From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-x243.google.com (mail-pg0-x243.google.com [IPv6:2607:f8b0:400e:c05::243]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3yY0Kb1sx4zDrKd for ; Fri, 10 Nov 2017 10:50:43 +1100 (AEDT) Received: by mail-pg0-x243.google.com with SMTP id z184so619117pgd.13 for ; Thu, 09 Nov 2017 15:50:43 -0800 (PST) From: Sergey Senozhatsky To: Tony Luck , Fenghua Yu , Helge Deller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , James Bottomley Cc: Andrew Morton , Jessica Yu , Petr Mladek , Steven Rostedt , linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: [PATCHv4 3/6] powerpc64: Add .opd based function descriptor dereference Date: Fri, 10 Nov 2017 08:48:27 +0900 Message-Id: <20171109234830.5067-4-sergey.senozhatsky@gmail.com> In-Reply-To: <20171109234830.5067-1-sergey.senozhatsky@gmail.com> References: <20171109234830.5067-1-sergey.senozhatsky@gmail.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 --- 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(+) 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); -- 2.15.0