Remove ARMv6 support

ARMv6 support is being removed from seL4.

Signed-off-by: Kent McLeod <kent@kry10.com>

.github/workflows/sel4test-sim.yml

diff --git a/.github/workflows/sel4test-sim.yml b/.github/workflows/sel4test-sim.yml
index 99488e1..eaba34c 100644
--- a/.github/workflows/sel4test-sim.yml
+++ b/.github/workflows/sel4test-sim.yml
@@ -19,7 +19,7 @@
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        march: [armv6a, armv7a, armv8a, nehalem, rv32imac, rv64imac]
+        march: [armv7a, armv8a, nehalem, rv32imac, rv64imac]
         compiler: [gcc, clang]
         exclude:
           - march: rv32imac

include/sel4_arch/aarch32/sel4runtime/thread_arch.h

diff --git a/include/sel4_arch/aarch32/sel4runtime/thread_arch.h b/include/sel4_arch/aarch32/sel4runtime/thread_arch.h
index 70a4f27..671fa13 100644
--- a/include/sel4_arch/aarch32/sel4runtime/thread_arch.h
+++ b/include/sel4_arch/aarch32/sel4runtime/thread_arch.h
@@ -7,12 +7,7 @@
 #include <sel4/arch/constants.h>
 #include <sel4runtime/stdint.h>
 
-#if ((\
-            defined(__ARM_ARCH_6K__) || \
-            defined(__ARM_ARCH_6ZK__) \
-        ) && !defined(__thumb__) \
-    ) || \
-    defined(__ARM_ARCH_7A__) || \
+#if defined(__ARM_ARCH_7A__) || \
     defined(__ARM_ARCH_7R__) || \
     (defined(__ARM_ARCH) && __ARM_ARCH >= 7)
 
@@ -43,39 +38,6 @@
     sel4runtime_write_tpidr_el0(tls_base);
 }
 
-#elif defined(CONFIG_KERNEL_GLOBALS_FRAME)
-
-/*
- * In the case of early versions of ARMv6, there are no hardware
- * registers provided for thread-local identifiers. seL4 resolves this
- * by placing the IPC buffer address and thread pointer in a
- * `GlobalsFrame` mapped at the same address in all virtual address
- * spaces. The IPC buffer and thread pointer occupy the first two words
- * in this frame respectively.
- */
-static inline sel4runtime_uintptr_t sel4runtime_read_tpidr_el0(void)
-{
-    void **globals_frame = (void **)seL4_GlobalsFrame;
-    return (sel4runtime_uintptr_t)globals_frame[0];
-}
-
-static inline sel4runtime_uintptr_t sel4runtime_read_tpidrro_el0(void)
-{
-    void **globals_frame = (void **)seL4_GlobalsFrame;
-    return (sel4runtime_uintptr_t)globals_frame[1];
-}
-
-#ifdef CONFIG_SET_TLS_BASE_SELF
-/*
- * Set the value of the TLS base for the current thread.
- */
-static inline void sel4runtime_set_tls_base(sel4runtime_uintptr_t tls_base)
-{
-    seL4_SetTLSBase(tls_base);
-}
-#else
-#error "No way to set TLS base provided."
-#endif
 #else
 #error "No TLS mechanism provided."
 #endif /* CONFIG_SET_TLS_BASE_SELF */