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Commit 91ab1073 authored by Pawan Gupta's avatar Pawan Gupta Committed by Greg Kroah-Hartman
Browse files

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



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: default avatarPawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarThadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 19aa53c9

arch/x86/kernel/cpu/bugs.c

+33 −26
Original line number Diff line number Diff line
@@ -39,7 +39,7 @@ 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);
@@ -112,10 +112,10 @@ 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();
@@ -256,14 +256,6 @@ 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))
@@ -311,7 +303,7 @@ 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()) {
@@ -325,7 +317,7 @@ 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;
@@ -357,18 +349,6 @@ 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)
@@ -392,6 +372,33 @@ 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