[PATCH AUTOSEL 6.17-5.4] sparc/module: Add R_SPARC_UA64 relocation handling

[Sasha Levin <sashal@kernel.org>]

From: Koakuma <koachan@protonmail.com>

[ Upstream commit 05457d96175d25c976ab6241c332ae2eb5e07833 ]

This is needed so that the kernel can handle R_SPARC_UA64 relocations,
which is emitted by LLVM's IAS.

Signed-off-by: Koakuma <koachan@protonmail.com>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

YES – this patch fixes a real module-loading bug for sparc64 systems
without touching unrelated code.

- `arch/sparc/include/asm/elf_64.h:61` adds the missing ABI constant
  `R_SPARC_UA64` (value 54), so the loader can even recognise
  relocations that LLVM’s integrated assembler already emits.
- `arch/sparc/kernel/module.c:90` folds `R_SPARC_UA64` into the existing
  `R_SPARC_64` handler, writing the eight relocation bytes individually
  just like the aligned case. Without this case the switch drops into
  the default branch (`module.c:134`) and aborts module loading with
  “Unknown relocation” and `-ENOEXEC`, so clang-built modules simply
  cannot load today.
- Scope and risk stay minimal: the bytes written are identical to the
  long-standing `R_SPARC_64` path, so nothing changes for GCC-produced
  objects; the new code only runs when the UA64 relocation is present,
  avoiding regressions elsewhere.

Given it unbreaks a supported toolchain configuration with a tiny, well-
contained fix, this is an appropriate stable backport.

 arch/sparc/include/asm/elf_64.h | 1 +
 arch/sparc/kernel/module.c      | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/sparc/include/asm/elf_64.h b/arch/sparc/include/asm/elf_64.h
index 8fb09eec8c3e7..694ed081cf8d9 100644
--- a/arch/sparc/include/asm/elf_64.h
+++ b/arch/sparc/include/asm/elf_64.h
@@ -58,6 +58,7 @@
 #define R_SPARC_7		43
 #define R_SPARC_5		44
 #define R_SPARC_6		45
+#define R_SPARC_UA64		54
 
 /* Bits present in AT_HWCAP, primarily for Sparc32.  */
 #define HWCAP_SPARC_FLUSH       0x00000001
diff --git a/arch/sparc/kernel/module.c b/arch/sparc/kernel/module.c
index b8c51cc23d969..6e3d4dde4f9ab 100644
--- a/arch/sparc/kernel/module.c
+++ b/arch/sparc/kernel/module.c
@@ -87,6 +87,7 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 			break;
 #ifdef CONFIG_SPARC64
 		case R_SPARC_64:
+		case R_SPARC_UA64:
 			location[0] = v >> 56;
 			location[1] = v >> 48;
 			location[2] = v >> 40;
-- 
2.51.0