Most of the code for Crashdump Accepting Active IOMMU is contained
in a large section at the end of intel-iommu.c -- beginning here.
This patch contains small utility functions used to access the
bit fields of the context entry, plus one to copy from a physically-
addressed area of memory (primarily pages from the panicked kernel)
into a virtually-addressed area within the crashdump kernel.
v1->v2:
Updated patch description
Signed-off-by: Bill Sumner <bill.sumner at hp.com>
---
drivers/iommu/intel-iommu.c | 74 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 74 insertions(+)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 17c4537..4172a2b 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4455,3 +4455,77 @@ static void __init check_tylersburg_isoch(void)
printk(KERN_WARNING "DMAR: Recommended TLB entries for ISOCH unit is 16; your BIOS set %d\n",
vtisochctrl);
}
+#ifdef CONFIG_CRASH_DUMP
+
+/* ========================================================================
+ * Utility functions for accessing the iommu Translation Tables
+ * ------------------------------------------------------------------------
+ */
+static inline struct context_entry *
+get_context_phys_from_root(struct root_entry *root)
+{
+ return (struct context_entry *)
+ (root_present(root) ? (void *) (root->val & VTD_PAGE_MASK)
+ : NULL);
+}
+
+static int
+context_get_p(struct context_entry *c) {return((c->lo >> 0) & 0x1); }
+
+static int
+context_get_fpdi(struct context_entry *c) {return((c->lo >> 1) & 0x1); }
+
+static int
+context_get_t(struct context_entry *c) {return((c->lo >> 2) & 0x3); }
+
+static u64
+context_get_asr(struct context_entry *c) {return((c->lo >> 12)); }
+
+static int
+context_get_aw(struct context_entry *c) {return((c->hi >> 0) & 0x7); }
+
+static int
+context_get_aval(struct context_entry *c) {return((c->hi >> 3) & 0xf); }
+
+static int
+context_get_did(struct context_entry *c) {return((c->hi >> 8) & 0xffff); }
+
+static void context_put_asr(struct context_entry *c, unsigned long asr)
+{
+ c->lo &= (~VTD_PAGE_MASK);
+ c->lo |= (asr << VTD_PAGE_SHIFT);
+}
+
+
+/*
+ * Copy memory from a physically-addressed area into a virtually-addressed area
+ */
+static int oldcopy(void *to, void *from, int size)
+{
+ size_t ret = 0; /* Length copied */
+ unsigned long pfn; /* Page Frame Number */
+ char *buf = to; /* Adr(Output buffer) */
+ size_t csize = (size_t)size; /* Num(bytes to copy) */
+ unsigned long offset; /* Lower 12 bits of from */
+ int userbuf = 0; /* to is in kernel space */
+
+ if (pr_dbg.enter_oldcopy)
+ pr_debug("ENTER %s to=%16.16llx, from = %16.16llx, size = %d\n",
+ __func__,
+ (unsigned long long) to,
+ (unsigned long long) from, size);
+
+ if (intel_iommu_translation_tables_are_mapped)
+ memcpy(to, phys_to_virt((phys_addr_t)from), csize);
+ else {
+ pfn = ((unsigned long) from) >> VTD_PAGE_SHIFT;
+ offset = ((unsigned long) from) & (~VTD_PAGE_MASK);
+ ret = copy_oldmem_page(pfn, buf, csize, offset, userbuf);
+ }
+
+ if (pr_dbg.leave_oldcopy)
+ pr_debug("LEAVE %s ret=%d\n", __func__, (int) ret);
+
+ return (int) ret;
+}
+#endif /* CONFIG_CRASH_DUMP */
--
Bill Sumner <bill.sumner at hp.com>
