ARM: 6207/1: Replace CONFIG_HAS_TLS_REG with HWCAP_TLS and check for it on V6
The TLS register is only available on ARM1136 r1p0 and later.
Set HWCAP_TLS flags if hardware TLS is available and test for
it if CONFIG_CPU_32v6K is not set for V6.
Note that we set the TLS instruction in __kuser_get_tls
dynamically as suggested by Jamie Lokier <jamie@shareable.org>.
Also the __switch_to code is optimized out in most cases as
suggested by Nicolas Pitre <nico@fluxnic.net>.
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 7ae65dc..648c3c1 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -269,6 +269,21 @@
extern struct proc_info_list *lookup_processor_type(unsigned int);
extern struct machine_desc *lookup_machine_type(unsigned int);
+static void __init feat_v6_fixup(void)
+{
+ int id = read_cpuid_id();
+
+ if ((id & 0xff0f0000) != 0x41070000)
+ return;
+
+ /*
+ * HWCAP_TLS is available only on 1136 r1p0 and later,
+ * see also kuser_get_tls_init.
+ */
+ if ((((id >> 4) & 0xfff) == 0xb36) && (((id >> 20) & 3) == 0))
+ elf_hwcap &= ~HWCAP_TLS;
+}
+
static void __init setup_processor(void)
{
struct proc_info_list *list;
@@ -311,6 +326,8 @@
elf_hwcap &= ~HWCAP_THUMB;
#endif
+ feat_v6_fixup();
+
cacheid_init();
cpu_proc_init();
}