[v6,2/3] riscv: Add remaining module relocations

Message ID	20231019-module_relocations-v6-2-94726e644321@rivosinc.com (mailing list archive)
State	New
Headers	show Return-Path: <owner-linux-mm@kvack.org> From: Charlie Jenkins <charlie@rivosinc.com> Date: Thu, 19 Oct 2023 14:41:25 -0700 Subject: [PATCH v6 2/3] riscv: Add remaining module relocations MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20231019-module_relocations-v6-2-94726e644321@rivosinc.com> References: <20231019-module_relocations-v6-0-94726e644321@rivosinc.com> In-Reply-To: <20231019-module_relocations-v6-0-94726e644321@rivosinc.com> To: linux-riscv@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Eric Biederman <ebiederm@xmission.com>, Kees Cook <keescook@chromium.org>, Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, Andreas Schwab <schwab@linux-m68k.org>, Emil Renner Berthing <emil.renner.berthing@canonical.com>, Samuel Holland <samuel.holland@sifive.com>, Charlie Jenkins <charlie@rivosinc.com> Sender: owner-linux-mm@kvack.org Precedence: bulk
Series	riscv: Add remaining module relocations and tests \| expand [v6,0/3] riscv: Add remaining module relocations and tests [v6,1/3] riscv: Avoid unaligned access when relocating modules [v6,2/3] riscv: Add remaining module relocations [v6,3/3] riscv: Add tests for riscv module loading

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);

[v6,2/3] riscv: Add remaining module relocations

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