feat(build): check that .text section starts at page boundary

Linker may decide to put new unspecified sections before .text
section. That will cause non-working image, because entry point isn't
at __BLXX_START__. Device just not booted with such image.

This happened for example with .note.gnu.build-id section generated
for LTO build in some cases. Now linker will report this situation as
an error.

```
/usr/lib/gcc-cross/aarch64-linux-gnu/13/../../../../aarch64-linux-gnu/bin/ld: .text is not aligned on a page boundary.
collect2: error: ld returned 1 exit status
```

Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Change-Id: I5ae46ddd1e6e431e1df1715d1d301f6dd7181cc7

bl1/bl1.ld.S

@@ -36,6 +36,9 @@ SECTIONS {
 
 #if SEPARATE_CODE_AND_RODATA
     .text . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".text address is not aligned on a page boundary.");
+
         __TEXT_START__ = .;
 
         *bl1_entrypoint.o(.text*)
@@ -80,6 +83,9 @@ SECTIONS {
     } >ROM
 #else /* SEPARATE_CODE_AND_RODATA */
     .ro . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".ro address is not aligned on a page boundary.");
+
         __RO_START__ = .;
 
         *bl1_entrypoint.o(.text*)

bl2/bl2.ld.S

@@ -25,6 +25,9 @@ SECTIONS {
 
 #if SEPARATE_CODE_AND_RODATA
     .text . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".text address is not aligned on a page boundary.");
+
         __TEXT_START__ = .;
 
 #if ENABLE_RME
@@ -65,6 +68,9 @@ SECTIONS {
     } >RAM
 #else /* SEPARATE_CODE_AND_RODATA */
     .ro . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".ro address is not aligned on a page boundary.");
+
         __RO_START__ = .;
 
         *bl2_entrypoint.o(.text*)

bl2/bl2_el3.ld.S

@@ -55,6 +55,9 @@ SECTIONS {
 
 #if SEPARATE_CODE_AND_RODATA
     .text . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".text address is not aligned on a page boundary.");
+
         __TEXT_START__ = .;
         __TEXT_RESIDENT_START__ = .;
 
@@ -89,6 +92,9 @@ SECTIONS {
         "Resident part of BL2 has exceeded its limit.")
 #else /* SEPARATE_CODE_AND_RODATA */
     .ro . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".ro address is not aligned on a page boundary.");
+
         __RO_START__ = .;
         __TEXT_RESIDENT_START__ = .;
 

bl2u/bl2u.ld.S

@@ -27,6 +27,9 @@ SECTIONS {
 
 #if SEPARATE_CODE_AND_RODATA
     .text . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".text address is not aligned on a page boundary.");
+
         __TEXT_START__ = .;
 
         *bl2u_entrypoint.o(.text*)
@@ -60,6 +63,9 @@ SECTIONS {
     } >RAM
 #else /* SEPARATE_CODE_AND_RODATA */
     .ro . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".ro address is not aligned on a page boundary.");
+
         __RO_START__ = .;
 
         *bl2u_entrypoint.o(.text*)

bl31/bl31.ld.S

@@ -37,6 +37,9 @@ SECTIONS {
 
 #if SEPARATE_CODE_AND_RODATA
     .text . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".text is not aligned on a page boundary.");
+
         __TEXT_START__ = .;
 
         *bl31_entrypoint.o(.text*)
@@ -71,6 +74,9 @@ SECTIONS {
     } >RAM
 #else /* SEPARATE_CODE_AND_RODATA */
     .ro . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".ro is not aligned on a page boundary.");
+
         __RO_START__ = .;
 
         *bl31_entrypoint.o(.text*)

bl32/sp_min/sp_min.ld.S

@@ -29,6 +29,9 @@ SECTIONS {
 
 #if SEPARATE_CODE_AND_RODATA
     .text . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".text address is not aligned on a page boundary.");
+
         __TEXT_START__ = .;
 
         *entrypoint.o(.text*)
@@ -67,6 +70,9 @@ SECTIONS {
     } >RAM
 #else /* SEPARATE_CODE_AND_RODATA */
     .ro . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".ro address is not aligned on a page boundary.");
+
         __RO_START__ = .;
 
         *entrypoint.o(.text*)

bl32/tsp/tsp.ld.S

@@ -25,6 +25,9 @@ SECTIONS {
 
 #if SEPARATE_CODE_AND_RODATA
     .text . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".text address is not aligned on a page boundary.");
+
         __TEXT_START__ = .;
 
         *tsp_entrypoint.o(.text*)
@@ -51,6 +54,9 @@ SECTIONS {
     } >RAM
 #else /* SEPARATE_CODE_AND_RODATA */
     .ro . : {
+        ASSERT(. == ALIGN(PAGE_SIZE),
+        ".ro address is not aligned on a page boundary.");
+
         __RO_START__ = .;
 
         *tsp_entrypoint.o(.text*)