arm64: compat: add support for big-endian (BE8) AArch32 binaries

This patch adds support for BE8 AArch32 tasks to the compat layer.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

4 files changed, 25 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
index 899af807ef0f..fda2704b3f9f 100644
--- a/arch/arm64/include/asm/compat.h
+++ b/arch/arm64/include/asm/compat.h
@@ -26,7 +26,11 @@
 #include <linux/ptrace.h>
 
 #define COMPAT_USER_HZ          100
+#ifdef __AARCH64EB__
+#define COMPAT_UTS_MACHINE      "armv8b\0\0"
+#else
 #define COMPAT_UTS_MACHINE      "armv8l\0\0"
+#endif
 
 typedef u32             compat_size_t;
 typedef s32             compat_ssize_t;
@@ -73,13 +77,23 @@ struct compat_timeval {
 };
 
 struct compat_stat {
+#ifdef __AARCH64EB__
+        short           st_dev;
+        short           __pad1;
+#else
         compat_dev_t    st_dev;
+#endif
         compat_ino_t    st_ino;
         compat_mode_t   st_mode;
         compat_ushort_t st_nlink;
         __compat_uid16_t        st_uid;
         __compat_gid16_t        st_gid;
+#ifdef __AARCH64EB__
+        short           st_rdev;
+        short           __pad2;
+#else
         compat_dev_t    st_rdev;
+#endif
         compat_off_t    st_size;
         compat_off_t    st_blksize;
         compat_off_t    st_blocks;
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index a3e4a5564ea3..01d3aab64b79 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -162,7 +162,12 @@ extern unsigned long arch_randomize_brk(struct mm_struct *mm);
 #define arch_randomize_brk arch_randomize_brk
 
 #ifdef CONFIG_COMPAT
+
+#ifdef __AARCH64EB__
+#define COMPAT_ELF_PLATFORM             ("v8b")
+#else
 #define COMPAT_ELF_PLATFORM             ("v8l")
+#endif
 
 #define COMPAT_ELF_ET_DYN_BASE          (randomize_et_dyn(2 * TASK_SIZE_32 / 3))
 
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index ab239b2c456f..45b20cd6cbca 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -107,6 +107,11 @@ static inline void compat_start_thread(struct pt_regs *regs, unsigned long pc,
         regs->pstate = COMPAT_PSR_MODE_USR;
         if (pc & 1)
                 regs->pstate |= COMPAT_PSR_T_BIT;
+
+#ifdef __AARCH64EB__
+        regs->pstate |= COMPAT_PSR_E_BIT;
+#endif
+
         regs->compat_sp = sp;
 }
 #endif
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 0dacbbf9458b..0e7fa4963735 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -42,6 +42,7 @@
 #define COMPAT_PSR_MODE_UND     0x0000001b
 #define COMPAT_PSR_MODE_SYS     0x0000001f
 #define COMPAT_PSR_T_BIT        0x00000020
+#define COMPAT_PSR_E_BIT        0x00000200
 #define COMPAT_PSR_F_BIT        0x00000040
 #define COMPAT_PSR_I_BIT        0x00000080
 #define COMPAT_PSR_A_BIT        0x00000100