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authorPalmer Dabbelt <palmer@rivosinc.com>2023-08-24 00:17:45 +0300
committerPalmer Dabbelt <palmer@rivosinc.com>2023-08-31 10:18:33 +0300
commit150e3c92a1455cc3971be1f5962f35c32ab3deee (patch)
tree25fb78935eb99b263237fd571ac138486dcea637 /arch/riscv/include
parent7f7d3ea6eb000bd329a6f2fe3f1c7596c4e783e1 (diff)
parent9549fb354ef1a451ceddfa404ae3e943c5c803d0 (diff)
downloadlinux-150e3c92a1455cc3971be1f5962f35c32ab3deee.tar.xz
Merge patch series "riscv: support ELF format binaries in nommu mode"
Greg Ungerer <gerg@kernel.org> says: The following changes add the ability to run ELF format binaries when running RISC-V in nommu mode. That support is actually part of the ELF-FDPIC loader, so these changes are all about making that work on RISC-V. The first issue to deal with is making the ELF-FDPIC loader capable of handling 64-bit ELF files. As coded right now it only supports 32-bit ELF files. Secondly some changes are required to enable and compile the ELF-FDPIC loader on RISC-V and to pass the ELF-FDPIC mapping addresses through to user space when execing the new program. These changes have not been used to run actual ELF-FDPIC binaries. It is used to load and run normal ELF - compiled -pie format. Though the underlying changes are expected to work with full ELF-FDPIC binaries if or when that is supported on RISC-V in gcc. To avoid needing changes to the C-library (tested with uClibc-ng currently) there is a simple runtime dynamic loader (interpreter) available to do the final relocations, https://github.com/gregungerer/uldso. The nice thing about doing it this way is that the same program binary can also be loaded with the usual ELF loader in MMU linux. The motivation here is to provide an easy to use alternative to the flat format binaries normally used for RISC-V nommu based systems. * b4-shazam-merge: riscv: support the elf-fdpic binfmt loader binfmt_elf_fdpic: support 64-bit systems Link: https://lore.kernel.org/r/20230711130754.481209-1-gerg@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/include')
-rw-r--r--arch/riscv/include/asm/elf.h11
-rw-r--r--arch/riscv/include/asm/mmu.h4
-rw-r--r--arch/riscv/include/uapi/asm/ptrace.h5
3 files changed, 19 insertions, 1 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 <linux/types.h>
+#define PTRACE_GETFDPIC 33
+
+#define PTRACE_GETFDPIC_EXEC 0
+#define PTRACE_GETFDPIC_INTERP 1
+
/*
* User-mode register state for core dumps, ptrace, sigcontext
*