From 33d839a72a47ddfebffb8ab72510fdeed3dca9fd Mon Sep 17 00:00:00 2001
From: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Date: Fri, 6 Dec 2024 10:50:46 -0500
Subject: [PATCH] util/printf: add context-ful helpers

drivers wishing to integrate driver CL printf/abort have to do some delicate
dances to maintain the data structure with the buffer size and abort flag. wrap
it all up in common helpers -- the driver just supplies the memory allocation
and calls in periodically.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Konstantin Seurer <konstantin.seurer@gmail.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32564>
---
 src/util/u_printf.h | 60 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/src/util/u_printf.h b/src/util/u_printf.h
index 8e00067f20b..82d0d337f87 100644
--- a/src/util/u_printf.h
+++ b/src/util/u_printf.h
@@ -25,6 +25,7 @@
 #include <stdarg.h>
 #include <stddef.h>
 #include <stdio.h>
+#include "simple_mtx.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -37,6 +38,12 @@ typedef struct u_printf_info {
    char *strings;
 } u_printf_info;
 
+struct u_printf_ctx {
+   simple_mtx_t lock;
+   void *bo;
+   uint32_t *map;
+};
+
 const char *util_printf_prev_tok(const char *str);
 
 /* find next valid printf specifier in a C string wrapper */
@@ -55,6 +62,59 @@ void u_printf(FILE *out, const char *buffer, size_t buffer_size,
 void u_printf_ptr(FILE *out, const char *buffer, size_t buffer_size,
                   const u_printf_info **info, unsigned info_size);
 
+static inline void
+u_printf_init(struct u_printf_ctx *ctx, void *bo, uint32_t *map)
+{
+   ctx->bo = bo;
+   ctx->map = map;
+   simple_mtx_init(&ctx->lock, mtx_plain);
+
+   /* Initialize the buffer head to point to just after the size + abort word */
+   map[0] = 8;
+
+   /* Initially there is no abort */
+   map[1] = 0;
+}
+
+static inline void
+u_printf_destroy(struct u_printf_ctx *ctx)
+{
+   simple_mtx_destroy(&ctx->lock);
+}
+
+static inline void
+u_printf_with_ctx(FILE *out, struct u_printf_ctx *ctx,
+                  const u_printf_info *info, unsigned info_size)
+{
+   /* If the printf buffer is empty, early-exit without taking the lock. The
+    * speeds up the happy path and makes this function reasonable to call even
+    * in release builds.
+    */
+   if (ctx->map[0] == 8)
+      return;
+
+   simple_mtx_lock(&ctx->lock);
+   u_printf(out, (char *)(ctx->map + 2), ctx->map[0] - 8, info, info_size);
+
+   /* Reset */
+   ctx->map[0] = 8;
+   simple_mtx_unlock(&ctx->lock);
+}
+
+/*
+ * Flush the printf buffer and return whether there was an abort. This is
+ * intended to be called periodically to handle aborts in a timely manner.
+ */
+static inline bool
+u_printf_check_abort(FILE *out, struct u_printf_ctx *ctx,
+                     const u_printf_info *info, unsigned info_size)
+{
+   u_printf_with_ctx(out, ctx, info, info_size);
+
+   /* Check the aborted flag */
+   return (ctx->map[1] != 0);
+}
+
 #ifdef __cplusplus
 }
 #endif