Hi Juergen,
On 14/12/2020 11:21, Jürgen Groß wrote:
On 14.12.20 12:14, Julien Grall wrote:
Hi Juergen,
On 14/12/2020 10:51, Jürgen Groß wrote:
On 14.12.20 11:17, Julien Grall wrote:
Hi Juergen,
On 14/12/2020 07:56, Juergen Gross wrote:
Add support to run a function in an exception handler for Arm. Do it
the same way as on x86 via a bug_frame.
Unfortunately inline assembly on Arm seems to be less capable than on
x86, leading to functions called via run_in_exception_handler() having
to be globally visible.
Jan already commented on this, so I am not going to comment again.
Maybe I can ask some Arm specific question related to this:
In my experiments the only working solution was using the "i" constraint
for the function pointer. Do you know whether this is supported for all
gcc versions we care about?
I don't know for sure. However, Linux has been using "i" since 2012.
So I would assume it ought to be fine for all the version we care.
Or is there another way to achieve the desired functionality? I'm using
now the following macros:
#define BUG_FRAME_run_fn(fn) do { \
asm
("1:"BUG_INSTR"\n" \
".pushsection .bug_frames."
__stringify(BUGFRAME_run_fn) \
", \"a\",
%%progbits\n" \
"2:\n" \
".p2align
2\n" \
".long (1b -
2b)\n" \
".long (%0 -
2b)\n" \
".long
0\n" \
".hword 0,
0\n" \
".popsection" :: "i"
(fn)); \
} while (0)
May I ask why we need a new macro?
Using a common one might be possible, but not with the current way how
BUG_FRAME() is defined: gcc complained about the input parameter in case
of ASSERT() and WARN().
Could you share the code and the error message?
I might be missing something, but this was the fastest way to at least
confirm the scheme is working for Arm.
Make senses. I also don't have much time to invest in trying to have a
common macro. So I am happy with a new macro.
Cheers,
--
Julien Grall
