Re: [PATCH] gdb: Add malloc and free symbols to kernel.exec to improve gdb functionality

[Daniel Kiper]

On Wed, Mar 02, 2022 at 06:25:12PM -0600, Glenn Washburn wrote:
> Add linker flags when linking kernel.exec to have malloc and free point to
> grub_malloc and grub_free respectively. Some gdb functionality depends on
> gdb locating the symbols "malloc" and "free", such as dynamically creating
> strings for arguments to injected function calls. A trivial example would
> the gdb command 'p strlen("astring")'.
>
> Signed-off-by: Glenn Washburn <development@efficientek.com>
> ---
> This should have been included in the gdb patch series I recently sent,
> although its not required by nor requires any of those patches.
>
> Glenn
>
> ---
>  conf/Makefile.common | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/conf/Makefile.common b/conf/Makefile.common
> index f0bb6e160a..069b428c1a 100644
> --- a/conf/Makefile.common
> +++ b/conf/Makefile.common
> @@ -36,6 +36,7 @@ BUILD_CPPFLAGS += $(CPPFLAGS_DEFAULT)
>
>  CFLAGS_KERNEL = $(CFLAGS_PLATFORM) -ffreestanding
>  LDFLAGS_KERNEL = $(LDFLAGS_PLATFORM) -nostdlib $(TARGET_LDFLAGS_OLDMAGIC)
> +LDFLAGS_KERNEL += -Wl,--defsym=malloc=grub_malloc -Wl,--defsym=free=grub_free

Could not we teach gdb somehow to use grub_malloc()/grub_free() instead
of malloc()/free()?

Daniel