From: Andy Lutomirski <luto@kernel.org>
Date: Sun, 14 Apr 2019 15:59:40 +0000 (+0200)
Subject: x86/irq/64: Remove a hardcoded irq_stack_union access
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=4f44b8f0b33b7111216f0fad353315f796b81617;p=openwrt%2Fstaging%2Fblogic.git

x86/irq/64: Remove a hardcoded irq_stack_union access

stack_overflow_check() is using both irq_stack_ptr and irq_stack_union
to find the IRQ stack. That's going to break when vmapped irq stacks are
introduced.

Change it to just use irq_stack_ptr.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190414160143.872549191@linutronix.de
---

diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index b50ac9c7397b..f6dcc8fea5c0 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -55,9 +55,8 @@ static inline void stack_overflow_check(struct pt_regs *regs)
 	    regs->sp <= curbase + THREAD_SIZE)
 		return;
 
-	irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
-			STACK_TOP_MARGIN;
 	irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
+	irq_stack_top = irq_stack_bottom - IRQ_STACK_SIZE + STACK_TOP_MARGIN;
 	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
 		return;