62 lines
2.2 KiB
Diff
62 lines
2.2 KiB
Diff
From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
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Date: Wed, 23 Oct 2019 12:28:57 +0200
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Subject: x86/tsx: Add "auto" option to the tsx= cmdline parameter
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commit 7531a3596e3272d1f6841e0d601a614555dc6b65 upstream.
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Platforms which are not affected by X86_BUG_TAA may want the TSX feature
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enabled. Add "auto" option to the TSX cmdline parameter. When tsx=auto
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disable TSX when X86_BUG_TAA is present, otherwise enable TSX.
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More details on X86_BUG_TAA can be found here:
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https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/tsx_async_abort.html
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[ bp: Extend the arg buffer to accommodate "auto\0". ]
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Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
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Signed-off-by: Borislav Petkov <bp@suse.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Reviewed-by: Tony Luck <tony.luck@intel.com>
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Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
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Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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---
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Documentation/admin-guide/kernel-parameters.txt | 3 +++
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arch/x86/kernel/cpu/tsx.c | 7 ++++++-
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2 files changed, 9 insertions(+), 1 deletion(-)
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--- a/Documentation/admin-guide/kernel-parameters.txt
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+++ b/Documentation/admin-guide/kernel-parameters.txt
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@@ -4706,6 +4706,9 @@
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update. This new MSR allows for the reliable
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deactivation of the TSX functionality.)
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+ auto - Disable TSX if X86_BUG_TAA is present,
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+ otherwise enable TSX on the system.
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+
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Not specifying this option is equivalent to tsx=off.
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See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
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--- a/arch/x86/kernel/cpu/tsx.c
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+++ b/arch/x86/kernel/cpu/tsx.c
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@@ -75,7 +75,7 @@ static bool __init tsx_ctrl_is_supported
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void __init tsx_init(void)
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{
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- char arg[4] = {};
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+ char arg[5] = {};
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int ret;
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if (!tsx_ctrl_is_supported())
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@@ -87,6 +87,11 @@ void __init tsx_init(void)
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tsx_ctrl_state = TSX_CTRL_ENABLE;
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} else if (!strcmp(arg, "off")) {
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tsx_ctrl_state = TSX_CTRL_DISABLE;
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+ } else if (!strcmp(arg, "auto")) {
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+ if (boot_cpu_has_bug(X86_BUG_TAA))
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+ tsx_ctrl_state = TSX_CTRL_DISABLE;
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+ else
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+ tsx_ctrl_state = TSX_CTRL_ENABLE;
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} else {
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tsx_ctrl_state = TSX_CTRL_DISABLE;
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pr_err("tsx: invalid option, defaulting to off\n");
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