From: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
[ Added checks for ELF HWCAP, Use cap bit in cap_hwcaps ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
arch/arm64/include/asm/elf.h | 3 ++-
arch/arm64/kernel/cpufeature.c | 7 +++++--
arch/arm64/kernel/sys.c | 4 ++++
3 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index faad6df..a1946f2 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -173,7 +173,8 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG];
/* 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 8f6b674..1ae545e 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -929,7 +929,8 @@ void verify_local_cpu_capabilities(void)
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)
@@ -946,7 +947,9 @@ void __init setup_cpu_features(void)
/* 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 817d860..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,
@@ -38,6 +39,9 @@ asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
SYSCALL_DEFINE1(arm64_personality, unsigned int, personality)
{
+ if (personality(personality) == PER_LINUX32 &&
+ !system_supports_32bit_el0())
+ return -EINVAL;
return sys_personality(personality);
}
--
1.7.9.5
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