[PATCH 2/2] arm64: Always provide compat /proc/cpuinfo for 32-bit tasks

[Catalin Marinas]

Currently, the compat /proc/cpuinfo is provided only if a task has the
PER_LINUX32 personality, either by setting it explicitly or by
inheriting it from the parent task. This is in line with the "uname -m"
behaviour.

However, there are 32-bit user applications making use of the
/proc/cpuinfo and unaware of a need to set the personality. This patch
changes the arm64 /proc/cpuinfo logic to provide the compat information
if the task is 32-bit _or_ the PER_LINUX32 personality is set.

Cc: <stable at vger.kernel.org>
Cc: Arnd Bergmann <arnd at arndb.de>
Cc: Will Deacon <will.deacon at arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
---
 arch/arm64/kernel/cpuinfo.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index c173d329397f..bd6a122ea856 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -106,7 +106,8 @@ static const char *const compat_hwcap2_str[] = {
 static int c_show(struct seq_file *m, void *v)
 {
 	int i, j;
-	bool compat = personality(current->personality) == PER_LINUX32;
+	bool compat = is_compat_task() ||
+		personality(current->personality) == PER_LINUX32;
 
 	for_each_online_cpu(i) {
 		struct cpuinfo_arm64 *cpuinfo = &per_cpu(cpu_data, i);