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 | 6 +-
arch/riscv/kernel/module.c | 207 +++++++++++++++++++++++++++++++++-----
2 files changed, 187 insertions(+), 26 deletions(-)
diff --git a/arch/riscv/include/uapi/asm/elf.h b/arch/riscv/include/uapi/asm/elf.h
index d696d6610231..a9307a1c9ceb 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 +82,7 @@ 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_RVC_LUI 46
#define R_RISCV_GPREL_I 47
#define R_RISCV_GPREL_S 48
#define R_RISCV_TPREL_I 49
@@ -93,6 +94,9 @@ 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 7c651d55fcbd..73f47de538d2 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>
@@ -268,6 +269,12 @@ static int apply_r_riscv_align_rela(struct module *me, u32 *location,
return -EINVAL;
}
+static int apply_r_riscv_add8_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ *(u8 *)location += (u8)v;
+ return 0;
+}
+
static int apply_r_riscv_add16_rela(struct module *me, u32 *location,
Elf_Addr v)
{
@@ -289,6 +296,12 @@ static int apply_r_riscv_add64_rela(struct module *me, u32 *location,
return 0;
}
+static int apply_r_riscv_sub8_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ *(u8 *)location -= (u8)v;
+ return 0;
+}
+
static int apply_r_riscv_sub16_rela(struct module *me, u32 *location,
Elf_Addr v)
{
@@ -310,31 +323,149 @@ static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
return 0;
}
-static int (*reloc_handlers_rela[]) (struct module *me, u32 *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, u32 *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, u32 *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, u32 *location, Elf_Addr v)
+{
+ *(u8 *)location -= (u8)v & 0x3F;
+ return 0;
+}
+
+static int apply_r_riscv_set6_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ *(u8 *)location = (*(u8 *)location & 0xc0) | ((u8)v & 0x3F);
+ return 0;
+}
+
+static int apply_r_riscv_set8_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ *(u8 *)location = (u8)v;
+ return 0;
+}
+
+static int apply_r_riscv_set16_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *(u16 *)location = (u16)v;
+ return 0;
+}
+
+static int apply_r_riscv_set32_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *(u32 *)location = (u32)v;
+ return 0;
+}
+
+static int apply_r_riscv_32_pcrel_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *(u32 *)location = (u32)v;
+ return 0;
+}
+
+static int apply_r_riscv_plt32_rela(struct module *me, u32 *location,
+ Elf_Addr v)
+{
+ *(u32 *)location = (u32)v;
+ return 0;
+}
+
+static int apply_r_riscv_set_uleb128(struct module *me, u32 *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, u32 *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;
+ }
+
+ *location = v;
+ return 0;
+}
+
+/*
+ * Relocations defined in the riscv-elf-psabi-doc.
+ * This handles static linking only.
+ */
+static int (*reloc_handlers_rela[])(struct module *me, u32 *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,
@@ -348,6 +479,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
unsigned int i, type;
Elf_Addr v;
int res;
+ bool uleb128_set_exists = false;
+ u32 *uleb128_set_loc;
+ unsigned long uleb128_set_sym_val;
+
pr_debug("Applying relocate section %u to %u\n", relsec,
sechdrs[relsec].sh_info);
@@ -425,6 +560,28 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
me->name);
return -EINVAL;
}
+ } else if (type == R_RISCV_SET_ULEB128) {
+ if (uleb128_set_exists) {
+ pr_err("%s: riscv psABI requires the next ULEB128 relocation to come after a R_RISCV_SET_ULEB128 is an R_RISCV_SUB_ULEB128, not another R_RISCV_SET_ULEB128.\n",
+ me->name);
+ return -EINVAL;
+ }
+ uleb128_set_exists = true;
+ uleb128_set_loc = location;
+ uleb128_set_sym_val =
+ ((Elf_Sym *)sechdrs[symindex].sh_addr +
+ ELF_RISCV_R_SYM(rel[i].r_info))
+ ->st_value +
+ rel[i].r_addend;
+ } else if (type == R_RISCV_SUB_ULEB128) {
+ if (uleb128_set_exists && uleb128_set_loc == location) {
+ /* Calculate set and subtraction */
+ v = uleb128_set_sym_val - v;
+ } else {
+ pr_err("%s: R_RISCV_SUB_ULEB128 must always be paired with the first R_RISCV_SET_ULEB128 that comes before it. PC = %p\n",
+ me->name, location);
+ return -EINVAL;
+ }
}
res = handler(me, location, v);
--
2.42.0
On Okt 16 2023, Charlie Jenkins wrote:
> @@ -81,7 +82,7 @@ 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_RVC_LUI 46
The latest ELF psABI defines 46 as reserved.
--
Andreas Schwab, [email protected]
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
On Mon, Oct 16, 2023 at 08:12:32PM +0200, Andreas Schwab wrote:
> On Okt 16 2023, Charlie Jenkins wrote:
>
> > @@ -81,7 +82,7 @@ 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_RVC_LUI 46
>
> The latest ELF psABI defines 46 as reserved.
I will remove that in the next version. Thank you.
- Charlie
>
> --
> Andreas Schwab, [email protected]
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
> "And now for something completely different."
On Mon, Oct 16, 2023 at 10:36:09AM -0700, Charlie Jenkins wrote:
> Add all final module relocations and add error logs explaining the ones
> that are not supported.
In the patchwork automation's clang/llvm allmodconfig:
../arch/riscv/kernel/tests/module_test/test_uleb128.S:18:17: error: unknown relocation name
../arch/riscv/kernel/tests/module_test/test_uleb128.S:19:17: error: unknown relocation name
(llvm-17 iirc)
Cheers,
Conor.
>
> Signed-off-by: Charlie Jenkins <[email protected]>
> ---
> arch/riscv/include/uapi/asm/elf.h | 6 +-
> arch/riscv/kernel/module.c | 207 +++++++++++++++++++++++++++++++++-----
> 2 files changed, 187 insertions(+), 26 deletions(-)
>
> diff --git a/arch/riscv/include/uapi/asm/elf.h b/arch/riscv/include/uapi/asm/elf.h
> index d696d6610231..a9307a1c9ceb 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 +82,7 @@ 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_RVC_LUI 46
> #define R_RISCV_GPREL_I 47
> #define R_RISCV_GPREL_S 48
> #define R_RISCV_TPREL_I 49
> @@ -93,6 +94,9 @@ 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 7c651d55fcbd..73f47de538d2 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>
> @@ -268,6 +269,12 @@ static int apply_r_riscv_align_rela(struct module *me, u32 *location,
> return -EINVAL;
> }
>
> +static int apply_r_riscv_add8_rela(struct module *me, u32 *location, Elf_Addr v)
> +{
> + *(u8 *)location += (u8)v;
> + return 0;
> +}
> +
> static int apply_r_riscv_add16_rela(struct module *me, u32 *location,
> Elf_Addr v)
> {
> @@ -289,6 +296,12 @@ static int apply_r_riscv_add64_rela(struct module *me, u32 *location,
> return 0;
> }
>
> +static int apply_r_riscv_sub8_rela(struct module *me, u32 *location, Elf_Addr v)
> +{
> + *(u8 *)location -= (u8)v;
> + return 0;
> +}
> +
> static int apply_r_riscv_sub16_rela(struct module *me, u32 *location,
> Elf_Addr v)
> {
> @@ -310,31 +323,149 @@ static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
> return 0;
> }
>
> -static int (*reloc_handlers_rela[]) (struct module *me, u32 *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, u32 *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, u32 *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, u32 *location, Elf_Addr v)
> +{
> + *(u8 *)location -= (u8)v & 0x3F;
> + return 0;
> +}
> +
> +static int apply_r_riscv_set6_rela(struct module *me, u32 *location, Elf_Addr v)
> +{
> + *(u8 *)location = (*(u8 *)location & 0xc0) | ((u8)v & 0x3F);
> + return 0;
> +}
> +
> +static int apply_r_riscv_set8_rela(struct module *me, u32 *location, Elf_Addr v)
> +{
> + *(u8 *)location = (u8)v;
> + return 0;
> +}
> +
> +static int apply_r_riscv_set16_rela(struct module *me, u32 *location,
> + Elf_Addr v)
> +{
> + *(u16 *)location = (u16)v;
> + return 0;
> +}
> +
> +static int apply_r_riscv_set32_rela(struct module *me, u32 *location,
> + Elf_Addr v)
> +{
> + *(u32 *)location = (u32)v;
> + return 0;
> +}
> +
> +static int apply_r_riscv_32_pcrel_rela(struct module *me, u32 *location,
> + Elf_Addr v)
> +{
> + *(u32 *)location = (u32)v;
> + return 0;
> +}
> +
> +static int apply_r_riscv_plt32_rela(struct module *me, u32 *location,
> + Elf_Addr v)
> +{
> + *(u32 *)location = (u32)v;
> + return 0;
> +}
> +
> +static int apply_r_riscv_set_uleb128(struct module *me, u32 *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, u32 *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;
> + }
> +
> + *location = v;
> + return 0;
> +}
> +
> +/*
> + * Relocations defined in the riscv-elf-psabi-doc.
> + * This handles static linking only.
> + */
> +static int (*reloc_handlers_rela[])(struct module *me, u32 *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,
> @@ -348,6 +479,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
> unsigned int i, type;
> Elf_Addr v;
> int res;
> + bool uleb128_set_exists = false;
> + u32 *uleb128_set_loc;
> + unsigned long uleb128_set_sym_val;
> +
>
> pr_debug("Applying relocate section %u to %u\n", relsec,
> sechdrs[relsec].sh_info);
> @@ -425,6 +560,28 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
> me->name);
> return -EINVAL;
> }
> + } else if (type == R_RISCV_SET_ULEB128) {
> + if (uleb128_set_exists) {
> + pr_err("%s: riscv psABI requires the next ULEB128 relocation to come after a R_RISCV_SET_ULEB128 is an R_RISCV_SUB_ULEB128, not another R_RISCV_SET_ULEB128.\n",
> + me->name);
> + return -EINVAL;
> + }
> + uleb128_set_exists = true;
> + uleb128_set_loc = location;
> + uleb128_set_sym_val =
> + ((Elf_Sym *)sechdrs[symindex].sh_addr +
> + ELF_RISCV_R_SYM(rel[i].r_info))
> + ->st_value +
> + rel[i].r_addend;
> + } else if (type == R_RISCV_SUB_ULEB128) {
> + if (uleb128_set_exists && uleb128_set_loc == location) {
> + /* Calculate set and subtraction */
> + v = uleb128_set_sym_val - v;
> + } else {
> + pr_err("%s: R_RISCV_SUB_ULEB128 must always be paired with the first R_RISCV_SET_ULEB128 that comes before it. PC = %p\n",
> + me->name, location);
> + return -EINVAL;
> + }
> }
>
> res = handler(me, location, v);
>
> --
> 2.42.0
>
On Tue, Oct 17, 2023 at 08:08:26AM +0100, Conor Dooley wrote:
> On Mon, Oct 16, 2023 at 10:36:09AM -0700, Charlie Jenkins wrote:
> > Add all final module relocations and add error logs explaining the ones
> > that are not supported.
>
> In the patchwork automation's clang/llvm allmodconfig:
> ../arch/riscv/kernel/tests/module_test/test_uleb128.S:18:17: error: unknown relocation name
> ../arch/riscv/kernel/tests/module_test/test_uleb128.S:19:17: error: unknown relocation name
>
> (llvm-17 iirc)
>
> Cheers,
> Conor.
Thank you, that slipped my mind that I needed to conditionally build the
uleb128 tests. I will send an updated version.
- Charlie
>
> >
> > Signed-off-by: Charlie Jenkins <[email protected]>
> > ---
> > arch/riscv/include/uapi/asm/elf.h | 6 +-
> > arch/riscv/kernel/module.c | 207 +++++++++++++++++++++++++++++++++-----
> > 2 files changed, 187 insertions(+), 26 deletions(-)
> >
> > diff --git a/arch/riscv/include/uapi/asm/elf.h b/arch/riscv/include/uapi/asm/elf.h
> > index d696d6610231..a9307a1c9ceb 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 +82,7 @@ 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_RVC_LUI 46
> > #define R_RISCV_GPREL_I 47
> > #define R_RISCV_GPREL_S 48
> > #define R_RISCV_TPREL_I 49
> > @@ -93,6 +94,9 @@ 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 7c651d55fcbd..73f47de538d2 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>
> > @@ -268,6 +269,12 @@ static int apply_r_riscv_align_rela(struct module *me, u32 *location,
> > return -EINVAL;
> > }
> >
> > +static int apply_r_riscv_add8_rela(struct module *me, u32 *location, Elf_Addr v)
> > +{
> > + *(u8 *)location += (u8)v;
> > + return 0;
> > +}
> > +
> > static int apply_r_riscv_add16_rela(struct module *me, u32 *location,
> > Elf_Addr v)
> > {
> > @@ -289,6 +296,12 @@ static int apply_r_riscv_add64_rela(struct module *me, u32 *location,
> > return 0;
> > }
> >
> > +static int apply_r_riscv_sub8_rela(struct module *me, u32 *location, Elf_Addr v)
> > +{
> > + *(u8 *)location -= (u8)v;
> > + return 0;
> > +}
> > +
> > static int apply_r_riscv_sub16_rela(struct module *me, u32 *location,
> > Elf_Addr v)
> > {
> > @@ -310,31 +323,149 @@ static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
> > return 0;
> > }
> >
> > -static int (*reloc_handlers_rela[]) (struct module *me, u32 *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, u32 *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, u32 *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, u32 *location, Elf_Addr v)
> > +{
> > + *(u8 *)location -= (u8)v & 0x3F;
> > + return 0;
> > +}
> > +
> > +static int apply_r_riscv_set6_rela(struct module *me, u32 *location, Elf_Addr v)
> > +{
> > + *(u8 *)location = (*(u8 *)location & 0xc0) | ((u8)v & 0x3F);
> > + return 0;
> > +}
> > +
> > +static int apply_r_riscv_set8_rela(struct module *me, u32 *location, Elf_Addr v)
> > +{
> > + *(u8 *)location = (u8)v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_riscv_set16_rela(struct module *me, u32 *location,
> > + Elf_Addr v)
> > +{
> > + *(u16 *)location = (u16)v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_riscv_set32_rela(struct module *me, u32 *location,
> > + Elf_Addr v)
> > +{
> > + *(u32 *)location = (u32)v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_riscv_32_pcrel_rela(struct module *me, u32 *location,
> > + Elf_Addr v)
> > +{
> > + *(u32 *)location = (u32)v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_riscv_plt32_rela(struct module *me, u32 *location,
> > + Elf_Addr v)
> > +{
> > + *(u32 *)location = (u32)v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_riscv_set_uleb128(struct module *me, u32 *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, u32 *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;
> > + }
> > +
> > + *location = v;
> > + return 0;
> > +}
> > +
> > +/*
> > + * Relocations defined in the riscv-elf-psabi-doc.
> > + * This handles static linking only.
> > + */
> > +static int (*reloc_handlers_rela[])(struct module *me, u32 *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,
> > @@ -348,6 +479,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
> > unsigned int i, type;
> > Elf_Addr v;
> > int res;
> > + bool uleb128_set_exists = false;
> > + u32 *uleb128_set_loc;
> > + unsigned long uleb128_set_sym_val;
> > +
> >
> > pr_debug("Applying relocate section %u to %u\n", relsec,
> > sechdrs[relsec].sh_info);
> > @@ -425,6 +560,28 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
> > me->name);
> > return -EINVAL;
> > }
> > + } else if (type == R_RISCV_SET_ULEB128) {
> > + if (uleb128_set_exists) {
> > + pr_err("%s: riscv psABI requires the next ULEB128 relocation to come after a R_RISCV_SET_ULEB128 is an R_RISCV_SUB_ULEB128, not another R_RISCV_SET_ULEB128.\n",
> > + me->name);
> > + return -EINVAL;
> > + }
> > + uleb128_set_exists = true;
> > + uleb128_set_loc = location;
> > + uleb128_set_sym_val =
> > + ((Elf_Sym *)sechdrs[symindex].sh_addr +
> > + ELF_RISCV_R_SYM(rel[i].r_info))
> > + ->st_value +
> > + rel[i].r_addend;
> > + } else if (type == R_RISCV_SUB_ULEB128) {
> > + if (uleb128_set_exists && uleb128_set_loc == location) {
> > + /* Calculate set and subtraction */
> > + v = uleb128_set_sym_val - v;
> > + } else {
> > + pr_err("%s: R_RISCV_SUB_ULEB128 must always be paired with the first R_RISCV_SET_ULEB128 that comes before it. PC = %p\n",
> > + me->name, location);
> > + return -EINVAL;
> > + }
> > }
> >
> > res = handler(me, location, v);
> >
> > --
> > 2.42.0
> >