SPL: tiny-printf: avoid any BSS usage
PATCH 1/1 SPL: tiny-printf: avoid any BSS usage
As printf calls may be executed quite early, we should avoid using any BSS stored variables, since some boards put BSS in DRAM, which may not have been initialised yet.
Explicitly mark those "static global" variables as belonging to the .data section, to keep tiny-printf clear of any BSS usage. Please note that this is quite a hack (which may need to be extended to other source files) and more sustainable solutions are warmly welcomed.
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Hi,
as mentioned before I don't like this hack very much, but as this fixes the WIP Pine64 SPL code I propose this solution for 2016.07.
Cheers,
Andre
lib/tiny-printf.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
lib/tiny-printf.c +10 -3
@@ -13,11 +13,18 @@#include <stdarg.h> #include <serial.h> -static char *bf; -static char zs; +/* +* This code in here may execute before the DRAM is initialised, so +* we should make sure that it doesn't touch BSS, which some boards +* put in DRAM. +*/ +#define NO_BSS __attribute__((section(".data"))) + +static char *bf NO_BSS; +static char zs NO_BSS;/* Current position in sprintf() output string */ -static char *outstr; +static char *outstr NO_BSS;static void out (char c) {
Signature · 1 line
2.8.2
PATCH 1/1 SPL: tiny-printf: avoid any BSS usage
Quoted 27 lines · Andre Przywara
As printf calls may be executed quite early, we should avoid using any BSS stored variables, since some boards put BSS in DRAM, which may not have been initialised yet.
Explicitly mark those "static global" variables as belonging to the .data section, to keep tiny-printf clear of any BSS usage. Please note that this is quite a hack (which may need to be extended to other source files) and more sustainable solutions are warmly welcomed.Signed-off-by Andre Przywara <[email protected]>---
Hi,as mentioned before I don't like this hack very much, but as this fixes the WIP Pine64 SPL code I propose this solution for 2016.07.
Cheers,
Andrelib/tiny-printf.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)lib/tiny-printf.c +0
-0@@ -13,11 +13,18 @@#include <stdarg.h>
lib/tiny-printf.c line 21
Quoted 10 lines
lib/tiny-printf.c +6
-2#include <serial.h> -static char *bf; -static char zs; +/* +* This code in here may execute before the DRAM is initialised, so +* we should make sure that it doesn't touch BSS, which some boards +* put in DRAM. +*/ +#define NO_BSS __attribute__((section(".data")))
Please don't introduce new macros, it's really not necessary here, the comment is enough.
Quoted 10 lines
lib/tiny-printf.c +3
-1+static char *bf NO_BSS; +static char zs NO_BSS;/* Current position in sprintf() output string */ -static char *outstr; +static char *outstr NO_BSS;static void out (char c) {
Signature · 2 lines
Best regards, Marek Vasut
PATCH 1/1 SPL: tiny-printf: avoid any BSS usage
Quoted 30 lines · Marek Vasut
Quoted 29 lines · Andre Przywara
As printf calls may be executed quite early, we should avoid using any BSS stored variables, since some boards put BSS in DRAM, which may not have been initialised yet.
Explicitly mark those "static global" variables as belonging to the .data section, to keep tiny-printf clear of any BSS usage. Please note that this is quite a hack (which may need to be extended to other source files) and more sustainable solutions are warmly welcomed.Signed-off-by Andre Przywara <[email protected]>---
Hi,as mentioned before I don't like this hack very much, but as this fixes the WIP Pine64 SPL code I propose this solution for 2016.07.
Cheers,
Andre
lib/tiny-printf.c| 13 ++++++++++---1 file changed, 10 insertions(+), 3 deletions(-)lib/tiny-printf.c +0
-0@@ -13,11 +13,18 @@#include <stdarg.h> #include <serial.h>
Quoted 11 lines
lib/tiny-printf.c line 21
Quoted 8 lines
lib/tiny-printf.c +6
-2-static char *bf; -static char zs; +/* +* This code in here may execute before the DRAM is initialised, so +* we should make sure that it doesn't touch BSS, which some boards +* put in DRAM. +*/ +#define NO_BSS __attribute__((section(".data")))Please don't introduce new macros, it's really not necessary here, the comment is enough.
And would also match the other areas where we have to do something "ugly" like this in order to function within constraints. Frankly, I don't see this exactly as a hack, but it should be tested on a few more platforms just to be safe.
Signature · 8 lines
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PATCH 1/1 SPL: tiny-printf: avoid any BSS usage
In reply to Andre PrzywaraQuoted 10 lines · Andre Przywara
As printf calls may be executed quite early, we should avoid using any BSS stored variables, since some boards put BSS in DRAM, which may not have been initialised yet.
Explicitly mark those "static global" variables as belonging to the .data section, to keep tiny-printf clear of any BSS usage. Please note that this is quite a hack (which may need to be extended to other source files) and more sustainable solutions are warmly welcomed.Signed-off-by Andre Przywara <[email protected]>---
There is atleast one place where I encountered same issue:drivers/i2c/i2c-uclass-compact.c:
static int cur_busnum;
I could verify that the below macro helps in that case as well.
Quoted 31 lines
lib/tiny-printf.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)lib/tiny-printf.c +10
-3@@ -13,11 +13,18 @@#include <stdarg.h> #include <serial.h> -static char *bf; -static char zs; +/* +* This code in here may execute before the DRAM is initialised, so +* we should make sure that it doesn't touch BSS, which some boards +* put in DRAM. +*/ +#define NO_BSS __attribute__((section(".data"))) + +static char *bf NO_BSS; +static char zs NO_BSS;/* Current position in sprintf() output string */ -static char *outstr; +static char *outstr NO_BSS;static void out (char c) {
Signature · 2 lines
Regards Vignesh