[PATCH 6/6] arm64: compat: Check for AArch32 state

From: Suzuki K Poulose
Date: Thu Jan 28 2016 - 06:33:08 EST


Make sure we have AArch32 state available for running COMPAT binaries.

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/cpuinfo.c | 3 ++-
3 files changed, 9 insertions(+), 4 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 8deaa20..cccc7ce 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -931,7 +931,8 @@ 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)
@@ -948,7 +949,9 @@ 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/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 8cc2a86..2890b74 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -124,7 +124,8 @@ static int c_show(struct seq_file *m, void *v)
* software which does already (at least for 32-bit).
*/
seq_puts(m, "Features\t:");
- if (personality(current->personality) == PER_LINUX32) {
+ if (system_supports_32bit_el0() &&
+ personality(current->personality) == PER_LINUX32) {
#ifdef CONFIG_COMPAT
for (j = 0; compat_hwcap_str[j]; j++)
if (compat_elf_hwcap & (1 << j))
--
1.7.9.5