[PATCH] display_options: Do not use %llu in print_size

[PATCH] display_options: Do not use %llu in print_size

[Matwey V. Kornilov]

tiny-printf variant doesn't know how to handle %llu format string, but both
tiny-printf and print_size can meet in SPL when TFTP is used to obtain main
u-boot image. This is known to lead to critical boot issue at AM335x platform
when printf is catched in infinite loop.

To avoid such issues and make print_size function tiny-printf friendly, use %u
instead of %luu. Note, that the size value is guaranteed to be less than 1024
in this conditional branch, so the cast to unsigned int is safe.

Signed-off-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
---
 lib/display_options.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/display_options.c b/lib/display_options.c
index c08a87e316..4da1f5244f 100644
--- a/lib/display_options.c
+++ b/lib/display_options.c
@@ -107,7 +107,12 @@ void print_size(uint64_t size, const char *s)
 	}
 
 	if (!c) {
-		printf("%llu Bytes%s", size, s);
+		/*
+		 * SPL tiny-printf is not capable for printing uint64_t.
+		 * We have just checked that the size is small enought to fit
+		 * unsigned int safely.
+		 */
+		printf("%u Bytes%s", (unsigned int)size, s);
 		return;
 	}
 
-- 
2.31.1

Re: [PATCH] display_options: Do not use %llu in print_size

[Simon Glass]

On Thu, 5 Aug 2021 at 15:23, Matwey V. Kornilov
<matwey.kornilov@gmail.com> wrote:
>
> tiny-printf variant doesn't know how to handle %llu format string, but both
> tiny-printf and print_size can meet in SPL when TFTP is used to obtain main
> u-boot image. This is known to lead to critical boot issue at AM335x platform
> when printf is catched in infinite loop.
>
> To avoid such issues and make print_size function tiny-printf friendly, use %u
> instead of %luu. Note, that the size value is guaranteed to be less than 1024
> in this conditional branch, so the cast to unsigned int is safe.
>
> Signed-off-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
> ---
>  lib/display_options.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)

Reviewed-by: Simon Glass <sjg@chromium.org>

Re: [PATCH] display_options: Do not use %llu in print_size

[Tom Rini]

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On Fri, Aug 06, 2021 at 12:22:58AM +0300, Matwey V. Kornilov wrote:

> tiny-printf variant doesn't know how to handle %llu format string, but both
> tiny-printf and print_size can meet in SPL when TFTP is used to obtain main
> u-boot image. This is known to lead to critical boot issue at AM335x platform
> when printf is catched in infinite loop.
> 
> To avoid such issues and make print_size function tiny-printf friendly, use %u
> instead of %luu. Note, that the size value is guaranteed to be less than 1024
> in this conditional branch, so the cast to unsigned int is safe.
> 
> Signed-off-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
> Reviewed-by: Simon Glass <sjg@chromium.org>

Applied to u-boot/master, thanks!

-- 
Tom

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