1 files changed, 28 insertions, 4 deletions

diff --git a/runlist.c b/runlist.c
index f6a05ac..ed35c7e 100644
--- a/runlist.c
+++ b/runlist.c
@@ -2,6 +2,8 @@
 
 #include "nvdebug.h"
 
+#define FALLBACK_TO_PRAMIN
+
 /* Get runlist head and info (incl. length)
    @param rl_iter Location at which to store output
    @param rl_id   Which runlist to obtain?
@@ -61,7 +63,7 @@ int get_runlist_iter(struct nvdebug_state *g, int rl_id, struct runlist_iter *rl
                 uint32_t bar_inst_pramin_offset = vram2PRAMIN(g, (uint64_t)bar2_block.ptr << 12);
                 if (!bar_inst_pramin_offset) {
                         printk(KERN_WARNING "[nvdebug] Unable to find instance block for BAR2/3 in the current NV_PRAMIN window. VRAM inaccessible.\n");
-                        return -EOPNOTSUPP;
+                        goto attempt_pramin_access;
                 }
                 /* TODO: Support BAR1?
                 bar_inst_pramin_offset = vram2PRAMIN(g, bar1_block.ptr << 12);
@@ -82,12 +84,12 @@ int get_runlist_iter(struct nvdebug_state *g, int rl_id, struct runlist_iter *rl
                 // TODO: SYSMEM support for page table location
                 if (pd_config.target != TARGET_VID_MEM) {
                         printk(KERN_WARNING "[nvdebug] BAR2 PDB is in an unsupported location.\n");
-                        return -EOPNOTSUPP;
+                        goto attempt_pramin_access;
                 }
                 uint32_t bar_pdb_pramin_offset = vram2PRAMIN(g, bar_pdb_vram_addr);
                 if (!bar_pdb_pramin_offset) {
                         printk(KERN_WARNING "[nvdebug] Unable to find page directory BAR2/3 in the current NV_PRAMIN window. VRAM inaccessible.\n");
-                        return -EOPNOTSUPP;
+                        goto attempt_pramin_access;
                 }
                 uint64_t runlist_bar_vaddr;
                 if (pd_config.is_ver2)
@@ -96,7 +98,7 @@ int get_runlist_iter(struct nvdebug_state *g, int rl_id, struct runlist_iter *rl
                         runlist_bar_vaddr = search_v1_page_directory(g, g->regs + NV_PRAMIN + bar_pdb_pramin_offset, phy2PRAMIN, runlist_iova);
                 if (!runlist_bar_vaddr) {
                         printk(KERN_WARNING "[nvdebug] Unable to find runlist mapping in BAR2/3 page tables.\n");
-                        return -EOPNOTSUPP;
+                        goto attempt_pramin_access;
                 }
                 printk(KERN_INFO "[nvdebug] Runlist @ %llx in BAR2 virtual address space.\n", runlist_bar_vaddr);
                 /* XXX: Old test code
@@ -121,6 +123,28 @@ int get_runlist_iter(struct nvdebug_state *g, int rl_id, struct runlist_iter *rl
         }
         rl_iter->rl_info = rl_info;
         return 0;
+attempt_pramin_access:
+#ifdef FALLBACK_TO_PRAMIN
+        printk(KERN_INFO "[nvdebug] Attempting to move PRAMIN window to runlist as BAR2/3-based access failed [DANGEROUS SIDE EFFECTS]!\n");
+        bar0_window_t win;
+        win.base = (runlist_iova >> 16);
+        win.target = TARGET_VID_MEM;
+        // Shift PRAMIN window. This will cause problems if it races with driver code
+        // that tries to do the same, or expects the window not to move.
+        nvdebug_writel(g, NV_PBUS_BAR0_WINDOW, win.raw);
+        uint32_t off = vram2PRAMIN(g, runlist_iova);
+        // Workaround bug for if `off` should be zero (vram2PRAMIN normally returns
+        // this on error)
+        if (!off && (runlist_iova & 0xffffull != runlist_iova)) {
+                printk(KERN_INFO "[nvdebug] Unable to shift PRAMIN to runlist. Aborting...\n");
+                return -EOPNOTSUPP;
+        }
+        rl_iter->curr_entry = g->regs + NV_PRAMIN + off;
+        rl_iter->rl_info = rl_info;
+        return 0;
+#else
+        return -EOPNOTSUPP;
+#endif // FALLBACK_TO_PRAMIN
 }
 
 int preempt_tsg(struct nvdebug_state *g, uint32_t tsg_id) {