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Wed, 01 Nov 2023 07:44:32 -0700 (PDT) Received: from 348282803490 named unknown by gmailapi.google.com with HTTPREST; Wed, 1 Nov 2023 15:44:30 +0100 From: Emil Renner Berthing In-Reply-To: <20231031-module_relocations-v8-2-09b5b720c1fe@rivosinc.com> References: <20231031-module_relocations-v8-0-09b5b720c1fe@rivosinc.com> <20231031-module_relocations-v8-2-09b5b720c1fe@rivosinc.com> Mime-Version: 1.0 Date: Wed, 1 Nov 2023 15:44:30 +0100 Message-ID: Subject: Re: [PATCH v8 2/3] riscv: Add remaining module relocations To: Charlie Jenkins , linux-riscv@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Eric Biederman , Kees Cook , Paul Walmsley , Palmer Dabbelt , Albert Ou , Andreas Schwab , Emil Renner Berthing , Samuel Holland , Nelson Chu Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: EA2A418000E X-Stat-Signature: gk6fttzjwo4yxs7obknyxq5i84md8pbf X-Rspam-User: X-HE-Tag: 1698849875-362139 X-HE-Meta: U2FsdGVkX1+vftHjoYeWu9Ao+mfAM154dQxNq8QIqUj2ou7nbr1PMlRnjFeM55oafOeJASFlWynijsf8R4JU0KfdIOM5L8PrHhZYfKhRaQtuVYw1e056n+rs+dZoBFBVHTyjMa8nV4YwHl6X3oSzvR7G5xE5m4QiVs6sSs5hsbkPZpGfHLK0yVQuo5WkwoaDkQFgy6gTKRydEI3ZWVE+DP7J/yxdMEYPMrBFr6qBCvj1e8YvOKwt71nT/q9lco4tm9wKCaLh0U6Wglg6AjR19llzUoBwF0zlvj/XnT7rXUS6mFs7SoR/NumEgKA/zJqWyaXQQc0UUgowobkqDJ1BfnyEDNvNy0Fh028FNL9ZnyXqWmMNH8uWSYw7vx7r8puCeIW91KtY51WDnHX9hZxoNvhfcH9GKtqa+rIPKIwvDJC0AW7ocbP8MYdd7DHYLLDsKpePB8JB6WtRX36yd9fehPfgJ63iSroUoev6PDQ+3WQ9CL2IaSFe/VulBgpRESwOL/L7SkhwZU9qFdp5eE85hYzVr+63XXAPNLhSYFnBu/QXLJpgY1Hf6gH6YxyqkMT+1pppbjHODMyFioH8hdKDAyeVldoeJcbwYAs1qYlT5GoOUxef2ZRmHCR62ajKxt5mlN7K3z41LOll0uLZnE2IjDen1UG9n7mpM2SsuU+hIGpm8YRCLngS7/qmLMPyd2CV6MA6+7XmswrZQ/MgCKCzNtC+rZ9g4CgrSAUU7IY5r9xtGcvij9hJ4+cYoo5txWJt5Awvtxgk1ccCnyMDuYHoPkDs0KWHihZ9b7VqCqKl5D/HiCKCg6e04rdvx32MjC2vyXr0rKhafSzss4HE+4ZgQAyrhQoBjoj3dqJ7Blemsb4CVwKjBpIzWRNLYCKo4bZd/nRyj5Qc3y8i5cWmuRAA3Pe1K29NfG8Ce9pElZRPIc3twRh9rxpItvySiLoWJh3GCkcEFjJS8pRgSzPvAl0 uQMziPv4 6INsX+KeQKTUqQTPGw5FxfuhpFdtkVylUbM4IYuANdik887NKrGlUtkGg+eRCIUaBg5VKXhK9Mf3N1cXQNXQwDz2KYVoW718qDSkEL3qIYSPTOWV5GsNQmqtkQVvE2rFgjdtzz3KpwlZCTHVQ6Akp1HkaQ35FUEtxoYaYGjnMbGWkm4VTyW/1y7kee1OJacc8YYQMh/IWs4ljlov5z87hZVd9VL8PP1XMZA3EIwBCmHpVt7xCicPWNqoJ3XI17Jr0p9g8tU6m8RBusn+YEd8X+X06/vI2dsb1npg0OZ//EKepjFVrtSz23SEvxefO87IHkbWngjLHBqR4vcAbGs5S+xOKUevZq1UlWEW0X2wzTm3os3SIQJwXtJN6e0Ve+cSS7C+GdmLvqFrmDxwLIs0vSTrdG36djkyqsXXEklwnvebMX63itcwCLylD7A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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. > + 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) > + 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