A handful of module relocations were missing, this patch includes the
remaining ones. I also wrote some test cases to ensure that module
loading works properly. Some relocations cannot be supported in the
kernel, these include the ones that rely on thread local storage and
dynamic linking.
ULEB128 handling is a bit special because SET and SUB relocations must
happen together, and SET must happen before SUB. A psABI proposal [1]
mandates that the first SET_ULEB128 that appears before a SUB_ULEB128
is the associated SET_ULEB128.
This can be tested by enabling KUNIT, RUNTIME_KERNEL_TESTING_MENU, and
RISCV_MODULE_LINKING_KUNIT.
[1] https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/403
Signed-off-by: Charlie Jenkins <[email protected]>
---
Changes in v6:
- Use (void *) instead of (u32 *) for handler type
- Constrain ULEB128 to be consecutive relocations
- Link to v5: https://lore.kernel.org/r/[email protected]
Changes in v5:
- Brought in patch by Emil and fixed it up to force little endian
- Fixed up issues with apply_r_riscv_32_pcrel_rela and
apply_r_riscv_plt32_rela (Samuel)
- Added u8 cast in apply_r_riscv_sub6_rela (Andreas)
- Link to v4: https://lore.kernel.org/r/[email protected]
Changes in v4:
- Complete removal of R_RISCV_RVC_LUI
- Fix bug in R_RISCV_SUB6 linking
- Only build ULEB128 tests if supported by toolchain
- Link to v3: https://lore.kernel.org/r/[email protected]
Changes in v3:
- Add prototypes to test_module_linking_main as recommended by intel
zero day bot
- Improve efficiency of ULEB128 pair matching
- Link to v2: https://lore.kernel.org/r/[email protected]
Changes in v2:
- Added ULEB128 relocations
- Link to v1: https://lore.kernel.org/r/[email protected]
---
Charlie Jenkins (2):
riscv: Add remaining module relocations
riscv: Add tests for riscv module loading
Emil Renner Berthing (1):
riscv: Avoid unaligned access when relocating modules
arch/riscv/Kconfig.debug | 1 +
arch/riscv/include/uapi/asm/elf.h | 5 +-
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/module.c | 368 +++++++++++++++------
arch/riscv/kernel/tests/Kconfig.debug | 35 ++
arch/riscv/kernel/tests/Makefile | 1 +
arch/riscv/kernel/tests/module_test/Makefile | 15 +
.../tests/module_test/test_module_linking_main.c | 85 +++++
arch/riscv/kernel/tests/module_test/test_set16.S | 23 ++
arch/riscv/kernel/tests/module_test/test_set32.S | 20 ++
arch/riscv/kernel/tests/module_test/test_set6.S | 23 ++
arch/riscv/kernel/tests/module_test/test_set8.S | 23 ++
arch/riscv/kernel/tests/module_test/test_sub16.S | 22 ++
arch/riscv/kernel/tests/module_test/test_sub32.S | 22 ++
arch/riscv/kernel/tests/module_test/test_sub6.S | 22 ++
arch/riscv/kernel/tests/module_test/test_sub64.S | 27 ++
arch/riscv/kernel/tests/module_test/test_sub8.S | 22 ++
arch/riscv/kernel/tests/module_test/test_uleb128.S | 20 ++
18 files changed, 633 insertions(+), 102 deletions(-)
---
base-commit: 4d320c2d9a2b22f53523a1b012cda17a50220965
change-id: 20230908-module_relocations-f63ced651bd7
--
- Charlie
Add all final module relocations and add error logs explaining the ones
that are not supported.
Signed-off-by: Charlie Jenkins <[email protected]>
---
arch/riscv/include/uapi/asm/elf.h | 5 +-
arch/riscv/kernel/module.c | 217 +++++++++++++++++++++++++++++++++-----
2 files changed, 195 insertions(+), 27 deletions(-)
diff --git a/arch/riscv/include/uapi/asm/elf.h b/arch/riscv/include/uapi/asm/elf.h
index d696d6610231..11a71b8533d5 100644
--- a/arch/riscv/include/uapi/asm/elf.h
+++ b/arch/riscv/include/uapi/asm/elf.h
@@ -49,6 +49,7 @@ typedef union __riscv_fp_state elf_fpregset_t;
#define R_RISCV_TLS_DTPREL64 9
#define R_RISCV_TLS_TPREL32 10
#define R_RISCV_TLS_TPREL64 11
+#define R_RISCV_IRELATIVE 58
/* Relocation types not used by the dynamic linker */
#define R_RISCV_BRANCH 16
@@ -81,7 +82,6 @@ typedef union __riscv_fp_state elf_fpregset_t;
#define R_RISCV_ALIGN 43
#define R_RISCV_RVC_BRANCH 44
#define R_RISCV_RVC_JUMP 45
-#define R_RISCV_LUI 46
#define R_RISCV_GPREL_I 47
#define R_RISCV_GPREL_S 48
#define R_RISCV_TPREL_I 49
@@ -93,6 +93,9 @@ typedef union __riscv_fp_state elf_fpregset_t;
#define R_RISCV_SET16 55
#define R_RISCV_SET32 56
#define R_RISCV_32_PCREL 57
+#define R_RISCV_PLT32 59
+#define R_RISCV_SET_ULEB128 60
+#define R_RISCV_SUB_ULEB128 61
#endif /* _UAPI_ASM_RISCV_ELF_H */
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c
index a9e94e939cb5..938eb5fa763f 100644
--- a/arch/riscv/kernel/module.c
+++ b/arch/riscv/kernel/module.c
@@ -7,6 +7,7 @@
#include <linux/elf.h>
#include <linux/err.h>
#include <linux/errno.h>
+#include <linux/kernel.h>
#include <linux/moduleloader.h>
#include <linux/vmalloc.h>
#include <linux/sizes.h>
@@ -269,6 +270,12 @@ static int apply_r_riscv_align_rela(struct module *me, void *location,
return -EINVAL;
}
+static int apply_r_riscv_add8_rela(struct module *me, void *location, Elf_Addr v)
+{
+ *(u8 *)location += (u8)v;
+ return 0;
+}
+
static int apply_r_riscv_add16_rela(struct module *me, void *location,
Elf_Addr v)
{
@@ -290,6 +297,12 @@ static int apply_r_riscv_add64_rela(struct module *me, void *location,
return 0;
}
+static int apply_r_riscv_sub8_rela(struct module *me, void *location, Elf_Addr v)
+{
+ *(u8 *)location -= (u8)v;
+ return 0;
+}
+
static int apply_r_riscv_sub16_rela(struct module *me, void *location,
Elf_Addr v)
{
@@ -311,31 +324,162 @@ static int apply_r_riscv_sub64_rela(struct module *me, void *location,
return 0;
}
-static int (*reloc_handlers_rela[]) (struct module *me, void *location,
- Elf_Addr v) = {
- [R_RISCV_32] = apply_r_riscv_32_rela,
- [R_RISCV_64] = apply_r_riscv_64_rela,
- [R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
- [R_RISCV_JAL] = apply_r_riscv_jal_rela,
- [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela,
- [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela,
- [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela,
- [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela,
- [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela,
- [R_RISCV_HI20] = apply_r_riscv_hi20_rela,
- [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela,
- [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela,
- [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela,
- [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela,
- [R_RISCV_CALL] = apply_r_riscv_call_rela,
- [R_RISCV_RELAX] = apply_r_riscv_relax_rela,
- [R_RISCV_ALIGN] = apply_r_riscv_align_rela,
- [R_RISCV_ADD16] = apply_r_riscv_add16_rela,
- [R_RISCV_ADD32] = apply_r_riscv_add32_rela,
- [R_RISCV_ADD64] = apply_r_riscv_add64_rela,
- [R_RISCV_SUB16] = apply_r_riscv_sub16_rela,
- [R_RISCV_SUB32] = apply_r_riscv_sub32_rela,
- [R_RISCV_SUB64] = apply_r_riscv_sub64_rela,
+static int dynamic_linking_not_supported(struct module *me, void *location,
+ Elf_Addr v)
+{
+ pr_err("%s: Dynamic linking not supported in kernel modules PC = %p\n",
+ me->name, location);
+ return -EINVAL;
+}
+
+static int tls_not_supported(struct module *me, void *location, Elf_Addr v)
+{
+ pr_err("%s: Thread local storage not supported in kernel modules PC = %p\n",
+ me->name, location);
+ return -EINVAL;
+}
+
+static int apply_r_riscv_sub6_rela(struct module *me, void *location, Elf_Addr v)
+{
+ *(u8 *)location = (*(u8 *)location - ((u8)v & 0x3F)) & 0x3F;
+ return 0;
+}
+
+static int apply_r_riscv_set6_rela(struct module *me, void *location, Elf_Addr v)
+{
+ *(u8 *)location = ((*(u8 *)location & 0xc0) | ((u8)v & 0x3F));
+ return 0;
+}
+
+static int apply_r_riscv_set8_rela(struct module *me, void *location, Elf_Addr v)
+{
+ *(u8 *)location = (u8)v;
+ return 0;
+}
+
+static int apply_r_riscv_set16_rela(struct module *me, void *location,
+ Elf_Addr v)
+{
+ *(u16 *)location = (u16)v;
+ return 0;
+}
+
+static int apply_r_riscv_set32_rela(struct module *me, void *location,
+ Elf_Addr v)
+{
+ *(u32 *)location = (u32)v;
+ return 0;
+}
+
+static int apply_r_riscv_32_pcrel_rela(struct module *me, void *location,
+ Elf_Addr v)
+{
+ *(u32 *)location = v - (unsigned long)location;
+ return 0;
+}
+
+static int apply_r_riscv_plt32_rela(struct module *me, void *location,
+ Elf_Addr v)
+{
+ ptrdiff_t offset = (void *)v - location;
+
+ if (!riscv_insn_valid_32bit_offset(offset)) {
+ /* Only emit the plt entry if offset over 32-bit range */
+ if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
+ offset = (void *)module_emit_plt_entry(me, v) - location;
+ } else {
+ pr_err("%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
+ me->name, (long long)v, location);
+ return -EINVAL;
+ }
+ }
+
+ *(u32 *)location = (u32)offset;
+ return 0;
+}
+
+static int apply_r_riscv_set_uleb128(struct module *me, void *location, Elf_Addr v)
+{
+ /*
+ * Relocation is only performed if R_RISCV_SET_ULEB128 is followed by
+ * R_RISCV_SUB_ULEB128 so do computation there
+ */
+ return 0;
+}
+
+static int apply_r_riscv_sub_uleb128(struct module *me, void *location, Elf_Addr v)
+{
+ if (v >= 128) {
+ pr_err("%s: uleb128 must be in [0, 127] (not %ld) at PC = %p\n",
+ me->name, (unsigned long)v, location);
+ return -EINVAL;
+ }
+
+ *(u32 *)location = (*(u32 *)location & ~((u32)127)) | (v & 127);
+ return 0;
+}
+
+/*
+ * Relocations defined in the riscv-elf-psabi-doc.
+ * This handles static linking only.
+ */
+static int (*reloc_handlers_rela[])(struct module *me, void *location,
+ Elf_Addr v) = {
+ [R_RISCV_32] = apply_r_riscv_32_rela,
+ [R_RISCV_64] = apply_r_riscv_64_rela,
+ [R_RISCV_RELATIVE] = dynamic_linking_not_supported,
+ [R_RISCV_COPY] = dynamic_linking_not_supported,
+ [R_RISCV_JUMP_SLOT] = dynamic_linking_not_supported,
+ [R_RISCV_TLS_DTPMOD32] = dynamic_linking_not_supported,
+ [R_RISCV_TLS_DTPMOD64] = dynamic_linking_not_supported,
+ [R_RISCV_TLS_DTPREL32] = dynamic_linking_not_supported,
+ [R_RISCV_TLS_DTPREL64] = dynamic_linking_not_supported,
+ [R_RISCV_TLS_TPREL32] = dynamic_linking_not_supported,
+ [R_RISCV_TLS_TPREL64] = dynamic_linking_not_supported,
+ /* 12-15 undefined */
+ [R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
+ [R_RISCV_JAL] = apply_r_riscv_jal_rela,
+ [R_RISCV_CALL] = apply_r_riscv_call_rela,
+ [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela,
+ [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela,
+ [R_RISCV_TLS_GOT_HI20] = tls_not_supported,
+ [R_RISCV_TLS_GD_HI20] = tls_not_supported,
+ [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela,
+ [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela,
+ [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela,
+ [R_RISCV_HI20] = apply_r_riscv_hi20_rela,
+ [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela,
+ [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela,
+ [R_RISCV_TPREL_HI20] = tls_not_supported,
+ [R_RISCV_TPREL_LO12_I] = tls_not_supported,
+ [R_RISCV_TPREL_LO12_S] = tls_not_supported,
+ [R_RISCV_TPREL_ADD] = tls_not_supported,
+ [R_RISCV_ADD8] = apply_r_riscv_add8_rela,
+ [R_RISCV_ADD16] = apply_r_riscv_add16_rela,
+ [R_RISCV_ADD32] = apply_r_riscv_add32_rela,
+ [R_RISCV_ADD64] = apply_r_riscv_add64_rela,
+ [R_RISCV_SUB8] = apply_r_riscv_sub8_rela,
+ [R_RISCV_SUB16] = apply_r_riscv_sub16_rela,
+ [R_RISCV_SUB32] = apply_r_riscv_sub32_rela,
+ [R_RISCV_SUB64] = apply_r_riscv_sub64_rela,
+ /* 41-42 reserved for future standard use */
+ [R_RISCV_ALIGN] = apply_r_riscv_align_rela,
+ [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela,
+ [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela,
+ /* 46-50 reserved for future standard use */
+ [R_RISCV_RELAX] = apply_r_riscv_relax_rela,
+ [R_RISCV_SUB6] = apply_r_riscv_sub6_rela,
+ [R_RISCV_SET6] = apply_r_riscv_set6_rela,
+ [R_RISCV_SET8] = apply_r_riscv_set8_rela,
+ [R_RISCV_SET16] = apply_r_riscv_set16_rela,
+ [R_RISCV_SET32] = apply_r_riscv_set32_rela,
+ [R_RISCV_32_PCREL] = apply_r_riscv_32_pcrel_rela,
+ [R_RISCV_IRELATIVE] = dynamic_linking_not_supported,
+ [R_RISCV_PLT32] = apply_r_riscv_plt32_rela,
+ [R_RISCV_SET_ULEB128] = apply_r_riscv_set_uleb128,
+ [R_RISCV_SUB_ULEB128] = apply_r_riscv_sub_uleb128,
+ /* 62-191 reserved for future standard use */
+ /* 192-255 nonstandard ABI extensions */
};
int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
@@ -349,6 +493,9 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
unsigned int i, type;
Elf_Addr v;
int res;
+ bool uleb128_set_found = false;
+ void *uleb128_set_loc;
+ unsigned long uleb128_set_sym_val;
pr_debug("Applying relocate section %u to %u\n", relsec,
sechdrs[relsec].sh_info);
@@ -384,7 +531,17 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
v = sym->st_value + rel[i].r_addend;
- if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) {
+ if (uleb128_set_found) {
+ if (type == R_RISCV_SUB_ULEB128 && uleb128_set_loc == location) {
+ /* Calculate set and subtraction */
+ v = uleb128_set_sym_val - v;
+ uleb128_set_found = false;
+ } else {
+ pr_err("%s: R_RISCV_SUB_ULEB128 must always be paired with an R_RISCV_SET_ULEB128, with the same offset, that comes before immediately it. PC = %p\n",
+ me->name, location);
+ return -EINVAL;
+ }
+ } else if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) {
unsigned int j;
for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) {
@@ -426,6 +583,14 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
me->name);
return -EINVAL;
}
+ } else if (type == R_RISCV_SET_ULEB128) {
+ uleb128_set_found = true;
+ uleb128_set_loc = location;
+ uleb128_set_sym_val = v;
+ } else if (type == R_RISCV_SUB_ULEB128) {
+ pr_err("%s: R_RISCV_SUB_ULEB128 must always be immediately preceded by an R_RISCV_SET_ULEB128 with the same offset. PC = %p\n",
+ me->name, location);
+ return -EINVAL;
}
res = handler(me, location, v);
--
2.42.0
Add test cases for the two main groups of relocations added: SUB and
SET, along with uleb128 which is a bit different because SUB and SET are
required to happen together.
Signed-off-by: Charlie Jenkins <[email protected]>
---
arch/riscv/Kconfig.debug | 1 +
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/tests/Kconfig.debug | 35 +++++++++
arch/riscv/kernel/tests/Makefile | 1 +
arch/riscv/kernel/tests/module_test/Makefile | 15 ++++
.../tests/module_test/test_module_linking_main.c | 85 ++++++++++++++++++++++
arch/riscv/kernel/tests/module_test/test_set16.S | 23 ++++++
arch/riscv/kernel/tests/module_test/test_set32.S | 20 +++++
arch/riscv/kernel/tests/module_test/test_set6.S | 23 ++++++
arch/riscv/kernel/tests/module_test/test_set8.S | 23 ++++++
arch/riscv/kernel/tests/module_test/test_sub16.S | 22 ++++++
arch/riscv/kernel/tests/module_test/test_sub32.S | 22 ++++++
arch/riscv/kernel/tests/module_test/test_sub6.S | 22 ++++++
arch/riscv/kernel/tests/module_test/test_sub64.S | 27 +++++++
arch/riscv/kernel/tests/module_test/test_sub8.S | 22 ++++++
arch/riscv/kernel/tests/module_test/test_uleb128.S | 20 +++++
16 files changed, 362 insertions(+)
diff --git a/arch/riscv/Kconfig.debug b/arch/riscv/Kconfig.debug
index e69de29bb2d1..eafe17ebf710 100644
--- a/arch/riscv/Kconfig.debug
+++ b/arch/riscv/Kconfig.debug
@@ -0,0 +1 @@
+source "arch/riscv/kernel/tests/Kconfig.debug"
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 95cf25d48405..bb99657252f4 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -57,6 +57,7 @@ obj-y += stacktrace.o
obj-y += cacheinfo.o
obj-y += patch.o
obj-y += probes/
+obj-y += tests/
obj-$(CONFIG_MMU) += vdso.o vdso/
obj-$(CONFIG_RISCV_M_MODE) += traps_misaligned.o
diff --git a/arch/riscv/kernel/tests/Kconfig.debug b/arch/riscv/kernel/tests/Kconfig.debug
new file mode 100644
index 000000000000..5dba64e8e977
--- /dev/null
+++ b/arch/riscv/kernel/tests/Kconfig.debug
@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "arch/riscv/kernel Testing and Coverage"
+
+config AS_HAS_ULEB128
+ def_bool $(as-instr,.reloc label$(comma) R_RISCV_SET_ULEB128$(comma) 127\n.reloc label$(comma) R_RISCV_SUB_ULEB128$(comma) 127\nlabel:\n.word 0)
+
+menuconfig RUNTIME_KERNEL_TESTING_MENU
+ bool "arch/riscv/kernel runtime Testing"
+ def_bool y
+ help
+ Enable riscv kernel runtime testing.
+
+if RUNTIME_KERNEL_TESTING_MENU
+
+config RISCV_MODULE_LINKING_KUNIT
+ bool "KUnit test riscv module linking at runtime" if !KUNIT_ALL_TESTS
+ depends on KUNIT
+ default KUNIT_ALL_TESTS
+ help
+ Enable this option to test riscv module linking at boot. This will
+ enable a module called "test_module_linking".
+
+ KUnit tests run during boot and output the results to the debug log
+ in TAP format (http://testanything.org/). Only useful for kernel devs
+ running the KUnit test harness, and not intended for inclusion into a
+ production build.
+
+ For more information on KUnit and unit tests in general please refer
+ to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+ If unsure, say N.
+
+endif # RUNTIME_TESTING_MENU
+
+endmenu # "arch/riscv/kernel runtime Testing"
diff --git a/arch/riscv/kernel/tests/Makefile b/arch/riscv/kernel/tests/Makefile
new file mode 100644
index 000000000000..7d6c76cffe20
--- /dev/null
+++ b/arch/riscv/kernel/tests/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_RISCV_MODULE_LINKING_KUNIT) += module_test/
diff --git a/arch/riscv/kernel/tests/module_test/Makefile b/arch/riscv/kernel/tests/module_test/Makefile
new file mode 100644
index 000000000000..d7a6fd8943de
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/Makefile
@@ -0,0 +1,15 @@
+obj-m += test_module_linking.o
+
+test_sub := test_sub6.o test_sub8.o test_sub16.o test_sub32.o test_sub64.o
+
+test_set := test_set6.o test_set8.o test_set16.o test_set32.o
+
+test_module_linking-objs += $(test_sub)
+
+test_module_linking-objs += $(test_set)
+
+ifeq ($(CONFIG_AS_HAS_ULEB128),y)
+test_module_linking-objs += test_uleb128.o
+endif
+
+test_module_linking-objs += test_module_linking_main.o
diff --git a/arch/riscv/kernel/tests/module_test/test_module_linking_main.c b/arch/riscv/kernel/tests/module_test/test_module_linking_main.c
new file mode 100644
index 000000000000..49820352f1df
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_module_linking_main.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <kunit/test.h>
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Test module linking");
+
+extern int test_set32(void);
+extern int test_set16(void);
+extern int test_set8(void);
+extern int test_set6(void);
+extern long test_sub64(void);
+extern int test_sub32(void);
+extern int test_sub16(void);
+extern int test_sub8(void);
+extern int test_sub6(void);
+
+#ifdef CONFIG_AS_HAS_ULEB128
+extern int test_uleb(void);
+#endif
+
+#define CHECK_EQ(lhs, rhs) KUNIT_ASSERT_EQ(test, lhs, rhs)
+
+void run_test_set(struct kunit *test);
+void run_test_sub(struct kunit *test);
+void run_test_uleb(struct kunit *test);
+
+void run_test_set(struct kunit *test)
+{
+ int val32 = test_set32();
+ int val16 = test_set16();
+ int val8 = test_set8();
+ int val6 = test_set6();
+
+ CHECK_EQ(val32, 0);
+ CHECK_EQ(val16, 0);
+ CHECK_EQ(val8, 0);
+ CHECK_EQ(val6, 0);
+}
+
+void run_test_sub(struct kunit *test)
+{
+ int val64 = test_sub64();
+ int val32 = test_sub32();
+ int val16 = test_sub16();
+ int val8 = test_sub8();
+ int val6 = test_sub6();
+
+ CHECK_EQ(val64, 0);
+ CHECK_EQ(val32, 0);
+ CHECK_EQ(val16, 0);
+ CHECK_EQ(val8, 0);
+ CHECK_EQ(val6, 0);
+}
+
+#ifdef CONFIG_AS_HAS_ULEB128
+void run_test_uleb(struct kunit *test)
+{
+ int valuleb = test_uleb();
+
+ CHECK_EQ(valuleb, 0);
+}
+#endif
+
+static struct kunit_case __refdata riscv_module_linking_test_cases[] = {
+ KUNIT_CASE(run_test_set),
+ KUNIT_CASE(run_test_sub),
+#ifdef CONFIG_AS_HAS_ULEB128
+ KUNIT_CASE(run_test_uleb),
+#endif
+ {}
+};
+
+static struct kunit_suite riscv_module_linking_test_suite = {
+ .name = "riscv_checksum",
+ .test_cases = riscv_module_linking_test_cases,
+};
+
+kunit_test_suites(&riscv_module_linking_test_suite);
diff --git a/arch/riscv/kernel/tests/module_test/test_set16.S b/arch/riscv/kernel/tests/module_test/test_set16.S
new file mode 100644
index 000000000000..2be0e441a12e
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_set16.S
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_set16
+test_set16:
+ lw a0, set16
+ la t0, set16
+#ifdef CONFIG_32BIT
+ slli t0, t0, 16
+ srli t0, t0, 16
+#else
+ slli t0, t0, 48
+ srli t0, t0, 48
+#endif
+ sub a0, a0, t0
+ ret
+.data
+set16:
+ .reloc set16, R_RISCV_SET16, set16
+ .word 0
diff --git a/arch/riscv/kernel/tests/module_test/test_set32.S b/arch/riscv/kernel/tests/module_test/test_set32.S
new file mode 100644
index 000000000000..de0444537e67
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_set32.S
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_set32
+test_set32:
+ lw a0, set32
+ la t0, set32
+#ifndef CONFIG_32BIT
+ slli t0, t0, 32
+ srli t0, t0, 32
+#endif
+ sub a0, a0, t0
+ ret
+.data
+set32:
+ .reloc set32, R_RISCV_SET32, set32
+ .word 0
diff --git a/arch/riscv/kernel/tests/module_test/test_set6.S b/arch/riscv/kernel/tests/module_test/test_set6.S
new file mode 100644
index 000000000000..c39ce4c219eb
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_set6.S
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_set6
+test_set6:
+ lw a0, set6
+ la t0, set6
+#ifdef CONFIG_32BIT
+ slli t0, t0, 26
+ srli t0, t0, 26
+#else
+ slli t0, t0, 58
+ srli t0, t0, 58
+#endif
+ sub a0, a0, t0
+ ret
+.data
+set6:
+ .reloc set6, R_RISCV_SET6, set6
+ .word 0
diff --git a/arch/riscv/kernel/tests/module_test/test_set8.S b/arch/riscv/kernel/tests/module_test/test_set8.S
new file mode 100644
index 000000000000..a656173f6f99
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_set8.S
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_set8
+test_set8:
+ lw a0, set8
+ la t0, set8
+#ifdef CONFIG_32BIT
+ slli t0, t0, 24
+ srli t0, t0, 24
+#else
+ slli t0, t0, 56
+ srli t0, t0, 56
+#endif
+ sub a0, a0, t0
+ ret
+.data
+set8:
+ .reloc set8, R_RISCV_SET8, set8
+ .word 0
diff --git a/arch/riscv/kernel/tests/module_test/test_sub16.S b/arch/riscv/kernel/tests/module_test/test_sub16.S
new file mode 100644
index 000000000000..c561e155d1db
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_sub16.S
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub16
+test_sub16:
+ lh a0, sub16
+ addi a0, a0, -32
+ ret
+first:
+ .rept 8
+ .word 0
+ .endr
+second:
+
+.data
+sub16:
+ .reloc sub16, R_RISCV_ADD16, second
+ .reloc sub16, R_RISCV_SUB16, first
+ .half 0
diff --git a/arch/riscv/kernel/tests/module_test/test_sub32.S b/arch/riscv/kernel/tests/module_test/test_sub32.S
new file mode 100644
index 000000000000..93232c70cae6
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_sub32.S
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub32
+test_sub32:
+ lw a0, sub32
+ addi a0, a0, -32
+ ret
+first:
+ .rept 8
+ .word 0
+ .endr
+second:
+
+.data
+sub32:
+ .reloc sub32, R_RISCV_ADD32, second
+ .reloc sub32, R_RISCV_SUB32, first
+ .word 0
diff --git a/arch/riscv/kernel/tests/module_test/test_sub6.S b/arch/riscv/kernel/tests/module_test/test_sub6.S
new file mode 100644
index 000000000000..d9c9526ceb62
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_sub6.S
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub6
+test_sub6:
+ lb a0, sub6
+ addi a0, a0, -32
+ ret
+first:
+ .rept 8
+ .word 0
+ .endr
+second:
+
+.data
+sub6:
+ .reloc sub6, R_RISCV_SET6, second
+ .reloc sub6, R_RISCV_SUB6, first
+ .byte 0
diff --git a/arch/riscv/kernel/tests/module_test/test_sub64.S b/arch/riscv/kernel/tests/module_test/test_sub64.S
new file mode 100644
index 000000000000..6d260e2a5d98
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_sub64.S
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub64
+test_sub64:
+#ifdef CONFIG_32BIT
+ lw a0, sub64
+#else
+ ld a0, sub64
+#endif
+ addi a0, a0, -32
+ ret
+first:
+ .rept 8
+ .word 0
+ .endr
+second:
+
+.data
+sub64:
+ .reloc sub64, R_RISCV_ADD64, second
+ .reloc sub64, R_RISCV_SUB64, first
+ .word 0
+ .word 0
diff --git a/arch/riscv/kernel/tests/module_test/test_sub8.S b/arch/riscv/kernel/tests/module_test/test_sub8.S
new file mode 100644
index 000000000000..af7849115d4d
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_sub8.S
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_sub8
+test_sub8:
+ lb a0, sub8
+ addi a0, a0, -32
+ ret
+first:
+ .rept 8
+ .word 0
+ .endr
+second:
+
+.data
+sub8:
+ .reloc sub8, R_RISCV_ADD8, second
+ .reloc sub8, R_RISCV_SUB8, first
+ .byte 0
diff --git a/arch/riscv/kernel/tests/module_test/test_uleb128.S b/arch/riscv/kernel/tests/module_test/test_uleb128.S
new file mode 100644
index 000000000000..db9f301092d0
--- /dev/null
+++ b/arch/riscv/kernel/tests/module_test/test_uleb128.S
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Rivos Inc.
+ */
+
+.text
+.global test_uleb
+test_uleb:
+ ld a0, second
+ addi a0, a0, -127
+ ret
+.data
+first:
+ .rept 127
+ .byte 0
+ .endr
+second:
+ .reloc second, R_RISCV_SET_ULEB128, second
+ .reloc second, R_RISCV_SUB_ULEB128, first
+ .dword 0
--
2.42.0