[U-Boot] [PATCH 0/2] improve hello_world standalone application for arm
This series addresses - hardcoded entry address, use LOADADDR if available as the entry point instead - fix thumb build, jumping with 'go' to the entry point expects arm code
Note that in addition to the two fixes I've seen random freezes or 'random' printed stuff when using an early linaro gcc 6 compiler. Adding an initialized variable helped in that case static int dummy_var_in_text = 1; I assume that this forces alignment of some linker sections. (e.g. I see that __bss_start points to 0x1201027e, with the variable this moves to 0x12010280)
However with the current linaro compilers this does not happen so I don't propose a patch for this issue. Linaro GCC 5.4-2017.05 5.4.1 20170404 Linaro GCC 6.3-2017.05 6.3.1 20170404 Linaro GCC 7.1-2017.05 7.1.1 20170510
This series is available at http://git.toradex.com/cgit/u-boot-toradex.git/log/?h=for-next
Max Krummenacher (2): arm: use $loadaddr as the standalone entry point hello_world.c: fix entry point in case of arm thumb binary
arch/arm/config.mk | 4 ++++ doc/README.standalone | 2 +- examples/standalone/hello_world.c | 15 +++++++++++++++ 3 files changed, 20 insertions(+), 1 deletion(-)
Different SoCs have different RAM layouts, so providing $(CONFIG_LOADADDR) instead of the constant 0xc100000 for CONFIG_STANDALONE_LOAD_ADDR is probably more appropriate.
Signed-off-by: Max Krummenacher max.krummenacher@toradex.com ---
arch/arm/config.mk | 4 ++++ doc/README.standalone | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/arm/config.mk b/arch/arm/config.mk index 1a77779db4..8f56c7433f 100644 --- a/arch/arm/config.mk +++ b/arch/arm/config.mk @@ -9,7 +9,11 @@ ifndef CONFIG_STANDALONE_LOAD_ADDR ifneq ($(CONFIG_ARCH_OMAP2PLUS),) CONFIG_STANDALONE_LOAD_ADDR = 0x80300000 else +ifndef CONFIG_LOADADDR CONFIG_STANDALONE_LOAD_ADDR = 0xc100000 +else +CONFIG_STANDALONE_LOAD_ADDR = $(CONFIG_LOADADDR) +endif endif endif
diff --git a/doc/README.standalone b/doc/README.standalone index 659a12f6cb..17d740c44b 100644 --- a/doc/README.standalone +++ b/doc/README.standalone @@ -53,7 +53,7 @@ Design Notes on Exporting U-Boot Functions to Standalone Applications: Load address Start address x86 0x00040000 0x00040000 PowerPC 0x00040000 0x00040004 - ARM 0x0c100000 0x0c100000 + ARM CONFIG_LOADADDR CONFIG_LOADADDR MIPS 0x80200000 0x80200000 Blackfin 0x00001000 0x00001000 NDS32 0x00300000 0x00300000
Dear Max,
In message 20170812090346.7887-2-max.krummenacher@toradex.com you wrote:
Different SoCs have different RAM layouts, so providing $(CONFIG_LOADADDR) instead of the constant 0xc100000 for CONFIG_STANDALONE_LOAD_ADDR is probably more appropriate.
At least the wording of the Subject should be fixed.
It is fundamentaaly broken to associate the names "loadaddr" and "entry point" with each other. Both are completely independent entities which mean totally different things. It is pure chance if the entry point of some loaded image should be at the very beginning of this image, but this is almost never the case.
Best regards,
Wolfgang Denk
Dear Wolfgang
Am Samstag, den 12.08.2017, 20:29 +0200 schrieb Wolfgang Denk:
Dear Max,
In message 20170812090346.7887-2-max.krummenacher@toradex.com you wrote:
Different SoCs have different RAM layouts, so providing $(CONFIG_LOADADDR) instead of the constant 0xc100000 for CONFIG_STANDALONE_LOAD_ADDR is probably more appropriate.
At least the wording of the Subject should be fixed.
Ok, will do. The issue is that linking the standalone application to have its text segment at a hardcoded address is less likely to work than using an address provided by the board configuration as a possible load address.
Will reword the commit message in a v2 series accordingly.
Max
It is fundamentaaly broken to associate the names "loadaddr" and "entry point" with each other. Both are completely independent entities which mean totally different things. It is pure chance if the entry point of some loaded image should be at the very beginning of this image, but this is almost never the case.
Best regards,
Wolfgang Denk
Dear Max,
In message 1502572898.17070.11.camel@gmail.com you wrote:
Ok, will do. The issue is that linking the standalone application to have its text segment at a hardcoded address is less likely to work than using an address provided by the board
This may (or may not) be the case - but no matter how youlook at it, chosing CONFIG_LOADADDR is definitely the wrong approach, as the LOAD address has nothing to do with the ENTRY point address, so it must in no case ever play a role when linking an image.
configuration as a possible load address.
You are confused in your wording, and I'm afraid in your thinking, too.
load address != entry point.
Best regards,
Wolfgang Denk
On Mon, Aug 14, 2017 at 09:36:35PM +0200, Wolfgang Denk wrote:
Dear Max,
In message 1502572898.17070.11.camel@gmail.com you wrote:
Ok, will do. The issue is that linking the standalone application to have its text segment at a hardcoded address is less likely to work than using an address provided by the board
This may (or may not) be the case - but no matter how youlook at it, chosing CONFIG_LOADADDR is definitely the wrong approach, as the LOAD address has nothing to do with the ENTRY point address, so it must in no case ever play a role when linking an image.
configuration as a possible load address.
You are confused in your wording, and I'm afraid in your thinking, too.
load address != entry point.
But we're talking about CONFIG_STANDALONE_LOAD_ADDR not CONFIG_STANDALONE_ENTRY_POINT. What we've been doing in arch/arm/config.mk has been on my to fix list for a long time, because it's been wrong for so many boards. Setting this to CONFIG_LOADADDR is a reasonable default value.
Dear Tom,
In message 20170814211300.GM20467@bill-the-cat you wrote:
But we're talking about CONFIG_STANDALONE_LOAD_ADDR not CONFIG_STANDALONE_ENTRY_POINT. What we've been doing in arch/arm/config.mk has been on my to fix list for a long time, because it's been wrong for so many boards. Setting this to CONFIG_LOADADDR is a reasonable default value.
No, it is not. It is fundamentally broken. If you need a default for the entry point address, then define one. CONFIG_LOADADDR means where the image gets loaded to, and almost all image formats have a header in front of the payuload, so the entry point is somewhere else. And even if you load raw binary images, there is no guarantee that the entry point is right at the start of the image,
Mixing things that are defined for different purposes (loading image versus start address of the code) is a really bad idea.
Best regards,
Wolfgang Denk
On Tue, Aug 15, 2017 at 09:32:30AM +0200, Wolfgang Denk wrote:
Dear Tom,
In message 20170814211300.GM20467@bill-the-cat you wrote:
But we're talking about CONFIG_STANDALONE_LOAD_ADDR not CONFIG_STANDALONE_ENTRY_POINT. What we've been doing in arch/arm/config.mk has been on my to fix list for a long time, because it's been wrong for so many boards. Setting this to CONFIG_LOADADDR is a reasonable default value.
No, it is not. It is fundamentally broken. If you need a default for the entry point address, then define one. CONFIG_LOADADDR means where the image gets loaded to, and almost all image formats have a header in front of the payuload, so the entry point is somewhere else. And even if you load raw binary images, there is no guarantee that the entry point is right at the start of the image,
Mixing things that are defined for different purposes (loading image versus start address of the code) is a really bad idea.
What CONFIG_STANDALONE_LOAD_ADDR is, is the location that we want hello_world, or other example stand alone applications loaded into memory at. CONFIG_LOADADDR is the safe default location to load things into memory at in order to run them. At least on ARM, where there's a good number of different default memory layouts, what arch/arm/config.mk does today is broken for the majority of platforms. We should be providing at least a functional default value here, which we are not today. This in no way precludes a 'real' standalone application from linking and running at whatever it wants within a platforms memory map.
Hello all
Am Dienstag, den 15.08.2017, 07:39 -0400 schrieb Tom Rini:
On Tue, Aug 15, 2017 at 09:32:30AM +0200, Wolfgang Denk wrote:
Dear Tom,
In message 20170814211300.GM20467@bill-the-cat you wrote:
But we're talking about CONFIG_STANDALONE_LOAD_ADDR not CONFIG_STANDALONE_ENTRY_POINT. What we've been doing in arch/arm/config.mk has been on my to fix list for a long time, because it's been wrong for so many boards. Setting this to CONFIG_LOADADDR is a reasonable default value.
No, it is not. It is fundamentally broken. If you need a default for the entry point address, then define one. CONFIG_LOADADDR means where the image gets loaded to, and almost all image formats have a header in front of the payuload, so the entry point is somewhere else. And even if you load raw binary images, there is no guarantee that the entry point is right at the start of the image,
Mixing things that are defined for different purposes (loading image versus start address of the code) is a really bad idea.
What CONFIG_STANDALONE_LOAD_ADDR is, is the location that we want hello_world, or other example stand alone applications loaded into memory at. CONFIG_LOADADDR is the safe default location to load things into memory at in order to run them. At least on ARM, where there's a good number of different default memory layouts, what arch/arm/config.mk does today is broken for the majority of platforms. We should be providing at least a functional default value here, which we are not today. This in no way precludes a 'real' standalone application from linking and running at whatever it wants within a platforms memory map.
Wolfgang says that a board needs to decide on what image type to use for the standalone application and then from that set an appropriate CONFIG_STANDALONE_LOAD_ADDR in its board configuration. Without that the standalone binaries are useless anyway and setting a default in arch/arm/config.mk only purpose is that the build succeeds.
My motivation to write the patch in the first place (and Tom seems to agree) is that for boards who define nothing at least the plain binary is linked to a memory address where one can load something.
I can live with both views.
Note that I sent a v2 of the patchset addressing Wolfgang's first emails. v2 hopefully dropped the wrong connection of load/link address with entry point.
Max
Dear Max,
In message 1502799746.3076.16.camel@gmail.com you wrote:
Wolfgang says that a board needs to decide on what image type to use for the standalone application and then from that set an
No, I did not say this. On contrary, this is not up to the "board" to decide. This is a decision tobe made by the end user, and U-Boot shall not put any restrictions on this. You may want to use a raw binary image, someone else uses an ELF file or an uImage, and I prefer to use a FIT image.
appropriate CONFIG_STANDALONE_LOAD_ADDR in its board configuration.
The LOAD_ADDR you use it is a misleading name for where the image gets loaded to in memory. Note that the payload can be compressed or encrypted or what else. The "load address" in the intended meaning (as present in the image headers) is where the payload of the images gets stored in memory (which may include decryption, uncompressing or else). And entry point is still something else.
Without that the standalone binaries are useless anyway and setting a default in arch/arm/config.mk only purpose is that the build succeeds.
For the build process, only the "load address" and "entry point address" in their original meaning should be interesting - but his is not what CONFIG_STANDALONE_LOAD_ADDR provides.
My motivation to write the patch in the first place (and Tom seems to agree) is that for boards who define nothing at least the plain binary is linked to a memory address where one can load something.
I also agree with this. I just want to use a misleading name for this default. If you need an start address for the text segment you should call it like that - we already have CONFIG_SYS_TEXT_BASE and CONFIG_SPL_TEXT_BASE, so why not use CONFIG_STANDALONE_TEXT_BASE here?
Note that I sent a v2 of the patchset addressing Wolfgang's first emails. v2 hopefully dropped the wrong connection of load/link address with entry point.
No, it does not, as it still uses CONFIG_LOADADDR (= default download address of some image type) where you in fact mean the default start address of the data payload only (and very likely this is the same as the start of the text segment).
Best regards,
Wolfgang Denk
Dear Tom,
In message 20170815113952.GE20467@bill-the-cat you wrote:
What CONFIG_STANDALONE_LOAD_ADDR is, is the location that we want hello_world, or other example stand alone applications loaded into memory at. CONFIG_LOADADDR is the safe default location to load things into memory at in order to run them. At least on ARM, where there's a good number of different default memory layouts, what arch/arm/config.mk does today is broken for the majority of platforms.
I agree up to here.
We should be providing at least a functional default value here, which we are not today. This in no way precludes a 'real' standalone application from linking and running at whatever it wants within a platforms memory map.
This is where things become fishy.
We should use clean terms.
Please keep in mind that even the term "load address" can mean two things: many people use this term (incorrectly) for the address where they load an image to on RAM, and unfortunately we even provide the "loadaddr" environment variable which carries this meaning. Originally, the term refers to the address where the image payload gets uncompressed and loaded to when unpacking the image. For example, on Power architecture, a typical setup would look like:
Output of mkimage -l:
Image Name: Linux-4.4.8 Created: Fri Apr 22 09:06:09 2016 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2009139 Bytes = 1962.05 kB = 1.92 MB Load Address: 00000000 Entry Point: 00000000
We download the uImage file to - say - 0x400000 in RAM (so the environment variable "loadaddr" might be 0x400000), but when we run "bootm", U-Boot will uncompress and _load_ the Linux kernel to the _Load_Address_ stored in the image header, i. e. 0x00000000, and then it will transfer control to the _Entry_Point_Address_, also stored in the image header, here also 0x00000000.
So we have:
download address (address of image in RAM): 0x00400000 load address (start of unpacked kernel image): 0x00000000 entry point (start of executable code): 0x00000000
The term "load address" has always been meant to mean the address where the kernel gets _loaded_to_ by the bootm command. I know that there has always been confusion of these terms, and I must have explained this at least a hundred times here before.
I would really appreciate if you helped to avoid mixing terms of different meaning. If you have an idea how to avoid this it would be more than welcome - unfortunately the (mis)use of the loadaddr environment variable is so widespread that I feat there is no easy way out.
Best regards,
Wolfgang Denk
On Tue, Aug 15, 2017 at 03:21:15PM +0200, Wolfgang Denk wrote:
Dear Tom,
In message 20170815113952.GE20467@bill-the-cat you wrote:
What CONFIG_STANDALONE_LOAD_ADDR is, is the location that we want hello_world, or other example stand alone applications loaded into memory at. CONFIG_LOADADDR is the safe default location to load things into memory at in order to run them. At least on ARM, where there's a good number of different default memory layouts, what arch/arm/config.mk does today is broken for the majority of platforms.
I agree up to here.
We should be providing at least a functional default value here, which we are not today. This in no way precludes a 'real' standalone application from linking and running at whatever it wants within a platforms memory map.
This is where things become fishy.
We should use clean terms.
OK.
Please keep in mind that even the term "load address" can mean two things: many people use this term (incorrectly) for the address where they load an image to on RAM, and unfortunately we even provide the "loadaddr" environment variable which carries this meaning.
We'll use this for now at least, for consistency.
Originally, the term refers to the address where the image payload gets uncompressed and loaded to when unpacking the image. For example, on Power architecture, a typical setup would look like:
Output of mkimage -l:
Image Name: Linux-4.4.8 Created: Fri Apr 22 09:06:09 2016 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2009139 Bytes = 1962.05 kB = 1.92 MB Load Address: 00000000 Entry Point: 00000000
We download the uImage file to - say - 0x400000 in RAM (so the environment variable "loadaddr" might be 0x400000), but when we run "bootm", U-Boot will uncompress and _load_ the Linux kernel to the _Load_Address_ stored in the image header, i. e. 0x00000000, and then it will transfer control to the _Entry_Point_Address_, also stored in the image header, here also 0x00000000.
So we have:
download address (address of image in RAM): 0x00400000 load address (start of unpacked kernel image): 0x00000000 entry point (start of executable code): 0x00000000
The term "load address" has always been meant to mean the address where the kernel gets _loaded_to_ by the bootm command. I know that there has always been confusion of these terms, and I must have explained this at least a hundred times here before.
This is all true. But it's also unrelated to what CONFIG_STANDALONE_LOAD_ADDR is used for. So...
I would really appreciate if you helped to avoid mixing terms of different meaning. If you have an idea how to avoid this it would be more than welcome - unfortunately the (mis)use of the loadaddr environment variable is so widespread that I feat there is no easy way out.
I think the first problem is that we need to rename CONFIG_STANDALONE_LOAD_ADDR to CONFIG_EXAMPLE_STANDALONE_ENTRY_POINT to be more precise about what it is doing and used for, all around. And then, I'm not sure. I had an idea, but I seem to have found that at least right this moment, hello_world.bin doesn't function for me and I would swear I had unit tested be1b8679ce42 but it is not working for me either. But I'm going to put this down for the evening at least...
If compiling for thumb the U-Boot 'go' command can not jump to the entry point, as the jump will be done in the assumption that the code jumped to is using the arm instruction set.
So add add a simple forwarder in arm instruction set which then jumps to the 'real' entry.
Signed-off-by: Max Krummenacher max.krummenacher@toradex.com
---
examples/standalone/hello_world.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/examples/standalone/hello_world.c b/examples/standalone/hello_world.c index bd8b392315..0b859ca4bd 100644 --- a/examples/standalone/hello_world.c +++ b/examples/standalone/hello_world.c @@ -8,6 +8,21 @@ #include <common.h> #include <exports.h>
+/* + * Make thumb work by providing a forwarder to the (thumb) entry point + * compiled for arm instruction set. + * Don't compile this for thumb only CPUs. + */ +#if defined(__thumb__) && defined(__ARM_ARCH_ISA_ARM) +void __attribute__((unused)) __attribute__ ((naked)) dummy2(void) +{ +asm volatile( \ +" .code 32\n" \ +" .arm\n" \ +" ldr pc,=hello_world\n"); +} +#endif + int hello_world (int argc, char * const argv[]) { int i;
Dear Max,
In message 20170812090346.7887-3-max.krummenacher@toradex.com you wrote:
If compiling for thumb the U-Boot 'go' command can not jump to the entry point, as the jump will be done in the assumption that the code jumped to is using the arm instruction set.
So add add a simple forwarder in arm instruction set which then jumps to the 'real' entry.
This description makes no sense to me. Whatever you do, the address where the image starts executuin is what is called the entry point. Whether this is needs special code to swutch to thumb mode or not does not make any difference. Whichever address you use with the "go" command is the "entry point".
Also, can the mode switching not be done inside the body of the regular hello_world() function? This would be much better as it wuld allow to always use the same method to determine the entry point address (line running "nm" on the binary and grepping for the name "hello_world"). With your code, you would have to fix all documentation and explain that the entry pooint name is suddenly domething totally different (and an unexpected, unusal name like "dummy2" as well) for thumb images.
Sorry, but this does not seem a good idea to me.
Naked-by: Wolfgang Denk wd@denx.de
Best regards,
Wolfgang Denk
Dear Wolfgang
Am Samstag, den 12.08.2017, 20:39 +0200 schrieb Wolfgang Denk:
Dear Max,
In message 20170812090346.7887-3-max.krummenacher@toradex.com you wrote:
If compiling for thumb the U-Boot 'go' command can not jump to the entry point, as the jump will be done in the assumption that the code jumped to is using the arm instruction set.
So add add a simple forwarder in arm instruction set which then jumps to the 'real' entry.
This description makes no sense to me. Whatever you do, the address where the image starts executuin is what is called the entry point. Whether this is needs special code to swutch to thumb mode or not does not make any difference. Whichever address you use with the "go" command is the "entry point".
Also, can the mode switching not be done inside the body of the regular hello_world() function? This would be much better as it wuld allow to always use the same method to determine the entry point address (line running "nm" on the binary and grepping for the name "hello_world"). With your code, you would have to fix all documentation and explain that the entry pooint name is suddenly domething totally different (and an unexpected, unusal name like "dummy2" as well) for thumb images.
This again stems from my assumption that one has to write the standalone application in a way that the entry point is actually linked to the beginning of the binary.
One cannot put the mode switching from thumb to arm instruction set inside the body of a C function, as the entry code prepended by the compiler would be in thumb and thus an exception would occur before the mode switching code gets executed.
Probably one can add a pragma conditionally so that the entry function gets compiled in arm instruction set. I investigate further and send a v2.
Max
Sorry, but this does not seem a good idea to me.
Naked-by: Wolfgang Denk wd@denx.de
Best regards,
Wolfgang Denk
Dear Max,
In message 1502573515.17070.20.camel@gmail.com you wrote:
This again stems from my assumption that one has to write the standalone application in a way that the entry point is actually linked to the beginning of the binary.
No, this stems from your confusion of load address and entry point address. Of course it is possib;e that the entry point is at the very beginning of the binary. In that case you must load the image such into memory, that the start addresss of the binary is the same as the entry point address.
But the load address is not the start of the binary in memory - it is the start address of the _image_. Almost always the bianry will be just a payload within the image - in the most simple cases of the lecagy uImage files the binary payload will be preceeded by a 64 byte image header. So when your load addess is set to 0x100000, the binary will NOT start at this address, but at an offset of 64 bytes. So the entry poin can NEVER be the same as the load address, as this is outside of the image payload.
One cannot put the mode switching from thumb to arm instruction set inside the body of a C function, as the entry code prepended by the compiler would be in thumb and thus an exception would occur before the mode switching code gets executed.
If this cannot be a regular C funtion, we should still be able to provide some trampoline code using the same name. My main goal is to avoid confugion to the user who expects that he can look up the entry point address in the nm ouutput under the well-known name.
Probably one can add a pragma conditionally so that the entry function gets compiled in arm instruction set. I investigate further and send a v2.
Thanks.
Best regards,
Wolfgang Denk
On Sat, Aug 12, 2017 at 11:03:46AM +0200, Max Krummenacher wrote:
If compiling for thumb the U-Boot 'go' command can not jump to the entry point, as the jump will be done in the assumption that the code jumped to is using the arm instruction set.
So add add a simple forwarder in arm instruction set which then jumps to the 'real' entry.
Signed-off-by: Max Krummenacher max.krummenacher@toradex.com
This looks like a special case of what we're doing in f99993c10882 and dc89c6fb778e and perhaps we need to move that kind of fixup around to somewhere else, as I assume you've found this problem on a custom application? Or are you utilizing hello_world in some test suites? Just curious, thanks!
Hello all
Am Montag, den 14.08.2017, 17:15 -0400 schrieb Tom Rini:
On Sat, Aug 12, 2017 at 11:03:46AM +0200, Max Krummenacher wrote:
If compiling for thumb the U-Boot 'go' command can not jump to the entry point, as the jump will be done in the assumption that the code jumped to is using the arm instruction set.
So add add a simple forwarder in arm instruction set which then jumps to the 'real' entry.
Signed-off-by: Max Krummenacher max.krummenacher@toradex.com
This looks like a special case of what we're doing in f99993c10882 and dc89c6fb778e and perhaps we need to move that kind of fixup around to somewhere else, as I assume you've found this problem on a custom application? Or are you utilizing hello_world in some test suites? Just curious, thanks!
I guess the difference to f99993c10882 and dc89c6fb778e is that one knows from armv7m that the CPU is thumb only while on an armv7a potentially both arm and thumb mode can be used.
Actually a customer asked how to run hello_world.bin, so I tested with our regular defconfig and the produced hello_world.bin.
I'm having 'CONFIG_SYS_THUMB_BUILD=y' in e.g. configs/colibri_imx6_nospl_defconfig thus all of the U-Boot code including hello_world.c is compiled for thumb.
If I boot that U-Boot, load hello_world.bin into RAM at CONFIG_STANDALONE_LOAD_ADDR and execute 'go CONFIG_STANDALONE_LOAD_ADDR' I get output from the go command and then the CPU resets.
Colibri iMX6 # tftp 0x12000000 hello_world.bin ... Colibri iMX6 # go 0x12000000 ## Starting application at 0x12000000 ...
With the patch I get the expected output.
But actually calling the 'go' command with bit 0 set works. So if the user knows that he is having a thumb binary that would fix the issue as well. With the current implementation the following works:
Colibri iMX6 # go 0x12000001 ## Starting application at 0x12000001 ... Example expects ABI version 9 Actual U-Boot ABI version 9 Hello World argc = 1 argv[0] = "0x12000001" argv[1] = "<NULL>" Hit any key to exit ...
Max
Dear Max,
In message 20170812090346.7887-1-max.krummenacher@toradex.com you wrote:
This series addresses
- hardcoded entry address, use LOADADDR if available as the entry point instead
I'm not sure which sort of problem you are trying to fix, but what you describe here is inherently broken.
The entry point of an image is almost never ever at the beginning of an image.
Naked-by: Wolfgang Denk wd@denx.de
Sorry!
Best regards,
Wolfgang Denk
Dear Wolfgang
Am Samstag, den 12.08.2017, 20:32 +0200 schrieb Wolfgang Denk:
Dear Max,
In message 20170812090346.7887-1-max.krummenacher@toradex.com you wrote:
This series addresses
- hardcoded entry address, use LOADADDR if available as the entry point instead
I'm not sure which sort of problem you are trying to fix, but what you describe here is inherently broken.
The entry point of an image is almost never ever at the beginning of an image.
I was mislead by the table in point 6. of doc/README.standalone that it is a design decision that the entry point is whatever is linked to the beginning of the text segment. Thus the sloppy use of entry point and load address.
Max
Naked-by: Wolfgang Denk wd@denx.de
Sorry!
Best regards,
Wolfgang Denk
participants (3)
-
Max Krummenacher -
Tom Rini -
Wolfgang Denk