Commit a1cdef04 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc: Convert stacktrace to generic ARCH_STACKWALK 



This patch converts powerpc stacktrace to the generic ARCH_STACKWALK
implemented by commit 214d8ca6 ("stacktrace: Provide common
infrastructure")

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/73b36bbb101299760b95ecd2cd3a46554bea8bf9.1615881400.git.christophe.leroy@csgroup.eu
parent 826a307b

arch/powerpc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -145,6 +145,7 @@ config PPC 
	select ARCH_MIGHT_HAVE_PC_PARPORT

	select ARCH_MIGHT_HAVE_PC_SERIO

	select ARCH_OPTIONAL_KERNEL_RWX		if ARCH_HAS_STRICT_KERNEL_RWX

	select ARCH_STACKWALK

	select ARCH_SUPPORTS_ATOMIC_RMW

	select ARCH_SUPPORTS_DEBUG_PAGEALLOC	if PPC32 || PPC_BOOK3S_64

	select ARCH_USE_BUILTIN_BSWAP

arch/powerpc/kernel/stacktrace.c

+16 −75
Original line number Diff line number Diff line
@@ -23,12 +23,18 @@ 


#include <asm/paca.h>



/*

 * Save stack-backtrace addresses into a stack_trace buffer.

 */

static void save_context_stack(struct stack_trace *trace, unsigned long sp,

			struct task_struct *task, int savesched)

void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,

		     struct task_struct *task, struct pt_regs *regs)

{

	unsigned long sp;



	if (regs)

		sp = regs->gpr[1];

	else if (task == current)

		sp = current_stack_frame();

	else

		sp = task->thread.ksp;



	for (;;) {

		unsigned long *stack = (unsigned long *) sp;

		unsigned long newsp, ip;
@@ -39,63 +45,21 @@ static void save_context_stack(struct stack_trace *trace, unsigned long sp, 
		newsp = stack[0];

		ip = stack[STACK_FRAME_LR_SAVE];



		if (savesched || !in_sched_functions(ip)) {

			if (!trace->skip)

				trace->entries[trace->nr_entries++] = ip;

			else

				trace->skip--;

		}



		if (trace->nr_entries >= trace->max_entries)

		if (!consume_entry(cookie, ip))

			return;



		sp = newsp;

	}

}



void save_stack_trace(struct stack_trace *trace)

{

	unsigned long sp;



	sp = current_stack_frame();



	save_context_stack(trace, sp, current, 1);

}

EXPORT_SYMBOL_GPL(save_stack_trace);



void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)

{

	unsigned long sp;



	if (!try_get_task_stack(tsk))

		return;



	if (tsk == current)

		sp = current_stack_frame();

	else

		sp = tsk->thread.ksp;



	save_context_stack(trace, sp, tsk, 0);



	put_task_stack(tsk);

}

EXPORT_SYMBOL_GPL(save_stack_trace_tsk);



void

save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)

{

	save_context_stack(trace, regs->gpr[1], current, 0);

}

EXPORT_SYMBOL_GPL(save_stack_trace_regs);



/*

 * This function returns an error if it detects any unreliable features of the

 * stack.  Otherwise it guarantees that the stack trace is reliable.

 *

 * If the task is not 'current', the caller *must* ensure the task is inactive.

 */

static int __save_stack_trace_tsk_reliable(struct task_struct *task,

					   struct stack_trace *trace)

int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,

			     void *cookie, struct task_struct *task)

{

	unsigned long sp;

	unsigned long newsp;
@@ -191,35 +155,12 @@ static int __save_stack_trace_tsk_reliable(struct task_struct *task, 
			return -EINVAL;

#endif



		if (trace->nr_entries >= trace->max_entries)

			return -E2BIG;

		if (!trace->skip)

			trace->entries[trace->nr_entries++] = ip;

		else

			trace->skip--;

		if (!consume_entry(cookie, ip))

			return -EINVAL;

	}

	return 0;

}



int save_stack_trace_tsk_reliable(struct task_struct *tsk,

				  struct stack_trace *trace)

{

	int ret;



	/*

	 * If the task doesn't have a stack (e.g., a zombie), the stack is

	 * "reliably" empty.

	 */

	if (!try_get_task_stack(tsk))

		return 0;



	ret = __save_stack_trace_tsk_reliable(tsk, trace);



	put_task_stack(tsk);



	return ret;

}



#if defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_NMI_IPI)

static void handle_backtrace_ipi(struct pt_regs *regs)

{