x86/fpu: Convert fpstate_init() to struct fpstate

Convert fpstate_init() and related code to the new register storage
mechanism in preparation for dynamically sized buffers.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145322.292157401@linutronix.de

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index d764311..19e14b5 100644 (file)
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -29,7 +29,7 @@
  * Represents the initial FPU state. It's mostly (but not completely) zeroes,
  * depending on the FPU hardware format:
  */
-union fpregs_state init_fpstate __ro_after_init;
+struct fpstate init_fpstate __ro_after_init;
 
 /*
  * Track whether the kernel is using the FPU state
@@ -157,7 +157,7 @@ void restore_fpregs_from_fpstate(union fpregs_state *fpstate, u64 mask)
 
 void fpu_reset_from_exception_fixup(void)
 {
-       restore_fpregs_from_fpstate(&init_fpstate, xfeatures_mask_fpstate());
+       restore_fpregs_from_fpstate(&init_fpstate.regs, xfeatures_mask_fpstate());
 }
 
 #if IS_ENABLED(CONFIG_KVM)
@@ -297,24 +297,24 @@ static inline unsigned int init_fpstate_copy_size(void)
                return fpu_kernel_xstate_size;
 
        /* XSAVE(S) just needs the legacy and the xstate header part */
-       return sizeof(init_fpstate.xsave);
+       return sizeof(init_fpstate.regs.xsave);
 }
 
-static inline void fpstate_init_fxstate(struct fxregs_state *fx)
+static inline void fpstate_init_fxstate(struct fpstate *fpstate)
 {
-       fx->cwd = 0x37f;
-       fx->mxcsr = MXCSR_DEFAULT;
+       fpstate->regs.fxsave.cwd = 0x37f;
+       fpstate->regs.fxsave.mxcsr = MXCSR_DEFAULT;
 }
 
 /*
  * Legacy x87 fpstate state init:
  */
-static inline void fpstate_init_fstate(struct fregs_state *fp)
+static inline void fpstate_init_fstate(struct fpstate *fpstate)
 {
-       fp->cwd = 0xffff037fu;
-       fp->swd = 0xffff0000u;
-       fp->twd = 0xffffffffu;
-       fp->fos = 0xffff0000u;
+       fpstate->regs.fsave.cwd = 0xffff037fu;
+       fpstate->regs.fsave.swd = 0xffff0000u;
+       fpstate->regs.fsave.twd = 0xffffffffu;
+       fpstate->regs.fsave.fos = 0xffff0000u;
 }
 
 /*
@@ -322,19 +322,19 @@ static inline void fpstate_init_fstate(struct fregs_state *fp)
  * 1) Early boot to setup init_fpstate for non XSAVE systems
  * 2) fpu_init_fpstate_user() which is invoked from KVM
  */
-void fpstate_init_user(union fpregs_state *state)
+void fpstate_init_user(struct fpstate *fpstate)
 {
        if (!cpu_feature_enabled(X86_FEATURE_FPU)) {
-               fpstate_init_soft(&state->soft);
+               fpstate_init_soft(&fpstate->regs.soft);
                return;
        }
 
-       xstate_init_xcomp_bv(&state->xsave, xfeatures_mask_uabi());
+       xstate_init_xcomp_bv(&fpstate->regs.xsave, xfeatures_mask_uabi());
 
        if (cpu_feature_enabled(X86_FEATURE_FXSR))
-               fpstate_init_fxstate(&state->fxsave);
+               fpstate_init_fxstate(fpstate);
        else
-               fpstate_init_fstate(&state->fsave);
+               fpstate_init_fstate(fpstate);
 }
 
 void fpstate_reset(struct fpu *fpu)
@@ -347,7 +347,7 @@ void fpstate_reset(struct fpu *fpu)
 void fpu_init_fpstate_user(struct fpu *fpu)
 {
        fpstate_reset(fpu);
-       fpstate_init_user(&fpu->fpstate->regs);
+       fpstate_init_user(fpu->fpstate);
 }
 EXPORT_SYMBOL_GPL(fpu_init_fpstate_user);
 #endif
@@ -378,7 +378,7 @@ int fpu_clone(struct task_struct *dst)
         */
        if (dst->flags & (PF_KTHREAD | PF_IO_WORKER)) {
                /* Clear out the minimal state */
-               memcpy(&dst_fpu->state, &init_fpstate,
+               memcpy(&dst_fpu->state, &init_fpstate.regs,
                       init_fpstate_copy_size());
                return 0;
        }
@@ -435,11 +435,11 @@ void fpu__drop(struct fpu *fpu)
 static inline void restore_fpregs_from_init_fpstate(u64 features_mask)
 {
        if (use_xsave())
-               os_xrstor(&init_fpstate.xsave, features_mask);
+               os_xrstor(&init_fpstate.regs.xsave, features_mask);
        else if (use_fxsr())
-               fxrstor(&init_fpstate.fxsave);
+               fxrstor(&init_fpstate.regs.fxsave);
        else
-               frstor(&init_fpstate.fsave);
+               frstor(&init_fpstate.regs.fsave);
 
        pkru_write_default();
 }
@@ -466,7 +466,7 @@ static void fpu_reset_fpstate(void)
         * user space as PKRU is eagerly written in switch_to() and
         * flush_thread().
         */
-       memcpy(&fpu->state, &init_fpstate, init_fpstate_copy_size());
+       memcpy(&fpu->state, &init_fpstate.regs, init_fpstate_copy_size());
        set_thread_flag(TIF_NEED_FPU_LOAD);
        fpregs_unlock();
 }

diff --git a/arch/x86/kernel/fpu/internal.h b/arch/x86/kernel/fpu/internal.h
index 63bd75f..e1d8a35 100644 (file)
--- a/arch/x86/kernel/fpu/internal.h
+++ b/arch/x86/kernel/fpu/internal.h
@@ -2,7 +2,7 @@
 #ifndef __X86_KERNEL_FPU_INTERNAL_H
 #define __X86_KERNEL_FPU_INTERNAL_H
 
-extern union fpregs_state init_fpstate;
+extern struct fpstate init_fpstate;
 
 /* CPU feature check wrappers */
 static __always_inline __pure bool use_xsave(void)
@@ -25,7 +25,7 @@ static __always_inline __pure bool use_fxsr(void)
 extern void fpu__init_prepare_fx_sw_frame(void);
 
 /* Used in init.c */
-extern void fpstate_init_user(union fpregs_state *state);
+extern void fpstate_init_user(struct fpstate *fpstate);
 extern void fpstate_reset(struct fpu *fpu);
 
 #endif

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 274cd58..416a110 100644 (file)
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -243,7 +243,7 @@ static int __restore_fpregs_from_user(void __user *buf, u64 xrestore,
                        ret = fxrstor_from_user_sigframe(buf);
 
                if (!ret && unlikely(init_bv))
-                       os_xrstor(&init_fpstate.xsave, init_bv);
+                       os_xrstor(&init_fpstate.regs.xsave, init_bv);
                return ret;
        } else if (use_fxsr()) {
                return fxrstor_from_user_sigframe(buf);

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index b022df9..937ad5b 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -408,12 +408,12 @@ static void __init setup_init_fpu_buf(void)
        setup_xstate_features();
        print_xstate_features();
 
-       xstate_init_xcomp_bv(&init_fpstate.xsave, xfeatures_mask_all);
+       xstate_init_xcomp_bv(&init_fpstate.regs.xsave, xfeatures_mask_all);
 
        /*
         * Init all the features state with header.xfeatures being 0x0
         */
-       os_xrstor_booting(&init_fpstate.xsave);
+       os_xrstor_booting(&init_fpstate.regs.xsave);
 
        /*
         * All components are now in init state. Read the state back so
@@ -431,7 +431,7 @@ static void __init setup_init_fpu_buf(void)
         * state is all zeroes or if not to add the necessary handling
         * here.
         */
-       fxsave(&init_fpstate.fxsave);
+       fxsave(&init_fpstate.regs.fxsave);
 }
 
 static int xfeature_uncompacted_offset(int xfeature_nr)
@@ -672,11 +672,11 @@ static unsigned int __init get_xsave_size(void)
  */
 static bool __init is_supported_xstate_size(unsigned int test_xstate_size)
 {
-       if (test_xstate_size <= sizeof(union fpregs_state))
+       if (test_xstate_size <= sizeof(init_fpstate.regs))
                return true;
 
        pr_warn("x86/fpu: xstate buffer too small (%zu < %d), disabling xsave\n",
-                       sizeof(union fpregs_state), test_xstate_size);
+                       sizeof(init_fpstate.regs), test_xstate_size);
        return false;
 }
 
@@ -981,7 +981,7 @@ void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
                               u32 pkru_val, enum xstate_copy_mode copy_mode)
 {
        const unsigned int off_mxcsr = offsetof(struct fxregs_state, mxcsr);
-       struct xregs_state *xinit = &init_fpstate.xsave;
+       struct xregs_state *xinit = &init_fpstate.regs.xsave;
        struct xstate_header header;
        unsigned int zerofrom;
        u64 mask;