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Subject[PATCH 4.16 102/110] x86/speculation: Rework speculative_store_bypass_update()
Date
4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@linutronix.de>

commit 0270be3e34efb05a88bc4c422572ece038ef3608 upstream

The upcoming support for the virtual SPEC_CTRL MSR on AMD needs to reuse
speculative_store_bypass_update() to avoid code duplication. Add an
argument for supplying a thread info (TIF) value and create a wrapper
speculative_store_bypass_update_current() which is used at the existing
call site.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/spec-ctrl.h | 7 ++++++-
arch/x86/kernel/cpu/bugs.c | 2 +-
arch/x86/kernel/process.c | 4 ++--
3 files changed, 9 insertions(+), 4 deletions(-)

--- a/arch/x86/include/asm/spec-ctrl.h
+++ b/arch/x86/include/asm/spec-ctrl.h
@@ -42,6 +42,11 @@ extern void speculative_store_bypass_ht_
static inline void speculative_store_bypass_ht_init(void) { }
#endif

-extern void speculative_store_bypass_update(void);
+extern void speculative_store_bypass_update(unsigned long tif);
+
+static inline void speculative_store_bypass_update_current(void)
+{
+ speculative_store_bypass_update(current_thread_info()->flags);
+}

#endif
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -598,7 +598,7 @@ static int ssb_prctl_set(struct task_str
* mitigation until it is next scheduled.
*/
if (task == current && update)
- speculative_store_bypass_update();
+ speculative_store_bypass_update_current();

return 0;
}
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -414,10 +414,10 @@ static __always_inline void __speculativ
intel_set_ssb_state(tifn);
}

-void speculative_store_bypass_update(void)
+void speculative_store_bypass_update(unsigned long tif)
{
preempt_disable();
- __speculative_store_bypass_update(current_thread_info()->flags);
+ __speculative_store_bypass_update(tif);
preempt_enable();
}


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