Linux 5.17+ support and allow including nvdebug.h independently

- Move Linux-specific functions to nvdebug_linux.h and .c
- Workaround PDE_DATA() being pde_data() on Linux 5.17+

1 files changed, 49 insertions, 0 deletions

diff --git a/nvdebug_linux.h b/nvdebug_linux.h
new file mode 100644
index 0000000..022d1cf
--- /dev/null
+++ b/nvdebug_linux.h
@@ -0,0 +1,49 @@
+/* Copyright 2024 Joshua Bakita
+ * SPDX-License-Identifier: MIT
+ *
+ * Helpers which are kernel-specific
+ */
+#include "nvdebug.h"
+
+#include <linux/device.h>   // For dev_get_drvdata()
+#include <linux/seq_file.h> // For struct seq_file
+#include <linux/proc_fs.h>  // For pde_data() macro
+#include <linux/version.h>  // For KERNEL_VERSION and LINUX_VERSION_CODE
+
+static inline struct gk20a *get_gk20a(struct device *dev) {
+        // Only works because gk20a* is the first member of gk20a_platform
+        return *((struct gk20a**)dev_get_drvdata(dev));
+}
+
+// PDE_DATA was Renamed to pde_data in Linux 5.17 to deconflict with a driver
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5,17,0)
+#define pde_data PDE_DATA
+#endif
+
+// We us the data field of the proc_dir_entry ("PDE" in this function) to store
+// our index into the g_nvdebug_state array
+static inline int seq2gpuidx(struct seq_file *s) {
+        const struct file *f = s->file;
+        return (uintptr_t)pde_data(file_inode(f));
+}
+static inline int file2gpuidx(const struct file *f) {
+        return (uintptr_t)pde_data(file_inode(f));
+}
+static inline int file2parentgpuidx(const struct file *f) {
+        // Should be safe to call on ProcFS entries, as our parent should (?)
+        // still exist if we're called. If not, there are worse races in this
+        // module.
+        return (uintptr_t)pde_data(file_dentry(f)->d_parent->d_inode);
+}
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0)
+// Commit 643eb158a3 in nvgpu moved the mapped registers to the second entry
+// of the gk20a struct (after a function pointer). This change was made as L4T
+// was upgraded from Linux 4.9 to 5.10 (r32 -> r34+)
+// Note that this is wrong if nvgpu was built without CONFIG_NVGPU_NON_FUSA
+// i.e. if FUSA was enabled, this is wrong.
+#define gk20a_regs(gk20a) (*(void**)((void*)gk20a + sizeof(void(*)(void))))
+#else
+#include <os/linux/os_linux.h>  // For struct nvgpu_os_linux, which holds regs
+#define gk20a_regs(gk20a) (container_of(gk20a, struct nvgpu_os_linux, g)->regs)
+#endif