RISC-V: Add section of GOT.PLT for kernel module (b8bde0ef) · Commits · e / devices / android_kernel_teracube_emerald

arch/riscv/include/asm/module.h

+25 −15

Original line number	Original line	Diff line number	Diff line
	@@ -21,6 +21,7 @@ struct mod_section {
	struct mod_arch_specific {		struct mod_arch_specific {
	struct mod_section got;		struct mod_section got;
	struct mod_section plt;		struct mod_section plt;
			struct mod_section got_plt;
	};		};

	struct got_entry {		struct got_entry {
	@@ -48,13 +49,10 @@ struct plt_entry {
	/*		/*
	* Trampoline code to real target address. The return address		* Trampoline code to real target address. The return address
	* should be the original (pc+4) before entring plt entry.		* should be the original (pc+4) before entring plt entry.
	* For 8 byte alignment of symbol_addr,
	* don't pack structure to remove the padding.
	*/		*/
	u32 insn_auipc; /* auipc t0, 0x0 */		u32 insn_auipc; /* auipc t0, 0x0 */
	u32 insn_ld; /* ld t1, 0x10(t0) */		u32 insn_ld; /* ld t1, 0x10(t0) */
	u32 insn_jr; /* jr t1 */		u32 insn_jr; /* jr t1 */
	u64 symbol_addr; /* the real jump target address */
	};		};

	#define OPC_AUIPC 0x0017		#define OPC_AUIPC 0x0017
	@@ -62,9 +60,8 @@ struct plt_entry {
	#define OPC_JALR 0x0067		#define OPC_JALR 0x0067
	#define REG_T0 0x5		#define REG_T0 0x5
	#define REG_T1 0x6		#define REG_T1 0x6
	#define IMM_OFFSET 0x10

	static inline struct plt_entry emit_plt_entry(u64 val)		static inline struct plt_entry emit_plt_entry(u64 val, u64 plt, u64 got_plt)
	{		{
	/*		/*
	* U-Type encoding:		* U-Type encoding:
	@@ -78,23 +75,36 @@ static inline struct plt_entry emit_plt_entry(u64 val)
	* +------------+------------+--------+----------+----------+		* +------------+------------+--------+----------+----------+
	*		*
	*/		*/
			u64 offset = got_plt - plt;
			u32 hi20 = (offset + 0x800) & 0xfffff000;
			u32 lo12 = (offset - hi20);
	return (struct plt_entry) {		return (struct plt_entry) {
	OPC_AUIPC \| (REG_T0 << 7),		OPC_AUIPC \| (REG_T0 << 7) \| hi20,
	OPC_LD \| (IMM_OFFSET << 20) \| (REG_T0 << 15) \| (REG_T1 << 7),		OPC_LD \| (lo12 << 20) \| (REG_T0 << 15) \| (REG_T1 << 7),
	OPC_JALR \| (REG_T1 << 15),		OPC_JALR \| (REG_T1 << 15)
	val
	};		};
	}		}

	static inline struct plt_entry *get_plt_entry(u64 val,		static inline int get_got_plt_idx(u64 val, const struct mod_section *sec)
	const struct mod_section *sec)
	{		{
	struct plt_entry plt = (struct plt_entry )sec->shdr->sh_addr;		struct got_entry got_plt = (struct got_entry )sec->shdr->sh_addr;
	int i;		int i;
	for (i = 0; i < sec->num_entries; i++) {		for (i = 0; i < sec->num_entries; i++) {
	if (plt[i].symbol_addr == val)		if (got_plt[i].symbol_addr == val)
	return &plt[i];		return i;
			}
			return -1;
	}		}

			static inline struct plt_entry *get_plt_entry(u64 val,
			const struct mod_section *sec_plt,
			const struct mod_section *sec_got_plt)
			{
			struct plt_entry plt = (struct plt_entry )sec_plt->shdr->sh_addr;
			int got_plt_idx = get_got_plt_idx(val, sec_got_plt);
			if (got_plt_idx >= 0)
			return plt + got_plt_idx;
			else
	return NULL;		return NULL;
	}		}

arch/riscv/kernel/module-sections.c

+19 −2

Original line number	Original line	Diff line number	Diff line
	@@ -30,18 +30,23 @@ u64 module_emit_got_entry(struct module *mod, u64 val)

	u64 module_emit_plt_entry(struct module *mod, u64 val)		u64 module_emit_plt_entry(struct module *mod, u64 val)
	{		{
			struct mod_section *got_plt_sec = &mod->arch.got_plt;
			struct got_entry *got_plt;
	struct mod_section *plt_sec = &mod->arch.plt;		struct mod_section *plt_sec = &mod->arch.plt;
	struct plt_entry *plt = get_plt_entry(val, plt_sec);		struct plt_entry *plt = get_plt_entry(val, plt_sec, got_plt_sec);
	int i = plt_sec->num_entries;		int i = plt_sec->num_entries;

	if (plt)		if (plt)
	return (u64)plt;		return (u64)plt;

	/* There is no duplicate entry, create a new one */		/* There is no duplicate entry, create a new one */
			got_plt = (struct got_entry *)got_plt_sec->shdr->sh_addr;
			got_plt[i] = emit_got_entry(val);
	plt = (struct plt_entry *)plt_sec->shdr->sh_addr;		plt = (struct plt_entry *)plt_sec->shdr->sh_addr;
	plt[i] = emit_plt_entry(val);		plt[i] = emit_plt_entry(val, (u64)&plt[i], (u64)&got_plt[i]);

	plt_sec->num_entries++;		plt_sec->num_entries++;
			got_plt_sec->num_entries++;
	BUG_ON(plt_sec->num_entries > plt_sec->max_entries);		BUG_ON(plt_sec->num_entries > plt_sec->max_entries);

	return (u64)&plt[i];		return (u64)&plt[i];
	@@ -94,6 +99,8 @@ int module_frob_arch_sections(Elf_Ehdr ehdr, Elf_Shdr sechdrs,
	mod->arch.plt.shdr = sechdrs + i;		mod->arch.plt.shdr = sechdrs + i;
	else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got"))		else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got"))
	mod->arch.got.shdr = sechdrs + i;		mod->arch.got.shdr = sechdrs + i;
			else if (!strcmp(secstrings + sechdrs[i].sh_name, ".got.plt"))
			mod->arch.got_plt.shdr = sechdrs + i;
	}		}

	if (!mod->arch.plt.shdr) {		if (!mod->arch.plt.shdr) {
	@@ -104,6 +111,10 @@ int module_frob_arch_sections(Elf_Ehdr ehdr, Elf_Shdr sechdrs,
	pr_err("%s: module GOT section(s) missing\n", mod->name);		pr_err("%s: module GOT section(s) missing\n", mod->name);
	return -ENOEXEC;		return -ENOEXEC;
	}		}
			if (!mod->arch.got_plt.shdr) {
			pr_err("%s: module GOT.PLT section(s) missing\n", mod->name);
			return -ENOEXEC;
			}

	/* Calculate the maxinum number of entries */		/* Calculate the maxinum number of entries */
	for (i = 0; i < ehdr->e_shnum; i++) {		for (i = 0; i < ehdr->e_shnum; i++) {
	@@ -135,5 +146,11 @@ int module_frob_arch_sections(Elf_Ehdr ehdr, Elf_Shdr sechdrs,
	mod->arch.got.num_entries = 0;		mod->arch.got.num_entries = 0;
	mod->arch.got.max_entries = num_gots;		mod->arch.got.max_entries = num_gots;

			mod->arch.got_plt.shdr->sh_type = SHT_NOBITS;
			mod->arch.got_plt.shdr->sh_flags = SHF_ALLOC;
			mod->arch.got_plt.shdr->sh_addralign = L1_CACHE_BYTES;
			mod->arch.got_plt.shdr->sh_size = (num_plts + 1) * sizeof(struct got_entry);
			mod->arch.got_plt.num_entries = 0;
			mod->arch.got_plt.max_entries = num_plts;
	return 0;		return 0;
	}		}

arch/riscv/kernel/module.lds

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -4,4 +4,5 @@
	SECTIONS {		SECTIONS {
	.plt (NOLOAD) : { BYTE(0) }		.plt (NOLOAD) : { BYTE(0) }
	.got (NOLOAD) : { BYTE(0) }		.got (NOLOAD) : { BYTE(0) }
			.got.plt (NOLOAD) : { BYTE(0) }
	}		}