extern int kernel_set_to_readonly;
#ifdef CONFIG_X86_64
-static inline int set_mce_nospec(unsigned long pfn)
+/*
+ * Prevent speculative access to the page by either unmapping
+ * it (if we do not require access to any part of the page) or
+ * marking it uncacheable (if we want to try to retrieve data
+ * from non-poisoned lines in the page).
+ */
+static inline int set_mce_nospec(unsigned long pfn, bool unmap)
{
unsigned long decoy_addr;
int rc;
/*
- * Mark the linear address as UC to make sure we don't log more
- * errors because of speculative access to the page.
* We would like to just call:
- * set_memory_uc((unsigned long)pfn_to_kaddr(pfn), 1);
+ * set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);
* but doing that would radically increase the odds of a
* speculative access to the poison page because we'd have
* the virtual address of the kernel 1:1 mapping sitting
* around in registers.
* Instead we get tricky. We create a non-canonical address
* that looks just like the one we want, but has bit 63 flipped.
- * This relies on set_memory_uc() properly sanitizing any __pa()
+ * This relies on set_memory_XX() properly sanitizing any __pa()
* results with __PHYSICAL_MASK or PTE_PFN_MASK.
*/
decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63));
- rc = set_memory_uc(decoy_addr, 1);
+ if (unmap)
+ rc = set_memory_np(decoy_addr, 1);
+ else
+ rc = set_memory_uc(decoy_addr, 1);
if (rc)
pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn);
return rc;
}
EXPORT_SYMBOL_GPL(mce_is_memory_error);
+static bool whole_page(struct mce *m)
+{
+ if (!mca_cfg.ser || !(m->status & MCI_STATUS_MISCV))
+ return true;
+
+ return MCI_MISC_ADDR_LSB(m->misc) >= PAGE_SHIFT;
+}
+
bool mce_is_correctable(struct mce *m)
{
if (m->cpuvendor == X86_VENDOR_AMD && m->status & MCI_STATUS_DEFERRED)
pfn = mce->addr >> PAGE_SHIFT;
if (!memory_failure(pfn, 0)) {
- set_mce_nospec(pfn);
+ set_mce_nospec(pfn, whole_page(mce));
mce->kflags |= MCE_HANDLED_UC;
}
int flags = MF_ACTION_REQUIRED;
pr_err("Uncorrected hardware memory error in user-access at %llx", p->mce_addr);
- if (!(p->mce_status & MCG_STATUS_RIPV))
+
+ if (!p->mce_ripv)
flags |= MF_MUST_KILL;
if (!memory_failure(p->mce_addr >> PAGE_SHIFT, flags)) {
- set_mce_nospec(p->mce_addr >> PAGE_SHIFT);
+ set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page);
return;
}
BUG_ON(!on_thread_stack() || !user_mode(regs));
current->mce_addr = m.addr;
- current->mce_status = m.mcgstatus;
+ current->mce_ripv = !!(m.mcgstatus & MCG_STATUS_RIPV);
+ current->mce_whole_page = whole_page(&m);
current->mce_kill_me.func = kill_me_maybe;
if (kill_it)
current->mce_kill_me.func = kill_me_now;