forked from Minki/linux
x86 mmiotrace: WARN_ONCE if dis/arming a page fails
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>
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@ -105,7 +105,7 @@ static struct kmmio_fault_page *get_kmmio_fault_page(unsigned long page)
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return NULL;
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return NULL;
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}
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}
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static void set_page_present(unsigned long addr, bool present,
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static int set_page_present(unsigned long addr, bool present,
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unsigned int *pglevel)
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unsigned int *pglevel)
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{
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{
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pteval_t pteval;
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pteval_t pteval;
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@ -116,7 +116,7 @@ static void set_page_present(unsigned long addr, bool present,
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if (!pte) {
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if (!pte) {
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pr_err("kmmio: no pte for page 0x%08lx\n", addr);
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pr_err("kmmio: no pte for page 0x%08lx\n", addr);
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return;
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return -1;
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}
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}
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if (pglevel)
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if (pglevel)
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@ -140,22 +140,27 @@ static void set_page_present(unsigned long addr, bool present,
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default:
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default:
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pr_err("kmmio: unexpected page level 0x%x.\n", level);
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pr_err("kmmio: unexpected page level 0x%x.\n", level);
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return;
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return -1;
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}
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}
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__flush_tlb_one(addr);
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__flush_tlb_one(addr);
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return 0;
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}
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}
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/** Mark the given page as not present. Access to it will trigger a fault. */
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/** Mark the given page as not present. Access to it will trigger a fault. */
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static void arm_kmmio_fault_page(unsigned long page, unsigned int *pglevel)
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static int arm_kmmio_fault_page(unsigned long page, unsigned int *pglevel)
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{
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{
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set_page_present(page & PAGE_MASK, false, pglevel);
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int ret = set_page_present(page & PAGE_MASK, false, pglevel);
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WARN_ONCE(ret < 0, KERN_ERR "kmmio arming 0x%08lx failed.\n", page);
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return ret;
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}
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}
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/** Mark the given page as present. */
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/** Mark the given page as present. */
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static void disarm_kmmio_fault_page(unsigned long page, unsigned int *pglevel)
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static void disarm_kmmio_fault_page(unsigned long page, unsigned int *pglevel)
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{
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{
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set_page_present(page & PAGE_MASK, true, pglevel);
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int ret = set_page_present(page & PAGE_MASK, true, pglevel);
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WARN_ONCE(ret < 0, KERN_ERR "kmmio disarming 0x%08lx failed.\n", page);
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}
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}
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/*
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/*
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@ -326,9 +331,13 @@ static int add_kmmio_fault_page(unsigned long page)
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f->count = 1;
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f->count = 1;
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f->page = page;
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f->page = page;
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list_add_rcu(&f->list, kmmio_page_list(f->page));
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arm_kmmio_fault_page(f->page, NULL);
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if (arm_kmmio_fault_page(f->page, NULL)) {
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kfree(f);
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return -1;
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}
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list_add_rcu(&f->list, kmmio_page_list(f->page));
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return 0;
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return 0;
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}
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}
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