From 3cb10cfafd83b9d7b3867b7deae29b8da3b5fe39 Mon Sep 17 00:00:00 2001 From: Christophe Lyon Date: Mon, 30 Apr 2018 10:03:43 +0200 Subject: [PATCH] linux-user: ARM-FDPIC: Add support of FDPIC for ARM. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add FDPIC info into image_info structure since interpreter info is on stack and needs to be saved to be accessed later on. Co-Authored-By: Mickaël Guêné Signed-off-by: Christophe Lyon Reviewed-by: Peter Maydell Message-Id: <20180430080404.7323-4-christophe.lyon@st.com> Signed-off-by: Laurent Vivier --- linux-user/elfload.c | 29 +++++++++++++++++++++++++++++ linux-user/qemu.h | 9 +++++++++ 2 files changed, 38 insertions(+) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 76d7718b3d..36d52194bc 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -78,6 +78,11 @@ enum { */ #define personality(pers) (pers & PER_MASK) +int info_is_fdpic(struct image_info *info) +{ + return info->personality == PER_LINUX_FDPIC; +} + /* this flag is uneffective under linux too, should be deleted */ #ifndef MAP_DENYWRITE #define MAP_DENYWRITE 0 @@ -287,6 +292,25 @@ static inline void init_thread(struct target_pt_regs *regs, /* For uClinux PIC binaries. */ /* XXX: Linux does this only on ARM with no MMU (do we care ?) */ regs->uregs[10] = infop->start_data; + + /* Support ARM FDPIC. */ + if (info_is_fdpic(infop)) { + /* As described in the ABI document, r7 points to the loadmap info + * prepared by the kernel. If an interpreter is needed, r8 points + * to the interpreter loadmap and r9 points to the interpreter + * PT_DYNAMIC info. If no interpreter is needed, r8 is zero, and + * r9 points to the main program PT_DYNAMIC info. + */ + regs->uregs[7] = infop->loadmap_addr; + if (infop->interpreter_loadmap_addr) { + /* Executable is dynamically loaded. */ + regs->uregs[8] = infop->interpreter_loadmap_addr; + regs->uregs[9] = infop->interpreter_pt_dynamic_addr; + } else { + regs->uregs[8] = 0; + regs->uregs[9] = infop->pt_dynamic_addr; + } + } } #define ELF_NREG 18 @@ -1745,6 +1769,11 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, if (interp_info) { interp_info->other_info = info; sp = loader_build_fdpic_loadmap(interp_info, sp); + info->interpreter_loadmap_addr = interp_info->loadmap_addr; + info->interpreter_pt_dynamic_addr = interp_info->pt_dynamic_addr; + } else { + info->interpreter_loadmap_addr = 0; + info->interpreter_pt_dynamic_addr = 0; } } diff --git a/linux-user/qemu.h b/linux-user/qemu.h index da3b51724c..c55c8e294b 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -57,6 +57,8 @@ struct image_info { uint16_t nsegs; void *loadsegs; abi_ulong pt_dynamic_addr; + abi_ulong interpreter_loadmap_addr; + abi_ulong interpreter_pt_dynamic_addr; struct image_info *other_info; }; @@ -183,6 +185,13 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, struct target_pt_regs * regs, struct image_info *infop, struct linux_binprm *); +/* Returns true if the image uses the FDPIC ABI. If this is the case, + * we have to provide some information (loadmap, pt_dynamic_info) such + * that the program can be relocated adequately. This is also useful + * when handling signals. + */ +int info_is_fdpic(struct image_info *info); + uint32_t get_elf_eflags(int fd); int load_elf_binary(struct linux_binprm *bprm, struct image_info *info); int load_flt_binary(struct linux_binprm *bprm, struct image_info *info);