[PATCH] Remove most of the special cases for the debug IST stack (f5741644) · Commits · 戴 / test

arch/x86_64/kernel/setup64.c

+5 −16

Original line number	Diff line number	Diff line
		@@ -237,28 +237,17 @@ void __cpuinit cpu_init (void)
		* set up and load the per-CPU TSS
		*/
		for (v = 0; v < N_EXCEPTION_STACKS; v++) {
		if (cpu) {
		static const unsigned int order[N_EXCEPTION_STACKS] = {
		[0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STACK_ORDER,
		[DEBUG_STACK - 1] = DEBUG_STACK_ORDER
		};

		if (cpu) {
		estacks = (char *)__get_free_pages(GFP_ATOMIC, order[v]);
		if (!estacks)
		panic("Cannot allocate exception stack %ld %d\n",
		v, cpu);
		}
		switch (v + 1) {
		#if DEBUG_STKSZ > EXCEPTION_STKSZ
		case DEBUG_STACK:
		cpu_pda(cpu)->debugstack = (unsigned long)estacks;
		estacks += DEBUG_STKSZ;
		break;
		#endif
		default:
		estacks += EXCEPTION_STKSZ;
		break;
		}
		estacks += PAGE_SIZE << order[v];
		orig_ist->ist[v] = t->ist[v] = (unsigned long)estacks;
		}

+1 −20

Original line number	Diff line number	Diff line
		@@ -162,26 +162,7 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
		* 'stack' is in one of them:
		*/
		for (k = 0; k < N_EXCEPTION_STACKS; k++) {
		unsigned long end;

		/*
		* set 'end' to the end of the exception stack.
		*/
		switch (k + 1) {
		/*
		* TODO: this block is not needed i think, because
		* setup64.c:cpu_init() sets up t->ist[DEBUG_STACK]
		* properly too.
		*/
		#if DEBUG_STKSZ > EXCEPTION_STKSZ
		case DEBUG_STACK:
		end = cpu_pda(cpu)->debugstack + DEBUG_STKSZ;
		break;
		#endif
		default:
		end = per_cpu(orig_ist, cpu).ist[k];
		break;
		}
		unsigned long end = per_cpu(orig_ist, cpu).ist[k];
		/*
		* Is 'stack' above this exception frame's end?
		* If yes then skip to the next frame.

+0 −3

Original line number	Diff line number	Diff line
		@@ -13,9 +13,6 @@ struct x8664_pda {
		unsigned long data_offset; /* Per cpu data offset from linker address */
		unsigned long kernelstack; /* top of kernel stack for current */
		unsigned long oldrsp; /* user rsp for system call */
		#if DEBUG_STKSZ > EXCEPTION_STKSZ
		unsigned long debugstack; /* #DB/#BP stack. */
		#endif
		int irqcount; /* Irq nesting counter. Starts with -1 */
		int cpunumber; /* Logical CPU number */
		char irqstackptr; / top of irqstack */