Merge branch 'work.regset' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull ptrace regset updates from Al Viro:
 "Internal regset API changes:

   - regularize copy_regset_{to,from}_user() callers

   - switch to saner calling conventions for ->get()

   - kill user_regset_copyout()

  The ->put() side of things will have to wait for the next cycle,
  unfortunately.

  The balance is about -1KLoC and replacements for ->get() instances are
  a lot saner"

* 'work.regset' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits)
  regset: kill user_regset_copyout{,_zero}()
  regset(): kill ->get_size()
  regset: kill ->get()
  csky: switch to ->regset_get()
  xtensa: switch to ->regset_get()
  parisc: switch to ->regset_get()
  nds32: switch to ->regset_get()
  nios2: switch to ->regset_get()
  hexagon: switch to ->regset_get()
  h8300: switch to ->regset_get()
  openrisc: switch to ->regset_get()
  riscv: switch to ->regset_get()
  c6x: switch to ->regset_get()
  ia64: switch to ->regset_get()
  arc: switch to ->regset_get()
  arm: switch to ->regset_get()
  sh: convert to ->regset_get()
  arm64: switch to ->regset_get()
  mips: switch to ->regset_get()
  sparc: switch to ->regset_get()
  ...

arch/arc/kernel/ptrace.c

@@ -18,88 +18,61 @@ static struct callee_regs *task_callee_regs(struct task_struct *tsk)
 
 static int genregs_get(struct task_struct *target,
 		       const struct user_regset *regset,
-		       unsigned int pos, unsigned int count,
-		       void *kbuf, void __user *ubuf)
+		       struct membuf to)
 {
 	const struct pt_regs *ptregs = task_pt_regs(target);
 	const struct callee_regs *cregs = task_callee_regs(target);
-	int ret = 0;
 	unsigned int stop_pc_val;
 
-#define REG_O_CHUNK(START, END, PTR)	\
-	if (!ret)	\
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, PTR, \
-			offsetof(struct user_regs_struct, START), \
-			offsetof(struct user_regs_struct, END));
-
-#define REG_O_ONE(LOC, PTR)	\
-	if (!ret)		\
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, PTR, \
-			offsetof(struct user_regs_struct, LOC), \
-			offsetof(struct user_regs_struct, LOC) + 4);
-
-#define REG_O_ZERO(LOC)		\
-	if (!ret)		\
-		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, \
-			offsetof(struct user_regs_struct, LOC), \
-			offsetof(struct user_regs_struct, LOC) + 4);
-
-	REG_O_ZERO(pad);
-	REG_O_ONE(scratch.bta, &ptregs->bta);
-	REG_O_ONE(scratch.lp_start, &ptregs->lp_start);
-	REG_O_ONE(scratch.lp_end, &ptregs->lp_end);
-	REG_O_ONE(scratch.lp_count, &ptregs->lp_count);
-	REG_O_ONE(scratch.status32, &ptregs->status32);
-	REG_O_ONE(scratch.ret, &ptregs->ret);
-	REG_O_ONE(scratch.blink, &ptregs->blink);
-	REG_O_ONE(scratch.fp, &ptregs->fp);
-	REG_O_ONE(scratch.gp, &ptregs->r26);
-	REG_O_ONE(scratch.r12, &ptregs->r12);
-	REG_O_ONE(scratch.r11, &ptregs->r11);
-	REG_O_ONE(scratch.r10, &ptregs->r10);
-	REG_O_ONE(scratch.r9, &ptregs->r9);
-	REG_O_ONE(scratch.r8, &ptregs->r8);
-	REG_O_ONE(scratch.r7, &ptregs->r7);
-	REG_O_ONE(scratch.r6, &ptregs->r6);
-	REG_O_ONE(scratch.r5, &ptregs->r5);
-	REG_O_ONE(scratch.r4, &ptregs->r4);
-	REG_O_ONE(scratch.r3, &ptregs->r3);
-	REG_O_ONE(scratch.r2, &ptregs->r2);
-	REG_O_ONE(scratch.r1, &ptregs->r1);
-	REG_O_ONE(scratch.r0, &ptregs->r0);
-	REG_O_ONE(scratch.sp, &ptregs->sp);
-
-	REG_O_ZERO(pad2);
-
-	REG_O_ONE(callee.r25, &cregs->r25);
-	REG_O_ONE(callee.r24, &cregs->r24);
-	REG_O_ONE(callee.r23, &cregs->r23);
-	REG_O_ONE(callee.r22, &cregs->r22);
-	REG_O_ONE(callee.r21, &cregs->r21);
-	REG_O_ONE(callee.r20, &cregs->r20);
-	REG_O_ONE(callee.r19, &cregs->r19);
-	REG_O_ONE(callee.r18, &cregs->r18);
-	REG_O_ONE(callee.r17, &cregs->r17);
-	REG_O_ONE(callee.r16, &cregs->r16);
-	REG_O_ONE(callee.r15, &cregs->r15);
-	REG_O_ONE(callee.r14, &cregs->r14);
-	REG_O_ONE(callee.r13, &cregs->r13);
-
-	REG_O_ONE(efa, &target->thread.fault_address);
-
-	if (!ret) {
-		if (in_brkpt_trap(ptregs)) {
-			stop_pc_val = target->thread.fault_address;
-			pr_debug("\t\tstop_pc (brk-pt)\n");
-		} else {
-			stop_pc_val = ptregs->ret;
-			pr_debug("\t\tstop_pc (others)\n");
-		}
-
-		REG_O_ONE(stop_pc, &stop_pc_val);
+	membuf_zero(&to, 4);	// pad
+	membuf_store(&to, ptregs->bta);
+	membuf_store(&to, ptregs->lp_start);
+	membuf_store(&to, ptregs->lp_end);
+	membuf_store(&to, ptregs->lp_count);
+	membuf_store(&to, ptregs->status32);
+	membuf_store(&to, ptregs->ret);
+	membuf_store(&to, ptregs->blink);
+	membuf_store(&to, ptregs->fp);
+	membuf_store(&to, ptregs->r26);	// gp
+	membuf_store(&to, ptregs->r12);
+	membuf_store(&to, ptregs->r11);
+	membuf_store(&to, ptregs->r10);
+	membuf_store(&to, ptregs->r9);
+	membuf_store(&to, ptregs->r8);
+	membuf_store(&to, ptregs->r7);
+	membuf_store(&to, ptregs->r6);
+	membuf_store(&to, ptregs->r5);
+	membuf_store(&to, ptregs->r4);
+	membuf_store(&to, ptregs->r3);
+	membuf_store(&to, ptregs->r2);
+	membuf_store(&to, ptregs->r1);
+	membuf_store(&to, ptregs->r0);
+	membuf_store(&to, ptregs->sp);
+	membuf_zero(&to, 4);	// pad2
+	membuf_store(&to, cregs->r25);
+	membuf_store(&to, cregs->r24);
+	membuf_store(&to, cregs->r23);
+	membuf_store(&to, cregs->r22);
+	membuf_store(&to, cregs->r21);
+	membuf_store(&to, cregs->r20);
+	membuf_store(&to, cregs->r19);
+	membuf_store(&to, cregs->r18);
+	membuf_store(&to, cregs->r17);
+	membuf_store(&to, cregs->r16);
+	membuf_store(&to, cregs->r15);
+	membuf_store(&to, cregs->r14);
+	membuf_store(&to, cregs->r13);
+	membuf_store(&to, target->thread.fault_address); // efa
+
+	if (in_brkpt_trap(ptregs)) {
+		stop_pc_val = target->thread.fault_address;
+		pr_debug("\t\tstop_pc (brk-pt)\n");
+	} else {
+		stop_pc_val = ptregs->ret;
+		pr_debug("\t\tstop_pc (others)\n");
 	}
 
-	return ret;
+	return membuf_store(&to, stop_pc_val); // stop_pc
 }
 
 static int genregs_set(struct task_struct *target,
@@ -184,25 +157,20 @@ static int genregs_set(struct task_struct *target,
 #ifdef CONFIG_ISA_ARCV2
 static int arcv2regs_get(struct task_struct *target,
 		       const struct user_regset *regset,
-		       unsigned int pos, unsigned int count,
-		       void *kbuf, void __user *ubuf)
+		       struct membuf to)
 {
 	const struct pt_regs *regs = task_pt_regs(target);
-	int ret, copy_sz;
 
 	if (IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS))
-		copy_sz = sizeof(struct user_regs_arcv2);
-	else
-		copy_sz = 4;	/* r30 only */
+		/*
+		 * itemized copy not needed like above as layout of regs (r30,r58,r59)
+		 * is exactly same in kernel (pt_regs) and userspace (user_regs_arcv2)
+		 */
+		return membuf_write(&to, &regs->r30, sizeof(struct user_regs_arcv2));
 
-	/*
-	 * itemized copy not needed like above as layout of regs (r30,r58,r59)
-	 * is exactly same in kernel (pt_regs) and userspace (user_regs_arcv2)
-	 */
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &regs->r30,
-				  0, copy_sz);
 
-	return ret;
+	membuf_write(&to, &regs->r30, 4); /* r30 only */
+	return membuf_zero(&to, sizeof(struct user_regs_arcv2) - 4);
 }
 
 static int arcv2regs_set(struct task_struct *target,
@@ -237,7 +205,7 @@ static const struct user_regset arc_regsets[] = {
 	       .n = ELF_NGREG,
 	       .size = sizeof(unsigned long),
 	       .align = sizeof(unsigned long),
-	       .get = genregs_get,
+	       .regset_get = genregs_get,
 	       .set = genregs_set,
 	},
 #ifdef CONFIG_ISA_ARCV2
@@ -246,7 +214,7 @@ static const struct user_regset arc_regsets[] = {
 	       .n = ELF_ARCV2REG,
 	       .size = sizeof(unsigned long),
 	       .align = sizeof(unsigned long),
-	       .get = arcv2regs_get,
+	       .regset_get = arcv2regs_get,
 	       .set = arcv2regs_set,
 	},
 #endif

arch/arm/kernel/ptrace.c

@@ -569,14 +569,9 @@ static int ptrace_sethbpregs(struct task_struct *tsk, long num,
 
 static int gpr_get(struct task_struct *target,
 		   const struct user_regset *regset,
-		   unsigned int pos, unsigned int count,
-		   void *kbuf, void __user *ubuf)
+		   struct membuf to)
 {
-	struct pt_regs *regs = task_pt_regs(target);
-
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				   regs,
-				   0, sizeof(*regs));
+	return membuf_write(&to, task_pt_regs(target), sizeof(struct pt_regs));
 }
 
 static int gpr_set(struct task_struct *target,
@@ -602,12 +597,10 @@ static int gpr_set(struct task_struct *target,
 
 static int fpa_get(struct task_struct *target,
 		   const struct user_regset *regset,
-		   unsigned int pos, unsigned int count,
-		   void *kbuf, void __user *ubuf)
+		   struct membuf to)
 {
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				   &task_thread_info(target)->fpstate,
-				   0, sizeof(struct user_fp));
+	return membuf_write(&to, &task_thread_info(target)->fpstate,
+				 sizeof(struct user_fp));
 }
 
 static int fpa_set(struct task_struct *target,
@@ -642,41 +635,20 @@ static int fpa_set(struct task_struct *target,
  *	vfp_set() ignores this chunk
  *
  * 1 word for the FPSCR
- *
- * The bounds-checking logic built into user_regset_copyout and friends
- * means that we can make a simple sequence of calls to map the relevant data
- * to/from the specified slice of the user regset structure.
  */
 static int vfp_get(struct task_struct *target,
 		   const struct user_regset *regset,
-		   unsigned int pos, unsigned int count,
-		   void *kbuf, void __user *ubuf)
+		   struct membuf to)
 {
-	int ret;
 	struct thread_info *thread = task_thread_info(target);
 	struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
-	const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
 	const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
 
 	vfp_sync_hwstate(thread);
 
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  &vfp->fpregs,
-				  user_fpregs_offset,
-				  user_fpregs_offset + sizeof(vfp->fpregs));
-	if (ret)
-		return ret;
-
-	ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-				       user_fpregs_offset + sizeof(vfp->fpregs),
-				       user_fpscr_offset);
-	if (ret)
-		return ret;
-
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				   &vfp->fpscr,
-				   user_fpscr_offset,
-				   user_fpscr_offset + sizeof(vfp->fpscr));
+	membuf_write(&to, vfp->fpregs, sizeof(vfp->fpregs));
+	membuf_zero(&to, user_fpscr_offset - sizeof(vfp->fpregs));
+	return membuf_store(&to, vfp->fpscr);
 }
 
 /*
@@ -739,7 +711,7 @@ static const struct user_regset arm_regsets[] = {
 		.n = ELF_NGREG,
 		.size = sizeof(u32),
 		.align = sizeof(u32),
-		.get = gpr_get,
+		.regset_get = gpr_get,
 		.set = gpr_set
 	},
 	[REGSET_FPR] = {
@@ -751,7 +723,7 @@ static const struct user_regset arm_regsets[] = {
 		.n = sizeof(struct user_fp) / sizeof(u32),
 		.size = sizeof(u32),
 		.align = sizeof(u32),
-		.get = fpa_get,
+		.regset_get = fpa_get,
 		.set = fpa_set
 	},
 #ifdef CONFIG_VFP
@@ -764,7 +736,7 @@ static const struct user_regset arm_regsets[] = {
 		.n = ARM_VFPREGS_SIZE / sizeof(u32),
 		.size = sizeof(u32),
 		.align = sizeof(u32),
-		.get = vfp_get,
+		.regset_get = vfp_get,
 		.set = vfp_set
 	},
 #endif /* CONFIG_VFP */

arch/c6x/kernel/ptrace.c

@@ -57,14 +57,9 @@ static inline int put_reg(struct task_struct *task,
 
 static int gpr_get(struct task_struct *target,
 		   const struct user_regset *regset,
-		   unsigned int pos, unsigned int count,
-		   void *kbuf, void __user *ubuf)
+		   struct membuf to)
 {
-	struct pt_regs *regs = task_pt_regs(target);
-
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				   regs,
-				   0, sizeof(*regs));
+	return membuf_write(&to, task_pt_regs(target), sizeof(struct pt_regs));
 }
 
 enum c6x_regset {
@@ -77,7 +72,7 @@ static const struct user_regset c6x_regsets[] = {
 		.n = ELF_NGREG,
 		.size = sizeof(u32),
 		.align = sizeof(u32),
-		.get = gpr_get,
+		.regset_get = gpr_get,
 	},
 };
 

arch/csky/kernel/ptrace.c

@@ -76,17 +76,14 @@ enum csky_regset {
 
 static int gpr_get(struct task_struct *target,
 		   const struct user_regset *regset,
-		   unsigned int pos, unsigned int count,
-		   void *kbuf, void __user *ubuf)
+		   struct membuf to)
 {
-	struct pt_regs *regs;
-
-	regs = task_pt_regs(target);
+	struct pt_regs *regs = task_pt_regs(target);
 
 	/* Abiv1 regs->tls is fake and we need sync here. */
 	regs->tls = task_thread_info(target)->tp_value;
 
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
+	return membuf_write(&to, regs, sizeof(regs));
 }
 
 static int gpr_set(struct task_struct *target,
@@ -114,8 +111,7 @@ static int gpr_set(struct task_struct *target,
 
 static int fpr_get(struct task_struct *target,
 		   const struct user_regset *regset,
-		   unsigned int pos, unsigned int count,
-		   void *kbuf, void __user *ubuf)
+		   struct membuf to)
 {
 	struct user_fp *regs = (struct user_fp *)&target->thread.user_fp;
 
@@ -131,9 +127,9 @@ static int fpr_get(struct task_struct *target,
 	for (i = 0; i < 32; i++)
 		tmp.vr[64 + i] = regs->vr[32 + i];
 
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &tmp, 0, -1);
+	return membuf_write(&to, &tmp, sizeof(tmp));
 #else
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
+	return membuf_write(&to, regs, sizeof(*regs));
 #endif
 }
 
@@ -173,16 +169,16 @@ static const struct user_regset csky_regsets[] = {
 		.n = sizeof(struct pt_regs) / sizeof(u32),
 		.size = sizeof(u32),
 		.align = sizeof(u32),
-		.get = &gpr_get,
-		.set = &gpr_set,
+		.regset_get = gpr_get,
+		.set = gpr_set,
 	},
 	[REGSET_FPR] = {
 		.core_note_type = NT_PRFPREG,
 		.n = sizeof(struct user_fp) / sizeof(u32),
 		.size = sizeof(u32),
 		.align = sizeof(u32),
-		.get = &fpr_get,
-		.set = &fpr_set,
+		.regset_get = fpr_get,
+		.set = fpr_set,
 	},
 };
 

arch/h8300/kernel/ptrace.c

@@ -87,20 +87,15 @@ int h8300_put_reg(struct task_struct *task, int regno, unsigned long data)
 
 static int regs_get(struct task_struct *target,
 		    const struct user_regset *regset,
-		    unsigned int pos, unsigned int count,
-		    void *kbuf, void __user *ubuf)
+		    struct membuf to)
 {
 	int r;
-	struct user_regs_struct regs;
-	long *reg = (long *)&regs;
 
-	/* build user regs in buffer */
-	BUILD_BUG_ON(sizeof(regs) % sizeof(long) != 0);
-	for (r = 0; r < sizeof(regs) / sizeof(long); r++)
-		*reg++ = h8300_get_reg(target, r);
+	BUILD_BUG_ON(sizeof(struct user_regs_struct) % sizeof(long) != 0);
+	for (r = 0; r < ELF_NGREG; r++)
+		membuf_store(&to, h8300_get_reg(target, r));
 
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				   &regs, 0, sizeof(regs));
+	return 0;
 }
 
 static int regs_set(struct task_struct *target,
@@ -139,7 +134,7 @@ static const struct user_regset h8300_regsets[] = {
 		.n		= ELF_NGREG,
 		.size		= sizeof(long),
 		.align		= sizeof(long),
-		.get		= regs_get,
+		.regset_get		= regs_get,
 		.set		= regs_set,
 	},
 };

arch/hexagon/kernel/ptrace.c

@@ -35,58 +35,38 @@ void user_disable_single_step(struct task_struct *child)
 
 static int genregs_get(struct task_struct *target,
 		   const struct user_regset *regset,
-		   unsigned int pos, unsigned int count,
-		   void *kbuf, void __user *ubuf)
+		   srtuct membuf to)
 {
-	int ret;
-	unsigned int dummy;
 	struct pt_regs *regs = task_pt_regs(target);
 
-
-	if (!regs)
-		return -EIO;
-
 	/* The general idea here is that the copyout must happen in
 	 * exactly the same order in which the userspace expects these
 	 * regs. Now, the sequence in userspace does not match the
 	 * sequence in the kernel, so everything past the 32 gprs
 	 * happens one at a time.
 	 */
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  &regs->r00, 0, 32*sizeof(unsigned long));
-
-#define ONEXT(KPT_REG, USR_REG) \
-	if (!ret) \
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, \
-			KPT_REG, offsetof(struct user_regs_struct, USR_REG), \
-			offsetof(struct user_regs_struct, USR_REG) + \
-				 sizeof(unsigned long));
-
+	membuf_write(&to, &regs->r00, 32*sizeof(unsigned long));
 	/* Must be exactly same sequence as struct user_regs_struct */
-	ONEXT(&regs->sa0, sa0);
-	ONEXT(&regs->lc0, lc0);
-	ONEXT(&regs->sa1, sa1);
-	ONEXT(&regs->lc1, lc1);
-	ONEXT(&regs->m0, m0);
-	ONEXT(&regs->m1, m1);
-	ONEXT(&regs->usr, usr);
-	ONEXT(&regs->preds, p3_0);
-	ONEXT(&regs->gp, gp);
-	ONEXT(&regs->ugp, ugp);
-	ONEXT(&pt_elr(regs), pc);
-	dummy = pt_cause(regs);
-	ONEXT(&dummy, cause);
-	ONEXT(&pt_badva(regs), badva);
+	membuf_store(&to, regs->sa0);
+	membuf_store(&to, regs->lc0);
+	membuf_store(&to, regs->sa1);
+	membuf_store(&to, regs->lc1);
+	membuf_store(&to, regs->m0);
+	membuf_store(&to, regs->m1);
+	membuf_store(&to, regs->usr);
+	membuf_store(&to, regs->p3_0);
+	membuf_store(&to, regs->gp);
+	membuf_store(&to, regs->ugp);
+	membuf_store(&to, pt_elr(regs)); // pc
+	membuf_store(&to, (unsigned long)pt_cause(regs)); // cause
+	membuf_store(&to, pt_badva(regs)); // badva
 #if CONFIG_HEXAGON_ARCH_VERSION >=4
-	ONEXT(&regs->cs0, cs0);
-	ONEXT(&regs->cs1, cs1);
+	membuf_store(&to, regs->cs0);
+	membuf_store(&to, regs->cs1);
+	return membuf_zero(&to, sizeof(unsigned long));
+#else
+	return membuf_zero(&to, 3 * sizeof(unsigned long));
 #endif
-
-	/* Pad the rest with zeros, if needed */
-	if (!ret)
-		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					offsetof(struct user_regs_struct, pad1), -1);
-	return ret;
 }
 
 static int genregs_set(struct task_struct *target,
@@ -159,7 +139,7 @@ static const struct user_regset hexagon_regsets[] = {
 		.n = ELF_NGREG,
 		.size = sizeof(unsigned long),
 		.align = sizeof(unsigned long),
-		.get = genregs_get,
+		.regset_get = genregs_get,
 		.set = genregs_set,
 	},
 };

arch/nds32/kernel/ptrace.c

@@ -13,11 +13,10 @@ enum nds32_regset {
 
 static int gpr_get(struct task_struct *target,
 		   const struct user_regset *regset,
-		   unsigned int pos, unsigned int count,
-		   void *kbuf, void __user * ubuf)
+		   struct membuf to)
 {
-	struct user_pt_regs *uregs = &task_pt_regs(target)->user_regs;
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
+	return membuf_write(&to, &task_pt_regs(target)->user_regs,
+				sizeof(struct user_pt_regs));
 }
 
 static int gpr_set(struct task_struct *target, const struct user_regset *regset,
@@ -41,7 +40,7 @@ static const struct user_regset nds32_regsets[] = {
 			.n = sizeof(struct user_pt_regs) / sizeof(u32),
 			.size = sizeof(elf_greg_t),
 			.align = sizeof(elf_greg_t),
-			.get = gpr_get,
+			.regset_get = gpr_get,
 			.set = gpr_set}
 };
 

arch/nios2/kernel/ptrace.c

@@ -21,45 +21,24 @@
 
 static int genregs_get(struct task_struct *target,
 		       const struct user_regset *regset,
-		       unsigned int pos, unsigned int count,
-		       void *kbuf, void __user *ubuf)
+		       struct membuf to)
 {
 	const struct pt_regs *regs = task_pt_regs(target);
 	const struct switch_stack *sw = (struct switch_stack *)regs - 1;
-	int ret = 0;
-
-#define REG_O_ZERO_RANGE(START, END)		\
-	if (!ret)					\
-		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, \
-			START * 4, (END * 4) + 4);
-
-#define REG_O_ONE(PTR, LOC)	\
-	if (!ret)			\
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, PTR, \
-			LOC * 4, (LOC * 4) + 4);
 
-#define REG_O_RANGE(PTR, START, END)	\
-	if (!ret)				\
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, PTR, \
-			START * 4, (END * 4) + 4);
-
-	REG_O_ZERO_RANGE(PTR_R0, PTR_R0);
-	REG_O_RANGE(&regs->r1, PTR_R1, PTR_R7);
-	REG_O_RANGE(&regs->r8, PTR_R8, PTR_R15);
-	REG_O_RANGE(sw, PTR_R16, PTR_R23);
-	REG_O_ZERO_RANGE(PTR_R24, PTR_R25); /* et and bt */
-	REG_O_ONE(&regs->gp, PTR_GP);
-	REG_O_ONE(&regs->sp, PTR_SP);
-	REG_O_ONE(&regs->fp, PTR_FP);
-	REG_O_ONE(&regs->ea, PTR_EA);
-	REG_O_ZERO_RANGE(PTR_BA, PTR_BA);
-	REG_O_ONE(&regs->ra, PTR_RA);
-	REG_O_ONE(&regs->ea, PTR_PC); /* use ea for PC */
-	if (!ret)
-		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					 PTR_STATUS * 4, -1);
-
-	return ret;
+	membuf_zero(&to, 4); // R0
+	membuf_write(&to, &regs->r1, 7 * 4); // R1..R7
+	membuf_write(&to, &regs->r8, 8 * 4); // R8..R15
+	membuf_write(&to, sw, 8 * 4); // R16..R23
+	membuf_zero(&to, 2 * 4); /* et and bt */
+	membuf_store(&to, regs->gp);
+	membuf_store(&to, regs->sp);
+	membuf_store(&to, regs->fp);
+	membuf_store(&to, regs->ea);
+	membuf_zero(&to, 4); // PTR_BA
+	membuf_store(&to, regs->ra);
+	membuf_store(&to, regs->ea); /* use ea for PC */
+	return membuf_zero(&to, (NUM_PTRACE_REG - PTR_PC) * 4);
 }
 
 /*
@@ -121,7 +100,7 @@ static const struct user_regset nios2_regsets[] = {
 		.n = NUM_PTRACE_REG,
 		.size = sizeof(unsigned long),
 		.align = sizeof(unsigned long),
-		.get = genregs_get,
+		.regset_get = genregs_get,
 		.set = genregs_set,
 	}
 };

arch/openrisc/kernel/ptrace.c

@@ -44,29 +44,15 @@
  */
 static int genregs_get(struct task_struct *target,
 		       const struct user_regset *regset,
-		       unsigned int pos, unsigned int count,
-		       void *kbuf, void __user * ubuf)
+		       struct membuf to)
 {
 	const struct pt_regs *regs = task_pt_regs(target);
-	int ret;
 
 	/* r0 */
-	ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, 0, 4);
-
-	if (!ret)
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-					  regs->gpr+1, 4, 4*32);
-	if (!ret)
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  &regs->pc, 4*32, 4*33);
-	if (!ret)
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-					  &regs->sr, 4*33, 4*34);
-	if (!ret)
-		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					       4*34, -1);
-
-	return ret;
+	membuf_zero(&to, 4);
+	membuf_write(&to, regs->gpr + 1, 31 * 4);
+	membuf_store(&to, regs->pc);
+	return membuf_store(&to, regs->sr);
 }
 
 /*
@@ -114,7 +100,7 @@ static const struct user_regset or1k_regsets[] = {
 			    .n = ELF_NGREG,
 			    .size = sizeof(long),
 			    .align = sizeof(long),
-			    .get = genregs_get,
+			    .regset_get = genregs_get,
 			    .set = genregs_set,
 			    },
 };

arch/parisc/kernel/ptrace.c

@@ -391,31 +391,11 @@ void do_syscall_trace_exit(struct pt_regs *regs)
 
 static int fpr_get(struct task_struct *target,
 		     const struct user_regset *regset,
-		     unsigned int pos, unsigned int count,
-		     void *kbuf, void __user *ubuf)
+		     struct membuf to)
 {
 	struct pt_regs *regs = task_regs(target);
-	__u64 *k = kbuf;
-	__u64 __user *u = ubuf;
-	__u64 reg;
-
-	pos /= sizeof(reg);
-	count /= sizeof(reg);
-
-	if (kbuf)
-		for (; count > 0 && pos < ELF_NFPREG; --count)
-			*k++ = regs->fr[pos++];
-	else
-		for (; count > 0 && pos < ELF_NFPREG; --count)
-			if (__put_user(regs->fr[pos++], u++))
-				return -EFAULT;
 
-	kbuf = k;
-	ubuf = u;
-	pos *= sizeof(reg);
-	count *= sizeof(reg);
-	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					ELF_NFPREG * sizeof(reg), -1);
+	return membuf_write(&to, regs->fr, ELF_NFPREG * sizeof(__u64));
 }
 
 static int fpr_set(struct task_struct *target,
@@ -527,30 +507,14 @@ static void set_reg(struct pt_regs *regs, int num, unsigned long val)
 
 static int gpr_get(struct task_struct *target,
 		     const struct user_regset *regset,
-		     unsigned int pos, unsigned int count,
-		     void *kbuf, void __user *ubuf)
+		     struct membuf to)
 {
 	struct pt_regs *regs = task_regs(target);
-	unsigned long *k = kbuf;
-	unsigned long __user *u = ubuf;
-	unsigned long reg;
+	unsigned int pos;
 
-	pos /= sizeof(reg);
-	count /= sizeof(reg);
-
-	if (kbuf)
-		for (; count > 0 && pos < ELF_NGREG; --count)
-			*k++ = get_reg(regs, pos++);
-	else
-		for (; count > 0 && pos < ELF_NGREG; --count)
-			if (__put_user(get_reg(regs, pos++), u++))
-				return -EFAULT;
-	kbuf = k;
-	ubuf = u;
-	pos *= sizeof(reg);
-	count *= sizeof(reg);
-	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					ELF_NGREG * sizeof(reg), -1);
+	for (pos = 0; pos < ELF_NGREG; pos++)
+		membuf_store(&to, get_reg(regs, pos));
+	return 0;
 }
 
 static int gpr_set(struct task_struct *target,
@@ -588,12 +552,12 @@ static const struct user_regset native_regsets[] = {
 	[REGSET_GENERAL] = {
 		.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
 		.size = sizeof(long), .align = sizeof(long),
-		.get = gpr_get, .set = gpr_set
+		.regset_get = gpr_get, .set = gpr_set
 	},
 	[REGSET_FP] = {
 		.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
 		.size = sizeof(__u64), .align = sizeof(__u64),
-		.get = fpr_get, .set = fpr_set
+		.regset_get = fpr_get, .set = fpr_set
 	}
 };
 
@@ -607,31 +571,15 @@ static const struct user_regset_view user_parisc_native_view = {
 
 static int gpr32_get(struct task_struct *target,
 		     const struct user_regset *regset,
-		     unsigned int pos, unsigned int count,
-		     void *kbuf, void __user *ubuf)
+		     struct membuf to)
 {
 	struct pt_regs *regs = task_regs(target);
-	compat_ulong_t *k = kbuf;
-	compat_ulong_t __user *u = ubuf;
-	compat_ulong_t reg;
+	unsigned int pos;
 
-	pos /= sizeof(reg);
-	count /= sizeof(reg);
+	for (pos = 0; pos < ELF_NGREG; pos++)
+		membuf_store(&to, (compat_ulong_t)get_reg(regs, pos));
 
-	if (kbuf)
-		for (; count > 0 && pos < ELF_NGREG; --count)
-			*k++ = get_reg(regs, pos++);
-	else
-		for (; count > 0 && pos < ELF_NGREG; --count)
-			if (__put_user((compat_ulong_t) get_reg(regs, pos++), u++))
-				return -EFAULT;
-
-	kbuf = k;
-	ubuf = u;
-	pos *= sizeof(reg);
-	count *= sizeof(reg);
-	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					ELF_NGREG * sizeof(reg), -1);
+	return 0;
 }
 
 static int gpr32_set(struct task_struct *target,
@@ -672,12 +620,12 @@ static const struct user_regset compat_regsets[] = {
 	[REGSET_GENERAL] = {
 		.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
 		.size = sizeof(compat_long_t), .align = sizeof(compat_long_t),
-		.get = gpr32_get, .set = gpr32_set
+		.regset_get = gpr32_get, .set = gpr32_set
 	},
 	[REGSET_FP] = {
 		.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
 		.size = sizeof(__u64), .align = sizeof(__u64),
-		.get = fpr_get, .set = fpr_set
+		.regset_get = fpr_get, .set = fpr_set
 	}
 };
 

arch/powerpc/kernel/ptrace/ptrace-altivec.c

@@ -41,38 +41,25 @@ int vr_active(struct task_struct *target, const struct user_regset *regset)
  * };
  */
 int vr_get(struct task_struct *target, const struct user_regset *regset,
-	   unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf)
+	   struct membuf to)
 {
-	int ret;
+	union {
+		elf_vrreg_t reg;
+		u32 word;
+	} vrsave;
 
 	flush_altivec_to_thread(target);
 
 	BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
 		     offsetof(struct thread_vr_state, vr[32]));
 
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  &target->thread.vr_state, 0,
-				  33 * sizeof(vector128));
-	if (!ret) {
-		/*
-		 * Copy out only the low-order word of vrsave.
-		 */
-		int start, end;
-		union {
-			elf_vrreg_t reg;
-			u32 word;
-		} vrsave;
-		memset(&vrsave, 0, sizeof(vrsave));
-
-		vrsave.word = target->thread.vrsave;
-
-		start = 33 * sizeof(vector128);
-		end = start + sizeof(vrsave);
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &vrsave,
-					  start, end);
-	}
-
-	return ret;
+	membuf_write(&to, &target->thread.vr_state, 33 * sizeof(vector128));
+	/*
+	 * Copy out only the low-order word of vrsave.
+	 */
+	memset(&vrsave, 0, sizeof(vrsave));
+	vrsave.word = target->thread.vrsave;
+	return membuf_write(&to, &vrsave, sizeof(vrsave));
 }
 
 /*

arch/powerpc/kernel/ptrace/ptrace-decl.h

@@ -63,8 +63,7 @@ enum powerpc_regset {
 
 /* ptrace-(no)vsx */
 
-int fpr_get(struct task_struct *target, const struct user_regset *regset,
-	    unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn fpr_get;
 int fpr_set(struct task_struct *target, const struct user_regset *regset,
 	    unsigned int pos, unsigned int count,
 	    const void *kbuf, const void __user *ubuf);
@@ -72,8 +71,7 @@ int fpr_set(struct task_struct *target, const struct user_regset *regset,
 /* ptrace-vsx */
 
 int vsr_active(struct task_struct *target, const struct user_regset *regset);
-int vsr_get(struct task_struct *target, const struct user_regset *regset,
-	    unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn vsr_get;
 int vsr_set(struct task_struct *target, const struct user_regset *regset,
 	    unsigned int pos, unsigned int count,
 	    const void *kbuf, const void __user *ubuf);
@@ -81,8 +79,7 @@ int vsr_set(struct task_struct *target, const struct user_regset *regset,
 /* ptrace-altivec */
 
 int vr_active(struct task_struct *target, const struct user_regset *regset);
-int vr_get(struct task_struct *target, const struct user_regset *regset,
-	   unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn vr_get;
 int vr_set(struct task_struct *target, const struct user_regset *regset,
 	   unsigned int pos, unsigned int count,
 	   const void *kbuf, const void __user *ubuf);
@@ -90,8 +87,7 @@ int vr_set(struct task_struct *target, const struct user_regset *regset,
 /* ptrace-spe */
 
 int evr_active(struct task_struct *target, const struct user_regset *regset);
-int evr_get(struct task_struct *target, const struct user_regset *regset,
-	    unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn evr_get;
 int evr_set(struct task_struct *target, const struct user_regset *regset,
 	    unsigned int pos, unsigned int count,
 	    const void *kbuf, const void __user *ubuf);
@@ -100,9 +96,8 @@ int evr_set(struct task_struct *target, const struct user_regset *regset,
 
 int gpr32_get_common(struct task_struct *target,
 		     const struct user_regset *regset,
-		     unsigned int pos, unsigned int count,
-			    void *kbuf, void __user *ubuf,
-			    unsigned long *regs);
+		     struct membuf to,
+		     unsigned long *regs);
 int gpr32_set_common(struct task_struct *target,
 		     const struct user_regset *regset,
 		     unsigned int pos, unsigned int count,
@@ -118,55 +113,46 @@ static inline void flush_tmregs_to_thread(struct task_struct *tsk) { }
 #endif
 
 int tm_cgpr_active(struct task_struct *target, const struct user_regset *regset);
-int tm_cgpr_get(struct task_struct *target, const struct user_regset *regset,
-		unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn tm_cgpr_get;
 int tm_cgpr_set(struct task_struct *target, const struct user_regset *regset,
 		unsigned int pos, unsigned int count,
 		const void *kbuf, const void __user *ubuf);
 int tm_cfpr_active(struct task_struct *target, const struct user_regset *regset);
-int tm_cfpr_get(struct task_struct *target, const struct user_regset *regset,
-		unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn tm_cfpr_get;
 int tm_cfpr_set(struct task_struct *target, const struct user_regset *regset,
 		unsigned int pos, unsigned int count,
 		const void *kbuf, const void __user *ubuf);
 int tm_cvmx_active(struct task_struct *target, const struct user_regset *regset);
-int tm_cvmx_get(struct task_struct *target, const struct user_regset *regset,
-		unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn tm_cvmx_get;
 int tm_cvmx_set(struct task_struct *target, const struct user_regset *regset,
 		unsigned int pos, unsigned int count,
 		const void *kbuf, const void __user *ubuf);
 int tm_cvsx_active(struct task_struct *target, const struct user_regset *regset);
-int tm_cvsx_get(struct task_struct *target, const struct user_regset *regset,
-		unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn tm_cvsx_get;
 int tm_cvsx_set(struct task_struct *target, const struct user_regset *regset,
 		unsigned int pos, unsigned int count,
 		const void *kbuf, const void __user *ubuf);
 int tm_spr_active(struct task_struct *target, const struct user_regset *regset);
-int tm_spr_get(struct task_struct *target, const struct user_regset *regset,
-	       unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn tm_spr_get;
 int tm_spr_set(struct task_struct *target, const struct user_regset *regset,
 	       unsigned int pos, unsigned int count,
 	       const void *kbuf, const void __user *ubuf);
 int tm_tar_active(struct task_struct *target, const struct user_regset *regset);
-int tm_tar_get(struct task_struct *target, const struct user_regset *regset,
-	       unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn tm_tar_get;
 int tm_tar_set(struct task_struct *target, const struct user_regset *regset,
 	       unsigned int pos, unsigned int count,
 	       const void *kbuf, const void __user *ubuf);
 int tm_ppr_active(struct task_struct *target, const struct user_regset *regset);
-int tm_ppr_get(struct task_struct *target, const struct user_regset *regset,
-	       unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn tm_ppr_get;
 int tm_ppr_set(struct task_struct *target, const struct user_regset *regset,
 	       unsigned int pos, unsigned int count,
 	       const void *kbuf, const void __user *ubuf);
 int tm_dscr_active(struct task_struct *target, const struct user_regset *regset);
-int tm_dscr_get(struct task_struct *target, const struct user_regset *regset,
-		unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn tm_dscr_get;
 int tm_dscr_set(struct task_struct *target, const struct user_regset *regset,
 		unsigned int pos, unsigned int count,
 		const void *kbuf, const void __user *ubuf);
-int tm_cgpr32_get(struct task_struct *target, const struct user_regset *regset,
-		  unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf);
+user_regset_get2_fn tm_cgpr32_get;
 int tm_cgpr32_set(struct task_struct *target, const struct user_regset *regset,
 		  unsigned int pos, unsigned int count,
 		  const void *kbuf, const void __user *ubuf);

arch/powerpc/kernel/ptrace/ptrace-novsx.c

@@ -19,15 +19,14 @@
  * };
  */
 int fpr_get(struct task_struct *target, const struct user_regset *regset,
-	    unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf)
+	    struct membuf to)
 {
 	BUILD_BUG_ON(offsetof(struct thread_fp_state, fpscr) !=
 		     offsetof(struct thread_fp_state, fpr[32]));
 
 	flush_fp_to_thread(target);
 
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				   &target->thread.fp_state, 0, -1);
+	return membuf_write(&to, &target->thread.fp_state, 33 * sizeof(u64));
 }
 
 /*

arch/powerpc/kernel/ptrace/ptrace-spe.c

@@ -23,25 +23,17 @@ int evr_active(struct task_struct *target, const struct user_regset *regset)
 }
 
 int evr_get(struct task_struct *target, const struct user_regset *regset,
-	    unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf)
+	    struct membuf to)
 {
-	int ret;
-
 	flush_spe_to_thread(target);
 
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  &target->thread.evr,
-				  0, sizeof(target->thread.evr));
+	membuf_write(&to, &target->thread.evr, sizeof(target->thread.evr));
 
 	BUILD_BUG_ON(offsetof(struct thread_struct, acc) + sizeof(u64) !=
 		     offsetof(struct thread_struct, spefscr));
 
-	if (!ret)
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-					  &target->thread.acc,
-					  sizeof(target->thread.evr), -1);
-
-	return ret;
+	return membuf_write(&to, &target->thread.acc,
+				sizeof(u64) + sizeof(u32));
 }
 
 int evr_set(struct task_struct *target, const struct user_regset *regset,

arch/powerpc/kernel/ptrace/ptrace-vsx.c

@@ -19,7 +19,7 @@
  * };
  */
 int fpr_get(struct task_struct *target, const struct user_regset *regset,
-	    unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf)
+	    struct membuf to)
 {
 	u64 buf[33];
 	int i;
@@ -30,7 +30,7 @@ int fpr_get(struct task_struct *target, const struct user_regset *regset,
 	for (i = 0; i < 32 ; i++)
 		buf[i] = target->thread.TS_FPR(i);
 	buf[32] = target->thread.fp_state.fpscr;
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, buf, 0, -1);
+	return membuf_write(&to, buf, 33 * sizeof(u64));
 }
 
 /*
@@ -95,10 +95,10 @@ int vsr_active(struct task_struct *target, const struct user_regset *regset)
  * };
  */
 int vsr_get(struct task_struct *target, const struct user_regset *regset,
-	    unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf)
+	    struct membuf to)
 {
 	u64 buf[32];
-	int ret, i;
+	int i;
 
 	flush_tmregs_to_thread(target);
 	flush_fp_to_thread(target);
@@ -108,10 +108,7 @@ int vsr_get(struct task_struct *target, const struct user_regset *regset,
 	for (i = 0; i < 32 ; i++)
 		buf[i] = target->thread.fp_state.fpr[i][TS_VSRLOWOFFSET];
 
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  buf, 0, 32 * sizeof(double));
-
-	return ret;
+	return membuf_write(&to, buf, 32 * sizeof(double));
 }
 
 /*

arch/riscv/kernel/ptrace.c

@@ -30,13 +30,10 @@ enum riscv_regset {
 
 static int riscv_gpr_get(struct task_struct *target,
 			 const struct user_regset *regset,
-			 unsigned int pos, unsigned int count,
-			 void *kbuf, void __user *ubuf)
+			 struct membuf to)
 {
-	struct pt_regs *regs;
-
-	regs = task_pt_regs(target);
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
+	return membuf_write(&to, task_pt_regs(target),
+			    sizeof(struct user_regs_struct));
 }
 
 static int riscv_gpr_set(struct task_struct *target,
@@ -55,21 +52,13 @@ static int riscv_gpr_set(struct task_struct *target,
 #ifdef CONFIG_FPU
 static int riscv_fpr_get(struct task_struct *target,
 			 const struct user_regset *regset,
-			 unsigned int pos, unsigned int count,
-			 void *kbuf, void __user *ubuf)
+			 struct membuf to)
 {
-	int ret;
 	struct __riscv_d_ext_state *fstate = &target->thread.fstate;
 
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, fstate, 0,
-				  offsetof(struct __riscv_d_ext_state, fcsr));
-	if (!ret) {
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, fstate, 0,
-					  offsetof(struct __riscv_d_ext_state, fcsr) +
-					  sizeof(fstate->fcsr));
-	}
-
-	return ret;
+	membuf_write(&to, fstate, offsetof(struct __riscv_d_ext_state, fcsr));
+	membuf_store(&to, fstate->fcsr);
+	return membuf_zero(&to, 4);	// explicitly pad
 }
 
 static int riscv_fpr_set(struct task_struct *target,
@@ -98,8 +87,8 @@ static const struct user_regset riscv_user_regset[] = {
 		.n = ELF_NGREG,
 		.size = sizeof(elf_greg_t),
 		.align = sizeof(elf_greg_t),
-		.get = &riscv_gpr_get,
-		.set = &riscv_gpr_set,
+		.regset_get = riscv_gpr_get,
+		.set = riscv_gpr_set,
 	},
 #ifdef CONFIG_FPU
 	[REGSET_F] = {
@@ -107,8 +96,8 @@ static const struct user_regset riscv_user_regset[] = {
 		.n = ELF_NFPREG,
 		.size = sizeof(elf_fpreg_t),
 		.align = sizeof(elf_fpreg_t),
-		.get = &riscv_fpr_get,
-		.set = &riscv_fpr_set,
+		.regset_get = riscv_fpr_get,
+		.set = riscv_fpr_set,
 	},
 #endif
 };

arch/sh/kernel/process_32.c

@@ -103,9 +103,8 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 
 	fpvalid = !!tsk_used_math(tsk);
 	if (fpvalid)
-		fpvalid = !fpregs_get(tsk, NULL, 0,
-				      sizeof(struct user_fpu_struct),
-				      fpu, NULL);
+		fpvalid = !fpregs_get(tsk, NULL,
+				      (struct membuf){fpu, sizeof(*fpu)});
 #endif
 
 	return fpvalid;

arch/sh/kernel/ptrace_32.c

@@ -134,26 +134,11 @@ void ptrace_disable(struct task_struct *child)
 
 static int genregs_get(struct task_struct *target,
 		       const struct user_regset *regset,
-		       unsigned int pos, unsigned int count,
-		       void *kbuf, void __user *ubuf)
+		       struct membuf to)
 {
 	const struct pt_regs *regs = task_pt_regs(target);
-	int ret;
 
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  regs->regs,
-				  0, 16 * sizeof(unsigned long));
-	if (!ret)
-		/* PC, PR, SR, GBR, MACH, MACL, TRA */
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-					  &regs->pc,
-					  offsetof(struct pt_regs, pc),
-					  sizeof(struct pt_regs));
-	if (!ret)
-		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					       sizeof(struct pt_regs), -1);
-
-	return ret;
+	return membuf_write(&to, regs, sizeof(struct pt_regs));
 }
 
 static int genregs_set(struct task_struct *target,
@@ -182,8 +167,7 @@ static int genregs_set(struct task_struct *target,
 #ifdef CONFIG_SH_FPU
 int fpregs_get(struct task_struct *target,
 	       const struct user_regset *regset,
-	       unsigned int pos, unsigned int count,
-	       void *kbuf, void __user *ubuf)
+	       struct membuf to)
 {
 	int ret;
 
@@ -191,12 +175,8 @@ int fpregs_get(struct task_struct *target,
 	if (ret)
 		return ret;
 
-	if ((boot_cpu_data.flags & CPU_HAS_FPU))
-		return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-					   &target->thread.xstate->hardfpu, 0, -1);
-
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				   &target->thread.xstate->softfpu, 0, -1);
+	return membuf_write(&to, target->thread.xstate,
+			    sizeof(struct user_fpu_struct));
 }
 
 static int fpregs_set(struct task_struct *target,
@@ -230,20 +210,12 @@ static int fpregs_active(struct task_struct *target,
 #ifdef CONFIG_SH_DSP
 static int dspregs_get(struct task_struct *target,
 		       const struct user_regset *regset,
-		       unsigned int pos, unsigned int count,
-		       void *kbuf, void __user *ubuf)
+		       struct membuf to)
 {
 	const struct pt_dspregs *regs =
 		(struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
-	int ret;
 
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs,
-				  0, sizeof(struct pt_dspregs));
-	if (!ret)
-		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					       sizeof(struct pt_dspregs), -1);
-
-	return ret;
+	return membuf_write(&to, regs, sizeof(struct pt_dspregs));
 }
 
 static int dspregs_set(struct task_struct *target,
@@ -324,7 +296,7 @@ static const struct user_regset sh_regsets[] = {
 		.n		= ELF_NGREG,
 		.size		= sizeof(long),
 		.align		= sizeof(long),
-		.get		= genregs_get,
+		.regset_get		= genregs_get,
 		.set		= genregs_set,
 	},
 
@@ -334,7 +306,7 @@ static const struct user_regset sh_regsets[] = {
 		.n		= sizeof(struct user_fpu_struct) / sizeof(long),
 		.size		= sizeof(long),
 		.align		= sizeof(long),
-		.get		= fpregs_get,
+		.regset_get		= fpregs_get,
 		.set		= fpregs_set,
 		.active		= fpregs_active,
 	},
@@ -345,7 +317,7 @@ static const struct user_regset sh_regsets[] = {
 		.n		= sizeof(struct pt_dspregs) / sizeof(long),
 		.size		= sizeof(long),
 		.align		= sizeof(long),
-		.get		= dspregs_get,
+		.regset_get		= dspregs_get,
 		.set		= dspregs_set,
 		.active		= dspregs_active,
 	},

arch/sparc/kernel/ptrace_32.c

@@ -83,41 +83,25 @@ static int regwindow32_set(struct task_struct *target,
 
 static int genregs32_get(struct task_struct *target,
 			 const struct user_regset *regset,
-			 unsigned int pos, unsigned int count,
-			 void *kbuf, void __user *ubuf)
+			 struct membuf to)
 {
 	const struct pt_regs *regs = target->thread.kregs;
 	u32 uregs[16];
-	int ret;
 
 	if (target == current)
 		flush_user_windows();
 
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  regs->u_regs,
-				  0, 16 * sizeof(u32));
-	if (ret || !count)
-		return ret;
-
-	if (pos < 32 * sizeof(u32)) {
-		if (regwindow32_get(target, regs, uregs))
-			return -EFAULT;
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-					  uregs,
-					  16 * sizeof(u32), 32 * sizeof(u32));
-		if (ret || !count)
-			return ret;
-	}
-
-	uregs[0] = regs->psr;
-	uregs[1] = regs->pc;
-	uregs[2] = regs->npc;
-	uregs[3] = regs->y;
-	uregs[4] = 0;	/* WIM */
-	uregs[5] = 0;	/* TBR */
-	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  uregs,
-				  32 * sizeof(u32), 38 * sizeof(u32));
+	membuf_write(&to, regs->u_regs, 16 * sizeof(u32));
+	if (!to.left)
+		return 0;
+	if (regwindow32_get(target, regs, uregs))
+		return -EFAULT;
+	membuf_write(&to, uregs, 16 * sizeof(u32));
+	membuf_store(&to, regs->psr);
+	membuf_store(&to, regs->pc);
+	membuf_store(&to, regs->npc);
+	membuf_store(&to, regs->y);
+	return membuf_zero(&to, 2 * sizeof(u32));
 }
 
 static int genregs32_set(struct task_struct *target,
@@ -139,19 +123,18 @@ static int genregs32_set(struct task_struct *target,
 	if (ret || !count)
 		return ret;
 
-	if (pos < 32 * sizeof(u32)) {
-		if (regwindow32_get(target, regs, uregs))
-			return -EFAULT;
-		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
-					 uregs,
-					 16 * sizeof(u32), 32 * sizeof(u32));
-		if (ret)
-			return ret;
-		if (regwindow32_set(target, regs, uregs))
-			return -EFAULT;
-		if (!count)
-			return 0;
-	}
+	if (regwindow32_get(target, regs, uregs))
+		return -EFAULT;
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 uregs,
+				 16 * sizeof(u32), 32 * sizeof(u32));
+	if (ret)
+		return ret;
+	if (regwindow32_set(target, regs, uregs))
+		return -EFAULT;
+	if (!count)
+		return 0;
+
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 				 &psr,
 				 32 * sizeof(u32), 33 * sizeof(u32));
@@ -182,46 +165,18 @@ static int genregs32_set(struct task_struct *target,
 
 static int fpregs32_get(struct task_struct *target,
 			const struct user_regset *regset,
-			unsigned int pos, unsigned int count,
-			void *kbuf, void __user *ubuf)
+			struct membuf to)
 {
-	const unsigned long *fpregs = target->thread.float_regs;
-	int ret = 0;
-
 #if 0
 	if (target == current)
 		save_and_clear_fpu();
 #endif
 
-	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-				  fpregs,
-				  0, 32 * sizeof(u32));
-
-	if (!ret)
-		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					       32 * sizeof(u32),
-					       33 * sizeof(u32));
-	if (!ret)
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-					  &target->thread.fsr,
-					  33 * sizeof(u32),
-					  34 * sizeof(u32));
-
-	if (!ret) {
-		unsigned long val;
-
-		val = (1 << 8) | (8 << 16);
-		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
-					  &val,
-					  34 * sizeof(u32),
-					  35 * sizeof(u32));
-	}
-
-	if (!ret)
-		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
-					       35 * sizeof(u32), -1);
-
-	return ret;
+	membuf_write(&to, target->thread.float_regs, 32 * sizeof(u32));
+	membuf_zero(&to, sizeof(u32));
+	membuf_write(&to, &target->thread.fsr, sizeof(u32));
+	membuf_store(&to, (u32)((1 << 8) | (8 << 16)));
+	return membuf_zero(&to, 64 * sizeof(u32));
 }
 
 static int fpregs32_set(struct task_struct *target,
@@ -243,13 +198,11 @@ static int fpregs32_set(struct task_struct *target,
 		user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 					  32 * sizeof(u32),
 					  33 * sizeof(u32));
-	if (!ret && count > 0) {
+	if (!ret)
 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 					 &target->thread.fsr,
 					 33 * sizeof(u32),
 					 34 * sizeof(u32));
-	}
-
 	if (!ret)
 		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 						34 * sizeof(u32), -1);
@@ -268,7 +221,7 @@ static const struct user_regset sparc32_regsets[] = {
 		.core_note_type = NT_PRSTATUS,
 		.n = 38,
 		.size = sizeof(u32), .align = sizeof(u32),
-		.get = genregs32_get, .set = genregs32_set
+		.regset_get = genregs32_get, .set = genregs32_set
 	},
 	/* Format is:
 	 *	F0 --> F31
@@ -284,10 +237,104 @@ static const struct user_regset sparc32_regsets[] = {
 		.core_note_type = NT_PRFPREG,
 		.n = 99,
 		.size = sizeof(u32), .align = sizeof(u32),
-		.get = fpregs32_get, .set = fpregs32_set
+		.regset_get = fpregs32_get, .set = fpregs32_set
+	},
+};
+
+static int getregs_get(struct task_struct *target,
+			 const struct user_regset *regset,
+			 struct membuf to)
+{
+	const struct pt_regs *regs = target->thread.kregs;
+
+	if (target == current)
+		flush_user_windows();
+
+	membuf_store(&to, regs->psr);
+	membuf_store(&to, regs->pc);
+	membuf_store(&to, regs->npc);
+	membuf_store(&to, regs->y);
+	return membuf_write(&to, regs->u_regs + 1, 15 * sizeof(u32));
+}
+
+static int setregs_set(struct task_struct *target,
+			 const struct user_regset *regset,
+			 unsigned int pos, unsigned int count,
+			 const void *kbuf, const void __user *ubuf)
+{
+	struct pt_regs *regs = target->thread.kregs;
+	u32 v[4];
+	int ret;
+
+	if (target == current)
+		flush_user_windows();
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 v,
+				 0, 4 * sizeof(u32));
+	if (ret)
+		return ret;
+	regs->psr = (regs->psr & ~(PSR_ICC | PSR_SYSCALL)) |
+		    (v[0] & (PSR_ICC | PSR_SYSCALL));
+	regs->pc = v[1];
+	regs->npc = v[2];
+	regs->y = v[3];
+	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 regs->u_regs + 1,
+				 4 * sizeof(u32) , 19 * sizeof(u32));
+}
+
+static int getfpregs_get(struct task_struct *target,
+			const struct user_regset *regset,
+			struct membuf to)
+{
+#if 0
+	if (target == current)
+		save_and_clear_fpu();
+#endif
+	membuf_write(&to, &target->thread.float_regs, 32 * sizeof(u32));
+	membuf_write(&to, &target->thread.fsr, sizeof(u32));
+	return membuf_zero(&to, 35 * sizeof(u32));
+}
+
+static int setfpregs_set(struct task_struct *target,
+			const struct user_regset *regset,
+			unsigned int pos, unsigned int count,
+			const void *kbuf, const void __user *ubuf)
+{
+	unsigned long *fpregs = target->thread.float_regs;
+	int ret;
+
+#if 0
+	if (target == current)
+		save_and_clear_fpu();
+#endif
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 fpregs,
+				 0, 32 * sizeof(u32));
+	if (ret)
+		return ret;
+	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 &target->thread.fsr,
+				 32 * sizeof(u32),
+				 33 * sizeof(u32));
+}
+
+static const struct user_regset ptrace32_regsets[] = {
+	[REGSET_GENERAL] = {
+		.n = 19, .size = sizeof(u32),
+		.regset_get = getregs_get, .set = setregs_set,
+	},
+	[REGSET_FP] = {
+		.n = 68, .size = sizeof(u32),
+		.regset_get = getfpregs_get, .set = setfpregs_set,
 	},
 };
 
+static const struct user_regset_view ptrace32_view = {
+	.regsets = ptrace32_regsets, .n = ARRAY_SIZE(ptrace32_regsets)
+};
+
 static const struct user_regset_view user_sparc32_view = {
 	.name = "sparc", .e_machine = EM_SPARC,
 	.regsets = sparc32_regsets, .n = ARRAY_SIZE(sparc32_regsets)
@@ -315,74 +362,44 @@ long arch_ptrace(struct task_struct *child, long request,
 {
 	unsigned long addr2 = current->thread.kregs->u_regs[UREG_I4];
 	void __user *addr2p;
-	const struct user_regset_view *view;
 	struct pt_regs __user *pregs;
 	struct fps __user *fps;
 	int ret;
 
-	view = task_user_regset_view(current);
 	addr2p = (void __user *) addr2;
 	pregs = (struct pt_regs __user *) addr;
 	fps = (struct fps __user *) addr;
 
 	switch(request) {
 	case PTRACE_GETREGS: {
-		ret = copy_regset_to_user(child, view, REGSET_GENERAL,
-					  32 * sizeof(u32),
-					  4 * sizeof(u32),
-					  &pregs->psr);
-		if (!ret)
-			copy_regset_to_user(child, view, REGSET_GENERAL,
-					    1 * sizeof(u32),
-					    15 * sizeof(u32),
-					    &pregs->u_regs[0]);
+		ret = copy_regset_to_user(child, &ptrace32_view,
+					  REGSET_GENERAL, 0,
+					  19 * sizeof(u32),
+					  pregs);
 		break;
 	}
 
 	case PTRACE_SETREGS: {
-		ret = copy_regset_from_user(child, view, REGSET_GENERAL,
-					    32 * sizeof(u32),
-					    4 * sizeof(u32),
-					    &pregs->psr);
-		if (!ret)
-			copy_regset_from_user(child, view, REGSET_GENERAL,
-					      1 * sizeof(u32),
-					      15 * sizeof(u32),
-					      &pregs->u_regs[0]);
+		ret = copy_regset_from_user(child, &ptrace32_view,
+					    REGSET_GENERAL, 0,
+					    19 * sizeof(u32),
+					    pregs);
 		break;
 	}
 
 	case PTRACE_GETFPREGS: {
-		ret = copy_regset_to_user(child, view, REGSET_FP,
-					  0 * sizeof(u32),
-					  32 * sizeof(u32),
-					  &fps->regs[0]);
-		if (!ret)
-			ret = copy_regset_to_user(child, view, REGSET_FP,
-						  33 * sizeof(u32),
-						  1 * sizeof(u32),
-						  &fps->fsr);
-
-		if (!ret) {
-			if (__put_user(0, &fps->fpqd) ||
-			    __put_user(0, &fps->flags) ||
-			    __put_user(0, &fps->extra) ||
-			    clear_user(fps->fpq, sizeof(fps->fpq)))
-				ret = -EFAULT;
-		}
+		ret = copy_regset_to_user(child, &ptrace32_view,
+					  REGSET_FP, 0,
+					  68 * sizeof(u32),
+					  fps);
 		break;
 	}
 
 	case PTRACE_SETFPREGS: {
-		ret = copy_regset_from_user(child, view, REGSET_FP,
-					    0 * sizeof(u32),
-					    32 * sizeof(u32),
-					    &fps->regs[0]);
-		if (!ret)
-			ret = copy_regset_from_user(child, view, REGSET_FP,
-						    33 * sizeof(u32),
-						    1 * sizeof(u32),
-						    &fps->fsr);
+		ret = copy_regset_from_user(child, &ptrace32_view,
+					  REGSET_FP, 0,
+					  33 * sizeof(u32),
+					  fps);
 		break;
 	}
 

arch/x86/include/asm/fpu/internal.h

@@ -34,7 +34,6 @@ extern int  fpu__copy(struct task_struct *dst, struct task_struct *src);
 extern void fpu__clear_user_states(struct fpu *fpu);
 extern void fpu__clear_all(struct fpu *fpu);
 extern int  fpu__exception_code(struct fpu *fpu, int trap_nr);
-extern int  dump_fpu(struct pt_regs *ptregs, struct user_i387_struct *fpstate);
 
 /*
  * Boot time FPU initialization functions:

arch/x86/include/asm/fpu/regset.h

@@ -8,8 +8,8 @@
 #include <linux/regset.h>
 
 extern user_regset_active_fn regset_fpregs_active, regset_xregset_fpregs_active;
-extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get,
-				xstateregs_get;
+extern user_regset_get2_fn fpregs_get, xfpregs_get, fpregs_soft_get,
+				 xstateregs_get;
 extern user_regset_set_fn fpregs_set, xfpregs_set, fpregs_soft_set,
 				 xstateregs_set;
 

arch/x86/include/asm/fpu/xstate.h

@@ -104,8 +104,8 @@ void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
 const void *get_xsave_field_ptr(int xfeature_nr);
 int using_compacted_format(void);
 int xfeature_size(int xfeature_nr);
-int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
-int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
+struct membuf;
+void copy_xstate_to_kernel(struct membuf to, struct xregs_state *xsave);
 int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf);
 int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf);
 void copy_supervisor_to_kernel(struct xregs_state *xsave);

arch/x86/kernel/fpu/signal.c

@@ -170,14 +170,15 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
 	ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) ||
 			 IS_ENABLED(CONFIG_IA32_EMULATION));
 
+	if (!static_cpu_has(X86_FEATURE_FPU)) {
+		struct user_i387_ia32_struct fp;
+		fpregs_soft_get(current, NULL, (struct membuf){.p = &fp,
+						.left = sizeof(fp)});
+		return copy_to_user(buf, &fp, sizeof(fp)) ? -EFAULT : 0;
+	}
+
 	if (!access_ok(buf, size))
 		return -EACCES;
-
-	if (!static_cpu_has(X86_FEATURE_FPU))
-		return fpregs_soft_get(current, NULL, 0,
-			sizeof(struct user_i387_ia32_struct), NULL,
-			(struct _fpstate_32 __user *) buf) ? -1 : 1;
-
 retry:
 	/*
 	 * Load the FPU registers if they are not valid for the current task.