diff options
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 97 | ||||
| -rw-r--r-- | arch/x86/kernel/process.c | 10 |
2 files changed, 99 insertions, 8 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 3d38558d594f..db0bfc2db8bf 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -12,6 +12,7 @@ #include <linux/pkeys.h> #include <linux/seq_file.h> #include <linux/proc_fs.h> +#include <linux/vmalloc.h> #include <asm/fpu/api.h> #include <asm/fpu/regset.h> @@ -22,6 +23,7 @@ #include <asm/prctl.h> #include <asm/elf.h> +#include "context.h" #include "internal.h" #include "legacy.h" #include "xstate.h" @@ -1371,6 +1373,91 @@ void xfd_validate_state(struct fpstate *fpstate, u64 mask, bool rstor) } #endif /* CONFIG_X86_DEBUG_FPU */ +void fpstate_free(struct fpu *fpu) +{ + if (fpu->fpstate || fpu->fpstate != &fpu->__fpstate) + vfree(fpu->fpstate); +} + +/** + * fpu_install_fpstate - Update the active fpstate in the FPU + * + * @fpu: A struct fpu * pointer + * @newfps: A struct fpstate * pointer + * + * Returns: A null pointer if the last active fpstate is the embedded + * one or the new fpstate is already installed; + * otherwise, a pointer to the old fpstate which has to + * be freed by the caller. + */ +static struct fpstate *fpu_install_fpstate(struct fpu *fpu, + struct fpstate *newfps) +{ + struct fpstate *oldfps = fpu->fpstate; + + if (fpu->fpstate == newfps) + return NULL; + + fpu->fpstate = newfps; + return oldfps != &fpu->__fpstate ? oldfps : NULL; +} + +/** + * fpstate_realloc - Reallocate struct fpstate for the requested new features + * + * @xfeatures: A bitmap of xstate features which extend the enabled features + * of that task + * @ksize: The required size for the kernel buffer + * @usize: The required size for user space buffers + * + * Note vs. vmalloc(): If the task with a vzalloc()-allocated buffer + * terminates quickly, vfree()-induced IPIs may be a concern, but tasks + * with large states are likely to live longer. + * + * Returns: 0 on success, -ENOMEM on allocation error. + */ +static int fpstate_realloc(u64 xfeatures, unsigned int ksize, + unsigned int usize) +{ + struct fpu *fpu = ¤t->thread.fpu; + struct fpstate *curfps, *newfps = NULL; + unsigned int fpsize; + + curfps = fpu->fpstate; + fpsize = ksize + ALIGN(offsetof(struct fpstate, regs), 64); + + newfps = vzalloc(fpsize); + if (!newfps) + return -ENOMEM; + newfps->size = ksize; + newfps->user_size = usize; + newfps->is_valloc = true; + + fpregs_lock(); + /* + * Ensure that the current state is in the registers before + * swapping fpstate as that might invalidate it due to layout + * changes. + */ + if (test_thread_flag(TIF_NEED_FPU_LOAD)) + fpregs_restore_userregs(); + + newfps->xfeatures = curfps->xfeatures | xfeatures; + newfps->user_xfeatures = curfps->user_xfeatures | xfeatures; + newfps->xfd = curfps->xfd & ~xfeatures; + + curfps = fpu_install_fpstate(fpu, newfps); + + /* Do the final updates within the locked region */ + xstate_init_xcomp_bv(&newfps->regs.xsave, newfps->xfeatures); + xfd_update_state(newfps); + + fpregs_unlock(); + + vfree(curfps); + return 0; +} + static int validate_sigaltstack(unsigned int usize) { struct task_struct *thread, *leader = current->group_leader; @@ -1393,7 +1480,8 @@ static int __xstate_request_perm(u64 permitted, u64 requested) /* * This deliberately does not exclude !XSAVES as we still might * decide to optionally context switch XCR0 or talk the silicon - * vendors into extending XFD for the pre AMX states. + * vendors into extending XFD for the pre AMX states, especially + * AVX512. */ bool compacted = cpu_feature_enabled(X86_FEATURE_XSAVES); struct fpu *fpu = ¤t->group_leader->thread.fpu; @@ -1465,13 +1553,6 @@ static int xstate_request_perm(unsigned long idx) return ret; } -/* Place holder for now */ -static int fpstate_realloc(u64 xfeatures, unsigned int ksize, - unsigned int usize) -{ - return -ENOMEM; -} - int xfd_enable_feature(u64 xfd_err) { u64 xfd_event = xfd_err & XFEATURE_MASK_USER_DYNAMIC; diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 99025e32f105..f3f251787b99 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -32,6 +32,7 @@ #include <asm/mwait.h> #include <asm/fpu/api.h> #include <asm/fpu/sched.h> +#include <asm/fpu/xstate.h> #include <asm/debugreg.h> #include <asm/nmi.h> #include <asm/tlbflush.h> @@ -90,9 +91,18 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) #endif /* Drop the copied pointer to current's fpstate */ dst->thread.fpu.fpstate = NULL; + return 0; } +#ifdef CONFIG_X86_64 +void arch_release_task_struct(struct task_struct *tsk) +{ + if (fpu_state_size_dynamic()) + fpstate_free(&tsk->thread.fpu); +} +#endif + /* * Free thread data structures etc.. */ |