Skip to content

Commit

Permalink
x86 mmiotrace: WARN_ONCE if dis/arming a page fails
Browse files Browse the repository at this point in the history
Print a full warning once, if arming or disarming a page fails.

Also, if initial arming fails, do not handle the page further. This
avoids the possibility of a page failing to arm and then later claiming
to have handled any fault on that page.

WARN_ONCE added by Pekka Paalanen.

Signed-off-by: Stuart Bennett <stuart@freedesktop.org>
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
  • Loading branch information
Stuart Bennett authored and Ingo Molnar committed Mar 2, 2009
1 parent 5ff9369 commit e9d54ca
Showing 1 changed file with 17 additions and 8 deletions.
25 changes: 17 additions & 8 deletions arch/x86/mm/kmmio.c
Original file line number Diff line number Diff line change
Expand Up @@ -105,7 +105,7 @@ static struct kmmio_fault_page *get_kmmio_fault_page(unsigned long page)
return NULL;
}

static void set_page_present(unsigned long addr, bool present,
static int set_page_present(unsigned long addr, bool present,
unsigned int *pglevel)
{
pteval_t pteval;
Expand All @@ -116,7 +116,7 @@ static void set_page_present(unsigned long addr, bool present,

if (!pte) {
pr_err("kmmio: no pte for page 0x%08lx\n", addr);
return;
return -1;
}

if (pglevel)
Expand All @@ -140,22 +140,27 @@ static void set_page_present(unsigned long addr, bool present,

default:
pr_err("kmmio: unexpected page level 0x%x.\n", level);
return;
return -1;
}

__flush_tlb_one(addr);

return 0;
}

/** Mark the given page as not present. Access to it will trigger a fault. */
static void arm_kmmio_fault_page(unsigned long page, unsigned int *pglevel)
static int arm_kmmio_fault_page(unsigned long page, unsigned int *pglevel)
{
set_page_present(page & PAGE_MASK, false, pglevel);
int ret = set_page_present(page & PAGE_MASK, false, pglevel);
WARN_ONCE(ret < 0, KERN_ERR "kmmio arming 0x%08lx failed.\n", page);
return ret;
}

/** Mark the given page as present. */
static void disarm_kmmio_fault_page(unsigned long page, unsigned int *pglevel)
{
set_page_present(page & PAGE_MASK, true, pglevel);
int ret = set_page_present(page & PAGE_MASK, true, pglevel);
WARN_ONCE(ret < 0, KERN_ERR "kmmio disarming 0x%08lx failed.\n", page);
}

/*
Expand Down Expand Up @@ -326,9 +331,13 @@ static int add_kmmio_fault_page(unsigned long page)

f->count = 1;
f->page = page;
list_add_rcu(&f->list, kmmio_page_list(f->page));

arm_kmmio_fault_page(f->page, NULL);
if (arm_kmmio_fault_page(f->page, NULL)) {
kfree(f);
return -1;
}

list_add_rcu(&f->list, kmmio_page_list(f->page));

return 0;
}
Expand Down

0 comments on commit e9d54ca

Please sign in to comment.