[patch 2/3] x86/smpboot: Remove stale tlb flush invocations

From: Thomas Gleixner
Date: Sat Dec 30 2017 - 16:22:47 EST


smpboot_setup_warm_reset_vector() and smpboot_restore_warm_reset_vector()
invoke local_flush_tlb() for no obvious reason.

Digging in history revealed that the original code in the 2.1 aera added
those because the code manipulated a swapper_pg_dir pagetable entry. The
pagetable manipulation was removed long ago in the 2.3 timeframe, but the
tlb flush invocations stayed around forever.

Remove them along with the pointless pr_debugs which come from the same 2.1
change.

Reported-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/smpboot.c | 9 ---------
1 file changed, 9 deletions(-)

--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -128,14 +128,10 @@ static inline void smpboot_setup_warm_re
spin_lock_irqsave(&rtc_lock, flags);
CMOS_WRITE(0xa, 0xf);
spin_unlock_irqrestore(&rtc_lock, flags);
- local_flush_tlb();
- pr_debug("1.\n");
*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) =
start_eip >> 4;
- pr_debug("2.\n");
*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) =
start_eip & 0xf;
- pr_debug("3.\n");
}

static inline void smpboot_restore_warm_reset_vector(void)
@@ -143,11 +139,6 @@ static inline void smpboot_restore_warm_
unsigned long flags;

/*
- * Install writable page 0 entry to set BIOS data area.
- */
- local_flush_tlb();
-
- /*
* Paranoid: Set warm reset code and vector here back
* to default values.
*/