Thread (30 messages) flat view 30 messages, 8 authors, 2024-03-18

Re: [PATCH 11/14] s390: Add support for suppressing warning backtraces

From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2024-03-14 07:57:58
Also in: dri-devel, linux-arch, linux-arm-kernel, linux-doc, linux-kselftest, linux-riscv, linux-s390, linux-sh, lkml, loongarch

Hi Günter,

On Tue, Mar 12, 2024 at 6:06 PM Guenter Roeck [off-list ref] wrote:
Add name of functions triggering warning backtraces to the __bug_table
object section to enable support for suppressing WARNING backtraces.

To limit image size impact, the pointer to the function name is only added
to the __bug_table section if both CONFIG_KUNIT and CONFIG_DEBUG_BUGVERBOSE
are enabled. Otherwise, the __func__ assembly parameter is replaced with a
(dummy) NULL parameter to avoid an image size increase due to unused
__func__ entries (this is necessary because __func__ is not a define but a
virtual variable).

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Thanks for your patch!
quoted hunk ↗ jump to hunk
--- a/arch/s390/include/asm/bug.h
+++ b/arch/s390/include/asm/bug.h
@@ -8,19 +8,30 @@

 #ifdef CONFIG_DEBUG_BUGVERBOSE

+#if IS_ENABLED(CONFIG_KUNIT)
+# define HAVE_BUG_FUNCTION
+# define __BUG_FUNC_PTR        "       .long   %0-.\n"
+# define __BUG_FUNC    __func__
+#else
+# define __BUG_FUNC_PTR
+# define __BUG_FUNC    NULL
+#endif /* IS_ENABLED(CONFIG_KUNIT) */
+
 #define __EMIT_BUG(x) do {                                     \
        asm_inline volatile(                                    \
                "0:     mc      0,0\n"                          \
                ".section .rodata.str,\"aMS\",@progbits,1\n"    \
                "1:     .asciz  \""__FILE__"\"\n"               \
                ".previous\n"                                   \
-               ".section __bug_table,\"awM\",@progbits,%2\n"   \
+               ".section __bug_table,\"awM\",@progbits,%3\n"   \
This change conflicts with commit 3938490e78f443fb ("s390/bug:
remove entry size from __bug_table section") in linus/master.
I guess it should just be dropped?
                "2:     .long   0b-.\n"                         \
                "       .long   1b-.\n"                         \
-               "       .short  %0,%1\n"                        \
-               "       .org    2b+%2\n"                        \
+               __BUG_FUNC_PTR                                  \
+               "       .short  %1,%2\n"                        \
+               "       .org    2b+%3\n"                        \
                ".previous\n"                                   \
-               : : "i" (__LINE__),                             \
+               : : "i" (__BUG_FUNC),                           \
+                   "i" (__LINE__),                             \
                    "i" (x),                                    \
                    "i" (sizeof(struct bug_entry)));            \
 } while (0)
Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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