[U-Boot] setjmp/longjmp prototype in U-Boot
Simon & Alexander,
It appears our setjmp/longjmp prototypes and implementations are in non-compliance with current C-standards (I checked against both C99 and C2011).
U-Boot defines setjmp as: int setjmp(struct jmp_buf_data *jmp_buf)
The standard however requires int setjmp(jmp_buf env) and has additional guidance regarding the definition of ‘jmp_buf’: "The type declared is jmp_buf which is an array type suitable for holding the information needed to restore a calling environment."
Note that I just reworked the ARM versions: i.e. here we now are in compliance. Even with this rework, I need to expose 'struct jmp_buf_data’ (which should be an implementation detail) as this is explicitly referenced from EFI code.
If agreeable for the EFI side, I'd like to change the remaining implementations to also comply with the standard, which is easy enough on by adding a 'typedef struct jmp_buf_data jmp_buf[1]'. This would also allow us to have a single 'setjmp.h' that just includes an arch-specific 'asm/setjmp.h' to retrieve the 'struct jmp_buf_data' definition.
Note that this will entail changes to the EFI code by replacing all occurrences where 'struct jmp_buf_data' is used or the address of a 'struct jmp_buf_data' struct-member is taken (i.e. all call-sites for setjmp/longjmp).
If this is a showstopper to the EFI implementation, let me know…
Regards, Philipp.
Hi Philipp,
On 09/21/2017 10:57 AM, Dr. Philipp Tomsich wrote:
Simon & Alexander,
It appears our setjmp/longjmp prototypes and implementations are in non-compliance with current C-standards (I checked against both C99 and C2011).
U-Boot defines setjmp as: int setjmp(struct jmp_buf_data *jmp_buf)
The standard however requires int setjmp(jmp_buf env) and has additional guidance regarding the definition of ‘jmp_buf’: "The type declared is jmp_buf which is an array type suitable for holding the information needed to restore a calling environment."
Note that I just reworked the ARM versions: i.e. here we now are in compliance. Even with this rework, I need to expose 'struct jmp_buf_data’ (which should be an implementation detail) as this is explicitly referenced from EFI code.
If agreeable for the EFI side, I'd like to change the remaining implementations to also comply with the standard, which is easy enough on by adding a 'typedef struct jmp_buf_data jmp_buf[1]'. This would also allow us to have a single 'setjmp.h' that just includes an arch-specific 'asm/setjmp.h' to retrieve the 'struct jmp_buf_data' definition.
Note that this will entail changes to the EFI code by replacing all occurrences where 'struct jmp_buf_data' is used or the address of a 'struct jmp_buf_data' struct-member is taken (i.e. all call-sites for setjmp/longjmp).
If this is a showstopper to the EFI implementation, let me know…
I don't see anything going against it OTOH :). Please double check the converted result still works though ;). IIRC we keep the jmp_buf data on the stack - it'd be nice to keep doing that going forward.
Alex
Hi,
On 22 September 2017 at 10:19, Alexander Graf agraf@suse.de wrote:
Hi Philipp,
On 09/21/2017 10:57 AM, Dr. Philipp Tomsich wrote:
Simon & Alexander,
It appears our setjmp/longjmp prototypes and implementations are in non-compliance with current C-standards (I checked against both C99 and C2011).
U-Boot defines setjmp as: int setjmp(struct jmp_buf_data *jmp_buf)
The standard however requires int setjmp(jmp_buf env) and has additional guidance regarding the definition of ‘jmp_buf’: "The type declared is jmp_buf which is an array type suitable for holding the information needed to restore a calling environment."
Note that I just reworked the ARM versions: i.e. here we now are in compliance. Even with this rework, I need to expose 'struct jmp_buf_data’ (which should be an implementation detail) as this is explicitly referenced from EFI code.
If agreeable for the EFI side, I'd like to change the remaining implementations to also comply with the standard, which is easy enough on by adding a 'typedef struct jmp_buf_data jmp_buf[1]'. This would also allow us to have a single 'setjmp.h' that just includes an arch-specific 'asm/setjmp.h' to retrieve the 'struct jmp_buf_data' definition.
Note that this will entail changes to the EFI code by replacing all occurrences where 'struct jmp_buf_data' is used or the address of a 'struct jmp_buf_data' struct-member is taken (i.e. all call-sites for setjmp/longjmp).
If this is a showstopper to the EFI implementation, let me know…
I don't see anything going against it OTOH :). Please double check the converted result still works though ;). IIRC we keep the jmp_buf data on the stack - it'd be nice to keep doing that going forward.
Alex
Yes I agree it makes sense.
Note the weird case of sandbox though. I sent a patch for os_setjmp() recently.
Regards, Simon
participants (3)
-
Alexander Graf -
Dr. Philipp Tomsich -
Simon Glass