* [PATCH] ldso: fix GDB dynamic linker info on MIPS
@ 2016-01-30 18:20 Felix Fietkau
2016-01-30 18:24 ` Rich Felker
0 siblings, 1 reply; 2+ messages in thread
From: Felix Fietkau @ 2016-01-30 18:20 UTC (permalink / raw)
To: musl
GDB is looking for a pointer to the ldso debug info in the data of the
.rld_map section.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
arch/mips/reloc.h | 1 +
src/ldso/dynlink.c | 9 ++++++++-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/mips/reloc.h b/arch/mips/reloc.h
index 9b40e3d..e9cb209 100644
--- a/arch/mips/reloc.h
+++ b/arch/mips/reloc.h
@@ -25,6 +25,7 @@
#define NEED_MIPS_GOT_RELOCS 1
#define DYNAMIC_IS_RO 1
+#define DT_DEBUG_INDIRECT DT_MIPS_RLD_MAP
#define ARCH_SYM_REJECT_UND(s) (!((s)->st_other & STO_MIPS_PLT))
#define CRTJMP(pc,sp) __asm__ __volatile__( \
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 93e7d67..dd85eea 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -1584,11 +1584,18 @@ _Noreturn void __dls3(size_t *sp)
load_deps(&app);
make_global(&app);
+ for (i=0; app.dynv[i]; i+=2) {
#ifndef DYNAMIC_IS_RO
- for (i=0; app.dynv[i]; i+=2)
if (app.dynv[i]==DT_DEBUG)
app.dynv[i+1] = (size_t)&debug;
#endif
+#ifdef DT_DEBUG_INDIRECT
+ if (app.dynv[i]==DT_DEBUG_INDIRECT) {
+ size_t *ptr = (size_t *) app.dynv[i+1];
+ *ptr = (size_t)&debug;
+ }
+#endif
+ }
/* The main program must be relocated LAST since it may contin
* copy relocations which depend on libraries' relocations. */
--
2.2.2
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] ldso: fix GDB dynamic linker info on MIPS
2016-01-30 18:20 [PATCH] ldso: fix GDB dynamic linker info on MIPS Felix Fietkau
@ 2016-01-30 18:24 ` Rich Felker
0 siblings, 0 replies; 2+ messages in thread
From: Rich Felker @ 2016-01-30 18:24 UTC (permalink / raw)
To: musl
On Sat, Jan 30, 2016 at 07:20:19PM +0100, Felix Fietkau wrote:
> GDB is looking for a pointer to the ldso debug info in the data of the
> ..rld_map section.
>
> Signed-off-by: Felix Fietkau <nbd@openwrt.org>
> ---
> arch/mips/reloc.h | 1 +
> src/ldso/dynlink.c | 9 ++++++++-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/arch/mips/reloc.h b/arch/mips/reloc.h
> index 9b40e3d..e9cb209 100644
> --- a/arch/mips/reloc.h
> +++ b/arch/mips/reloc.h
> @@ -25,6 +25,7 @@
>
> #define NEED_MIPS_GOT_RELOCS 1
> #define DYNAMIC_IS_RO 1
> +#define DT_DEBUG_INDIRECT DT_MIPS_RLD_MAP
> #define ARCH_SYM_REJECT_UND(s) (!((s)->st_other & STO_MIPS_PLT))
>
> #define CRTJMP(pc,sp) __asm__ __volatile__( \
> diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
> index 93e7d67..dd85eea 100644
> --- a/src/ldso/dynlink.c
> +++ b/src/ldso/dynlink.c
> @@ -1584,11 +1584,18 @@ _Noreturn void __dls3(size_t *sp)
> load_deps(&app);
> make_global(&app);
>
> + for (i=0; app.dynv[i]; i+=2) {
> #ifndef DYNAMIC_IS_RO
> - for (i=0; app.dynv[i]; i+=2)
> if (app.dynv[i]==DT_DEBUG)
> app.dynv[i+1] = (size_t)&debug;
> #endif
> +#ifdef DT_DEBUG_INDIRECT
> + if (app.dynv[i]==DT_DEBUG_INDIRECT) {
> + size_t *ptr = (size_t *) app.dynv[i+1];
> + *ptr = (size_t)&debug;
> + }
> +#endif
> + }
>
> /* The main program must be relocated LAST since it may contin
> * copy relocations which depend on libraries' relocations. */
> --
> 2.2.2
This certainly works, but DYNAMIC_IS_RO and DT_DEBUG_INDIRECT are
probably redundant now; I can't imagine wanting one without the other.
I've also tried to replace #if/#ifdef in dynlink.c with if, in the
interest of catching warnings/errors no matter what arch we're
compiling for, so maybe we could do in internal/dynlink.h:
#ifndef DT_DEBUG_INDIRECT
#define DT_DEBUG_INDIRECT 0
#endif
then in dynlink.c:
if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
...
if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT)
What do you think?
Rich
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2016-01-30 18:20 [PATCH] ldso: fix GDB dynamic linker info on MIPS Felix Fietkau
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