arm64: compat: Check for AArch32 state
Make sure we have AArch32 state available for running COMPAT
binaries and also for switching the personality to PER_LINUX32.
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
[ Added cap bit, checks for HWCAP, personality ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 24ed037..7a09c48 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -177,7 +177,8 @@
/* AArch32 EABI. */
#define EF_ARM_EABI_MASK 0xff000000
-#define compat_elf_check_arch(x) (((x)->e_machine == EM_ARM) && \
+#define compat_elf_check_arch(x) (system_supports_32bit_el0() && \
+ ((x)->e_machine == EM_ARM) && \
((x)->e_flags & EF_ARM_EABI_MASK))
#define compat_start_thread compat_start_thread
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 40a23f2..8e62d61 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -987,7 +987,8 @@
verify_local_cpu_features(arm64_features);
verify_local_elf_hwcaps(arm64_elf_hwcaps);
- verify_local_elf_hwcaps(compat_elf_hwcaps);
+ if (system_supports_32bit_el0())
+ verify_local_elf_hwcaps(compat_elf_hwcaps);
}
static void __init setup_feature_capabilities(void)
@@ -1004,7 +1005,9 @@
/* Set the CPU feature capabilies */
setup_feature_capabilities();
setup_elf_hwcaps(arm64_elf_hwcaps);
- setup_elf_hwcaps(compat_elf_hwcaps);
+
+ if (system_supports_32bit_el0())
+ setup_elf_hwcaps(compat_elf_hwcaps);
/* Advertise that we have computed the system capabilities */
set_sys_caps_initialised();
diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c
index 75151aa..26fe8ea 100644
--- a/arch/arm64/kernel/sys.c
+++ b/arch/arm64/kernel/sys.c
@@ -25,6 +25,7 @@
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
+#include <asm/cpufeature.h>
asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags,
@@ -36,11 +37,20 @@
return sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
}
+SYSCALL_DEFINE1(arm64_personality, unsigned int, personality)
+{
+ if (personality(personality) == PER_LINUX32 &&
+ !system_supports_32bit_el0())
+ return -EINVAL;
+ return sys_personality(personality);
+}
+
/*
* Wrappers to pass the pt_regs argument.
*/
asmlinkage long sys_rt_sigreturn_wrapper(void);
#define sys_rt_sigreturn sys_rt_sigreturn_wrapper
+#define sys_personality sys_arm64_personality
#undef __SYSCALL
#define __SYSCALL(nr, sym) [nr] = sym,