[PATCH V9 14/20] riscv: compat: Add elf.h implementation

guoren
2022-03-22T14:52:00Z

From: Guo Ren <guoren@linux.alibaba.com>

Implement necessary type and macro for compat elf. See the code
comment for detail.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
---
arch/riscv/include/asm/elf.h | 41 +++++++++++++++++++++++++++++++++++-
1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h
index f53c40026c7a..a234656cfb5d 100644
--- a/arch/riscv/include/asm/elf.h
+++ b/arch/riscv/include/asm/elf.h
@@ -8,6 +8,8 @@
#ifndef _ASM_RISCV_ELF_H
#define _ASM_RISCV_ELF_H

+#include <uapi/linux/elf.h>
+#include <linux/compat.h>
#include <uapi/asm/elf.h>
#include <asm/auxvec.h>
#include <asm/byteorder.h>
@@ -18,11 +20,13 @@
*/
#define ELF_ARCH EM_RISCV

+#ifndef ELF_CLASS
#ifdef CONFIG_64BIT
#define ELF_CLASS ELFCLASS64
#else
#define ELF_CLASS ELFCLASS32
#endif
+#endif

#define ELF_DATA ELFDATA2LSB

@@ -31,6 +35,8 @@
*/
#define elf_check_arch(x) ((x)->e_machine == EM_RISCV)

+#define compat_elf_check_arch(x) ((x)->e_machine == EM_RISCV)
+
#define CORE_DUMP_USE_REGSET
#define ELF_EXEC_PAGESIZE (PAGE_SIZE)

@@ -43,8 +49,14 @@
#define ELF_ET_DYN_BASE ((TASK_SIZE / 3) * 2)

#ifdef CONFIG_64BIT
+#ifdef CONFIG_COMPAT
+#define STACK_RND_MASK (test_thread_flag(TIF_32BIT) ? \
+ 0x7ff >> (PAGE_SHIFT - 12) : \
+ 0x3ffff >> (PAGE_SHIFT - 12))
+#else
#define STACK_RND_MASK (0x3ffff >> (PAGE_SHIFT - 12))
#endif
+#endif
/*
* This yields a mask that user programs can use to figure out what
* instruction set this CPU supports. This could be done in user space,
@@ -60,11 +72,19 @@ extern unsigned long elf_hwcap;
*/
#define ELF_PLATFORM (NULL)

+#define COMPAT_ELF_PLATFORM (NULL)
+
#ifdef CONFIG_MMU
#define ARCH_DLINFO \
do { \
+ /* \
+ * Note that we add ulong after elf_addr_t because \
+ * casting current->mm->context.vdso triggers a cast \
+ * warning of cast from pointer to integer for \
+ * COMPAT ELFCLASS32. \
+ */ \
NEW_AUX_ENT(AT_SYSINFO_EHDR, \
- (elf_addr_t)current->mm->context.vdso); \
+ (elf_addr_t)(ulong)current->mm->context.vdso); \
NEW_AUX_ENT(AT_L1I_CACHESIZE, \
get_cache_size(1, CACHE_TYPE_INST)); \
NEW_AUX_ENT(AT_L1I_CACHEGEOMETRY, \
@@ -90,4 +110,23 @@ do { \
*(struct user_regs_struct *)regs; \
} while (0);

+#ifdef CONFIG_COMPAT
+
+#define SET_PERSONALITY(ex) \
+do { if ((ex).e_ident[EI_CLASS] == ELFCLASS32) \
+ set_thread_flag(TIF_32BIT); \
+ else \
+ clear_thread_flag(TIF_32BIT); \
+ if (personality(current->personality) != PER_LINUX32) \
+ set_personality(PER_LINUX | \
+ (current->personality & (~PER_MASK))); \
+} while (0)
+
+#define COMPAT_ELF_ET_DYN_BASE ((TASK_SIZE_32 / 3) * 2)
+
+/* rv32 registers */
+typedef compat_ulong_t compat_elf_greg_t;
+typedef compat_elf_greg_t compat_elf_gregset_t[ELF_NGREG];
+
+#endif /* CONFIG_COMPAT */
#endif /* _ASM_RISCV_ELF_H */