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authorLinus Torvalds <torvalds@linux-foundation.org>2018-07-11 02:18:09 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-07-11 02:18:09 +0300
commit1e09177acae32a61586af26d83ca5ef591cdcaf5 (patch)
treed57340607c1c0c9623157afcc448f3e243485390 /arch
parent30c2c32d7f703530a6a0c9d2435117a9907d7109 (diff)
parent523402fa9101090c91d2033b7ebdfdcf65880488 (diff)
downloadlinux-1e09177acae32a61586af26d83ca5ef591cdcaf5.tar.xz
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()
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/kernel/process.c43
-rw-r--r--arch/mips/kernel/traps.c1
-rw-r--r--arch/mips/mm/ioremap.c37
3 files changed, 55 insertions, 26 deletions
diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 8d85046adcc8..9670e70139fd 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -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)
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index d67fa74622ee..8d505a21396e 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -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)
diff --git a/arch/mips/mm/ioremap.c b/arch/mips/mm/ioremap.c
index 1986e09fb457..1601d90b087b 100644
--- a/arch/mips/mm/ioremap.c
+++ b/arch/mips/mm/ioremap.c
@@ -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;
@@ -137,18 +152,16 @@ 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))
- return NULL;
+ 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;
}
/*