Hi Ard,
On Tue, Jun 26, 2018 at 08:27:58PM +0200, Ard Biesheuvel wrote:
> An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab
> entries, each consisting of two 64-bit fields containing absolute
> references, to the symbol itself and to a char array containing
> its name, respectively.
[...]
> diff --git a/include/linux/export.h b/include/linux/export.h
> index ea7df303d68d..ae072bc5aacf 100644
> --- a/include/linux/export.h
> +++ b/include/linux/export.h
> @@ -18,12 +18,6 @@
> #define VMLINUX_SYMBOL_STR(x) __VMLINUX_SYMBOL_STR(x)
>
> #ifndef __ASSEMBLY__
> -struct kernel_symbol
> -{
> - unsigned long value;
> - const char *name;
> -};
> -
> #ifdef MODULE
> extern struct module __this_module;
> #define THIS_MODULE (&__this_module)
> @@ -54,17 +48,47 @@ extern struct module __this_module;
> #define __CRC_SYMBOL(sym, sec)
> #endif
>
> +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
> +#include <linux/compiler.h>
> +/*
> + * Emit the ksymtab entry as a pair of relative references: this reduces
> + * the size by half on 64-bit architectures, and eliminates the need for
> + * absolute relocations that require runtime processing on relocatable
> + * kernels.
> + */
> +#define __KSYMTAB_ENTRY(sym, sec) \
> + __ADDRESSABLE(sym) \
> + asm(" .section \"___ksymtab" sec "+" #sym "\", \"a\" \n" \
> + " .balign 8 \n" \
Can we use KSYM_ALIGN here instead of 8, or do we need the 8-byte alignment
even on 32-bit architectures?
Will
