds_mitigation = MDS_MITIGATION_FULL;
mds_select_mitigation();
}
out:
pr_info("%s\n", taa_strings[taa_mitigation]);
}
static int __init tsx_async_abort_parse_cmdline(char *str)
@ -401,6 +381,33 @@ static int __init tsx_async_abort_parse_cmdline(char *str)
}
early_param("tsx_async_abort", tsx_async_abort_parse_cmdline);
#undef pr_fmt
#define pr_fmt(fmt) "" fmt
static void __init md_clear_update_mitigation(void)
{
if (cpu_mitigations_off())
return;
if (!static_key_enabled(&mds_user_clear))
goto out;
/*
* mds_user_clear is now enabled. Update MDS mitigation, if
* necessary.
*/
if (mds_mitigation == MDS_MITIGATION_OFF &&
boot_cpu_has_bug(X86_BUG_MDS)) {
mds_mitigation = MDS_MITIGATION_FULL;
mds_select_mitigation();
}
out:
if (boot_cpu_has_bug(X86_BUG_MDS))
pr_info("MDS: %s\n", mds_strings[mds_mitigation]);
if (boot_cpu_has_bug(X86_BUG_TAA))
pr_info("TAA: %s\n", taa_strings[taa_mitigation]);
}
#undef pr_fmt
#define pr_fmt(fmt) "SRBDS: " fmt