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x86 mmiotrace: WARN_ONCE if dis/arming a page fails

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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>
This commit is contained in:
Stuart Bennett 2009-01-30 17:38:59 +00:00 committed by Ingo Molnar
parent 5ff93697fc
commit e9d54cae8f
1 changed files with 17 additions and 8 deletions
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25
arch/x86/mm/kmmio.c
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@ -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;
@ -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)
@ -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);
}
/*
@ -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;
}