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author | H. Peter Anvin <hpa@zytor.com> | 2013-04-29 16:04:20 +0200 |
---|---|---|
committer | H. Peter Anvin <hpa@linux.intel.com> | 2013-06-06 23:32:04 +0200 |
commit | 60e019eb37a8d989031ad47ae9810453536f3127 (patch) | |
tree | c9db47f4c97862b46a2a1481d35e89ee9358ed6a /arch/x86/kernel | |
parent | Linux 3.10-rc4 (diff) | |
download | linux-60e019eb37a8d989031ad47ae9810453536f3127.tar.xz linux-60e019eb37a8d989031ad47ae9810453536f3127.zip |
x86: Get rid of ->hard_math and all the FPU asm fu
Reimplement FPU detection code in C and drop old, not-so-recommended
detection method in asm. Move all the relevant stuff into i387.c where
it conceptually belongs. Finally drop cpuinfo_x86.hard_math.
[ hpa: huge thanks to Borislav for taking my original concept patch
and productizing it ]
[ Boris, note to self: do not use static_cpu_has before alternatives! ]
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1367244262-29511-2-git-send-email-bp@alien8.de
Link: http://lkml.kernel.org/r/1365436666-9837-2-git-send-email-bp@alien8.de
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r-- | arch/x86/kernel/asm-offsets_32.c | 1 | ||||
-rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 21 | ||||
-rw-r--r-- | arch/x86/kernel/cpu/common.c | 3 | ||||
-rw-r--r-- | arch/x86/kernel/cpu/cyrix.c | 2 | ||||
-rw-r--r-- | arch/x86/kernel/cpu/proc.c | 4 | ||||
-rw-r--r-- | arch/x86/kernel/head_32.S | 21 | ||||
-rw-r--r-- | arch/x86/kernel/i387.c | 59 | ||||
-rw-r--r-- | arch/x86/kernel/xsave.c | 5 |
8 files changed, 56 insertions, 60 deletions
diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c index 0ef4bba2acb7..d67c4be3e8b1 100644 --- a/arch/x86/kernel/asm-offsets_32.c +++ b/arch/x86/kernel/asm-offsets_32.c @@ -28,7 +28,6 @@ void foo(void) OFFSET(CPUINFO_x86_vendor, cpuinfo_x86, x86_vendor); OFFSET(CPUINFO_x86_model, cpuinfo_x86, x86_model); OFFSET(CPUINFO_x86_mask, cpuinfo_x86, x86_mask); - OFFSET(CPUINFO_hard_math, cpuinfo_x86, hard_math); OFFSET(CPUINFO_cpuid_level, cpuinfo_x86, cpuid_level); OFFSET(CPUINFO_x86_capability, cpuinfo_x86, x86_capability); OFFSET(CPUINFO_x86_vendor_id, cpuinfo_x86, x86_vendor_id); diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 4112be9a4659..03445346ee0a 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -17,15 +17,6 @@ #include <asm/paravirt.h> #include <asm/alternative.h> -static int __init no_387(char *s) -{ - boot_cpu_data.hard_math = 0; - write_cr0(X86_CR0_TS | X86_CR0_EM | X86_CR0_MP | read_cr0()); - return 1; -} - -__setup("no387", no_387); - static double __initdata x = 4195835.0; static double __initdata y = 3145727.0; @@ -44,15 +35,6 @@ static void __init check_fpu(void) { s32 fdiv_bug; - if (!boot_cpu_data.hard_math) { -#ifndef CONFIG_MATH_EMULATION - pr_emerg("No coprocessor found and no math emulation present\n"); - pr_emerg("Giving up\n"); - for (;;) ; -#endif - return; - } - kernel_fpu_begin(); /* @@ -107,5 +89,6 @@ void __init check_bugs(void) * kernel_fpu_begin/end() in check_fpu() relies on the patched * alternative instructions. */ - check_fpu(); + if (cpu_has_fpu) + check_fpu(); } diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 22018f70a671..d4dd99350e9d 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -711,10 +711,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) return; cpu_detect(c); - get_cpu_vendor(c); - get_cpu_cap(c); + fpu_detect(c); if (this_cpu->c_early_init) this_cpu->c_early_init(c); diff --git a/arch/x86/kernel/cpu/cyrix.c b/arch/x86/kernel/cpu/cyrix.c index d048d5ca43c1..7582f475b163 100644 --- a/arch/x86/kernel/cpu/cyrix.c +++ b/arch/x86/kernel/cpu/cyrix.c @@ -333,7 +333,7 @@ static void __cpuinit init_cyrix(struct cpuinfo_x86 *c) switch (dir0_lsn) { case 0xd: /* either a 486SLC or DLC w/o DEVID */ dir0_msn = 0; - p = Cx486_name[(c->hard_math) ? 1 : 0]; + p = Cx486_name[(cpu_has_fpu ? 1 : 0)]; break; case 0xe: /* a 486S A step */ diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c index 37a198bd48c8..aee6317b902f 100644 --- a/arch/x86/kernel/cpu/proc.c +++ b/arch/x86/kernel/cpu/proc.c @@ -37,8 +37,8 @@ static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c) static_cpu_has_bug(X86_BUG_FDIV) ? "yes" : "no", static_cpu_has_bug(X86_BUG_F00F) ? "yes" : "no", static_cpu_has_bug(X86_BUG_COMA) ? "yes" : "no", - c->hard_math ? "yes" : "no", - c->hard_math ? "yes" : "no", + static_cpu_has(X86_FEATURE_FPU) ? "yes" : "no", + static_cpu_has(X86_FEATURE_FPU) ? "yes" : "no", c->cpuid_level, c->wp_works_ok ? "yes" : "no"); } diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 73afd11799ca..e65ddc62e113 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -444,7 +444,6 @@ is486: orl %ecx,%eax movl %eax,%cr0 - call check_x87 lgdt early_gdt_descr lidt idt_descr ljmp $(__KERNEL_CS),$1f @@ -467,26 +466,6 @@ is486: pushl $0 # fake return address for unwinder jmp *(initial_code) -/* - * We depend on ET to be correct. This checks for 287/387. - */ -check_x87: - movb $0,X86_HARD_MATH - clts - fninit - fstsw %ax - cmpb $0,%al - je 1f - movl %cr0,%eax /* no coprocessor: have to set bits */ - xorl $4,%eax /* set EM */ - movl %eax,%cr0 - ret - ALIGN -1: movb $1,X86_HARD_MATH - .byte 0xDB,0xE4 /* fsetpm for 287, ignored by 387 */ - ret - - #include "verify_cpu.S" /* diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index cb339097b9ea..b627746f6b1a 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -131,7 +131,7 @@ static void __cpuinit init_thread_xstate(void) * xsave_init(). */ - if (!HAVE_HWFP) { + if (!cpu_has_fpu) { /* * Disable xsave as we do not support it if i387 * emulation is enabled. @@ -158,6 +158,14 @@ void __cpuinit fpu_init(void) unsigned long cr0; unsigned long cr4_mask = 0; +#ifndef CONFIG_MATH_EMULATION + if (!cpu_has_fpu) { + pr_emerg("No FPU found and no math emulation present\n"); + pr_emerg("Giving up\n"); + for (;;) + asm volatile("hlt"); + } +#endif if (cpu_has_fxsr) cr4_mask |= X86_CR4_OSFXSR; if (cpu_has_xmm) @@ -167,7 +175,7 @@ void __cpuinit fpu_init(void) cr0 = read_cr0(); cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */ - if (!HAVE_HWFP) + if (!cpu_has_fpu) cr0 |= X86_CR0_EM; write_cr0(cr0); @@ -185,7 +193,7 @@ void __cpuinit fpu_init(void) void fpu_finit(struct fpu *fpu) { - if (!HAVE_HWFP) { + if (!cpu_has_fpu) { finit_soft_fpu(&fpu->state->soft); return; } @@ -214,7 +222,7 @@ int init_fpu(struct task_struct *tsk) int ret; if (tsk_used_math(tsk)) { - if (HAVE_HWFP && tsk == current) + if (cpu_has_fpu && tsk == current) unlazy_fpu(tsk); tsk->thread.fpu.last_cpu = ~0; return 0; @@ -511,14 +519,13 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, if (ret) return ret; - if (!HAVE_HWFP) + if (!static_cpu_has(X86_FEATURE_FPU)) return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf); - if (!cpu_has_fxsr) { + if (!cpu_has_fxsr) return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &target->thread.fpu.state->fsave, 0, -1); - } sanitize_i387_state(target); @@ -545,13 +552,13 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, sanitize_i387_state(target); - if (!HAVE_HWFP) + if (!static_cpu_has(X86_FEATURE_FPU)) return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf); - if (!cpu_has_fxsr) { + if (!cpu_has_fxsr) return user_regset_copyin(&pos, &count, &kbuf, &ubuf, - &target->thread.fpu.state->fsave, 0, -1); - } + &target->thread.fpu.state->fsave, 0, + -1); if (pos > 0 || count < sizeof(env)) convert_from_fxsr(&env, target); @@ -592,3 +599,33 @@ int dump_fpu(struct pt_regs *regs, struct user_i387_struct *fpu) EXPORT_SYMBOL(dump_fpu); #endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */ + +static int __init no_387(char *s) +{ + setup_clear_cpu_cap(X86_FEATURE_FPU); + return 1; +} + +__setup("no387", no_387); + +void __cpuinit fpu_detect(struct cpuinfo_x86 *c) +{ + unsigned long cr0; + u16 fsw, fcw; + + fsw = fcw = 0xffff; + + cr0 = read_cr0(); + cr0 &= ~(X86_CR0_TS | X86_CR0_EM); + write_cr0(cr0); + + asm volatile("fninit ; fnstsw %0 ; fnstcw %1" + : "+m" (fsw), "+m" (fcw)); + + if (fsw == 0 && (fcw & 0x103f) == 0x003f) + set_cpu_cap(c, X86_FEATURE_FPU); + else + clear_cpu_cap(c, X86_FEATURE_FPU); + + /* The final cr0 value is set in fpu_init() */ +} diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index ada87a329edc..d6c28acdf99c 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -243,7 +243,7 @@ int save_xstate_sig(void __user *buf, void __user *buf_fx, int size) if (!access_ok(VERIFY_WRITE, buf, size)) return -EACCES; - if (!HAVE_HWFP) + if (!static_cpu_has(X86_FEATURE_FPU)) return fpregs_soft_get(current, NULL, 0, sizeof(struct user_i387_ia32_struct), NULL, (struct _fpstate_ia32 __user *) buf) ? -1 : 1; @@ -350,11 +350,10 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size) if (!used_math() && init_fpu(tsk)) return -1; - if (!HAVE_HWFP) { + if (!static_cpu_has(X86_FEATURE_FPU)) return fpregs_soft_set(current, NULL, 0, sizeof(struct user_i387_ia32_struct), NULL, buf) != 0; - } if (use_xsave()) { struct _fpx_sw_bytes fx_sw_user; |