[patch V3 05/32] x86/irq/64: Sanitize the top/bottom confusion

[Thomas Gleixner]

On x86 stacks go top to bottom, but the stack overflow check uses it the
other way round, which is just confusing. Clean it up and sanitize the
warning string a bit.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
 arch/x86/kernel/irq_64.c |   22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -42,7 +42,7 @@ int sysctl_panic_on_stackoverflow;
 static inline void stack_overflow_check(struct pt_regs *regs)
 {
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
-#define STACK_TOP_MARGIN	128
+#define STACK_MARGIN	128
 	struct orig_ist *oist;
 	u64 irq_stack_top, irq_stack_bottom;
 	u64 estack_top, estack_bottom;
@@ -51,25 +51,25 @@ static inline void stack_overflow_check(
 	if (user_mode(regs))
 		return;
 
-	if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
+	if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_MARGIN &&
 	    regs->sp <= curbase + THREAD_SIZE)
 		return;
 
-	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)
+	irq_stack_top = (u64)__this_cpu_read(irq_stack_ptr);
+	irq_stack_bottom = irq_stack_top - IRQ_STACK_SIZE + STACK_MARGIN;
+	if (regs->sp >= irq_stack_bottom && regs->sp <= irq_stack_top)
 		return;
 
 	oist = this_cpu_ptr(&orig_ist);
-	estack_bottom = (u64)oist->ist[DEBUG_STACK];
-	estack_top = estack_bottom - DEBUG_STKSZ + STACK_TOP_MARGIN;
-	if (regs->sp >= estack_top && regs->sp <= estack_bottom)
+	estack_top = (u64)oist->ist[DEBUG_STACK];
+	estack_bottom = estack_top - DEBUG_STKSZ + STACK_MARGIN;
+	if (regs->sp >= estack_bottom && regs->sp <= estack_top)
 		return;
 
-	WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx,ip:%pF)\n",
+	WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx, irq stack:%Lx-%Lx, exception stack: %Lx-%Lx, ip:%pF)\n",
 		current->comm, curbase, regs->sp,
-		irq_stack_top, irq_stack_bottom,
-		estack_top, estack_bottom, (void *)regs->ip);
+		irq_stack_bottom, irq_stack_top,
+		estack_bottom, estack_top, (void *)regs->ip);
 
 	if (sysctl_panic_on_stackoverflow)
 		panic("low stack detected by irq handler - check messages\n");