diff options
author | Zong Li <zong@andestech.com> | 2018-03-15 16:50:42 +0800 |
---|---|---|
committer | Palmer Dabbelt <palmer@sifive.com> | 2018-04-02 20:00:54 -0700 |
commit | b8bde0ef12bd43f013d879973a1900930bfb95ee (patch) | |
tree | 953afd76c9ed57a34ed2ee3c042c4e061bc9d5dc /arch/riscv/include | |
parent | ab1ef68e54019937cf859f2c86c9ead6f3e62f19 (diff) | |
download | linux-b8bde0ef12bd43f013d879973a1900930bfb95ee.tar.bz2 |
RISC-V: Add section of GOT.PLT for kernel module
Separate the function symbol address from .plt to .got.plt section.
The original plt entry has trampoline code with symbol address,
there is a 32-bit padding bwtween jar instruction and symbol address.
Extract the symbol address to .got.plt to reduce the module size.
Signed-off-by: Zong Li <zong@andestech.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv/include')
-rw-r--r-- | arch/riscv/include/asm/module.h | 40 |
1 files changed, 25 insertions, 15 deletions
diff --git a/arch/riscv/include/asm/module.h b/arch/riscv/include/asm/module.h index e61d73f82d4d..349df33808c4 100644 --- a/arch/riscv/include/asm/module.h +++ b/arch/riscv/include/asm/module.h @@ -21,6 +21,7 @@ struct mod_section { struct mod_arch_specific { struct mod_section got; struct mod_section plt; + struct mod_section got_plt; }; struct got_entry { @@ -48,13 +49,10 @@ struct plt_entry { /* * Trampoline code to real target address. The return address * 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_ld; /* ld t1, 0x10(t0) */ u32 insn_jr; /* jr t1 */ - u64 symbol_addr; /* the real jump target address */ }; #define OPC_AUIPC 0x0017 @@ -62,9 +60,8 @@ struct plt_entry { #define OPC_JALR 0x0067 #define REG_T0 0x5 #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: @@ -78,24 +75,37 @@ 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) { - OPC_AUIPC | (REG_T0 << 7), - OPC_LD | (IMM_OFFSET << 20) | (REG_T0 << 15) | (REG_T1 << 7), - OPC_JALR | (REG_T1 << 15), - val + OPC_AUIPC | (REG_T0 << 7) | hi20, + OPC_LD | (lo12 << 20) | (REG_T0 << 15) | (REG_T1 << 7), + OPC_JALR | (REG_T1 << 15) }; } -static inline struct plt_entry *get_plt_entry(u64 val, - const struct mod_section *sec) +static inline int get_got_plt_idx(u64 val, 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; for (i = 0; i < sec->num_entries; i++) { - if (plt[i].symbol_addr == val) - return &plt[i]; + if (got_plt[i].symbol_addr == val) + return i; } - return NULL; + 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; } #endif /* CONFIG_MODULE_SECTIONS */ |