* Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx> wrote (on 2017-11-10 08:48:27 +0900):
> We are moving towards separate kernel and module function descriptor
> dereference callbacks. This patch enables it for powerpc64.
>
> For pointers that belong to the kernel
> - Added __start_opd and __end_opd pointers, to track the kernel
> .opd section address range;
>
> - Added dereference_kernel_function_descriptor(). Now we
> will dereference only function pointers that are within
> [__start_opd, __end_opd);
>
> For pointers that belong to a module
> - Added dereference_module_function_descriptor() to handle module
> function descriptor dereference. Now we will dereference only
> pointers that are within [module->opd.start, module->opd.end).
>
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> ---
> arch/powerpc/include/asm/module.h | 3 +++
> arch/powerpc/include/asm/sections.h | 12 ++++++++++++
> arch/powerpc/kernel/module_64.c | 14 ++++++++++++++
> arch/powerpc/kernel/vmlinux.lds.S | 2 ++
> 4 files changed, 31 insertions(+)
>
Looks good on powerpc. If you wish:
Tested-by: Santosh Sivaraj <santosh@xxxxxxxxxx> # for powerpc
Thanks,
Santosh
> diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h
> index 6c0132c7212f..7e28442827f1 100644
> --- a/arch/powerpc/include/asm/module.h
> +++ b/arch/powerpc/include/asm/module.h
> @@ -45,6 +45,9 @@ struct mod_arch_specific {
> unsigned long tramp;
> #endif
>
> + /* For module function descriptor dereference */
> + unsigned long start_opd;
> + unsigned long end_opd;
> #else /* powerpc64 */
> /* Indices of PLT sections within module. */
> unsigned int core_plt_section;
> diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
> index 82bec63bbd4f..e335a8f846af 100644
> --- a/arch/powerpc/include/asm/sections.h
> +++ b/arch/powerpc/include/asm/sections.h
> @@ -66,6 +66,9 @@ static inline int overlaps_kvm_tmp(unsigned long start, unsigned long end)
> }
>
> #ifdef PPC64_ELF_ABI_v1
> +
> +#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
> +
> #undef dereference_function_descriptor
> static inline void *dereference_function_descriptor(void *ptr)
> {
> @@ -76,6 +79,15 @@ static inline void *dereference_function_descriptor(void *ptr)
> ptr = p;
> return ptr;
> }
> +
> +#undef dereference_kernel_function_descriptor
> +static inline void *dereference_kernel_function_descriptor(void *ptr)
> +{
> + if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd)
> + return ptr;
> +
> + return dereference_function_descriptor(ptr);
> +}
> #endif /* PPC64_ELF_ABI_v1 */
>
> #endif
> diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
> index 759104b99f9f..218971ac7e04 100644
> --- a/arch/powerpc/kernel/module_64.c
> +++ b/arch/powerpc/kernel/module_64.c
> @@ -93,6 +93,15 @@ static unsigned int local_entry_offset(const Elf64_Sym *sym)
> {
> return 0;
> }
> +
> +void *dereference_module_function_descriptor(struct module *mod, void *ptr)
> +{
> + if (ptr < (void *)mod->arch.start_opd ||
> + ptr >= (void *)mod->arch.end_opd)
> + return ptr;
> +
> + return dereference_function_descriptor(ptr);
> +}
> #endif
>
> #define STUB_MAGIC 0x73747562 /* stub */
> @@ -344,6 +353,11 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr,
> else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
> dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
> sechdrs[i].sh_size);
> + else if (!strcmp(secstrings + sechdrs[i].sh_name, ".opd")) {
> + me->arch.start_opd = sechdrs[i].sh_addr;
> + me->arch.end_opd = sechdrs[i].sh_addr +
> + sechdrs[i].sh_size;
> + }
>
> /* We don't handle .init for the moment: rename to _init */
> while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init")))
> diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
> index 0494e1566ee2..5dac5ab22fa2 100644
> --- a/arch/powerpc/kernel/vmlinux.lds.S
> +++ b/arch/powerpc/kernel/vmlinux.lds.S
> @@ -278,7 +278,9 @@ SECTIONS
> }
>
> .opd : AT(ADDR(.opd) - LOAD_OFFSET) {
> + __start_opd = .;
> *(.opd)
> + __end_opd = .;
> }
>
> . = ALIGN(256);
--
--
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