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Wed, 01 Nov 2023 10:12:00 -0700 (PDT) Date: Wed, 1 Nov 2023 10:11:58 -0700 From: Charlie Jenkins To: Emil Renner Berthing Cc: linux-riscv@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Eric Biederman , Kees Cook , Paul Walmsley , Palmer Dabbelt , Albert Ou , Andreas Schwab , Samuel Holland , Nelson Chu Subject: Re: [PATCH v8 2/3] riscv: Add remaining module relocations Message-ID: References: <20231031-module_relocations-v8-0-09b5b720c1fe@rivosinc.com> <20231031-module_relocations-v8-2-09b5b720c1fe@rivosinc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231101_101205_647883_B0123591 X-CRM114-Status: GOOD ( 33.09 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Wed, Nov 01, 2023 at 03:44:30PM +0100, Emil Renner Berthing wrote: > Charlie Jenkins wrote: > > Add all final module relocations and add error logs explaining the ones > > that are not supported. Implement overflow checks for > > ADD/SUB/SET/ULEB128 relocations. > > > > Signed-off-by: Charlie Jenkins > > --- > > arch/riscv/include/uapi/asm/elf.h | 5 +- > > arch/riscv/kernel/module.c | 503 +++++++++++++++++++++++++++++++++++--- > > 2 files changed, 476 insertions(+), 32 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..0f5d41eaa596 100644 > > --- a/arch/riscv/kernel/module.c > > +++ b/arch/riscv/kernel/module.c > > @@ -7,6 +7,9 @@ > > #include > > #include > > #include > > +#include > > +#include > > +#include > > #include > > #include > > #include > > @@ -14,6 +17,39 @@ > > #include > > #include > > > > +struct used_bucket { > > + struct list_head head; > > + struct hlist_head *bucket; > > +}; > > + > > +struct relocation_head { > > + struct hlist_node node; > > + struct list_head *rel_entry; > > + void *location; > > +}; > > + > > +struct relocation_entry { > > + struct list_head head; > > + Elf_Addr value; > > + unsigned int type; > > +}; > > + > > +struct relocation_handlers { > > + int (*reloc_handler)(struct module *me, void *location, Elf_Addr v); > > + bool accumulate_relocations; > > + int (*accumulate_handler)(struct module *me, void *location, > > + long buffer); > > +}; > > + > > +unsigned int initialize_relocation_hashtable(unsigned int num_relocations); > > +void process_accumulated_relocations(struct module *me); > > +int add_relocation_to_accumulate(struct module *me, int type, void *location, > > + unsigned int hashtable_bits, Elf_Addr v); > > + > > +struct hlist_head *relocation_hashtable; > > + > > +struct list_head used_buckets_list; > > + > > /* > > * The auipc+jalr instruction pair can reach any PC-relative offset > > * in the range [-2^31 - 2^11, 2^31 - 2^11) > > @@ -35,7 +71,7 @@ static int riscv_insn_rmw(void *location, u32 keep, u32 set) > > insn &= keep; > > insn |= set; > > > > - parcel[0] = cpu_to_le32(insn); > > + parcel[0] = cpu_to_le16(insn); > > parcel[1] = cpu_to_le16(insn >> 16); > > return 0; > > } > > @@ -43,8 +79,12 @@ static int riscv_insn_rmw(void *location, u32 keep, u32 set) > > static int riscv_insn_rvc_rmw(void *location, u16 keep, u16 set) > > { > > u16 *parcel = location; > > + u16 insn = le16_to_cpu(*parcel); > > > > - *parcel = cpu_to_le16((le16_to_cpu(*parcel) & keep) | set); > > + insn &= keep; > > + insn |= set; > > + > > + *parcel = cpu_to_le16(insn); > > return 0; > > } > > I think you meant to squash these two chunks into the previous patch. > > > > > @@ -269,6 +309,12 @@ 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 +336,12 @@ 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) > > { > > @@ -311,33 +363,415 @@ 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 *byte = location; > > + u8 value = v; > > + > > + *byte = (*byte - (value & 0x3f)) & 0x3f; > > + return 0; > > +} > > + > > +static int apply_r_riscv_set6_rela(struct module *me, void *location, Elf_Addr v) > > +{ > > + u8 *byte = location; > > + u8 value = v; > > + > > + *byte = (*byte & 0xc0) | (value & 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; > > nit: in other reviews i've been told to use uintptr_t when casting pointers to > an unsigned integer. > Okay will do. > > + 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) > > +{ > > + *(long *)location = v; > > + return 0; > > +} > > + > > +static int apply_r_riscv_sub_uleb128(struct module *me, void *location, Elf_Addr v) > > +{ > > + *(long *)location -= v; > > + return 0; > > +} > > + > > +static int accumulation_not_supported(struct module *me, void *location, long buffer) > > +{ > > + pr_err("%s: Internal error. Only ADD/SUB/SET/ULEB128 should be accumulated.", me->name); > > + return -EINVAL; > > +} > > + > > +static int apply_6_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + u8 *byte = location; > > + u8 value = buffer; > > + > > + if (buffer > 0x3f) { > > + pr_err("%s: value %ld out of range for 6-bit relocation.\n", > > + me->name, buffer); > > + return -EINVAL; > > + } > > + > > + *byte = (*byte & 0xc0) | (value & 0x3f); > > + return 0; > > +} > > + > > +static int apply_8_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + if (buffer > U8_MAX) { > > + pr_err("%s: value %ld out of range for 8-bit relocation.\n", > > + me->name, buffer); > > + return -EINVAL; > > + } > > + *(u8 *)location = (u8)buffer; > > + return 0; > > +} > > + > > +static int apply_16_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + if (buffer > U16_MAX) { > > + pr_err("%s: value %ld out of range for 16-bit relocation.\n", > > + me->name, buffer); > > + return -EINVAL; > > + } > > + *(u16 *)location = (u16)buffer; > > + return 0; > > +} > > + > > +static int apply_32_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + if (buffer > U32_MAX) { > > + pr_err("%s: value %ld out of range for 32-bit relocation.\n", > > + me->name, buffer); > > + return -EINVAL; > > + } > > + *(u32 *)location = (u32)buffer; > > + return 0; > > +} > > + > > +static int apply_64_bit_accumulation(struct module *me, void *location, long buffer) > > +{ > > + *(u64 *)location = (u64)buffer; > > + return 0; > > +} > > + > > +static int apply_uleb128_accumulation(struct module *me, void *location, long buffer) > > +{ > > + /* > > + * ULEB128 is a variable length encoding. Encode the buffer into > > + * the ULEB128 data format. > > + */ > > + u8 *p = location; > > + > > + while (buffer != 0) { > > + u8 value = buffer & 0x7f; > > + > > + buffer >>= 7; > > + value |= (!!buffer) << 7; > > + > > + *p++ = value; > > + } > > + return 0; > > +} > > + > > +/* > > + * Relocations defined in the riscv-elf-psabi-doc. > > + * This handles static linking only. > > + */ > > +static struct relocation_handlers reloc_handlers[] = { > > I don't see anywhere this table is written to. Can we maybe make it const? > > > + [R_RISCV_32] = { apply_r_riscv_32_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_64] = { apply_r_riscv_64_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_RELATIVE] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_COPY] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_JUMP_SLOT] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TLS_DTPMOD32] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TLS_DTPMOD64] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TLS_DTPREL32] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TLS_DTPREL64] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TLS_TPREL32] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TLS_TPREL64] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + /* 12-15 undefined */ > > + [R_RISCV_BRANCH] = { apply_r_riscv_branch_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_JAL] = { apply_r_riscv_jal_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_CALL] = { apply_r_riscv_call_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_CALL_PLT] = { apply_r_riscv_call_plt_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_GOT_HI20] = { apply_r_riscv_got_hi20_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_TLS_GOT_HI20] = { tls_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TLS_GD_HI20] = { tls_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_PCREL_HI20] = { apply_r_riscv_pcrel_hi20_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_PCREL_LO12_I] = { apply_r_riscv_pcrel_lo12_i_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_PCREL_LO12_S] = { apply_r_riscv_pcrel_lo12_s_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_HI20] = { apply_r_riscv_hi20_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_LO12_I] = { apply_r_riscv_lo12_i_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_LO12_S] = { apply_r_riscv_lo12_s_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_TPREL_HI20] = { tls_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TPREL_LO12_I] = { tls_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TPREL_LO12_S] = { tls_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_TPREL_ADD] = { tls_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_ADD8] = { apply_r_riscv_add8_rela, true, > > + apply_8_bit_accumulation }, > > + [R_RISCV_ADD16] = { apply_r_riscv_add16_rela, true, > > + apply_16_bit_accumulation }, > > + [R_RISCV_ADD32] = { apply_r_riscv_add32_rela, true, > > + apply_32_bit_accumulation }, > > + [R_RISCV_ADD64] = { apply_r_riscv_add64_rela, true, > > + apply_64_bit_accumulation }, > > + [R_RISCV_SUB8] = { apply_r_riscv_sub8_rela, true, > > + apply_8_bit_accumulation }, > > + [R_RISCV_SUB16] = { apply_r_riscv_sub16_rela, true, > > + apply_16_bit_accumulation }, > > + [R_RISCV_SUB32] = { apply_r_riscv_sub32_rela, true, > > + apply_32_bit_accumulation }, > > + [R_RISCV_SUB64] = { apply_r_riscv_sub64_rela, true, > > + apply_64_bit_accumulation }, > > + /* 41-42 reserved for future standard use */ > > + [R_RISCV_ALIGN] = { apply_r_riscv_align_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_RVC_BRANCH] = { apply_r_riscv_rvc_branch_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_RVC_JUMP] = { apply_r_riscv_rvc_jump_rela, false, > > + accumulation_not_supported }, > > + /* 46-50 reserved for future standard use */ > > + [R_RISCV_RELAX] = { apply_r_riscv_relax_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_SUB6] = { apply_r_riscv_sub6_rela, true, > > + apply_6_bit_accumulation }, > > + [R_RISCV_SET6] = { apply_r_riscv_set6_rela, true, > > + apply_6_bit_accumulation }, > > + [R_RISCV_SET8] = { apply_r_riscv_set8_rela, true, > > + apply_8_bit_accumulation }, > > + [R_RISCV_SET16] = { apply_r_riscv_set16_rela, true, > > + apply_16_bit_accumulation }, > > + [R_RISCV_SET32] = { apply_r_riscv_set32_rela, true, > > + apply_32_bit_accumulation }, > > + [R_RISCV_32_PCREL] = { apply_r_riscv_32_pcrel_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_IRELATIVE] = { dynamic_linking_not_supported, false, > > + accumulation_not_supported }, > > + [R_RISCV_PLT32] = { apply_r_riscv_plt32_rela, false, > > + accumulation_not_supported }, > > + [R_RISCV_SET_ULEB128] = { apply_r_riscv_set_uleb128, true, > > + apply_uleb128_accumulation }, > > + [R_RISCV_SUB_ULEB128] = { apply_r_riscv_sub_uleb128, true, > > + apply_uleb128_accumulation }, > > + /* 62-191 reserved for future standard use */ > > + /* 192-255 nonstandard ABI extensions */ > > }; > > > > +void process_accumulated_relocations(struct module *me) > > +{ > > + /* > > + * Only ADD/SUB/SET/ULEB128 should end up here. > > + * > > + * Each bucket may have more than one relocation location. All > > + * relocations for a location are stored in a list in a bucket. > > + * > > + * Relocations are applied to a temp variable before being stored to the > > + * provided location to check for overflow. This also allows ULEB128 to > > + * properly decide how many entries are needed before storing to > > + * location. The final value is stored into location using the handler > > + * for the last relocation to an address. > > + * > > + * Three layers of indexing: > > + * - Each of the buckets in use > > + * - Groups of relocations in each bucket by location address > > + * - Each relocation entry for a location address > > + */ > > + struct used_bucket *bucket_iter; > > + struct relocation_head *rel_head_iter; > > + struct relocation_entry *rel_entry_iter; > > + int curr_type; > > + void *location; > > + long buffer; > > + > > + list_for_each_entry(bucket_iter, &used_buckets_list, head) { > > + hlist_for_each_entry(rel_head_iter, bucket_iter->bucket, node) { > > + buffer = 0; > > + location = rel_head_iter->location; > > + list_for_each_entry(rel_entry_iter, > > + rel_head_iter->rel_entry, head) { > > + curr_type = rel_entry_iter->type; > > + reloc_handlers[curr_type].reloc_handler( > > + me, &buffer, rel_entry_iter->value); > > + kfree(rel_entry_iter); > > + } > > + reloc_handlers[curr_type].accumulate_handler( > > + me, location, buffer); > > + kfree(rel_head_iter); > > + } > > + kfree(bucket_iter); > > + } > > + > > + kfree(relocation_hashtable); > > +} > > + > > +int add_relocation_to_accumulate(struct module *me, int type, void *location, > > + unsigned int hashtable_bits, Elf_Addr v) > > +{ > > + struct relocation_entry *entry; > > + struct relocation_head *rel_head; > > + struct hlist_head *current_head; > > + struct used_bucket *bucket; > > + unsigned long hash; > > + > > + entry = kmalloc(sizeof(*entry), GFP_KERNEL); > > + INIT_LIST_HEAD(&entry->head); > > + entry->type = type; > > + entry->value = v; > > + > > + hash = hash_min((unsigned long)location, hashtable_bits); > > uintptr_t > > > + > > + current_head = &relocation_hashtable[hash]; > > + > > + /* Find matching location (if any) */ > > + bool found = false; > > + struct relocation_head *rel_head_iter; > > + > > + hlist_for_each_entry(rel_head_iter, current_head, node) { > > + if (rel_head_iter->location == location) { > > + found = true; > > + rel_head = rel_head_iter; > > + break; > > + } > > + } > > + > > + if (!found) { > > + rel_head = kmalloc(sizeof(*rel_head), GFP_KERNEL); > > + rel_head->rel_entry = > > + kmalloc(sizeof(struct list_head), GFP_KERNEL); > > + INIT_LIST_HEAD(rel_head->rel_entry); > > + rel_head->location = location; > > + INIT_HLIST_NODE(&rel_head->node); > > + if (!current_head->first) { > > + bucket = > > + kmalloc(sizeof(struct used_bucket), GFP_KERNEL); > > + INIT_LIST_HEAD(&bucket->head); > > + bucket->bucket = current_head; > > + list_add(&bucket->head, &used_buckets_list); > > + } > > + hlist_add_head(&rel_head->node, current_head); > > + } > > + > > + /* Add relocation to head of discovered rel_head */ > > + list_add_tail(&entry->head, rel_head->rel_entry); > > + > > + return 0; > > +} > > + > > +unsigned int initialize_relocation_hashtable(unsigned int num_relocations) > > +{ > > + /* Can safely assume that bits is not greater than sizeof(long) */ > > + unsigned long hashtable_size = roundup_pow_of_two(num_relocations); > > + unsigned int hashtable_bits = ilog2(hashtable_size); > > + > > + /* > > + * Double size of hashtable if num_relocations * 1.25 is greater than > > + * hashtable_size. > > + */ > > + int should_double_size = ((num_relocations + (num_relocations >> 2)) > (hashtable_size)); > > + > > + hashtable_bits += should_double_size; > > + > > + hashtable_size <<= should_double_size; > > + > > + relocation_hashtable = kmalloc_array(hashtable_size, > > + sizeof(*relocation_hashtable), > > + GFP_KERNEL); > > + __hash_init(relocation_hashtable, hashtable_size); > > + > > + INIT_LIST_HEAD(&used_buckets_list); > > + > > + return hashtable_bits; > > +} > > + > > int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > > unsigned int symindex, unsigned int relsec, > > struct module *me) > > @@ -349,11 +783,13 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > > unsigned int i, type; > > Elf_Addr v; > > int res; > > + unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel); > > + unsigned int hashtable_bits = initialize_relocation_hashtable(num_relocations); > > > > pr_debug("Applying relocate section %u to %u\n", relsec, > > sechdrs[relsec].sh_info); > > > > - for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { > > + for (i = 0; i < num_relocations; i++) { > > /* This is where to make the change */ > > location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr > > + rel[i].r_offset; > > @@ -371,8 +807,8 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > > > > type = ELF_RISCV_R_TYPE(rel[i].r_info); > > > > - if (type < ARRAY_SIZE(reloc_handlers_rela)) > > - handler = reloc_handlers_rela[type]; > > + if (type < ARRAY_SIZE(reloc_handlers)) > > + handler = reloc_handlers[type].reloc_handler; > > else > > handler = NULL; > > > > @@ -428,11 +864,16 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > > } > > } > > > > - res = handler(me, location, v); > > + if (reloc_handlers[type].accumulate_relocations) > > As far as I can tell the table above has accumulate_relocations == false if and > only if .accumulate_handler == accumulation_not_supported. Could we maybe drop > the bool and just check for that? > > Are there situations where we might end up calling > accumulation_not_supported()? If not we could just let .accumulate_handler be > NULL where accumulation is not supported. Then the table could be initialised > with > > { reloc_handler }, // when accumulation is not supported and > { reloc_handler, accumulate_handler }, // when it is > > ..and the test above would just be > > if (reloc_handlers[type].accumulate_handler) > Yes it will always be the case that accumulate_relocations == false and it uses accumulation_not_supported. This suggestion will make the code much cleaner. - Charlie > > + res = add_relocation_to_accumulate(me, type, location, hashtable_bits, v); > > + else > > + res = handler(me, location, v); > > if (res) > > return res; > > } > > > > + process_accumulated_relocations(me); > > + > > return 0; > > } > > > > > > -- > > 2.34.1 > > > > > > _______________________________________________ > > linux-riscv mailing list > > linux-riscv@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-riscv _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv