diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug index 88a9f433f6fc3ca7affc6c9a011622d26e10ada9..3a2b775e845893513e2ab187ca95955e0be17848 100644 --- a/arch/mips/Kconfig.debug +++ b/arch/mips/Kconfig.debug @@ -122,17 +122,4 @@ config SPINLOCK_TEST help Add several files to the debugfs to test spinlock speed. -config FP32XX_HYBRID_FPRS - bool "Run FP32 & FPXX code with hybrid FPRs" - depends on MIPS_O32_FP64_SUPPORT - help - The hybrid FPR scheme is normally used only when a program needs to - execute a mix of FP32 & FP64A code, since the trapping & emulation - that it entails is expensive. When enabled, this option will lead - to the kernel running programs which use the FP32 & FPXX FP ABIs - using the hybrid FPR scheme, which can be useful for debugging - purposes. - - If unsure, say N. - endmenu diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h index eb4d95de619c5dca7543ed551267e43799f4ca11..535f196ffe02da7ad769ab0b7053b4dd5253dd82 100644 --- a/arch/mips/include/asm/elf.h +++ b/arch/mips/include/asm/elf.h @@ -417,13 +417,15 @@ extern unsigned long arch_randomize_brk(struct mm_struct *mm); struct arch_elf_state { int fp_abi; int interp_fp_abi; - int overall_abi; + int overall_fp_mode; }; +#define MIPS_ABI_FP_UNKNOWN (-1) /* Unknown FP ABI (kernel internal) */ + #define INIT_ARCH_ELF_STATE { \ - .fp_abi = -1, \ - .interp_fp_abi = -1, \ - .overall_abi = -1, \ + .fp_abi = MIPS_ABI_FP_UNKNOWN, \ + .interp_fp_abi = MIPS_ABI_FP_UNKNOWN, \ + .overall_fp_mode = -1, \ } extern int arch_elf_pt_proc(void *ehdr, void *phdr, struct file *elf, diff --git a/arch/mips/kernel/elf.c b/arch/mips/kernel/elf.c index c92b15df6893f555549bf3cc51bf6c39f78e1875..d2c09f6475c5cb5454b34ed1c498d43fdc31b29e 100644 --- a/arch/mips/kernel/elf.c +++ b/arch/mips/kernel/elf.c @@ -11,29 +11,112 @@ #include #include +/* FPU modes */ enum { - FP_ERROR = -1, - FP_DOUBLE_64A = -2, + FP_FRE, + FP_FR0, + FP_FR1, }; +/** + * struct mode_req - ABI FPU mode requirements + * @single: The program being loaded needs an FPU but it will only issue + * single precision instructions meaning that it can execute in + * either FR0 or FR1. + * @soft: The soft(-float) requirement means that the program being + * loaded needs has no FPU dependency at all (i.e. it has no + * FPU instructions). + * @fr1: The program being loaded depends on FPU being in FR=1 mode. + * @frdefault: The program being loaded depends on the default FPU mode. + * That is FR0 for O32 and FR1 for N32/N64. + * @fre: The program being loaded depends on FPU with FRE=1. This mode is + * a bridge which uses FR=1 whilst still being able to maintain + * full compatibility with pre-existing code using the O32 FP32 + * ABI. + * + * More information about the FP ABIs can be found here: + * + * https://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking#10.4.1._Basic_mode_set-up + * + */ + +struct mode_req { + bool single; + bool soft; + bool fr1; + bool frdefault; + bool fre; +}; + +static const struct mode_req fpu_reqs[] = { + [MIPS_ABI_FP_ANY] = { true, true, true, true, true }, + [MIPS_ABI_FP_DOUBLE] = { false, false, false, true, true }, + [MIPS_ABI_FP_SINGLE] = { true, false, false, false, false }, + [MIPS_ABI_FP_SOFT] = { false, true, false, false, false }, + [MIPS_ABI_FP_OLD_64] = { false, false, false, false, false }, + [MIPS_ABI_FP_XX] = { false, false, true, true, true }, + [MIPS_ABI_FP_64] = { false, false, true, false, false }, + [MIPS_ABI_FP_64A] = { false, false, true, false, true } +}; + +/* + * Mode requirements when .MIPS.abiflags is not present in the ELF. + * Not present means that everything is acceptable except FR1. + */ +static struct mode_req none_req = { true, true, false, true, true }; + int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf, bool is_interp, struct arch_elf_state *state) { - struct elfhdr *ehdr = _ehdr; - struct elf_phdr *phdr = _phdr; + struct elf32_hdr *ehdr32 = _ehdr; + struct elf32_phdr *phdr32 = _phdr; + struct elf64_phdr *phdr64 = _phdr; struct mips_elf_abiflags_v0 abiflags; int ret; - if (config_enabled(CONFIG_64BIT) && - (ehdr->e_ident[EI_CLASS] != ELFCLASS32)) - return 0; - if (phdr->p_type != PT_MIPS_ABIFLAGS) - return 0; - if (phdr->p_filesz < sizeof(abiflags)) - return -EINVAL; + /* Lets see if this is an O32 ELF */ + if (ehdr32->e_ident[EI_CLASS] == ELFCLASS32) { + /* FR = 1 for N32 */ + if (ehdr32->e_flags & EF_MIPS_ABI2) + state->overall_fp_mode = FP_FR1; + else + /* Set a good default FPU mode for O32 */ + state->overall_fp_mode = cpu_has_mips_r6 ? + FP_FRE : FP_FR0; + + if (ehdr32->e_flags & EF_MIPS_FP64) { + /* + * Set MIPS_ABI_FP_OLD_64 for EF_MIPS_FP64. We will override it + * later if needed + */ + if (is_interp) + state->interp_fp_abi = MIPS_ABI_FP_OLD_64; + else + state->fp_abi = MIPS_ABI_FP_OLD_64; + } + if (phdr32->p_type != PT_MIPS_ABIFLAGS) + return 0; + + if (phdr32->p_filesz < sizeof(abiflags)) + return -EINVAL; + + ret = kernel_read(elf, phdr32->p_offset, + (char *)&abiflags, + sizeof(abiflags)); + } else { + /* FR=1 is really the only option for 64-bit */ + state->overall_fp_mode = FP_FR1; + + if (phdr64->p_type != PT_MIPS_ABIFLAGS) + return 0; + if (phdr64->p_filesz < sizeof(abiflags)) + return -EINVAL; + + ret = kernel_read(elf, phdr64->p_offset, + (char *)&abiflags, + sizeof(abiflags)); + } - ret = kernel_read(elf, phdr->p_offset, (char *)&abiflags, - sizeof(abiflags)); if (ret < 0) return ret; if (ret != sizeof(abiflags)) @@ -48,35 +131,30 @@ int arch_elf_pt_proc(void *_ehdr, void *_phdr, struct file *elf, return 0; } -static inline unsigned get_fp_abi(struct elfhdr *ehdr, int in_abi) +static inline unsigned get_fp_abi(int in_abi) { /* If the ABI requirement is provided, simply return that */ - if (in_abi != -1) + if (in_abi != MIPS_ABI_FP_UNKNOWN) return in_abi; - /* If the EF_MIPS_FP64 flag was set, return MIPS_ABI_FP_64 */ - if (ehdr->e_flags & EF_MIPS_FP64) - return MIPS_ABI_FP_64; - - /* Default to MIPS_ABI_FP_DOUBLE */ - return MIPS_ABI_FP_DOUBLE; + /* Unknown ABI */ + return MIPS_ABI_FP_UNKNOWN; } int arch_check_elf(void *_ehdr, bool has_interpreter, struct arch_elf_state *state) { - struct elfhdr *ehdr = _ehdr; - unsigned fp_abi, interp_fp_abi, abi0, abi1; + struct elf32_hdr *ehdr = _ehdr; + struct mode_req prog_req, interp_req; + int fp_abi, interp_fp_abi, abi0, abi1, max_abi; - /* Ignore non-O32 binaries */ - if (config_enabled(CONFIG_64BIT) && - (ehdr->e_ident[EI_CLASS] != ELFCLASS32)) + if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT)) return 0; - fp_abi = get_fp_abi(ehdr, state->fp_abi); + fp_abi = get_fp_abi(state->fp_abi); if (has_interpreter) { - interp_fp_abi = get_fp_abi(ehdr, state->interp_fp_abi); + interp_fp_abi = get_fp_abi(state->interp_fp_abi); abi0 = min(fp_abi, interp_fp_abi); abi1 = max(fp_abi, interp_fp_abi); @@ -84,108 +162,103 @@ int arch_check_elf(void *_ehdr, bool has_interpreter, abi0 = abi1 = fp_abi; } - state->overall_abi = FP_ERROR; - - if (abi0 == abi1) { - state->overall_abi = abi0; - } else if (abi0 == MIPS_ABI_FP_ANY) { - state->overall_abi = abi1; - } else if (abi0 == MIPS_ABI_FP_DOUBLE) { - switch (abi1) { - case MIPS_ABI_FP_XX: - state->overall_abi = MIPS_ABI_FP_DOUBLE; - break; - - case MIPS_ABI_FP_64A: - state->overall_abi = FP_DOUBLE_64A; - break; - } - } else if (abi0 == MIPS_ABI_FP_SINGLE || - abi0 == MIPS_ABI_FP_SOFT) { - /* Cannot link with other ABIs */ - } else if (abi0 == MIPS_ABI_FP_OLD_64) { - switch (abi1) { - case MIPS_ABI_FP_XX: - case MIPS_ABI_FP_64: - case MIPS_ABI_FP_64A: - state->overall_abi = MIPS_ABI_FP_64; - break; - } - } else if (abi0 == MIPS_ABI_FP_XX || - abi0 == MIPS_ABI_FP_64 || - abi0 == MIPS_ABI_FP_64A) { - state->overall_abi = MIPS_ABI_FP_64; - } + /* ABI limits. O32 = FP_64A, N32/N64 = FP_SOFT */ + max_abi = ((ehdr->e_ident[EI_CLASS] == ELFCLASS32) && + (!(ehdr->e_flags & EF_MIPS_ABI2))) ? + MIPS_ABI_FP_64A : MIPS_ABI_FP_SOFT; - switch (state->overall_abi) { - case MIPS_ABI_FP_64: - case MIPS_ABI_FP_64A: - case FP_DOUBLE_64A: - if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT)) - return -ELIBBAD; - break; + if ((abi0 > max_abi && abi0 != MIPS_ABI_FP_UNKNOWN) || + (abi1 > max_abi && abi1 != MIPS_ABI_FP_UNKNOWN)) + return -ELIBBAD; + + /* It's time to determine the FPU mode requirements */ + prog_req = (abi0 == MIPS_ABI_FP_UNKNOWN) ? none_req : fpu_reqs[abi0]; + interp_req = (abi1 == MIPS_ABI_FP_UNKNOWN) ? none_req : fpu_reqs[abi1]; - case FP_ERROR: + /* + * Check whether the program's and interp's ABIs have a matching FPU + * mode requirement. + */ + prog_req.single = interp_req.single && prog_req.single; + prog_req.soft = interp_req.soft && prog_req.soft; + prog_req.fr1 = interp_req.fr1 && prog_req.fr1; + prog_req.frdefault = interp_req.frdefault && prog_req.frdefault; + prog_req.fre = interp_req.fre && prog_req.fre; + + /* + * Determine the desired FPU mode + * + * Decision making: + * + * - We want FR_FRE if FRE=1 and both FR=1 and FR=0 are false. This + * means that we have a combination of program and interpreter + * that inherently require the hybrid FP mode. + * - If FR1 and FRDEFAULT is true, that means we hit the any-abi or + * fpxx case. This is because, in any-ABI (or no-ABI) we have no FPU + * instructions so we don't care about the mode. We will simply use + * the one preferred by the hardware. In fpxx case, that ABI can + * handle both FR=1 and FR=0, so, again, we simply choose the one + * preferred by the hardware. Next, if we only use single-precision + * FPU instructions, and the default ABI FPU mode is not good + * (ie single + any ABI combination), we set again the FPU mode to the + * one is preferred by the hardware. Next, if we know that the code + * will only use single-precision instructions, shown by single being + * true but frdefault being false, then we again set the FPU mode to + * the one that is preferred by the hardware. + * - We want FP_FR1 if that's the only matching mode and the default one + * is not good. + * - Return with -ELIBADD if we can't find a matching FPU mode. + */ + if (prog_req.fre && !prog_req.frdefault && !prog_req.fr1) + state->overall_fp_mode = FP_FRE; + else if ((prog_req.fr1 && prog_req.frdefault) || + (prog_req.single && !prog_req.frdefault)) + /* Make sure 64-bit MIPS III/IV/64R1 will not pick FR1 */ + state->overall_fp_mode = ((current_cpu_data.fpu_id & MIPS_FPIR_F64) && + cpu_has_mips_r2_r6) ? + FP_FR1 : FP_FR0; + else if (prog_req.fr1) + state->overall_fp_mode = FP_FR1; + else if (!prog_req.fre && !prog_req.frdefault && + !prog_req.fr1 && !prog_req.single && !prog_req.soft) return -ELIBBAD; - } return 0; } -void mips_set_personality_fp(struct arch_elf_state *state) +static inline void set_thread_fp_mode(int hybrid, int regs32) { - if (config_enabled(CONFIG_FP32XX_HYBRID_FPRS)) { - /* - * Use hybrid FPRs for all code which can correctly execute - * with that mode. - */ - switch (state->overall_abi) { - case MIPS_ABI_FP_DOUBLE: - case MIPS_ABI_FP_SINGLE: - case MIPS_ABI_FP_SOFT: - case MIPS_ABI_FP_XX: - case MIPS_ABI_FP_ANY: - /* FR=1, FRE=1 */ - clear_thread_flag(TIF_32BIT_FPREGS); - set_thread_flag(TIF_HYBRID_FPREGS); - return; - } - } - - switch (state->overall_abi) { - case MIPS_ABI_FP_DOUBLE: - case MIPS_ABI_FP_SINGLE: - case MIPS_ABI_FP_SOFT: - /* FR=0 */ - set_thread_flag(TIF_32BIT_FPREGS); + if (hybrid) + set_thread_flag(TIF_HYBRID_FPREGS); + else clear_thread_flag(TIF_HYBRID_FPREGS); - break; - - case FP_DOUBLE_64A: - /* FR=1, FRE=1 */ + if (regs32) + set_thread_flag(TIF_32BIT_FPREGS); + else clear_thread_flag(TIF_32BIT_FPREGS); - set_thread_flag(TIF_HYBRID_FPREGS); - break; +} - case MIPS_ABI_FP_64: - case MIPS_ABI_FP_64A: - /* FR=1, FRE=0 */ - clear_thread_flag(TIF_32BIT_FPREGS); - clear_thread_flag(TIF_HYBRID_FPREGS); - break; +void mips_set_personality_fp(struct arch_elf_state *state) +{ + /* + * This function is only ever called for O32 ELFs so we should + * not be worried about N32/N64 binaries. + */ - case MIPS_ABI_FP_XX: - case MIPS_ABI_FP_ANY: - if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT)) - set_thread_flag(TIF_32BIT_FPREGS); - else - clear_thread_flag(TIF_32BIT_FPREGS); + if (!config_enabled(CONFIG_MIPS_O32_FP64_SUPPORT)) + return; - clear_thread_flag(TIF_HYBRID_FPREGS); + switch (state->overall_fp_mode) { + case FP_FRE: + set_thread_fp_mode(1, 0); + break; + case FP_FR0: + set_thread_fp_mode(0, 1); + break; + case FP_FR1: + set_thread_fp_mode(0, 0); break; - default: - case FP_ERROR: BUG(); } }