| Message ID | 1683717018-12882-1-git-send-email-lixiaoyun@binary-semi.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Palmer Dabbelt |
| Headers | show |
| Series | riscv: optimize ELF relocation function in riscv | expand |
Hey Amma, The patchwork automation seems to have skipped this patch for some reason, so here I am doing it manually instead! On Wed, May 10, 2023 at 07:10:18PM +0800, Amma.Lee wrote: > The patch can optimize the running times of "insmod" command by modify ELF > relocation function. > In the riscv kernel, when install the ELF driver which contains multiple > symbol table items to be relocated, kernel takes a lot of time to > execute the relocation. For example, we install a 3+MB driver need 180+s. > > We focus on the riscv kernel handle R_RISCV_HI20 and R_RISCV_LO12 type > items relocation function and find that there are two for-loops in this > function. If we modify the begin number in the second for-loops iteration, > we could save significant time for installation. We install the 3+MB > driver could just need 2s. > > Signed-off-by: Amma.Lee<lixiaoyun@binary-semi.com> Firstly, please remove the . between your names, and add a space before the <. `git commit -s` will automagically add a SoB FYI. When I applied this patch I got: Applying: riscv: optimize ELF relocation function in riscv warning: arch/riscv/kernel/module.c has type 100644, expected 100755 There are also quite a lot of checkpatch coding-style issues: | 65: CHECK: Lines should not end with a '(' | 71: CHECK: Please don't use multiple blank lines | 78: CHECK: Please don't use multiple blank lines | 81: CHECK: Logical continuations should be on the previous line | 82: CHECK: Logical continuations should be on the previous line | 91: CHECK: Please don't use multiple blank lines | 95: WARNING: Too many leading tabs - consider code refactoring | 96: CHECK: Logical continuations should be on the previous line | 97: CHECK: Lines should not end with a '(' | 101: CHECK: Blank lines aren't necessary before a close brace '}' | 111: CHECK: Lines should not end with a '(' | 117: CHECK: Please don't use multiple blank lines | total: 0 errors, 1 warnings, 11 checks, 93 lines checked Hopefully you get some comments on the code itself, and when you resend, the automation does actually pick it up. Thanks, Conor.
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c index 7c651d5..55507b0 100755 --- a/arch/riscv/kernel/module.c +++ b/arch/riscv/kernel/module.c @@ -345,13 +345,13 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, int (*handler)(struct module *me, u32 *location, Elf_Addr v); Elf_Sym *sym; u32 *location; - unsigned int i, type; + unsigned int i, type, j_idx; Elf_Addr v; int res; pr_debug("Applying relocate section %u to %u\n", relsec, sechdrs[relsec].sh_info); - + j_idx = 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 @@ -385,8 +385,9 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) { unsigned int j; - - for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) { + /*Modify the j for-loops begin number from last iterates end value*/ + for (j = j_idx; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) { + /* Modify end */ unsigned long hi20_loc = sechdrs[sechdrs[relsec].sh_info].sh_addr + rel[j].r_offset; @@ -420,11 +421,63 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, } } if (j == sechdrs[relsec].sh_size / sizeof(*rel)) { - pr_err( - "%s: Can not find HI20 relocation information\n", - me->name); - return -EINVAL; + if (j_idx == 0) { + pr_err( + "%s: Can not find HI20 relocation information\n", + me->name); + return -EINVAL; + } + + + for (j = 0; j < j_idx; j++) { + unsigned long hi20_loc = + sechdrs[sechdrs[relsec].sh_info].sh_addr + + rel[j].r_offset; + u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info); + + + /* Find the corresponding HI20 relocation entry */ + if (hi20_loc == sym->st_value + && (hi20_type == R_RISCV_PCREL_HI20 + || hi20_type == R_RISCV_GOT_HI20)) { + s32 hi20, lo12; + Elf_Sym *hi20_sym = + (Elf_Sym *)sechdrs[symindex].sh_addr + + ELF_RISCV_R_SYM(rel[j].r_info); + unsigned long hi20_sym_val = + hi20_sym->st_value + + rel[j].r_addend; + + + /* Calculate lo12 */ + size_t offset = hi20_sym_val - hi20_loc; + /* Calculate lo12 */ + if (IS_ENABLED(CONFIG_MODULE_SECTIONS) + && hi20_type == R_RISCV_GOT_HI20) { + offset = module_emit_got_entry( + me, hi20_sym_val); + offset = offset - hi20_loc; + + } + hi20 = (offset + 0x800) & 0xfffff000; + lo12 = offset - hi20; + v = lo12; + + break; + } + } + + if (j == j_idx) { + pr_err( + "%s: Can not find HI20 relocation information\n", + me->name); + return -EINVAL; + } + + } + + j_idx = j; } res = handler(me, location, v);
The patch can optimize the running times of "insmod" command by modify ELF relocation function. In the riscv kernel, when install the ELF driver which contains multiple symbol table items to be relocated, kernel takes a lot of time to execute the relocation. For example, we install a 3+MB driver need 180+s. We focus on the riscv kernel handle R_RISCV_HI20 and R_RISCV_LO12 type items relocation function and find that there are two for-loops in this function. If we modify the begin number in the second for-loops iteration, we could save significant time for installation. We install the 3+MB driver could just need 2s. Signed-off-by: Amma.Lee<lixiaoyun@binary-semi.com> --- arch/riscv/kernel/module.c | 69 ++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 61 insertions(+), 8 deletions(-)