Re: [PATCH V3 15/22] LoongArch: Add elf and module support

From: Huacai Chen
Date: Sat Sep 18 2021 - 03:14:50 EST

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Hi, Arnd,

On Fri, Sep 17, 2021 at 4:29 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:
>
> On Fri, Sep 17, 2021 at 5:57 AM Huacai Chen <chenhuacai@xxxxxxxxxxx> wrote:
> >
> > This patch adds elf definition and module relocate codes.
> >
> > Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> > ---
> > arch/loongarch/include/asm/cpufeature.h | 24 +
> > arch/loongarch/include/asm/elf.h | 308 +++++++++++
> > arch/loongarch/include/asm/exec.h | 10 +
> > arch/loongarch/include/asm/module.h | 15 +
> > arch/loongarch/include/asm/vermagic.h | 19 +
> > arch/loongarch/include/uapi/asm/auxvec.h | 17 +
> > arch/loongarch/include/uapi/asm/hwcap.h | 20 +
> > arch/loongarch/kernel/elf.c | 41 ++
> > arch/loongarch/kernel/module.c | 652 +++++++++++++++++++++++
> > 9 files changed, 1106 insertions(+)
> > create mode 100644 arch/loongarch/include/asm/cpufeature.h
> > create mode 100644 arch/loongarch/include/asm/elf.h
> > create mode 100644 arch/loongarch/include/asm/exec.h
> > create mode 100644 arch/loongarch/include/asm/module.h
> > create mode 100644 arch/loongarch/include/asm/vermagic.h
> > create mode 100644 arch/loongarch/include/uapi/asm/auxvec.h
> > create mode 100644 arch/loongarch/include/uapi/asm/hwcap.h
> > create mode 100644 arch/loongarch/kernel/elf.c
> > create mode 100644 arch/loongarch/kernel/module.c
>
> Please add Jessica Yu and Luis Chamberlain as reviewers to Cc in the
> future. I have no further comments on this patch, fullquote below for them
> as reference.
OK, thanks, I will CC them.

Huacai
>
> Arnd
>
> > diff --git a/arch/loongarch/include/asm/cpufeature.h b/arch/loongarch/include/asm/cpufeature.h
> > new file mode 100644
> > index 000000000000..7e4c6a769830
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/cpufeature.h
> > @@ -0,0 +1,24 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * CPU feature definitions for module loading, used by
> > + * module_cpu_feature_match(), see uapi/asm/hwcap.h for LoongArch CPU features.
> > + *
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +
> > +#ifndef __ASM_CPUFEATURE_H
> > +#define __ASM_CPUFEATURE_H
> > +
> > +#include <uapi/asm/hwcap.h>
> > +#include <asm/elf.h>
> > +
> > +#define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap))
> > +
> > +#define cpu_feature(x) ilog2(HWCAP_ ## x)
> > +
> > +static inline bool cpu_have_feature(unsigned int num)
> > +{
> > + return elf_hwcap & (1UL << num);
> > +}
> > +
> > +#endif /* __ASM_CPUFEATURE_H */
> > diff --git a/arch/loongarch/include/asm/elf.h b/arch/loongarch/include/asm/elf.h
> > new file mode 100644
> > index 000000000000..9f8c2ab1a206
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/elf.h
> > @@ -0,0 +1,308 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +#ifndef _ASM_ELF_H
> > +#define _ASM_ELF_H
> > +
> > +#include <linux/auxvec.h>
> > +#include <linux/fs.h>
> > +#include <linux/mm_types.h>
> > +
> > +#include <uapi/linux/elf.h>
> > +
> > +#include <asm/current.h>
> > +
> > +/* ELF header e_flags defines. */
> > +
> > +/* The ABI of a file. */
> > +#define EF_LARCH_ABI_LP32 0x00000001 /* LP32 ABI. */
> > +#define EF_LARCH_ABI_LPX32 0x00000002 /* LPX32 ABI */
> > +#define EF_LARCH_ABI_LP64 0x00000003 /* LP64 ABI */
> > +#define EF_LARCH_ABI 0x00000003
> > +
> > +/* LoongArch relocation types used by the dynamic linker */
> > +#define R_LARCH_NONE 0
> > +#define R_LARCH_32 1
> > +#define R_LARCH_64 2
> > +#define R_LARCH_RELATIVE 3
> > +#define R_LARCH_COPY 4
> > +#define R_LARCH_JUMP_SLOT 5
> > +#define R_LARCH_TLS_DTPMOD32 6
> > +#define R_LARCH_TLS_DTPMOD64 7
> > +#define R_LARCH_TLS_DTPREL32 8
> > +#define R_LARCH_TLS_DTPREL64 9
> > +#define R_LARCH_TLS_TPREL32 10
> > +#define R_LARCH_TLS_TPREL64 11
> > +#define R_LARCH_IRELATIVE 12
> > +#define R_LARCH_MARK_LA 20
> > +#define R_LARCH_MARK_PCREL 21
> > +#define R_LARCH_SOP_PUSH_PCREL 22
> > +#define R_LARCH_SOP_PUSH_ABSOLUTE 23
> > +#define R_LARCH_SOP_PUSH_DUP 24
> > +#define R_LARCH_SOP_PUSH_GPREL 25
> > +#define R_LARCH_SOP_PUSH_TLS_TPREL 26
> > +#define R_LARCH_SOP_PUSH_TLS_GOT 27
> > +#define R_LARCH_SOP_PUSH_TLS_GD 28
> > +#define R_LARCH_SOP_PUSH_PLT_PCREL 29
> > +#define R_LARCH_SOP_ASSERT 30
> > +#define R_LARCH_SOP_NOT 31
> > +#define R_LARCH_SOP_SUB 32
> > +#define R_LARCH_SOP_SL 33
> > +#define R_LARCH_SOP_SR 34
> > +#define R_LARCH_SOP_ADD 35
> > +#define R_LARCH_SOP_AND 36
> > +#define R_LARCH_SOP_IF_ELSE 37
> > +#define R_LARCH_SOP_POP_32_S_10_5 38
> > +#define R_LARCH_SOP_POP_32_U_10_12 39
> > +#define R_LARCH_SOP_POP_32_S_10_12 40
> > +#define R_LARCH_SOP_POP_32_S_10_16 41
> > +#define R_LARCH_SOP_POP_32_S_10_16_S2 42
> > +#define R_LARCH_SOP_POP_32_S_5_20 43
> > +#define R_LARCH_SOP_POP_32_S_0_5_10_16_S2 44
> > +#define R_LARCH_SOP_POP_32_S_0_10_10_16_S2 45
> > +#define R_LARCH_SOP_POP_32_U 46
> > +#define R_LARCH_ADD8 47
> > +#define R_LARCH_ADD16 48
> > +#define R_LARCH_ADD24 49
> > +#define R_LARCH_ADD32 50
> > +#define R_LARCH_ADD64 51
> > +#define R_LARCH_SUB8 52
> > +#define R_LARCH_SUB16 53
> > +#define R_LARCH_SUB24 54
> > +#define R_LARCH_SUB32 55
> > +#define R_LARCH_SUB64 56
> > +#define R_LARCH_GNU_VTINHERIT 57
> > +#define R_LARCH_GNU_VTENTRY 58
> > +
> > +#ifndef ELF_ARCH
> > +
> > +/* ELF register definitions */
> > +
> > +/*
> > + * General purpose have the following registers:
> > + * Register Number
> > + * GPRs 32
> > + * EPC 1
> > + * BADVADDR 1
> > + * CRMD 1
> > + * PRMD 1
> > + * EUEN 1
> > + * ECFG 1
> > + * ESTAT 1
> > + * Reserved 6
> > + */
> > +#define ELF_NGREG 45
> > +
> > +/*
> > + * Floating point have the following registers:
> > + * Register Number
> > + * FPR 32
> > + * FCC 1
> > + * FCSR 1
> > + */
> > +#define ELF_NFPREG 34
> > +
> > +typedef unsigned long elf_greg_t;
> > +typedef elf_greg_t elf_gregset_t[ELF_NGREG];
> > +
> > +typedef double elf_fpreg_t;
> > +typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
> > +
> > +void loongarch_dump_regs64(u64 *uregs, const struct pt_regs *regs);
> > +
> > +#ifdef CONFIG_32BIT
> > +/*
> > + * This is used to ensure we don't load something for the wrong architecture.
> > + */
> > +#define elf_check_arch elf32_check_arch
> > +
> > +/*
> > + * These are used to set parameters in the core dumps.
> > + */
> > +#define ELF_CLASS ELFCLASS32
> > +
> > +#define ELF_CORE_COPY_REGS(dest, regs) \
> > + loongarch_dump_regs32((u32 *)&(dest), (regs));
> > +
> > +#endif /* CONFIG_32BIT */
> > +
> > +#ifdef CONFIG_64BIT
> > +/*
> > + * This is used to ensure we don't load something for the wrong architecture.
> > + */
> > +#define elf_check_arch elf64_check_arch
> > +
> > +/*
> > + * These are used to set parameters in the core dumps.
> > + */
> > +#define ELF_CLASS ELFCLASS64
> > +
> > +#define ELF_CORE_COPY_REGS(dest, regs) \
> > + loongarch_dump_regs64((u64 *)&(dest), (regs));
> > +
> > +#endif /* CONFIG_64BIT */
> > +
> > +/*
> > + * These are used to set parameters in the core dumps.
> > + */
> > +#define ELF_DATA ELFDATA2LSB
> > +#define ELF_ARCH EM_LOONGARCH
> > +
> > +#endif /* !defined(ELF_ARCH) */
> > +
> > +#define loongarch_elf_check_machine(x) ((x)->e_machine == EM_LOONGARCH)
> > +
> > +#define vmcore_elf32_check_arch loongarch_elf_check_machine
> > +#define vmcore_elf64_check_arch loongarch_elf_check_machine
> > +
> > +/*
> > + * Return non-zero if HDR identifies an 32bit ELF binary.
> > + */
> > +#define elf32_check_arch(hdr) \
> > +({ \
> > + int __res = 1; \
> > + struct elfhdr *__h = (hdr); \
> > + \
> > + if (!loongarch_elf_check_machine(__h)) \
> > + __res = 0; \
> > + if (__h->e_ident[EI_CLASS] != ELFCLASS32) \
> > + __res = 0; \
> > + \
> > + __res; \
> > +})
> > +
> > +/*
> > + * Return non-zero if HDR identifies an 64bit ELF binary.
> > + */
> > +#define elf64_check_arch(hdr) \
> > +({ \
> > + int __res = 1; \
> > + struct elfhdr *__h = (hdr); \
> > + \
> > + if (!loongarch_elf_check_machine(__h)) \
> > + __res = 0; \
> > + if (__h->e_ident[EI_CLASS] != ELFCLASS64) \
> > + __res = 0; \
> > + \
> > + __res; \
> > +})
> > +
> > +struct loongarch_abi;
> > +extern struct loongarch_abi loongarch_abi;
> > +
> > +#ifdef CONFIG_32BIT
> > +
> > +#define SET_PERSONALITY2(ex, state) \
> > +do { \
> > + current->thread.abi = &loongarch_abi; \
> > + \
> > + loongarch_set_personality_fcsr(state); \
> > + \
> > + if (personality(current->personality) != PER_LINUX) \
> > + set_personality(PER_LINUX); \
> > +} while (0)
> > +
> > +#endif /* CONFIG_32BIT */
> > +
> > +#ifdef CONFIG_64BIT
> > +
> > +#define SET_PERSONALITY2(ex, state) \
> > +do { \
> > + unsigned int p; \
> > + \
> > + clear_thread_flag(TIF_32BIT_REGS); \
> > + clear_thread_flag(TIF_32BIT_ADDR); \
> > + \
> > + current->thread.abi = &loongarch_abi; \
> > + loongarch_set_personality_fcsr(state); \
> > + \
> > + p = personality(current->personality); \
> > + if (p != PER_LINUX32 && p != PER_LINUX) \
> > + set_personality(PER_LINUX); \
> > +} while (0)
> > +
> > +#endif /* CONFIG_64BIT */
> > +
> > +#define CORE_DUMP_USE_REGSET
> > +#define ELF_EXEC_PAGESIZE PAGE_SIZE
> > +
> > +/*
> > + * This yields a mask that user programs can use to figure out what
> > + * instruction set this cpu supports. This could be done in userspace,
> > + * but it's not easy, and we've already done it here.
> > + */
> > +
> > +#define ELF_HWCAP (elf_hwcap)
> > +extern unsigned int elf_hwcap;
> > +#include <asm/hwcap.h>
> > +
> > +/*
> > + * This yields a string that ld.so will use to load implementation
> > + * specific libraries for optimization. This is more specific in
> > + * intent than poking at uname or /proc/cpuinfo.
> > + */
> > +
> > +#define ELF_PLATFORM __elf_platform
> > +extern const char *__elf_platform;
> > +
> > +/* The regs[11] (a7) holds the syscall number and should not cleared */
> > +#define ELF_PLAT_INIT(_r, load_addr) do { \
> > + _r->regs[1] = _r->regs[2] = _r->regs[3] = _r->regs[4] = 0; \
> > + _r->regs[5] = _r->regs[6] = _r->regs[7] = _r->regs[8] = 0; \
> > + _r->regs[9] = _r->regs[10] = _r->regs[12] = _r->regs[13] = 0; \
> > + _r->regs[14] = _r->regs[15] = _r->regs[16] = _r->regs[17] = 0; \
> > + _r->regs[18] = _r->regs[19] = _r->regs[20] = _r->regs[21] = 0; \
> > + _r->regs[22] = _r->regs[23] = _r->regs[24] = _r->regs[25] = 0; \
> > + _r->regs[26] = _r->regs[27] = _r->regs[28] = _r->regs[29] = 0; \
> > + _r->regs[30] = _r->regs[31] = 0; \
> > +} while (0)
> > +
> > +/*
> > + * This is the location that an ET_DYN program is loaded if exec'ed. Typical
> > + * use of this is to invoke "./ld.so someprog" to test out a new version of
> > + * the loader. We need to make sure that it is out of the way of the program
> > + * that it will "exec", and that there is sufficient room for the brk.
> > + */
> > +
> > +#ifndef ELF_ET_DYN_BASE
> > +#define ELF_ET_DYN_BASE (TASK_SIZE / 3 * 2)
> > +#endif
> > +
> > +/* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
> > +#define ARCH_DLINFO \
> > +do { \
> > + NEW_AUX_ENT(AT_SYSINFO_EHDR, \
> > + (unsigned long)current->mm->context.vdso); \
> > +} while (0)
> > +
> > +#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
> > +struct linux_binprm;
> > +extern int arch_setup_additional_pages(struct linux_binprm *bprm,
> > + int uses_interp);
> > +
> > +struct arch_elf_state {
> > + int fp_abi;
> > + int interp_fp_abi;
> > +};
> > +
> > +#define LOONGARCH_ABI_FP_ANY (0)
> > +
> > +#define INIT_ARCH_ELF_STATE { \
> > + .fp_abi = LOONGARCH_ABI_FP_ANY, \
> > + .interp_fp_abi = LOONGARCH_ABI_FP_ANY, \
> > +}
> > +
> > +
> > +extern int arch_elf_pt_proc(void *ehdr, void *phdr, struct file *elf,
> > + bool is_interp, struct arch_elf_state *state);
> > +
> > +extern int arch_check_elf(void *ehdr, bool has_interpreter, void *interp_ehdr,
> > + struct arch_elf_state *state);
> > +
> > +extern void loongarch_set_personality_fcsr(struct arch_elf_state *state);
> > +
> > +#define elf_read_implies_exec(ex, stk) loongarch_elf_read_implies_exec(&(ex), stk)
> > +extern int loongarch_elf_read_implies_exec(void *elf_ex, int exstack);
> > +
> > +#endif /* _ASM_ELF_H */
> > diff --git a/arch/loongarch/include/asm/exec.h b/arch/loongarch/include/asm/exec.h
> > new file mode 100644
> > index 000000000000..00df07ce3529
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/exec.h
> > @@ -0,0 +1,10 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +#ifndef _ASM_EXEC_H
> > +#define _ASM_EXEC_H
> > +
> > +extern unsigned long arch_align_stack(unsigned long sp);
> > +
> > +#endif /* _ASM_EXEC_H */
> > diff --git a/arch/loongarch/include/asm/module.h b/arch/loongarch/include/asm/module.h
> > new file mode 100644
> > index 000000000000..6df72c6228e0
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/module.h
> > @@ -0,0 +1,15 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +#ifndef _ASM_MODULE_H
> > +#define _ASM_MODULE_H
> > +
> > +#include <asm-generic/module.h>
> > +
> > +#define RELA_STACK_DEPTH 16
> > +
> > +struct mod_arch_specific {
> > +};
> > +
> > +#endif /* _ASM_MODULE_H */
> > diff --git a/arch/loongarch/include/asm/vermagic.h b/arch/loongarch/include/asm/vermagic.h
> > new file mode 100644
> > index 000000000000..9882dfd4702a
> > --- /dev/null
> > +++ b/arch/loongarch/include/asm/vermagic.h
> > @@ -0,0 +1,19 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +#ifndef _ASM_VERMAGIC_H
> > +#define _ASM_VERMAGIC_H
> > +
> > +#define MODULE_PROC_FAMILY "LOONGARCH "
> > +
> > +#ifdef CONFIG_32BIT
> > +#define MODULE_KERNEL_TYPE "32BIT "
> > +#elif defined CONFIG_64BIT
> > +#define MODULE_KERNEL_TYPE "64BIT "
> > +#endif
> > +
> > +#define MODULE_ARCH_VERMAGIC \
> > + MODULE_PROC_FAMILY MODULE_KERNEL_TYPE
> > +
> > +#endif /* _ASM_VERMAGIC_H */
> > diff --git a/arch/loongarch/include/uapi/asm/auxvec.h b/arch/loongarch/include/uapi/asm/auxvec.h
> > new file mode 100644
> > index 000000000000..5a2200fd75bf
> > --- /dev/null
> > +++ b/arch/loongarch/include/uapi/asm/auxvec.h
> > @@ -0,0 +1,17 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
> > +/*
> > + * Author: Hanlu Li <lihanlu@xxxxxxxxxxx>
> > + * Huacai Chen <chenhuacai@xxxxxxxxxxx>
> > + *
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +
> > +#ifndef __ASM_AUXVEC_H
> > +#define __ASM_AUXVEC_H
> > +
> > +/* Location of VDSO image. */
> > +#define AT_SYSINFO_EHDR 33
> > +
> > +#define AT_VECTOR_SIZE_ARCH 1 /* entries in ARCH_DLINFO */
> > +
> > +#endif /* __ASM_AUXVEC_H */
> > diff --git a/arch/loongarch/include/uapi/asm/hwcap.h b/arch/loongarch/include/uapi/asm/hwcap.h
> > new file mode 100644
> > index 000000000000..8840b72fa8e8
> > --- /dev/null
> > +++ b/arch/loongarch/include/uapi/asm/hwcap.h
> > @@ -0,0 +1,20 @@
> > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> > +#ifndef _UAPI_ASM_HWCAP_H
> > +#define _UAPI_ASM_HWCAP_H
> > +
> > +/* HWCAP flags */
> > +#define HWCAP_LOONGARCH_CPUCFG (1 << 0)
> > +#define HWCAP_LOONGARCH_LAM (1 << 1)
> > +#define HWCAP_LOONGARCH_UAL (1 << 2)
> > +#define HWCAP_LOONGARCH_FPU (1 << 3)
> > +#define HWCAP_LOONGARCH_LSX (1 << 4)
> > +#define HWCAP_LOONGARCH_LASX (1 << 5)
> > +#define HWCAP_LOONGARCH_CRC32 (1 << 6)
> > +#define HWCAP_LOONGARCH_COMPLEX (1 << 7)
> > +#define HWCAP_LOONGARCH_CRYPTO (1 << 8)
> > +#define HWCAP_LOONGARCH_LVZ (1 << 9)
> > +#define HWCAP_LOONGARCH_LBT_X86 (1 << 10)
> > +#define HWCAP_LOONGARCH_LBT_ARM (1 << 11)
> > +#define HWCAP_LOONGARCH_LBT_MIPS (1 << 12)
> > +
> > +#endif /* _UAPI_ASM_HWCAP_H */
> > diff --git a/arch/loongarch/kernel/elf.c b/arch/loongarch/kernel/elf.c
> > new file mode 100644
> > index 000000000000..072dfd40f0b5
> > --- /dev/null
> > +++ b/arch/loongarch/kernel/elf.c
> > @@ -0,0 +1,41 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Author: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +
> > +#include <linux/binfmts.h>
> > +#include <linux/elf.h>
> > +#include <linux/export.h>
> > +#include <linux/sched.h>
> > +
> > +#include <asm/cpu-features.h>
> > +#include <asm/cpu-info.h>
> > +
> > +int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf,
> > + bool is_interp, struct arch_elf_state *state)
> > +{
> > + return 0;
> > +}
> > +
> > +int arch_check_elf(void *_ehdr, bool has_interpreter, void *_interp_ehdr,
> > + struct arch_elf_state *state)
> > +{
> > + return 0;
> > +}
> > +
> > +void loongarch_set_personality_fcsr(struct arch_elf_state *state)
> > +{
> > + current->thread.fpu.fcsr = boot_cpu_data.fpu_csr0;
> > +}
> > +
> > +int loongarch_elf_read_implies_exec(void *elf_ex, int exstack)
> > +{
> > + if (exstack != EXSTACK_DISABLE_X) {
> > + /* The binary doesn't request a non-executable stack */
> > + return 1;
> > + }
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(loongarch_elf_read_implies_exec);
> > diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
> > new file mode 100644
> > index 000000000000..af7c403b032b
> > --- /dev/null
> > +++ b/arch/loongarch/kernel/module.c
> > @@ -0,0 +1,652 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Author: Hanlu Li <lihanlu@xxxxxxxxxxx>
> > + * Huacai Chen <chenhuacai@xxxxxxxxxxx>
> > + *
> > + * Copyright (C) 2020-2021 Loongson Technology Corporation Limited
> > + */
> > +
> > +#undef DEBUG
> > +
> > +#include <linux/moduleloader.h>
> > +#include <linux/elf.h>
> > +#include <linux/mm.h>
> > +#include <linux/vmalloc.h>
> > +#include <linux/slab.h>
> > +#include <linux/fs.h>
> > +#include <linux/string.h>
> > +#include <linux/kernel.h>
> > +
> > +static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + if (*rela_stack_top >= RELA_STACK_DEPTH)
> > + return -ENOEXEC;
> > +
> > + rela_stack[(*rela_stack_top)++] = stack_value;
> > + pr_debug("%s stack_value = 0x%llx\n", __func__, stack_value);
> > +
> > + return 0;
> > +}
> > +
> > +static int rela_stack_pop(s64 *stack_value, s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + if (*rela_stack_top == 0)
> > + return -ENOEXEC;
> > +
> > + *stack_value = rela_stack[--(*rela_stack_top)];
> > + pr_debug("%s stack_value = 0x%llx\n", __func__, *stack_value);
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_none(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_32(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + *location = v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_64(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + *(Elf_Addr *)location = v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_mark_la(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_mark_pcrel(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_push_pcrel(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + return rela_stack_push(v - (u64)location, rela_stack, rela_stack_top);
> > +}
> > +
> > +static int apply_r_larch_sop_push_absolute(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + return rela_stack_push(v, rela_stack, rela_stack_top);
> > +}
> > +
> > +static int apply_r_larch_sop_push_dup(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_push(opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_push(opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_push_plt_pcrel(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + return apply_r_larch_sop_push_pcrel(me, location, v, rela_stack, rela_stack_top);
> > +}
> > +
> > +static int apply_r_larch_sop_sub(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1, opr2;
> > +
> > + err = rela_stack_pop(&opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_push(opr1 - opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_sl(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1, opr2;
> > +
> > + err = rela_stack_pop(&opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_push(opr1 << opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_sr(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1, opr2;
> > +
> > + err = rela_stack_pop(&opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_push(opr1 >> opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_add(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1, opr2;
> > +
> > + err = rela_stack_pop(&opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_push(opr1 + opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + return 0;
> > +}
> > +static int apply_r_larch_sop_and(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1, opr2;
> > +
> > + err = rela_stack_pop(&opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_push(opr1 & opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_if_else(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1, opr2, opr3;
> > +
> > + err = rela_stack_pop(&opr3, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_pop(&opr2, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > + err = rela_stack_push(opr1 ? opr2 : opr3, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_pop_32_s_10_5(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + /* check 5-bit signed */
> > + if ((opr1 & ~(u64)0xf) &&
> > + (opr1 & ~(u64)0xf) != ~(u64)0xf) {
> > + pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + /* (*(uint32_t *) PC) [14 ... 10] = opr [4 ... 0] */
> > + *location = (*location & (~(u32)0x7c00)) | ((opr1 & 0x1f) << 10);
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_pop_32_u_10_12(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + /* check 12-bit unsigned */
> > + if (opr1 & ~(u64)0xfff) {
> > + pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + /* (*(uint32_t *) PC) [21 ... 10] = opr [11 ... 0] */
> > + *location = (*location & (~(u32)0x3ffc00)) | ((opr1 & 0xfff) << 10);
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_pop_32_s_10_12(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + /* check 12-bit signed */
> > + if ((opr1 & ~(u64)0x7ff) &&
> > + (opr1 & ~(u64)0x7ff) != ~(u64)0x7ff) {
> > + pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + /* (*(uint32_t *) PC) [21 ... 10] = opr [11 ... 0] */
> > + *location = (*location & (~(u32)0x3ffc00)) | ((opr1 & 0xfff) << 10);
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_pop_32_s_10_16(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + /* check 16-bit signed */
> > + if ((opr1 & ~(u64)0x7fff) &&
> > + (opr1 & ~(u64)0x7fff) != ~(u64)0x7fff) {
> > + pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + /* (*(uint32_t *) PC) [25 ... 10] = opr [15 ... 0] */
> > + *location = (*location & 0xfc0003ff) | ((opr1 & 0xffff) << 10);
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_pop_32_s_10_16_s2(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + /* check 4-aligned */
> > + if (opr1 % 4) {
> > + pr_err("module %s: opr1 = 0x%llx unaligned! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + opr1 >>= 2;
> > + /* check 18-bit signed */
> > + if ((opr1 & ~(u64)0x7fff) &&
> > + (opr1 & ~(u64)0x7fff) != ~(u64)0x7fff) {
> > + pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + /* (*(uint32_t *) PC) [25 ... 10] = opr [17 ... 2] */
> > + *location = (*location & 0xfc0003ff) | ((opr1 & 0xffff) << 10);
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_pop_32_s_5_20(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + /* check 20-bit signed */
> > + if ((opr1 & ~(u64)0x7ffff) &&
> > + (opr1 & ~(u64)0x7ffff) != ~(u64)0x7ffff) {
> > + pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + /* (*(uint32_t *) PC) [24 ... 5] = opr [19 ... 0] */
> > + *location = (*location & (~(u32)0x1ffffe0)) | ((opr1 & 0xfffff) << 5);
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_pop_32_s_0_5_10_16_s2(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + /* check 4-aligned */
> > + if (opr1 % 4) {
> > + pr_err("module %s: opr1 = 0x%llx unaligned! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + opr1 >>= 2;
> > + /* check 23-bit signed */
> > + if ((opr1 & ~(u64)0xfffff) &&
> > + (opr1 & ~(u64)0xfffff) != ~(u64)0xfffff) {
> > + pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + /*
> > + * (*(uint32_t *) PC) [4 ... 0] = opr [22 ... 18]
> > + * (*(uint32_t *) PC) [25 ... 10] = opr [17 ... 2]
> > + */
> > + *location = (*location & 0xfc0003e0)
> > + | ((opr1 & 0x1f0000) >> 16) | ((opr1 & 0xffff) << 10);
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_pop_32_s_0_10_10_16_s2(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + /* check 4-aligned */
> > + if (opr1 % 4) {
> > + pr_err("module %s: opr1 = 0x%llx unaligned! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + opr1 >>= 2;
> > + /* check 28-bit signed */
> > + if ((opr1 & ~(u64)0x1ffffff) &&
> > + (opr1 & ~(u64)0x1ffffff) != ~(u64)0x1ffffff) {
> > + pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + /*
> > + * (*(uint32_t *) PC) [9 ... 0] = opr [27 ... 18]
> > + * (*(uint32_t *) PC) [25 ... 10] = opr [17 ... 2]
> > + */
> > + *location = (*location & 0xfc000000)
> > + | ((opr1 & 0x3ff0000) >> 16) | ((opr1 & 0xffff) << 10);
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sop_pop_32_u(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + int err = 0;
> > + s64 opr1;
> > +
> > + err = rela_stack_pop(&opr1, rela_stack, rela_stack_top);
> > + if (err)
> > + return err;
> > +
> > + /* check 32-bit unsigned */
> > + if (opr1 & ~(u64)0xffffffff) {
> > + pr_err("module %s: opr1 = 0x%llx overflow! dangerous %s relocation\n",
> > + me->name, opr1, __func__);
> > + return -ENOEXEC;
> > + }
> > +
> > + /* (*(uint32_t *) PC) = opr */
> > + *location = (u32)opr1;
> > +
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_add32(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + *(s32 *)location += v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_add64(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + *(s64 *)location += v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sub32(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + *(s32 *)location -= v;
> > + return 0;
> > +}
> > +
> > +static int apply_r_larch_sub64(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top)
> > +{
> > + *(s64 *)location -= v;
> > + return 0;
> > +}
> > +
> > +/*
> > + * reloc_handlers_rela() - Apply a particular relocation to a module
> > + * @me: the module to apply the reloc to
> > + * @location: the address at which the reloc is to be applied
> > + * @v: the value of the reloc, with addend for RELA-style
> > + * @rela_stack: the stack used for store relocation info, LOCAL to THIS module
> > + * @rela_stac_top: where the stack operation(pop/push) applies to
> > + *
> > + * Return: 0 upon success, else -ERRNO
> > + */
> > +typedef int (*reloc_rela_handler)(struct module *me, u32 *location, Elf_Addr v,
> > + s64 *rela_stack, size_t *rela_stack_top);
> > +
> > +/* The handlers for known reloc types */
> > +static reloc_rela_handler reloc_rela_handlers[] = {
> > + [R_LARCH_NONE] = apply_r_larch_none,
> > + [R_LARCH_32] = apply_r_larch_32,
> > + [R_LARCH_64] = apply_r_larch_64,
> > + [R_LARCH_MARK_LA] = apply_r_larch_mark_la,
> > + [R_LARCH_MARK_PCREL] = apply_r_larch_mark_pcrel,
> > + [R_LARCH_SOP_PUSH_PCREL] = apply_r_larch_sop_push_pcrel,
> > + [R_LARCH_SOP_PUSH_ABSOLUTE] = apply_r_larch_sop_push_absolute,
> > + [R_LARCH_SOP_PUSH_DUP] = apply_r_larch_sop_push_dup,
> > + [R_LARCH_SOP_PUSH_PLT_PCREL] = apply_r_larch_sop_push_plt_pcrel,
> > + [R_LARCH_SOP_SUB] = apply_r_larch_sop_sub,
> > + [R_LARCH_SOP_SL] = apply_r_larch_sop_sl,
> > + [R_LARCH_SOP_SR] = apply_r_larch_sop_sr,
> > + [R_LARCH_SOP_ADD] = apply_r_larch_sop_add,
> > + [R_LARCH_SOP_AND] = apply_r_larch_sop_and,
> > + [R_LARCH_SOP_IF_ELSE] = apply_r_larch_sop_if_else,
> > + [R_LARCH_SOP_POP_32_S_10_5] = apply_r_larch_sop_pop_32_s_10_5,
> > + [R_LARCH_SOP_POP_32_U_10_12] = apply_r_larch_sop_pop_32_u_10_12,
> > + [R_LARCH_SOP_POP_32_S_10_12] = apply_r_larch_sop_pop_32_s_10_12,
> > + [R_LARCH_SOP_POP_32_S_10_16] = apply_r_larch_sop_pop_32_s_10_16,
> > + [R_LARCH_SOP_POP_32_S_10_16_S2] = apply_r_larch_sop_pop_32_s_10_16_s2,
> > + [R_LARCH_SOP_POP_32_S_5_20] = apply_r_larch_sop_pop_32_s_5_20,
> > + [R_LARCH_SOP_POP_32_S_0_5_10_16_S2] = apply_r_larch_sop_pop_32_s_0_5_10_16_s2,
> > + [R_LARCH_SOP_POP_32_S_0_10_10_16_S2] = apply_r_larch_sop_pop_32_s_0_10_10_16_s2,
> > + [R_LARCH_SOP_POP_32_U] = apply_r_larch_sop_pop_32_u,
> > + [R_LARCH_ADD32] = apply_r_larch_add32,
> > + [R_LARCH_ADD64] = apply_r_larch_add64,
> > + [R_LARCH_SUB32] = apply_r_larch_sub32,
> > + [R_LARCH_SUB64] = apply_r_larch_sub64,
> > +};
> > +
> > +int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
> > + unsigned int symindex, unsigned int relsec,
> > + struct module *me)
> > +{
> > + int i, err;
> > + unsigned int type;
> > + s64 rela_stack[RELA_STACK_DEPTH];
> > + size_t rela_stack_top = 0;
> > + reloc_rela_handler handler;
> > + void *location;
> > + Elf_Addr v;
> > + Elf_Sym *sym;
> > + Elf_Rel *rel = (void *) sechdrs[relsec].sh_addr;
> > +
> > + pr_debug("%s: Applying relocate section %u to %u\n", __func__, relsec,
> > + sechdrs[relsec].sh_info);
> > +
> > + rela_stack_top = 0;
> > + for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
> > + /* This is where to make the change */
> > + location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr + rel[i].r_offset;
> > + /* This is the symbol it is referring to */
> > + sym = (Elf_Sym *)sechdrs[symindex].sh_addr + ELF_R_SYM(rel[i].r_info);
> > + if (IS_ERR_VALUE(sym->st_value)) {
> > + /* Ignore unresolved weak symbol */
> > + if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
> > + continue;
> > + pr_warn("%s: Unknown symbol %s\n", me->name, strtab + sym->st_name);
> > + return -ENOENT;
> > + }
> > +
> > + type = ELF_R_TYPE(rel[i].r_info);
> > +
> > + if (type < ARRAY_SIZE(reloc_rela_handlers))
> > + handler = reloc_rela_handlers[type];
> > + else
> > + handler = NULL;
> > +
> > + if (!handler) {
> > + pr_err("%s: Unknown relocation type %u\n", me->name, type);
> > + return -EINVAL;
> > + }
> > +
> > + v = sym->st_value;
> > + err = handler(me, location, v, rela_stack, &rela_stack_top);
> > + if (err)
> > + return err;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
> > + unsigned int symindex, unsigned int relsec,
> > + struct module *me)
> > +{
> > + int i, err;
> > + unsigned int type;
> > + s64 rela_stack[RELA_STACK_DEPTH];
> > + size_t rela_stack_top = 0;
> > + reloc_rela_handler handler;
> > + void *location;
> > + Elf_Addr v;
> > + Elf_Sym *sym;
> > + Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr;
> > +
> > + pr_debug("%s: Applying relocate section %u to %u\n", __func__, relsec,
> > + sechdrs[relsec].sh_info);
> > +
> > + rela_stack_top = 0;
> > + for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
> > + /* This is where to make the change */
> > + location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr + rel[i].r_offset;
> > + /* This is the symbol it is referring to */
> > + sym = (Elf_Sym *)sechdrs[symindex].sh_addr + ELF_R_SYM(rel[i].r_info);
> > + if (IS_ERR_VALUE(sym->st_value)) {
> > + /* Ignore unresolved weak symbol */
> > + if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
> > + continue;
> > + pr_warn("%s: Unknown symbol %s\n", me->name, strtab + sym->st_name);
> > + return -ENOENT;
> > + }
> > +
> > + type = ELF_R_TYPE(rel[i].r_info);
> > +
> > + if (type < ARRAY_SIZE(reloc_rela_handlers))
> > + handler = reloc_rela_handlers[type];
> > + else
> > + handler = NULL;
> > +
> > + if (!handler) {
> > + pr_err("%s: Unknown relocation type %u\n", me->name, type);
> > + return -EINVAL;
> > + }
> > +
> > + pr_debug("type %d st_value %llx r_addend %llx loc %llx\n",
> > + (int)ELF64_R_TYPE(rel[i].r_info),
> > + sym->st_value, rel[i].r_addend, (u64)location);
> > +
> > + v = sym->st_value + rel[i].r_addend;
> > + err = handler(me, location, v, rela_stack, &rela_stack_top);
> > + if (err)
> > + return err;
> > + }
> > +
> > + return 0;
> > +}
> > --
> > 2.27.0
> >

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