Commit 1e09177a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'mips_fixes_4.18_3' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux 

Pull MIPS fixes from Paul Burton:
 "A couple more MIPS fixes for 4.18:

   - Use async IPIs for arch_trigger_cpumask_backtrace() in order to
     avoid warnings & deadlocks, fixing a problem introduced in v3.19
     with the fix trivial to backport as far as v4.9.

   - Fix ioremap()'s MMU/TLB backed path to avoid spuriously rejecting
     valid requests due to an incorrect belief that the memory region is
     backed by potentially-in-use RAM. This fixes a regression in v4.2"

* tag 'mips_fixes_4.18_3' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: Fix ioremap() RAM check
  MIPS: Use async IPIs for arch_trigger_cpumask_backtrace()
  MIPS: Call dump_stack() from show_regs()
parents 30c2c32d 523402fa

arch/mips/kernel/process.c

+29 −14
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/kallsyms.h>

#include <linux/random.h>

#include <linux/prctl.h>

#include <linux/nmi.h>



#include <asm/asm.h>

#include <asm/bootinfo.h>
@@ -655,28 +656,42 @@ unsigned long arch_align_stack(unsigned long sp) 
	return sp & ALMASK;

}



static void arch_dump_stack(void *info)

static DEFINE_PER_CPU(call_single_data_t, backtrace_csd);

static struct cpumask backtrace_csd_busy;



static void handle_backtrace(void *info)

{

	struct pt_regs *regs;

	nmi_cpu_backtrace(get_irq_regs());

	cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy);

}



	regs = get_irq_regs();

static void raise_backtrace(cpumask_t *mask)

{

	call_single_data_t *csd;

	int cpu;



	if (regs)

		show_regs(regs);

	for_each_cpu(cpu, mask) {

		/*

		 * If we previously sent an IPI to the target CPU & it hasn't

		 * cleared its bit in the busy cpumask then it didn't handle

		 * our previous IPI & it's not safe for us to reuse the

		 * call_single_data_t.

		 */

		if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) {

			pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n",

				cpu);

			continue;

		}



	dump_stack();

		csd = &per_cpu(backtrace_csd, cpu);

		csd->func = handle_backtrace;

		smp_call_function_single_async(cpu, csd);

	}

}



void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)

{

	long this_cpu = get_cpu();



	if (cpumask_test_cpu(this_cpu, mask) && !exclude_self)

		dump_stack();



	smp_call_function_many(mask, arch_dump_stack, NULL, 1);



	put_cpu();

	nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace);

}



int mips_get_process_fp_mode(struct task_struct *task)

arch/mips/kernel/traps.c

+1 −0
Original line number Diff line number Diff line
@@ -351,6 +351,7 @@ static void __show_regs(const struct pt_regs *regs) 
void show_regs(struct pt_regs *regs)

{

	__show_regs((struct pt_regs *)regs);

	dump_stack();

}



void show_registers(struct pt_regs *regs)

arch/mips/mm/ioremap.c

+25 −12
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/export.h>

#include <asm/addrspace.h>

#include <asm/byteorder.h>

#include <linux/ioport.h>

#include <linux/sched.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>
@@ -98,6 +99,20 @@ static int remap_area_pages(unsigned long address, phys_addr_t phys_addr, 
	return error;

}



static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,

			       void *arg)

{

	unsigned long i;



	for (i = 0; i < nr_pages; i++) {

		if (pfn_valid(start_pfn + i) &&

		    !PageReserved(pfn_to_page(start_pfn + i)))

			return 1;

	}



	return 0;

}



/*

 * Generic mapping function (not visible outside):

 */
@@ -116,8 +131,8 @@ static int remap_area_pages(unsigned long address, phys_addr_t phys_addr, 


void __iomem * __ioremap(phys_addr_t phys_addr, phys_addr_t size, unsigned long flags)

{

	unsigned long offset, pfn, last_pfn;

	struct vm_struct * area;

	unsigned long offset;

	phys_addr_t last_addr;

	void * addr;
@@ -137,17 +152,15 @@ void __iomem * __ioremap(phys_addr_t phys_addr, phys_addr_t size, unsigned long 
		return (void __iomem *) CKSEG1ADDR(phys_addr);



	/*

	 * Don't allow anybody to remap normal RAM that we're using..

	 * Don't allow anybody to remap RAM that may be allocated by the page

	 * allocator, since that could lead to races & data clobbering.

	 */

	if (phys_addr < virt_to_phys(high_memory)) {

		char *t_addr, *t_end;

		struct page *page;



		t_addr = __va(phys_addr);

		t_end = t_addr + (size - 1);



		for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)

			if(!PageReserved(page))

	pfn = PFN_DOWN(phys_addr);

	last_pfn = PFN_DOWN(last_addr);

	if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,

				  __ioremap_check_ram) == 1) {

		WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",

			  &phys_addr, &last_addr);

		return NULL;

	}

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