check_fpu() currently relies on being called early in the init sequence, when CR0::TS has not been set up yet.
Save/restore CR0::TS across this function, to make it invariant to init ordering. This way we'll be able to move the generic FPU setup routines earlier in the init sequence. Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Fenghua Yu <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Thomas Gleixner <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/kernel/fpu/bugs.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kernel/fpu/bugs.c b/arch/x86/kernel/fpu/bugs.c index 400a3d713fb2..449b5f3f4925 100644 --- a/arch/x86/kernel/fpu/bugs.c +++ b/arch/x86/kernel/fpu/bugs.c @@ -23,8 +23,13 @@ static double __initdata y = 3145727.0; */ static void __init check_fpu(void) { + u32 cr0_saved; s32 fdiv_bug; + /* We might have CR0::TS set already, clear it: */ + cr0_saved = read_cr0(); + write_cr0(cr0_saved & ~X86_CR0_TS); + kernel_fpu_begin(); /* @@ -47,6 +52,8 @@ static void __init check_fpu(void) kernel_fpu_end(); + write_cr0(cr0_saved); + if (fdiv_bug) { set_cpu_bug(&boot_cpu_data, X86_BUG_FDIV); pr_warn("Hmm, FPU with FDIV bug\n"); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
