[PATCH v2025.09.y 15/58] ARM: cpu: common: skip R_ARM_NONE relocations

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

From: Ahmad Fatoum <a.fatoum@barebox.org>

Relocations may be turned into no-op in place by strip running on an
executable by having their type set to 0 (R_ARM_NONE).

This can happen with the incoming ELF loading in PBL support, so teach
relocate_to_current_adr() to skip these no-op relocation entries.

(cherry picked from commit 9ef816e176d9ace3a88911e37eb280552c2223e4)

Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
Link: https://lore.barebox.org/20260106081659.3491945-1-a.fatoum@barebox.org
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 arch/arm/cpu/common.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/arch/arm/cpu/common.c b/arch/arm/cpu/common.c
index 339ef2db2534..5b65b0745b98 100644
--- a/arch/arm/cpu/common.c
+++ b/arch/arm/cpu/common.c
@@ -36,6 +36,7 @@ void sync_caches_for_execution(void)
 	arm_early_mmu_cache_flush();
 }
 
+#define R_ARM_NONE 0
 #define R_ARM_RELATIVE 23
 #define R_AARCH64_RELATIVE 1027
 
@@ -78,14 +79,19 @@ void __prereloc relocate_to_current_adr(void)
 #if defined(CONFIG_CPU_64)
 	while (dstart < dend) {
 		struct elf64_rela *rel = dstart;
+		unsigned long *fixup;
 
-		if (ELF64_R_TYPE(rel->r_info) == R_AARCH64_RELATIVE) {
-			unsigned long *fixup = (unsigned long *)(rel->r_offset + offset);
+		switch(ELF64_R_TYPE(rel->r_info)) {
+		case R_AARCH64_RELATIVE:
+			fixup = (unsigned long *)(rel->r_offset + offset);
 
 			*fixup = rel->r_addend + offset;
 			rel->r_addend += offset;
 			rel->r_offset += offset;
-		} else {
+			break;
+		case R_ARM_NONE:
+			break;
+		default:
 			putc_ll('>');
 			puthex_ll(rel->r_info);
 			putc_ll(' ');
@@ -104,20 +110,26 @@ void __prereloc relocate_to_current_adr(void)
 
 	while (dstart < dend) {
 		struct elf32_rel *rel = dstart;
+		unsigned long r, *fixup;
 
-		if (ELF32_R_TYPE(rel->r_info) == R_ARM_RELATIVE) {
-			unsigned long *fixup = (unsigned long *)(rel->r_offset + offset);
+		switch (ELF32_R_TYPE(rel->r_info)) {
+		case R_ARM_RELATIVE:
+			fixup = (unsigned long *)(rel->r_offset + offset);
 
 			*fixup = *fixup + offset;
 
 			rel->r_offset += offset;
-		} else if (ELF32_R_TYPE(rel->r_info) == R_ARM_ABS32) {
-			unsigned long r = dynsym[ELF32_R_SYM(rel->r_info) * 4 + 1];
-			unsigned long *fixup = (unsigned long *)(rel->r_offset + offset);
+			break;
+		case R_ARM_ABS32:
+			r = dynsym[ELF32_R_SYM(rel->r_info) * 4 + 1];
+			fixup = (unsigned long *)(rel->r_offset + offset);
 
 			*fixup = *fixup + r + offset;
 			rel->r_offset += offset;
-		} else {
+			break;
+		case R_ARM_NONE:
+			break;
+		default:
 			putc_ll('>');
 			puthex_ll(rel->r_info);
 			putc_ll(' ');
-- 
2.47.3