bad asm goto ?

I just ran sparse on a kernel tree for the first time in ages, and got hundreds of warnings, many of which related to the tracepoint macros in the kernel, which use the new asm goto feature.

Looking at the git log of sparse, I see there was some support added for asm goto, but it seems to choke every time, printing ..

include/trace/events/kmem.h:45:1: error: bad asm output
include/trace/events/kmem.h:45:1: error: incompatible types in comparison expression (different address spaces)

(this is with a sparse built from git head from a few minutes ago)

Quoted 7 lines · Dave Jones

I just ran sparse on a kernel tree for the first time in ages, and got hundreds of warnings, many of which related to the tracepoint macros in the kernel, which use the new asm goto feature.

Looking at the git log of sparse, I see there was some support added for asm goto, but it seems to choke every time, printing ..

Quoted 5 lines

include/trace/events/kmem.h:45:1: error: bad asm output
include/trace/events/kmem.h:45:1: error: incompatible types in comparison expression (different address spaces)

(this is with a sparse built from git head from a few minutes ago)

Do you have a smaller test case to reproduce the error?

I tried unwinding some of the nested macros, and came up with ..

# define __ASM_FORM(x)  " " #x " "
# define JUMP_LABEL_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"
# define __ASM_SEL(a,b) __ASM_FORM(b)
#define _ASM_PTR        __ASM_SEL(.long, .quad)

# define JUMP_LABEL(key, label)                                 \
       do {                                                    \
               asm goto("1:"                                   \
                       JUMP_LABEL_INITIAL_NOP                  \
                       ".pushsection __jump_table,  \"a\" \n\t"\
                       _ASM_PTR "1b, %l[" #label "], %c0 \n\t" \
                       ".popsection \n\t"                      \
                       : :  "i" (key) :  : label);             \
       } while (0)

int main(int argc, char *argv[])
{
       JUMP_LABEL("1", do_trace );
       return 1;
do_trace:
       return 0;
}

It seems that the error is not from the goto. It is from the malformed asm_clobber.
For empty asm_clobber list, sparse currently add nil expr into the list. Evaluate will
complain about the nil pointer thinking it has a bad type.

Any way, this patch should fix it.

Please let me know that help you or not. I am going to apply it after the 0.4.3 release.

I'm afraid this didn't solve it for me when applying on top of v0.4.3, if you have any other patches to try,
I'd be glad to test them out.

On Wed, Oct 27, 2010 at 7:45 PM, Harvey Harrison
<[email protected]> wrote:
\>

Quoted 3 lines

I'm afraid this didn't solve it for me when applying on top of v0.4.3, if you have any other patches to try,
I'd be glad to test them out.

What is your test case? The patch does work for me on the small test case provide by
Dave. I am just wondering if you are running the same thing. If not, please let me know what you run and what is the error message.

Sorry about that, just ran again and had a leftover binary elsewhere in my path, your patch does fix
the error, all that's left is the:

It seems that the error is not from the goto. It is from the malformed asm_clobber.
For empty asm_clobber list, sparse currently add nil expr into the list. Evaluate will
complain about the nil pointer thinking it has a bad type.

Any way, this patch should fix it.

Please let me know that help you or not. I am going to apply it after the 0.4.3 release.

Chris

evaluate.c +1 -1

index f8343c2..1fb03ed 100644
@@ -3221,7 +3221,7 @@ static void evaluate_asm_statement(struct statement *stmt)
 
        FOR_EACH_PTR(stmt->asm_clobbers, expr) {
                if (!expr) {
-                       sparse_error(stmt->pos, "bad asm output");
+                       sparse_error(stmt->pos, "bad asm clobbers");
                        return;
                }
                if (expr->type == EXPR_STRING)

parse.c +0 -0

index 537055f..6b7d656 100644
@@ -1894,7 +1894,8 @@ static struct token *parse_asm_clobbers(struct

token *token, struct statement *s

       do {
               token = primary_expression(token->next, &expr);
-               add_expression(clobbers, expr);
+               if (expr)
+                       add_expression(clobbers, expr);
       } while (match_op(token, ','));
       return token;
 }
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Ping, noticed you moving towards a 0.4.4 release and this was still not applied.