From 9549fb354ef1a451ceddfa404ae3e943c5c803d0 Mon Sep 17 00:00:00 2001 From: Greg Ungerer Date: Tue, 11 Jul 2023 23:07:54 +1000 Subject: [PATCH] riscv: support the elf-fdpic binfmt loader Add support for enabling and using the binfmt_elf_fdpic program loader on RISC-V platforms. The most important change is to setup registers during program load to pass the mapping addresses to the new process. One of the interesting features of the elf-fdpic loader is that it also allows appropriately compiled ELF format binaries to be loaded on nommu systems. Appropriate being those compiled with -pie. Signed-off-by: Greg Ungerer Acked-by: Kees Cook Link: https://lore.kernel.org/r/20230711130754.481209-3-gerg@kernel.org Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/elf.h | 11 ++++++++++- arch/riscv/include/asm/mmu.h | 4 ++++ arch/riscv/include/uapi/asm/ptrace.h | 5 +++++ fs/Kconfig.binfmt | 2 +- 4 files changed, 20 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h index c24280774caf..c33fe923ef6d 100644 --- a/arch/riscv/include/asm/elf.h +++ b/arch/riscv/include/asm/elf.h @@ -41,6 +41,7 @@ extern bool compat_elf_check_arch(Elf32_Ehdr *hdr); #define compat_elf_check_arch compat_elf_check_arch #define CORE_DUMP_USE_REGSET +#define ELF_FDPIC_CORE_EFLAGS 0 #define ELF_EXEC_PAGESIZE (PAGE_SIZE) /* @@ -69,6 +70,13 @@ extern bool compat_elf_check_arch(Elf32_Ehdr *hdr); #define ELF_HWCAP riscv_get_elf_hwcap() extern unsigned long elf_hwcap; +#define ELF_FDPIC_PLAT_INIT(_r, _exec_map_addr, _interp_map_addr, dynamic_addr) \ + do { \ + (_r)->a1 = _exec_map_addr; \ + (_r)->a2 = _interp_map_addr; \ + (_r)->a3 = dynamic_addr; \ + } while (0) + /* * This yields a string that ld.so will use to load implementation * specific libraries for optimization. This is more specific in @@ -78,7 +86,6 @@ extern unsigned long elf_hwcap; #define COMPAT_ELF_PLATFORM (NULL) -#ifdef CONFIG_MMU #define ARCH_DLINFO \ do { \ /* \ @@ -115,6 +122,8 @@ do { \ else \ NEW_AUX_ENT(AT_IGNORE, 0); \ } while (0) + +#ifdef CONFIG_MMU #define ARCH_HAS_SETUP_ADDITIONAL_PAGES struct linux_binprm; extern int arch_setup_additional_pages(struct linux_binprm *bprm, diff --git a/arch/riscv/include/asm/mmu.h b/arch/riscv/include/asm/mmu.h index 0099dc116168..355504b37f8e 100644 --- a/arch/riscv/include/asm/mmu.h +++ b/arch/riscv/include/asm/mmu.h @@ -20,6 +20,10 @@ typedef struct { /* A local icache flush is needed before user execution can resume. */ cpumask_t icache_stale_mask; #endif +#ifdef CONFIG_BINFMT_ELF_FDPIC + unsigned long exec_fdpic_loadmap; + unsigned long interp_fdpic_loadmap; +#endif } mm_context_t; void __init create_pgd_mapping(pgd_t *pgdp, uintptr_t va, phys_addr_t pa, diff --git a/arch/riscv/include/uapi/asm/ptrace.h b/arch/riscv/include/uapi/asm/ptrace.h index e17c550986a6..30f6d6537adc 100644 --- a/arch/riscv/include/uapi/asm/ptrace.h +++ b/arch/riscv/include/uapi/asm/ptrace.h @@ -10,6 +10,11 @@ #include +#define PTRACE_GETFDPIC 33 + +#define PTRACE_GETFDPIC_EXEC 0 +#define PTRACE_GETFDPIC_INTERP 1 + /* * User-mode register state for core dumps, ptrace, sigcontext * diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt index 93539aac0e5b..f5693164ca9a 100644 --- a/fs/Kconfig.binfmt +++ b/fs/Kconfig.binfmt @@ -58,7 +58,7 @@ config ARCH_USE_GNU_PROPERTY config BINFMT_ELF_FDPIC bool "Kernel support for FDPIC ELF binaries" default y if !BINFMT_ELF - depends on ARM || ((M68K || SUPERH || XTENSA) && !MMU) + depends on ARM || ((M68K || RISCV || SUPERH || XTENSA) && !MMU) select ELFCORE help ELF FDPIC binaries are based on ELF, but allow the individual load