core: asan: tag access for .ARM.extab and .ARM.exidx

The two sections .ARM.extab and .ARM.exidx are accessed when printing a
stack trace. Tag access for these two sections to avoid recursive panics
due to failing checks against shadow area.

Tested-by: Jens Wiklander <jens.wiklander@linaro.org> (QEMU)
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

core/arch/arm/include/kernel/linker.h

@@ -45,6 +45,8 @@
  */
 extern const uint8_t __exidx_start[];
 extern const uint8_t __exidx_end[];
+extern const uint8_t __extab_start[];
+extern const uint8_t __extab_end[];
 
 extern const struct pseudo_ta_head __start_ta_head_section;
 extern const struct pseudo_ta_head __stop_ta_head_section;

core/arch/arm/kernel/generic_boot.c

@@ -346,6 +346,8 @@ static void init_asan(void)
 	asan_tag_access(&__ctor_list, &__ctor_end);
 	asan_tag_access(__rodata_start, __rodata_end);
 	asan_tag_access(__nozi_start, __nozi_end);
+	asan_tag_access(__exidx_start, __exidx_end);
+	asan_tag_access(__extab_start, __extab_end);
 
 	init_run_constructors();
 

core/arch/arm/kernel/link_dummy.ld

@@ -47,6 +47,8 @@ __end_phys_nsec_ddr_section = .;
 __end_phys_sdp_mem_section = .;
 __exidx_end = .;
 __exidx_start = .;
+__extab_end = .;
+__extab_start = .;
 __heap1_end = .;
 __heap1_start = .;
 __heap2_end = .;