[#5104] user/blkfin-test/crash_test/traps_test.c lies...

Submitted By: Robin Getz

Open Date

2009-04-30 16:56:04 Close Date

2009-05-05 16:53:51

Priority:

Medium Assignee:

Robin Getz

Status:

Closed Fixed In Release:

N/A

Found In Release:

2010R1 Release:

Category:

N/A Board:

N/A

Processor:

ALL Silicon Revision:

Is this bug repeatable?:

Yes Resolution:

Fixed

Uboot version or rev.:

Toolchain version or rev.:

any

App binary format:

N/A

Summary: user/blkfin-test/crash_test/traps_test.c lies...

Details:

In an effort to make things compile with no errors, the errors don't actually do what was indented anymore...

void instruction_fetch_miss(void)

{

int (*foo)(void);

int i;

i=0x87654320;

foo = (void *)i;

(*foo)();

}

compiles to:

000010f8 <_instruction_fetch_miss>:

10f8: 4b e1 65 87 P3.H = 0x8765; /* P3=0x87650000 */

10fc: 00 e8 00 00 LINK 0x0; /* (0) */

1100: 0b e1 20 43 P3.L = 0x4320; /* P3=0x87654320 */

1104: 59 91 P1 = [P3];

1106: 5b ac P3 = [P3 + 0x4];

1108: 01 e8 00 00 UNLINK;

110c: 51 00 JUMP (P1);

Which dereferences P3, not jumps to it.

Can someone break these properly?

Follow-ups

--- Mike Frysinger 2009-04-30 17:02:42

i think the code is correct. you're looking at the output of FDPIC which has to

handle function descriptors.

the FLAT output looks like what you'd expect:

P2.H = 34661;

P2.L = 17184;

jump (P2);

Jie/Bernd would have to comment further

otherwise the only way to get what you want is with asm()

--- Robin Getz 2009-04-30 19:05:05

Ah - gottcha.

Hmmm...

I'll wait for Bernd/Jie to comment, and then maybe use some more #ifdef

__FDPIC__ in the source...

For now, I guess I'll just compile as flat, and assign to me.

-Robin

--- Bernd Schmidt 2009-05-04 17:39:37

What Mike said.

--- Jie Zhang 2009-05-04 23:06:22

Both __FDPIC__ and asm can work. I have no preference on either one. The

__FDPIC__ version might look like:

void instruction_fetch_miss(void)

{

int (*foo)(void);

#ifdef __FDPIC__

int i[2] = {0x87654320, 0};

#else

int i = 0x87654320;

#endif

foo = (void *)i;

(*foo)();

}

--- Mike Frysinger 2009-05-04 23:20:41

this seems to work:

#ifdef __FDPIC__

# define _get_func_ptr(addr) ({ unsigned long __addr[2] = { addr, 0 }; __addr;

})

#else

# define _get_func_ptr(addr) (addr)

#endif

#define get_func_ptr(addr) (void *)(_get_func_ptr(addr))

...

foo = get_func_ptr(0x87654320);

--- Robin Getz 2009-05-05 16:53:51

Works for me.

Thanks for the tip.

Fixed.

-Robin

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