[PATCH] lockdep: x86_64 document stack frame internals (c9ca1ba5) · Commits · e / devices / android_kernel_xiaomi_markw

arch/x86_64/kernel/traps.c

+60 −1

Original line number	Diff line number	Diff line
		@@ -152,10 +152,22 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
		};
		unsigned k;

		/*
		* Iterate over all exception stacks, and figure out whether
		* '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;
		@@ -165,19 +177,43 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
		end = per_cpu(init_tss, cpu).ist[k];
		break;
		}
		/*
		* Is 'stack' above this exception frame's end?
		* If yes then skip to the next frame.
		*/
		if (stack >= end)
		continue;
		/*
		* Is 'stack' above this exception frame's start address?
		* If yes then we found the right frame.
		*/
		if (stack >= end - EXCEPTION_STKSZ) {
		/*
		* Make sure we only iterate through an exception
		* stack once. If it comes up for the second time
		* then there's something wrong going on - just
		* break out and return NULL:
		*/
		if (*usedp & (1U << k))
		break;
		*usedp \|= 1U << k;
		*idp = ids[k];
		return (unsigned long *)end;
		}
		/*
		* If this is a debug stack, and if it has a larger size than
		* the usual exception stacks, then 'stack' might still
		* be within the lower portion of the debug stack:
		*/
		#if DEBUG_STKSZ > EXCEPTION_STKSZ
		if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
		unsigned j = N_EXCEPTION_STACKS - 1;

		/*
		* Black magic. A large debug stack is composed of
		* multiple exception stack entries, which we
		* iterate through now. Dont look:
		*/
		do {
		++j;
		end -= EXCEPTION_STKSZ;
		@@ -247,6 +283,11 @@ void show_trace(struct task_struct tsk, struct pt_regs regs, unsigned long * s
		}
		}

		/*
		* Print function call entries within a stack. 'cond' is the
		* "end of stackframe" condition, that the 'stack++'
		* iteration will eventually trigger.
		*/
		#define HANDLE_STACK(cond) \
		do while (cond) { \
		unsigned long addr = *stack++; \
		@@ -263,6 +304,11 @@ void show_trace(struct task_struct tsk, struct pt_regs regs, unsigned long * s
		} \
		} while (0)

		/*
		* Print function call entries in all stacks, starting at the
		* current stack address. If the stacks consist of nested
		* exceptions
		*/
		for ( ; ; ) {
		const char *id;
		unsigned long *estack_end;
		@@ -273,6 +319,11 @@ void show_trace(struct task_struct tsk, struct pt_regs regs, unsigned long * s
		printk(" <%s>", id);
		HANDLE_STACK (stack < estack_end);
		printk(" <EOE>");
		/*
		* We link to the next stack via the
		* second-to-last pointer (index -2 to end) in the
		* exception stack:
		*/
		stack = (unsigned long *) estack_end[-2];
		continue;
		}
		@@ -284,6 +335,11 @@ void show_trace(struct task_struct tsk, struct pt_regs regs, unsigned long * s
		if (stack >= irqstack && stack < irqstack_end) {
		printk(" <IRQ>");
		HANDLE_STACK (stack < irqstack_end);
		/*
		* We link to the next stack (which would be
		* the process stack normally) the last
		* pointer (index -1 to end) in the IRQ stack:
		*/
		stack = (unsigned long *) (irqstack_end[-1]);
		irqstack_end = NULL;
		printk(" <EOI>");
		@@ -293,6 +349,9 @@ void show_trace(struct task_struct tsk, struct pt_regs regs, unsigned long * s
		break;
		}

		/*
		* This prints the process stack:
		*/
		HANDLE_STACK (((long) stack & (THREAD_SIZE-1)) != 0);
		#undef HANDLE_STACK