Unification of regset and non-regset sides of ELF coredump

handling.  Collecting per-thread register values is the
 only thing that needs to be ifdefed there...
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-elfcore' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull elf coredumping updates from Al Viro:
 "Unification of regset and non-regset sides of ELF coredump handling.

  Collecting per-thread register values is the only thing that needs to
  be ifdefed there..."

* tag 'pull-elfcore' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  [elf] get rid of get_note_info_size()
  [elf] unify regset and non-regset cases
  [elf][non-regset] use elf_core_copy_task_regs() for dumper as well
  [elf][non-regset] uninline elf_core_copy_task_fpregs() (and lose pt_regs argument)
  elf_core_copy_task_regs(): task_pt_regs is defined everywhere
  [elf][regset] simplify thread list handling in fill_note_info()
  [elf][regset] clean fill_note_info() a bit
  kill extern of vsyscall32_sysctl
  kill coredump_params->regs
  kill signal_pt_regs()

arch/alpha/include/asm/elf.h

@@ -120,12 +120,6 @@ extern int dump_elf_task(elf_greg_t *dest, struct task_struct *task);
 #define ELF_CORE_COPY_TASK_REGS(TASK, DEST) \
 	dump_elf_task(*(DEST), TASK)
 
-/* Similar, but for the FP registers.  */
-
-extern int dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task);
-#define ELF_CORE_COPY_FPREGS(TASK, DEST) \
-	dump_elf_task_fp(*(DEST), TASK)
-
 /* This yields a mask that user programs can use to figure out what
    instruction set this CPU supports.  This is trivial on Alpha, 
    but not so on other machines. */

arch/alpha/include/asm/ptrace.h

@@ -16,7 +16,6 @@
 
 #define current_pt_regs() \
   ((struct pt_regs *) ((char *)current_thread_info() + 2*PAGE_SIZE) - 1)
-#define signal_pt_regs current_pt_regs
 
 #define force_successful_syscall_return() (current_pt_regs()->r0 = 0)
 

arch/alpha/kernel/process.c

@@ -333,14 +333,12 @@ dump_elf_task(elf_greg_t *dest, struct task_struct *task)
 }
 EXPORT_SYMBOL(dump_elf_task);
 
-int
+int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
-dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task)
 {
-	struct switch_stack *sw = (struct switch_stack *)task_pt_regs(task) - 1;
+	struct switch_stack *sw = (struct switch_stack *)task_pt_regs(t) - 1;
-	memcpy(dest, sw->fp, 32 * 8);
+	memcpy(fpu, sw->fp, 32 * 8);
 	return 1;
 }
-EXPORT_SYMBOL(dump_elf_task_fp);
 
 /*
  * Return saved PC of a blocked thread.  This assumes the frame

arch/csky/kernel/process.c

@@ -9,6 +9,7 @@
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
 #include <linux/ptrace.h>
+#include <linux/elfcore.h>
 
 #include <asm/elf.h>
 #include <abi/reg_ops.h>
@@ -69,12 +70,11 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 }
 
 /* Fill in the fpu structure for a core dump.  */
-int dump_fpu(struct pt_regs *regs, struct user_fp *fpu)
+int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
 {
 	memcpy(fpu, &current->thread.user_fp, sizeof(*fpu));
 	return 1;
 }
-EXPORT_SYMBOL(dump_fpu);
 
 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *pr_regs)
 {

arch/m68k/kernel/process.c

@@ -32,6 +32,7 @@
 #include <linux/rcupdate.h>
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
+#include <linux/elfcore.h>
 
 #include <asm/traps.h>
 #include <asm/machdep.h>
@@ -213,7 +214,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 }
 
 /* Fill in the fpu structure for a core dump.  */
-int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
+int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
 {
 	if (FPU_IS_EMU) {
 		int i;
@@ -262,7 +263,6 @@ int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 
 	return 1;
 }
-EXPORT_SYMBOL(dump_fpu);
 
 unsigned long __get_wchan(struct task_struct *p)
 {

arch/microblaze/kernel/process.c

@@ -133,7 +133,7 @@ void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
 /*
  * Set up a thread for executing a new program
  */
-int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
+int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
 {
 	return 0; /* MicroBlaze has no separate FPU registers */
 }

arch/um/kernel/process.c

@@ -33,6 +33,7 @@
 #include <skas.h>
 #include <registers.h>
 #include <linux/time-internal.h>
+#include <linux/elfcore.h>
 
 /*
  * This is a per-cpu array.  A processor only modifies its entry and it only
@@ -393,7 +394,7 @@ unsigned long __get_wchan(struct task_struct *p)
 	return 0;
 }
 
-int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
+int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu)
 {
 	int cpu = current_thread_info()->cpu;
 

arch/x86/include/asm/elf.h

@@ -222,7 +222,6 @@ do {								\
 /* I'm not sure if we can use '-' here */
 #define ELF_PLATFORM       ("x86_64")
 extern void set_personality_64bit(void);
-extern unsigned int sysctl_vsyscall32;
 extern int force_personality32;
 
 #endif /* !CONFIG_X86_32 */

arch/x86/um/asm/elf.h

@@ -201,10 +201,6 @@ typedef struct user_i387_struct elf_fpregset_t;
 
 struct task_struct;
 
-extern int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu);
-
-#define ELF_CORE_COPY_FPREGS(t, fpu) elf_core_copy_fpregs(t, fpu)
-
 #define ELF_EXEC_PAGESIZE 4096
 
 #define ELF_ET_DYN_BASE (TASK_SIZE / 3 * 2)

fs/binfmt_elf.c

@@ -1718,7 +1718,6 @@ static int fill_files_note(struct memelfnote *note, struct coredump_params *cprm
 	return 0;
 }
 
-#ifdef CORE_DUMP_USE_REGSET
 #include <linux/regset.h>
 
 struct elf_thread_core_info {
@@ -1739,6 +1738,7 @@ struct elf_note_info {
 	int thread_notes;
 };
 
+#ifdef CORE_DUMP_USE_REGSET
 /*
  * When a regset has a writeback hook, we call it on each thread before
  * dumping user memory.  On register window machines, this makes sure the
@@ -1818,34 +1818,58 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 
 	return 1;
 }
+#else
+static int fill_thread_core_info(struct elf_thread_core_info *t,
+				 const struct user_regset_view *view,
+				 long signr, struct elf_note_info *info)
+{
+	struct task_struct *p = t->task;
+	elf_fpregset_t *fpu;
+
+	fill_prstatus(&t->prstatus.common, p, signr);
+	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
+
+	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
+		  &(t->prstatus));
+	info->size += notesize(&t->notes[0]);
+
+	fpu = kzalloc(sizeof(elf_fpregset_t), GFP_KERNEL);
+	if (!fpu || !elf_core_copy_task_fpregs(p, fpu)) {
+		kfree(fpu);
+		return 1;
+	}
+
+	t->prstatus.pr_fpvalid = 1;
+	fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
+	info->size += notesize(&t->notes[1]);
+
+	return 1;
+}
+#endif
 
 static int fill_note_info(struct elfhdr *elf, int phdrs,
 			  struct elf_note_info *info,
 			  struct coredump_params *cprm)
 {
 	struct task_struct *dump_task = current;
-	const struct user_regset_view *view = task_user_regset_view(dump_task);
+	const struct user_regset_view *view;
 	struct elf_thread_core_info *t;
 	struct elf_prpsinfo *psinfo;
 	struct core_thread *ct;
-	unsigned int i;
-
-	info->size = 0;
-	info->thread = NULL;
 
 	psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
-	if (psinfo == NULL) {
+	if (!psinfo)
-		info->psinfo.data = NULL; /* So we don't free this wrongly */
 		return 0;
-	}
-
 	fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
 
+#ifdef CORE_DUMP_USE_REGSET
+	view = task_user_regset_view(dump_task);
+
 	/*
 	 * Figure out how many notes we're going to need for each thread.
 	 */
 	info->thread_notes = 0;
-	for (i = 0; i < view->n; ++i)
+	for (int i = 0; i < view->n; ++i)
 		if (view->regsets[i].core_note_type != 0)
 			++info->thread_notes;
 
@@ -1864,11 +1888,23 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
 	 */
 	fill_elf_header(elf, phdrs,
 			view->e_machine, view->e_flags);
+#else
+	view = NULL;
+	info->thread_notes = 2;
+	fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS);
+#endif
 
 	/*
 	 * Allocate a structure for each thread.
 	 */
-	for (ct = &dump_task->signal->core_state->dumper; ct; ct = ct->next) {
+	info->thread = kzalloc(offsetof(struct elf_thread_core_info,
+				     notes[info->thread_notes]),
+			    GFP_KERNEL);
+	if (unlikely(!info->thread))
+		return 0;
+
+	info->thread->task = dump_task;
+	for (ct = dump_task->signal->core_state->dumper.next; ct; ct = ct->next) {
 		t = kzalloc(offsetof(struct elf_thread_core_info,
 				     notes[info->thread_notes]),
 			    GFP_KERNEL);
@@ -1876,17 +1912,8 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
 			return 0;
 
 		t->task = ct->task;
-		if (ct->task == dump_task || !info->thread) {
+		t->next = info->thread->next;
-			t->next = info->thread;
+		info->thread->next = t;
-			info->thread = t;
-		} else {
-			/*
-			 * Make sure to keep the original task at
-			 * the head of the list.
-			 */
-			t->next = info->thread->next;
-			info->thread->next = t;
-		}
 	}
 
 	/*
@@ -1914,11 +1941,6 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
 	return 1;
 }
 
-static size_t get_note_info_size(struct elf_note_info *info)
-{
-	return info->size;
-}
-
 /*
  * Write all the notes for each thread.  When writing the first thread, the
  * process-wide notes are interleaved after the first thread-specific note.
@@ -1973,197 +1995,6 @@ static void free_note_info(struct elf_note_info *info)
 	kvfree(info->files.data);
 }
 
-#else
-
-/* Here is the structure in which status of each thread is captured. */
-struct elf_thread_status
-{
-	struct list_head list;
-	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
-	elf_fpregset_t fpu;		/* NT_PRFPREG */
-	struct task_struct *thread;
-	struct memelfnote notes[3];
-	int num_notes;
-};
-
-/*
- * In order to add the specific thread information for the elf file format,
- * we need to keep a linked list of every threads pr_status and then create
- * a single section for them in the final core file.
- */
-static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
-{
-	int sz = 0;
-	struct task_struct *p = t->thread;
-	t->num_notes = 0;
-
-	fill_prstatus(&t->prstatus.common, p, signr);
-	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
-
-	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
-		  &(t->prstatus));
-	t->num_notes++;
-	sz += notesize(&t->notes[0]);
-
-	if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL,
-								&t->fpu))) {
-		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
-			  &(t->fpu));
-		t->num_notes++;
-		sz += notesize(&t->notes[1]);
-	}
-	return sz;
-}
-
-struct elf_note_info {
-	struct memelfnote *notes;
-	struct memelfnote *notes_files;
-	struct elf_prstatus *prstatus;	/* NT_PRSTATUS */
-	struct elf_prpsinfo *psinfo;	/* NT_PRPSINFO */
-	struct list_head thread_list;
-	elf_fpregset_t *fpu;
-	user_siginfo_t csigdata;
-	int thread_status_size;
-	int numnote;
-};
-
-static int elf_note_info_init(struct elf_note_info *info)
-{
-	memset(info, 0, sizeof(*info));
-	INIT_LIST_HEAD(&info->thread_list);
-
-	/* Allocate space for ELF notes */
-	info->notes = kmalloc_array(8, sizeof(struct memelfnote), GFP_KERNEL);
-	if (!info->notes)
-		return 0;
-	info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
-	if (!info->psinfo)
-		return 0;
-	info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL);
-	if (!info->prstatus)
-		return 0;
-	info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL);
-	if (!info->fpu)
-		return 0;
-	return 1;
-}
-
-static int fill_note_info(struct elfhdr *elf, int phdrs,
-			  struct elf_note_info *info,
-			  struct coredump_params *cprm)
-{
-	struct core_thread *ct;
-	struct elf_thread_status *ets;
-
-	if (!elf_note_info_init(info))
-		return 0;
-
-	for (ct = current->signal->core_state->dumper.next;
-					ct; ct = ct->next) {
-		ets = kzalloc(sizeof(*ets), GFP_KERNEL);
-		if (!ets)
-			return 0;
-
-		ets->thread = ct->task;
-		list_add(&ets->list, &info->thread_list);
-	}
-
-	list_for_each_entry(ets, &info->thread_list, list) {
-		int sz;
-
-		sz = elf_dump_thread_status(cprm->siginfo->si_signo, ets);
-		info->thread_status_size += sz;
-	}
-	/* now collect the dump for the current */
-	memset(info->prstatus, 0, sizeof(*info->prstatus));
-	fill_prstatus(&info->prstatus->common, current, cprm->siginfo->si_signo);
-	elf_core_copy_regs(&info->prstatus->pr_reg, cprm->regs);
-
-	/* Set up header */
-	fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS);
-
-	/*
-	 * Set up the notes in similar form to SVR4 core dumps made
-	 * with info from their /proc.
-	 */
-
-	fill_note(info->notes + 0, "CORE", NT_PRSTATUS,
-		  sizeof(*info->prstatus), info->prstatus);
-	fill_psinfo(info->psinfo, current->group_leader, current->mm);
-	fill_note(info->notes + 1, "CORE", NT_PRPSINFO,
-		  sizeof(*info->psinfo), info->psinfo);
-
-	fill_siginfo_note(info->notes + 2, &info->csigdata, cprm->siginfo);
-	fill_auxv_note(info->notes + 3, current->mm);
-	info->numnote = 4;
-
-	if (fill_files_note(info->notes + info->numnote, cprm) == 0) {
-		info->notes_files = info->notes + info->numnote;
-		info->numnote++;
-	}
-
-	/* Try to dump the FPU. */
-	info->prstatus->pr_fpvalid =
-		elf_core_copy_task_fpregs(current, cprm->regs, info->fpu);
-	if (info->prstatus->pr_fpvalid)
-		fill_note(info->notes + info->numnote++,
-			  "CORE", NT_PRFPREG, sizeof(*info->fpu), info->fpu);
-	return 1;
-}
-
-static size_t get_note_info_size(struct elf_note_info *info)
-{
-	int sz = 0;
-	int i;
-
-	for (i = 0; i < info->numnote; i++)
-		sz += notesize(info->notes + i);
-
-	sz += info->thread_status_size;
-
-	return sz;
-}
-
-static int write_note_info(struct elf_note_info *info,
-			   struct coredump_params *cprm)
-{
-	struct elf_thread_status *ets;
-	int i;
-
-	for (i = 0; i < info->numnote; i++)
-		if (!writenote(info->notes + i, cprm))
-			return 0;
-
-	/* write out the thread status notes section */
-	list_for_each_entry(ets, &info->thread_list, list) {
-		for (i = 0; i < ets->num_notes; i++)
-			if (!writenote(&ets->notes[i], cprm))
-				return 0;
-	}
-
-	return 1;
-}
-
-static void free_note_info(struct elf_note_info *info)
-{
-	while (!list_empty(&info->thread_list)) {
-		struct list_head *tmp = info->thread_list.next;
-		list_del(tmp);
-		kfree(list_entry(tmp, struct elf_thread_status, list));
-	}
-
-	/* Free data possibly allocated by fill_files_note(): */
-	if (info->notes_files)
-		kvfree(info->notes_files->data);
-
-	kfree(info->prstatus);
-	kfree(info->psinfo);
-	kfree(info->notes);
-	kfree(info->fpu);
-}
-
-#endif
-
 static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
 			     elf_addr_t e_shoff, int segs)
 {
@@ -2227,7 +2058,7 @@ static int elf_core_dump(struct coredump_params *cprm)
 
 	/* Write notes phdr entry */
 	{
-		size_t sz = get_note_info_size(&info);
+		size_t sz = info.size;
 
 		/* For cell spufs */
 		sz += elf_coredump_extra_notes_size();

fs/coredump.c

@@ -529,7 +529,6 @@ void do_coredump(const kernel_siginfo_t *siginfo)
 	static atomic_t core_dump_count = ATOMIC_INIT(0);
 	struct coredump_params cprm = {
 		.siginfo = siginfo,
-		.regs = signal_pt_regs(),
 		.limit = rlimit(RLIMIT_CORE),
 		/*
 		 * We must use the same mm->flags while dumping core to avoid

include/linux/coredump.h

@@ -18,7 +18,6 @@ struct core_vma_metadata {
 
 struct coredump_params {
 	const kernel_siginfo_t *siginfo;
-	struct pt_regs *regs;
 	struct file *file;
 	unsigned long limit;
 	unsigned long mm_flags;

include/linux/elfcore.h

@@ -88,22 +88,13 @@ static inline int elf_core_copy_task_regs(struct task_struct *t, elf_gregset_t*
 {
 #if defined (ELF_CORE_COPY_TASK_REGS)
 	return ELF_CORE_COPY_TASK_REGS(t, elfregs);
-#elif defined (task_pt_regs)
+#else
 	elf_core_copy_regs(elfregs, task_pt_regs(t));
 #endif
 	return 0;
 }
 
-extern int dump_fpu (struct pt_regs *, elf_fpregset_t *);
+int elf_core_copy_task_fpregs(struct task_struct *t, elf_fpregset_t *fpu);
-
-static inline int elf_core_copy_task_fpregs(struct task_struct *t, struct pt_regs *regs, elf_fpregset_t *fpu)
-{
-#ifdef ELF_CORE_COPY_FPREGS
-	return ELF_CORE_COPY_FPREGS(t, fpu);
-#else
-	return dump_fpu(regs, fpu);
-#endif
-}
 
 #ifdef CONFIG_ARCH_BINFMT_ELF_EXTRA_PHDRS
 /*

include/linux/ptrace.h

@@ -389,15 +389,6 @@ static inline void user_single_step_report(struct pt_regs *regs)
 #define current_pt_regs() task_pt_regs(current)
 #endif
 
-/*
- * unlike current_pt_regs(), this one is equal to task_pt_regs(current)
- * on *all* architectures; the only reason to have a per-arch definition
- * is optimisation.
- */
-#ifndef signal_pt_regs
-#define signal_pt_regs() task_pt_regs(current)
-#endif
-
 #ifndef current_user_stack_pointer
 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
 #endif

kernel/signal.c

@@ -1255,7 +1255,7 @@ int send_signal_locked(int sig, struct kernel_siginfo *info,
 
 static void print_fatal_signal(int signr)
 {
-	struct pt_regs *regs = signal_pt_regs();
+	struct pt_regs *regs = task_pt_regs(current);
 	pr_info("potentially unexpected fatal signal %d.\n", signr);
 
 #if defined(__i386__) && !defined(__arch_um__)