[PATCH v1 12/54] efi: loader: add support for tracing calls back into UEFI

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

This will be very verbose, but when trying to pinpoint what operation
is bothering an EFI payload, it's very useful to know every entry and
exit into barebox-provided services.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 common/Kconfig.debug       |   7 +++
 efi/loader/Makefile        |   1 +
 efi/loader/trace.c         |  44 +++++++++++++++
 include/efi/loader/trace.h | 111 +++++++++++++++++++++++++++++++++++++
 4 files changed, 163 insertions(+)
 create mode 100644 efi/loader/trace.c
 create mode 100644 include/efi/loader/trace.h

diff --git a/common/Kconfig.debug b/common/Kconfig.debug
index 2de885ebb3f8..64127143a5d6 100644
--- a/common/Kconfig.debug
+++ b/common/Kconfig.debug
@@ -77,6 +77,13 @@ config DEBUG_PROBES
 	  Most consoles do not implement a remove callback to remain operable until
 	  the very end. Consoles using DMA, however, must be removed.
 
+config DEBUG_EFI_LOADER_ENTRY
+	bool "Debug EFI loader entry/exit"
+	depends on EFI_LOADER
+	help
+	  If enabled, this will print whenever an EFI payload/app calls
+	  into barebox or is returned to before ExitBootServices.
+
 config DMA_API_DEBUG
 	bool "Enable debugging of DMA-API usage"
 	depends on HAS_DMA
diff --git a/efi/loader/Makefile b/efi/loader/Makefile
index 0475cfc7452f..1f07cf6005b9 100644
--- a/efi/loader/Makefile
+++ b/efi/loader/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-y += memory.o pool_alloc.o
+obj-y += trace.o
diff --git a/efi/loader/trace.c b/efi/loader/trace.c
new file mode 100644
index 000000000000..9eb22805e12e
--- /dev/null
+++ b/efi/loader/trace.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <efi/loader/trace.h>
+#include <linux/minmax.h>
+
+/* 1 if inside barebox code, 0 if inside EFI payload code */
+static int nesting_level = 1;
+
+/**
+ * indent_string() - returns a string for indenting with two spaces per level
+ * @level: indent level
+ *
+ * A maximum of ten indent levels is supported. Higher indent levels will be
+ * truncated.
+ *
+ * Return: A string for indenting with two spaces per level is
+ *         returned.
+ */
+static const char *indent_string(int level)
+{
+	const char *indent = "                    ";
+	const int max = strlen(indent);
+
+	if (level < 0)
+		return "!!EFI_EXIT called without matching EFI_ENTRY!! ";
+
+	level = min(max, level * 2);
+	return &indent[max - level];
+}
+
+const char *__efi_nesting(void)
+{
+	return indent_string(nesting_level);
+}
+
+const char *__efi_nesting_inc(void)
+{
+	return indent_string(nesting_level++);
+}
+
+const char *__efi_nesting_dec(void)
+{
+	return indent_string(--nesting_level);
+}
diff --git a/include/efi/loader/trace.h b/include/efi/loader/trace.h
new file mode 100644
index 000000000000..93bba7bb88c7
--- /dev/null
+++ b/include/efi/loader/trace.h
@@ -0,0 +1,111 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __EFI_LOADER_TRACE_H__
+#define __EFI_LOADER_TRACE_H__
+
+#include <efi/error.h>
+#include <linux/printk.h>
+
+#ifndef __EFI_PRINT
+#ifdef CONFIG_DEBUG_EFI_LOADER_ENTRY
+#define __EFI_PRINT(...)	pr_info(__VA_ARGS__)
+#define __EFI_WARN(...)		pr_warning(__VA_ARGS__)
+#else
+#define __EFI_PRINT(...)	pr_debug(__VA_ARGS__)
+#define __EFI_WARN(...)		pr_debug(__VA_ARGS__)
+#endif
+#endif
+
+const char *__efi_nesting(void);
+const char *__efi_nesting_inc(void);
+const char *__efi_nesting_dec(void);
+
+/*
+ * Enter the barebox world from UEFI:
+ */
+#ifndef EFI_ENTRY
+#define EFI_ENTRY(format, ...) do { \
+	__EFI_PRINT("%sEFI: Entry %s(" format ")\n", __efi_nesting_inc(), \
+		__func__, ##__VA_ARGS__); \
+	} while(0)
+#endif
+
+/*
+ * Exit the barebox world back to UEFI:
+ */
+#ifndef EFI_EXIT
+#define EFI_EXIT(ret) ({ \
+	typeof(ret) _r = ret; \
+	__EFI_PRINT("%sEFI: Exit: %s: %s (%u)\n", __efi_nesting_dec(), \
+		__func__, efi_strerror((uintptr_t)_r), (u32)((uintptr_t) _r & ~EFI_ERROR_MASK)); \
+	_r; \
+	})
+#endif
+
+#ifndef EFI_EXIT2
+#define EFI_EXIT2(ret, val) ({ \
+	typeof(ret) _r = ret; \
+	__EFI_PRINT("%sEFI: Exit: %s: %s (%u) = 0x%llx\n", __efi_nesting_dec(), \
+		__func__, efi_strerror((uintptr_t)_r), (u32)((uintptr_t) _r & ~EFI_ERROR_MASK), \
+		(u64)(uintptr_t)(val)); \
+	_r; \
+	})
+#endif
+
+/*
+ * Call non-void UEFI function from barebox and retrieve return value:
+ */
+#ifndef EFI_CALL
+#define EFI_CALL(exp) ({ \
+	__EFI_PRINT("%sEFI: Call: %s\n", __efi_nesting_inc(), #exp); \
+	typeof(exp) _r = exp; \
+	__EFI_PRINT("%sEFI: %lu returned by %s\n", __efi_nesting_dec(), \
+	      (unsigned long)((uintptr_t)_r & ~EFI_ERROR_MASK), #exp); \
+	_r; \
+})
+#endif
+
+/**
+ * define EFI_RETURN() - return from EFI_CALL in efi_start_image()
+ *
+ * @ret:	status code
+ */
+#ifndef EFI_RETURN
+#define EFI_RETURN(ret) ({ \
+	typeof(ret) _r = ret; \
+	__EFI_PRINT("%sEFI: %lu returned by started image", __efi_nesting_dec(), \
+		    (unsigned long)((uintptr_t)_r & ~EFI_ERROR_MASK)); \
+})
+#endif
+
+/*
+ * Call void UEFI function from barebox:
+ */
+#ifndef EFI_CALL_VOID
+#define EFI_CALL_VOID(exp) do { \
+	__EFI_PRINT("%sEFI: Call: %s\n", __efi_nesting_inc(), #exp); \
+	exp; \
+	__EFI_PRINT("%sEFI: Return From: %s\n", __efi_nesting_dec(), #exp); \
+	} while(0)
+#endif
+
+/*
+ * Write an indented message with EFI prefix
+ */
+#ifndef EFI_PRINT
+#define EFI_PRINT(format, ...) ({ \
+	__EFI_PRINT("%sEFI: " format, __efi_nesting(), \
+		##__VA_ARGS__); \
+	})
+#endif
+
+/*
+ * Write an indented warning with EFI prefix
+ */
+#ifndef EFI_WARN
+#define EFI_WARN(format, ...) ({ \
+	__EFI_WARN("%sEFI: " format, __efi_nesting(), \
+		##__VA_ARGS__); \
+	})
+#endif
+
+#endif
-- 
2.47.3