x86/irq/64: Use cpu entry area instead of orig_ist (bf5882ab) · Commits · 戴 / test

The orig_ist[] array is a shadow copy of the IST array in the TSS. The reason why it exists is that older kernels used two TSS variants with different pointers into the debug stack. orig_ist[] contains the real starting points. There is no point anymore to do so because the same information can be retrieved using the base address of the cpu entry area mapping and the offsets of the various exception stacks. No functional change. Preparation for removing orig_ist. Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> Signed-off-by:

Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Nicolai Stange <nstange@suse.de> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190414160144.885741626@linutronix.de

arch/x86/kernel/irq_64.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -18,6 +18,8 @@
		#include <linux/uaccess.h>
		#include <linux/smp.h>
		#include <linux/sched/task_stack.h>

		#include <asm/cpu_entry_area.h>
		#include <asm/io_apic.h>
		#include <asm/apic.h>

		@@ -43,10 +45,9 @@ static inline void stack_overflow_check(struct pt_regs *regs)
		{
		#ifdef CONFIG_DEBUG_STACKOVERFLOW
		#define STACK_MARGIN 128
		struct orig_ist *oist;
		u64 irq_stack_top, irq_stack_bottom;
		u64 estack_top, estack_bottom;
		u64 irq_stack_top, irq_stack_bottom, estack_top, estack_bottom;
		u64 curbase = (u64)task_stack_page(current);
		struct cea_exception_stacks *estacks;

		if (user_mode(regs))
		return;
		@@ -60,9 +61,9 @@ static inline void stack_overflow_check(struct pt_regs *regs)
		if (regs->sp >= irq_stack_bottom && regs->sp <= irq_stack_top)
		return;

		oist = this_cpu_ptr(&orig_ist);
		estack_top = (u64)oist->ist[ESTACK_DB];
		estack_bottom = estack_top - DEBUG_STKSZ + STACK_MARGIN;
		estacks = __this_cpu_read(cea_exception_stacks);
		estack_top = CEA_ESTACK_TOP(estacks, DB);
		estack_bottom = CEA_ESTACK_BOT(estacks, DB) + STACK_MARGIN;
		if (regs->sp >= estack_bottom && regs->sp <= estack_top)
		return;

Admin message