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

Pull ELF compat updates from Al Viro:
 "Sanitizing ELF compat support, especially for triarch architectures:

   - X32 handling cleaned up

   - MIPS64 uses compat_binfmt_elf.c both for O32 and N32 now

   - Kconfig side of things regularized

  Eventually I hope to have compat_binfmt_elf.c killed, with both native
  and compat built from fs/binfmt_elf.c, with -DELF_BITS={64,32} passed
  by kbuild, but that's a separate story - not included here"

* 'work.elf-compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  get rid of COMPAT_ELF_EXEC_PAGESIZE
  compat_binfmt_elf: don't bother with undef of ELF_ARCH
  Kconfig: regularize selection of CONFIG_BINFMT_ELF
  mips compat: switch to compat_binfmt_elf.c
  mips: don't bother with ELF_CORE_EFLAGS
  mips compat: don't bother with ELF_ET_DYN_BASE
  mips: KVM_GUEST makes no sense for 64bit builds...
  mips: kill unused definitions in binfmt_elf[on]32.c
  mips binfmt_elf*32.c: use elfcore-compat.h
  x32: make X32, !IA32_EMULATION setups able to execute x32 binaries
  [amd64] clean PRSTATUS_SIZE/SET_PR_FPVALID up properly
  elf_prstatus: collect the common part (everything before pr_reg) into a struct
  binfmt_elf: partially sanitize PRSTATUS_SIZE and SET_PR_FPVALID

27 files changed, 129 insertions, 339 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 24862d15f3a3..b8bbfd3c66b8 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1111,6 +1111,9 @@ config ARCH_SPLIT_ARG64
 	   If a 32-bit architecture requires 64-bit arguments to be split into
 	   pairs of 32-bit arguments, select this option.
 
+config ARCH_HAS_ELFCORE_COMPAT
+	bool
+
 source "kernel/gcov/Kconfig"
 
 source "scripts/gcc-plugins/Kconfig"
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f39568b28ec1..52bc8f6206b7 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1213,7 +1213,6 @@ config ARM64_TAGGED_ADDR_ABI
 menuconfig COMPAT
 	bool "Kernel support for 32-bit EL0"
 	depends on ARM64_4K_PAGES || EXPERT
-	select COMPAT_BINFMT_ELF if BINFMT_ELF
 	select HAVE_UID16
 	select OLD_SIGSUSPEND3
 	select COMPAT_OLD_SIGACTION
diff --git a/arch/ia64/kernel/crash.c b/arch/ia64/kernel/crash.c
index fec70d662d0c..4f47741005d2 100644
--- a/arch/ia64/kernel/crash.c
+++ b/arch/ia64/kernel/crash.c
@@ -43,7 +43,7 @@ crash_save_this_cpu(void)
 
 	elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg);
 	memset(prstatus, 0, sizeof(*prstatus));
-	prstatus->pr_pid = current->pid;
+	prstatus->common.pr_pid = current->pid;
 
 	ia64_dump_cpu_regs(dst);
 	cfm = dst[43];
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 0a17bedf4f0d..f29ec95e3458 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -92,6 +92,7 @@ config MIPS
 	select SET_FS
 	select SYSCTL_EXCEPTION_TRACE
 	select VIRT_TO_BUS
+	select ARCH_HAS_ELFCORE_COMPAT
 
 config MIPS_FIXUP_BIGPHYS_ADDR
 	bool
@@ -2182,7 +2183,7 @@ endchoice
 config KVM_GUEST
 	bool "KVM Guest Kernel"
 	depends on CPU_MIPS32_R2
-	depends on BROKEN_ON_SMP
+	depends on !64BIT && BROKEN_ON_SMP
 	help
 	  Select this option if building a guest kernel for KVM (Trap & Emulate)
 	  mode.
@@ -3300,11 +3301,6 @@ config MIPS32_N32
 
 	  If unsure, say N.
 
-config BINFMT_ELF32
-	bool
-	default y if MIPS32_O32 || MIPS32_N32
-	select ELFCORE
-
 menu "Power management options"
 
 config ARCH_HIBERNATION_POSSIBLE
diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index 71c7622025d1..dc8d2863752c 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -201,7 +201,6 @@ struct mips_elf_abiflags_v0 {
 	uint32_t flags2;
 };
 
-#ifndef ELF_ARCH
 /* ELF register definitions */
 #define ELF_NGREG	45
 #define ELF_NFPREG	33
@@ -219,7 +218,7 @@ void mips_dump_regs64(u64 *uregs, const struct pt_regs *regs);
 /*
  * This is used to ensure we don't load something for the wrong architecture.
  */
-#define elf_check_arch elfo32_check_arch
+#define elf_check_arch elf32_check_arch
 
 /*
  * These are used to set parameters in the core dumps.
@@ -235,7 +234,8 @@ void mips_dump_regs64(u64 *uregs, const struct pt_regs *regs);
 /*
  * This is used to ensure we don't load something for the wrong architecture.
  */
-#define elf_check_arch elfn64_check_arch
+#define elf_check_arch elf64_check_arch
+#define compat_elf_check_arch elf32_check_arch
 
 /*
  * These are used to set parameters in the core dumps.
@@ -257,8 +257,6 @@ void mips_dump_regs64(u64 *uregs, const struct pt_regs *regs);
 #endif
 #define ELF_ARCH	EM_MIPS
 
-#endif /* !defined(ELF_ARCH) */
-
 /*
  * In order to be sure that we don't attempt to execute an O32 binary which
  * requires 64 bit FP (FR=1) on a system which does not support it we refuse
@@ -277,9 +275,9 @@ void mips_dump_regs64(u64 *uregs, const struct pt_regs *regs);
 #define vmcore_elf64_check_arch mips_elf_check_machine
 
 /*
- * Return non-zero if HDR identifies an o32 ELF binary.
+ * Return non-zero if HDR identifies an o32 or n32 ELF binary.
  */
-#define elfo32_check_arch(hdr)						\
+#define elf32_check_arch(hdr)						\
 ({									\
 	int __res = 1;							\
 	struct elfhdr *__h = (hdr);					\
@@ -288,21 +286,26 @@ void mips_dump_regs64(u64 *uregs, const struct pt_regs *regs);
 		__res = 0;						\
 	if (__h->e_ident[EI_CLASS] != ELFCLASS32)			\
 		__res = 0;						\
-	if ((__h->e_flags & EF_MIPS_ABI2) != 0)				\
-		__res = 0;						\
-	if (((__h->e_flags & EF_MIPS_ABI) != 0) &&			\
-	    ((__h->e_flags & EF_MIPS_ABI) != EF_MIPS_ABI_O32))		\
-		__res = 0;						\
-	if (__h->e_flags & __MIPS_O32_FP64_MUST_BE_ZERO)		\
-		__res = 0;						\
-									\
+	if ((__h->e_flags & EF_MIPS_ABI2) != 0) {			\
+		if (!IS_ENABLED(CONFIG_MIPS32_N32) ||			\
+		     (__h->e_flags & EF_MIPS_ABI))			\
+			__res = 0;					\
+	} else {							\
+		if (IS_ENABLED(CONFIG_64BIT) && !IS_ENABLED(CONFIG_MIPS32_O32)) \
+			__res = 0;					\
+		if (((__h->e_flags & EF_MIPS_ABI) != 0) &&		\
+		    ((__h->e_flags & EF_MIPS_ABI) != EF_MIPS_ABI_O32))	\
+			__res = 0;					\
+		if (__h->e_flags & __MIPS_O32_FP64_MUST_BE_ZERO)	\
+			__res = 0;					\
+	}								\
 	__res;								\
 })
 
 /*
  * Return non-zero if HDR identifies an n64 ELF binary.
  */
-#define elfn64_check_arch(hdr)						\
+#define elf64_check_arch(hdr)						\
 ({									\
 	int __res = 1;							\
 	struct elfhdr *__h = (hdr);					\
@@ -315,25 +318,6 @@ void mips_dump_regs64(u64 *uregs, const struct pt_regs *regs);
 	__res;								\
 })
 
-/*
- * Return non-zero if HDR identifies an n32 ELF binary.
- */
-#define elfn32_check_arch(hdr)						\
-({									\
-	int __res = 1;							\
-	struct elfhdr *__h = (hdr);					\
-									\
-	if (!mips_elf_check_machine(__h))				\
-		__res = 0;						\
-	if (__h->e_ident[EI_CLASS] != ELFCLASS32)			\
-		__res = 0;						\
-	if (((__h->e_flags & EF_MIPS_ABI2) == 0) ||			\
-	    ((__h->e_flags & EF_MIPS_ABI) != 0))			\
-		__res = 0;						\
-									\
-	__res;								\
-})
-
 struct mips_abi;
 
 extern struct mips_abi mips_abi;
@@ -469,9 +453,7 @@ extern const char *__elf_base_platform;
    the loader.	We need to make sure that it is out of the way of the program
    that it will "exec", and that there is sufficient room for the brk.	*/
 
-#ifndef ELF_ET_DYN_BASE
 #define ELF_ET_DYN_BASE		(TASK_SIZE / 3 * 2)
-#endif
 
 /* update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT entries changes */
 #define ARCH_DLINFO							\
diff --git a/arch/mips/include/asm/elfcore-compat.h b/arch/mips/include/asm/elfcore-compat.h
new file mode 100644
index 000000000000..2f0f0103c75b
--- /dev/null
+++ b/arch/mips/include/asm/elfcore-compat.h
@@ -0,0 +1,29 @@
+#ifndef _ASM_MIPS_ELFCORE_COMPAT_H
+#define _ASM_MIPS_ELFCORE_COMPAT_H
+
+/*
+ * On mips we have two 32bit ABIs - o32 and n32.  The latter
+ * has bigger registers, so we use it for compat_elf_regset_t.
+ * The former uses o32_elf_prstatus and PRSTATUS_SIZE/SET_PR_FPVALID
+ * are used to choose the size and location of ->pr_fpvalid of
+ * the layout actually used.
+ */
+typedef elf_gregset_t compat_elf_gregset_t;
+
+struct o32_elf_prstatus
+{
+	struct compat_elf_prstatus_common	common;
+	unsigned int 			pr_reg[ELF_NGREG];
+	compat_int_t			pr_fpvalid;
+};
+
+#define PRSTATUS_SIZE \
+	(!test_thread_flag(TIF_32BIT_REGS) \
+		? sizeof(struct compat_elf_prstatus) \
+		: sizeof(struct o32_elf_prstatus))
+#define SET_PR_FPVALID(S) \
+	(*(!test_thread_flag(TIF_32BIT_REGS) \
+		? &(S)->pr_fpvalid 	\
+		: &((struct o32_elf_prstatus *)(S))->pr_fpvalid) = 1)
+
+#endif
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 2a05b923f579..943eaeef73e9 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -80,8 +80,8 @@ obj-$(CONFIG_KPROBES)		+= kprobes.o
 obj-$(CONFIG_32BIT)		+= scall32-o32.o
 obj-$(CONFIG_64BIT)		+= scall64-n64.o
 obj-$(CONFIG_MIPS32_COMPAT)	+= linux32.o ptrace32.o signal32.o
-obj-$(CONFIG_MIPS32_N32)	+= binfmt_elfn32.o scall64-n32.o signal_n32.o
-obj-$(CONFIG_MIPS32_O32)	+= binfmt_elfo32.o scall64-o32.o signal_o32.o
+obj-$(CONFIG_MIPS32_N32)	+= scall64-n32.o signal_n32.o
+obj-$(CONFIG_MIPS32_O32)	+= scall64-o32.o signal_o32.o
 
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_PROC_FS)		+= proc.o
diff --git a/arch/mips/kernel/binfmt_elfn32.c b/arch/mips/kernel/binfmt_elfn32.c
deleted file mode 100644
index c4441416e96b..000000000000
--- a/arch/mips/kernel/binfmt_elfn32.c
+++ /dev/null
@@ -1,113 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Support for n32 Linux/MIPS ELF binaries.
- * Author: Ralf Baechle (ralf@linux-mips.org)
- *
- * Copyright (C) 1999, 2001 Ralf Baechle
- * Copyright (C) 1999, 2001 Silicon Graphics, Inc.
- *
- * Heavily inspired by the 32-bit Sparc compat code which is
- * Copyright (C) 1995, 1996, 1997, 1998 David S. Miller (davem@redhat.com)
- * Copyright (C) 1995, 1996, 1997, 1998 Jakub Jelinek	(jj@ultra.linux.cz)
- */
-
-#define ELF_ARCH		EM_MIPS
-#define ELF_CLASS		ELFCLASS32
-#ifdef __MIPSEB__
-#define ELF_DATA		ELFDATA2MSB;
-#else /* __MIPSEL__ */
-#define ELF_DATA		ELFDATA2LSB;
-#endif
-
-/* ELF register definitions */
-#define ELF_NGREG	45
-#define ELF_NFPREG	33
-
-typedef unsigned long elf_greg_t;
-typedef elf_greg_t elf_gregset_t[ELF_NGREG];
-
-typedef double elf_fpreg_t;
-typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
-
-/*
- * This is used to ensure we don't load something for the wrong architecture.
- */
-#define elf_check_arch elfn32_check_arch
-
-#define TASK32_SIZE		0x7fff8000UL
-#undef ELF_ET_DYN_BASE
-#define ELF_ET_DYN_BASE		(TASK32_SIZE / 3 * 2)
-
-#include <asm/processor.h>
-#include <linux/elfcore.h>
-#include <linux/compat.h>
-#include <linux/math64.h>
-
-#define elf_prstatus elf_prstatus32
-struct elf_prstatus32
-{
-	struct elf_siginfo pr_info;	/* Info associated with signal */
-	short	pr_cursig;		/* Current signal */
-	unsigned int pr_sigpend;	/* Set of pending signals */
-	unsigned int pr_sighold;	/* Set of held signals */
-	pid_t	pr_pid;
-	pid_t	pr_ppid;
-	pid_t	pr_pgrp;
-	pid_t	pr_sid;
-	struct old_timeval32 pr_utime; /* User time */
-	struct old_timeval32 pr_stime; /* System time */
-	struct old_timeval32 pr_cutime;/* Cumulative user time */
-	struct old_timeval32 pr_cstime;/* Cumulative system time */
-	elf_gregset_t pr_reg;	/* GP registers */
-	int pr_fpvalid;		/* True if math co-processor being used.  */
-};
-
-#define elf_prpsinfo elf_prpsinfo32
-struct elf_prpsinfo32
-{
-	char	pr_state;	/* numeric process state */
-	char	pr_sname;	/* char for pr_state */
-	char	pr_zomb;	/* zombie */
-	char	pr_nice;	/* nice val */
-	unsigned int pr_flag;	/* flags */
-	__kernel_uid_t	pr_uid;
-	__kernel_gid_t	pr_gid;
-	pid_t	pr_pid, pr_ppid, pr_pgrp, pr_sid;
-	/* Lots missing */
-	char	pr_fname[16];	/* filename of executable */
-	char	pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */
-};
-
-#define elf_caddr_t	u32
-#define init_elf_binfmt init_elfn32_binfmt
-
-#define jiffies_to_timeval jiffies_to_old_timeval32
-static __inline__ void
-jiffies_to_old_timeval32(unsigned long jiffies, struct old_timeval32 *value)
-{
-	/*
-	 * Convert jiffies to nanoseconds and separate with
-	 * one divide.
-	 */
-	u64 nsec = (u64)jiffies * TICK_NSEC;
-	u32 rem;
-	value->tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
-	value->tv_usec = rem / NSEC_PER_USEC;
-}
-
-#define ELF_CORE_EFLAGS EF_MIPS_ABI2
-
-#undef TASK_SIZE
-#define TASK_SIZE TASK_SIZE32
-
-#undef ns_to_kernel_old_timeval
-#define ns_to_kernel_old_timeval ns_to_old_timeval32
-
-/*
- * Some data types as stored in coredump.
- */
-#define user_long_t             compat_long_t
-#define user_siginfo_t          compat_siginfo_t
-#define copy_siginfo_to_external        copy_siginfo_to_external32
-
-#include "../../../fs/binfmt_elf.c"
diff --git a/arch/mips/kernel/binfmt_elfo32.c b/arch/mips/kernel/binfmt_elfo32.c
deleted file mode 100644
index 7b2a23f48c1a..000000000000
--- a/arch/mips/kernel/binfmt_elfo32.c
+++ /dev/null
@@ -1,116 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Support for o32 Linux/MIPS ELF binaries.
- * Author: Ralf Baechle (ralf@linux-mips.org)
- *
- * Copyright (C) 1999, 2001 Ralf Baechle
- * Copyright (C) 1999, 2001 Silicon Graphics, Inc.
- *
- * Heavily inspired by the 32-bit Sparc compat code which is
- * Copyright (C) 1995, 1996, 1997, 1998 David S. Miller (davem@redhat.com)
- * Copyright (C) 1995, 1996, 1997, 1998 Jakub Jelinek	(jj@ultra.linux.cz)
- */
-
-#define ELF_ARCH		EM_MIPS
-#define ELF_CLASS		ELFCLASS32
-#ifdef __MIPSEB__
-#define ELF_DATA		ELFDATA2MSB;
-#else /* __MIPSEL__ */
-#define ELF_DATA		ELFDATA2LSB;
-#endif
-
-/* ELF register definitions */
-#define ELF_NGREG	45
-#define ELF_NFPREG	33
-
-typedef unsigned int elf_greg_t;
-typedef elf_greg_t elf_gregset_t[ELF_NGREG];
-
-typedef double elf_fpreg_t;
-typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
-
-/*
- * This is used to ensure we don't load something for the wrong architecture.
- */
-#define elf_check_arch elfo32_check_arch
-
-#ifdef CONFIG_KVM_GUEST
-#define TASK32_SIZE		0x3fff8000UL
-#else
-#define TASK32_SIZE		0x7fff8000UL
-#endif
-#undef ELF_ET_DYN_BASE
-#define ELF_ET_DYN_BASE		(TASK32_SIZE / 3 * 2)
-
-#include <asm/processor.h>
-
-#include <linux/elfcore.h>
-#include <linux/compat.h>
-#include <linux/math64.h>
-
-#define elf_prstatus elf_prstatus32
-struct elf_prstatus32
-{
-	struct elf_siginfo pr_info;	/* Info associated with signal */
-	short	pr_cursig;		/* Current signal */
-	unsigned int pr_sigpend;	/* Set of pending signals */
-	unsigned int pr_sighold;	/* Set of held signals */
-	pid_t	pr_pid;
-	pid_t	pr_ppid;
-	pid_t	pr_pgrp;
-	pid_t	pr_sid;
-	struct old_timeval32 pr_utime; /* User time */
-	struct old_timeval32 pr_stime; /* System time */
-	struct old_timeval32 pr_cutime;/* Cumulative user time */
-	struct old_timeval32 pr_cstime;/* Cumulative system time */
-	elf_gregset_t pr_reg;	/* GP registers */
-	int pr_fpvalid;		/* True if math co-processor being used.  */
-};
-
-#define elf_prpsinfo elf_prpsinfo32
-struct elf_prpsinfo32
-{
-	char	pr_state;	/* numeric process state */
-	char	pr_sname;	/* char for pr_state */
-	char	pr_zomb;	/* zombie */
-	char	pr_nice;	/* nice val */
-	unsigned int pr_flag;	/* flags */
-	__kernel_uid_t	pr_uid;
-	__kernel_gid_t	pr_gid;
-	pid_t	pr_pid, pr_ppid, pr_pgrp, pr_sid;
-	/* Lots missing */
-	char	pr_fname[16];	/* filename of executable */
-	char	pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */
-};
-
-#define elf_caddr_t	u32
-#define init_elf_binfmt init_elf32_binfmt
-
-#define jiffies_to_timeval jiffies_to_old_timeval32
-static inline void
-jiffies_to_old_timeval32(unsigned long jiffies, struct old_timeval32 *value)
-{
-	/*
-	 * Convert jiffies to nanoseconds and separate with
-	 * one divide.
-	 */
-	u64 nsec = (u64)jiffies * TICK_NSEC;
-	u32 rem;
-	value->tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
-	value->tv_usec = rem / NSEC_PER_USEC;
-}
-
-#undef TASK_SIZE
-#define TASK_SIZE TASK_SIZE32
-
-#undef ns_to_kernel_old_timeval
-#define ns_to_kernel_old_timeval ns_to_old_timeval32
-
-/*
- * Some data types as stored in coredump.
- */
-#define user_long_t             compat_long_t
-#define user_siginfo_t          compat_siginfo_t
-#define copy_siginfo_to_external        copy_siginfo_to_external32
-
-#include "../../../fs/binfmt_elf.c"
diff --git a/arch/mips/kernel/scall64-n64.S b/arch/mips/kernel/scall64-n64.S
index 23b2e2b1609c..5e9c497ce099 100644
--- a/arch/mips/kernel/scall64-n64.S
+++ b/arch/mips/kernel/scall64-n64.S
@@ -20,7 +20,7 @@
 #include <asm/unistd.h>
 #include <asm/war.h>
 
-#ifndef CONFIG_BINFMT_ELF32
+#ifndef CONFIG_MIPS32_COMPAT
 /* Neither O32 nor N32, so define handle_sys here */
 #define handle_sys64 handle_sys
 #endif
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 278462186ac4..b09d6923f156 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -335,7 +335,6 @@ source "kernel/Kconfig.hz"
 config COMPAT
 	def_bool y
 	depends on 64BIT
-	select COMPAT_BINFMT_ELF if BINFMT_ELF
 
 config SYSVIPC_COMPAT
 	def_bool y
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 107bb4319e0e..d26a89cd8908 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -282,7 +282,6 @@ config COMPAT
 	bool "Enable support for 32bit binaries"
 	depends on PPC64
 	default y if !CPU_LITTLE_ENDIAN
-	select COMPAT_BINFMT_ELF
 	select ARCH_WANT_OLD_COMPAT_IPC
 	select COMPAT_OLD_SIGACTION
 
diff --git a/arch/powerpc/platforms/powernv/opal-core.c b/arch/powerpc/platforms/powernv/opal-core.c
index 23571f0b555a..0d9ba70f7251 100644
--- a/arch/powerpc/platforms/powernv/opal-core.c
+++ b/arch/powerpc/platforms/powernv/opal-core.c
@@ -119,8 +119,8 @@ static void fill_prstatus(struct elf_prstatus *prstatus, int pir,
 	 * As a PIR value could also be '0', add an offset of '100'
 	 * to every PIR to avoid misinterpretations in GDB.
 	 */
-	prstatus->pr_pid  = cpu_to_be32(100 + pir);
-	prstatus->pr_ppid = cpu_to_be32(1);
+	prstatus->common.pr_pid  = cpu_to_be32(100 + pir);
+	prstatus->common.pr_ppid = cpu_to_be32(1);
 
 	/*
 	 * Indicate SIGUSR1 for crash initiated from kernel.
@@ -130,7 +130,7 @@ static void fill_prstatus(struct elf_prstatus *prstatus, int pir,
 		short sig;
 
 		sig = kernel_initiated ? SIGUSR1 : SIGTERM;
-		prstatus->pr_cursig = cpu_to_be16(sig);
+		prstatus->common.pr_cursig = cpu_to_be16(sig);
 	}
 }
 
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index c72874f09741..73483614b66b 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -426,7 +426,6 @@ config 64BIT
 config COMPAT
 	def_bool y
 	prompt "Kernel support for 31 bit emulation"
-	select COMPAT_BINFMT_ELF if BINFMT_ELF
 	select ARCH_WANT_OLD_COMPAT_IPC
 	select COMPAT_OLD_SIGACTION
 	select HAVE_UID16
diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 205b2e2648aa..0e36dfc9ccd6 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -365,7 +365,7 @@ static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
 	memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
 	memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
 	memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
-	nt_prstatus.pr_pid = cpu;
+	nt_prstatus.common.pr_pid = cpu;
 	/* Prepare fpregset (floating point) note */
 	memset(&nt_fpregset, 0, sizeof(nt_fpregset));
 	memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index c9c34dc52b7d..1a2b5649d267 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -494,7 +494,6 @@ config COMPAT
 	bool
 	depends on SPARC64
 	default y
-	select COMPAT_BINFMT_ELF
 	select HAVE_UID16
 	select ARCH_WANT_OLD_COMPAT_IPC
 	select COMPAT_OLD_SIGACTION
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 3d498caca1ea..31d94448b4e1 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -32,6 +32,7 @@ config X86_64
 	select MODULES_USE_ELF_RELA
 	select NEED_DMA_MAP_STATE
 	select SWIOTLB
+	select ARCH_HAS_ELFCORE_COMPAT
 
 config FORCE_DYNAMIC_FTRACE
 	def_bool y
@@ -2860,7 +2861,6 @@ config IA32_EMULATION
 	depends on X86_64
 	select ARCH_WANT_OLD_COMPAT_IPC
 	select BINFMT_ELF
-	select COMPAT_BINFMT_ELF
 	select COMPAT_OLD_SIGACTION
 	help
 	  Include code to run legacy 32-bit programs under a
diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index f145e3326c6d..be09c7eac89f 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -159,17 +159,6 @@ struct compat_shmid64_ds {
 	compat_ulong_t __unused5;
 };
 
-/*
- * The type of struct elf_prstatus.pr_reg in compatible core dumps.
- */
-typedef struct user_regs_struct compat_elf_gregset_t;
-
-/* Full regset -- prstatus on x32, otherwise on ia32 */
-#define PRSTATUS_SIZE(S, R) (R != sizeof(S.pr_reg) ? 144 : 296)
-#define SET_PR_FPVALID(S, V, R) \
-  do { *(int *) (((void *) &((S)->pr_reg)) + R) = (V); } \
-  while (0)
-
 #ifdef CONFIG_X86_X32_ABI
 #define COMPAT_USE_64BIT_TIME \
 	(!!(task_pt_regs(current)->orig_ax & __X32_SYSCALL_BIT))
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 66bdfe838d61..9224d40cdefe 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -364,7 +364,7 @@ do {									\
 #define COMPAT_ARCH_DLINFO						\
 if (exec->e_machine == EM_X86_64)					\
 	ARCH_DLINFO_X32;						\
-else									\
+else if (IS_ENABLED(CONFIG_IA32_EMULATION))				\
 	ARCH_DLINFO_IA32
 
 #define COMPAT_ELF_ET_DYN_BASE	(TASK_UNMAPPED_BASE + 0x1000000)
diff --git a/arch/x86/include/asm/elfcore-compat.h b/arch/x86/include/asm/elfcore-compat.h
new file mode 100644
index 000000000000..f1b6c7a8d8fc
--- /dev/null
+++ b/arch/x86/include/asm/elfcore-compat.h
@@ -0,0 +1,31 @@
+#ifndef _ASM_X86_ELFCORE_COMPAT_H
+#define _ASM_X86_ELFCORE_COMPAT_H
+
+#include <asm/user32.h>
+
+/*
+ * On amd64 we have two 32bit ABIs - i386 and x32.  The latter
+ * has bigger registers, so we use it for compat_elf_regset_t.
+ * The former uses i386_elf_prstatus and PRSTATUS_SIZE/SET_PR_FPVALID
+ * are used to choose the size and location of ->pr_fpvalid of
+ * the layout actually used.
+ */
+typedef struct user_regs_struct compat_elf_gregset_t;
+
+struct i386_elf_prstatus
+{
+	struct compat_elf_prstatus_common	common;
+	struct user_regs_struct32		pr_reg;
+	compat_int_t			pr_fpvalid;
+};
+
+#define PRSTATUS_SIZE \
+	(user_64bit_mode(task_pt_regs(current)) \
+		? sizeof(struct compat_elf_prstatus) \
+		: sizeof(struct i386_elf_prstatus))
+#define SET_PR_FPVALID(S) \
+	(*(user_64bit_mode(task_pt_regs(current)) \
+		? &(S)->pr_fpvalid 	\
+		: &((struct i386_elf_prstatus *)(S))->pr_fpvalid) = 1)
+
+#endif
diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index 647439c2c05a..c6f1c8c1934e 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -29,7 +29,7 @@ config BINFMT_ELF
 	  latest version).
 
 config COMPAT_BINFMT_ELF
-	bool
+	def_bool y
 	depends on COMPAT && BINFMT_ELF
 	select ELFCORE
 
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 950bc177238a..4c1550b13899 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1495,7 +1495,7 @@ static void fill_note(struct memelfnote *note, const char *name, int type,
  * fill up all the fields in prstatus from the given task struct, except
  * registers which need to be filled up separately.
  */
-static void fill_prstatus(struct elf_prstatus *prstatus,
+static void fill_prstatus(struct elf_prstatus_common *prstatus,
 		struct task_struct *p, long signr)
 {
 	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
@@ -1717,11 +1717,11 @@ static void do_thread_regset_writeback(struct task_struct *task,
 }
 
 #ifndef PRSTATUS_SIZE
-#define PRSTATUS_SIZE(S, R) sizeof(S)
+#define PRSTATUS_SIZE sizeof(struct elf_prstatus)
 #endif
 
 #ifndef SET_PR_FPVALID
-#define SET_PR_FPVALID(S, V, R) ((S)->pr_fpvalid = (V))
+#define SET_PR_FPVALID(S) ((S)->pr_fpvalid = 1)
 #endif
 
 static int fill_thread_core_info(struct elf_thread_core_info *t,
@@ -1729,7 +1729,6 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 				 long signr, size_t *total)
 {
 	unsigned int i;
-	int regset0_size;
 
 	/*
 	 * NT_PRSTATUS is the one special case, because the regset data
@@ -1737,14 +1736,12 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 	 * than being the whole note contents.  We fill the reset in here.
 	 * We assume that regset 0 is NT_PRSTATUS.
 	 */
-	fill_prstatus(&t->prstatus, t->task, signr);
-	regset0_size = regset_get(t->task, &view->regsets[0],
+	fill_prstatus(&t->prstatus.common, t->task, signr);
+	regset_get(t->task, &view->regsets[0],
 		   sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
-	if (regset0_size < 0)
-		return 0;
 
 	fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
-		  PRSTATUS_SIZE(t->prstatus, regset0_size), &t->prstatus);
+		  PRSTATUS_SIZE, &t->prstatus);
 	*total += notesize(&t->notes[0]);
 
 	do_thread_regset_writeback(t->task, &view->regsets[0]);
@@ -1772,7 +1769,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 			continue;
 
 		if (is_fpreg)
-			SET_PR_FPVALID(&t->prstatus, 1, regset0_size);
+			SET_PR_FPVALID(&t->prstatus);
 
 		fill_note(&t->notes[i], is_fpreg ? "CORE" : "LINUX",
 			  note_type, ret, data);
@@ -1961,7 +1958,7 @@ static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
 	struct task_struct *p = t->thread;
 	t->num_notes = 0;
 
-	fill_prstatus(&t->prstatus, p, signr);
+	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),
@@ -2040,7 +2037,7 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
 	}
 	/* now collect the dump for the current */
 	memset(info->prstatus, 0, sizeof(*info->prstatus));
-	fill_prstatus(info->prstatus, current, siginfo->si_signo);
+	fill_prstatus(&info->prstatus->common, current, siginfo->si_signo);
 	elf_core_copy_regs(&info->prstatus->pr_reg, regs);
 
 	/* Set up header */
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index be4062b8ba75..03d81a14bcbf 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1191,18 +1191,7 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
 
 struct elf_prstatus_fdpic
 {
-	struct elf_siginfo pr_info;	/* Info associated with signal */
-	short	pr_cursig;		/* Current signal */
-	unsigned long pr_sigpend;	/* Set of pending signals */
-	unsigned long pr_sighold;	/* Set of held signals */
-	pid_t	pr_pid;
-	pid_t	pr_ppid;
-	pid_t	pr_pgrp;
-	pid_t	pr_sid;
-	struct __kernel_old_timeval pr_utime;	/* User time */
-	struct __kernel_old_timeval pr_stime;	/* System time */
-	struct __kernel_old_timeval pr_cutime;	/* Cumulative user time */
-	struct __kernel_old_timeval pr_cstime;	/* Cumulative system time */
+	struct elf_prstatus_common	common;
 	elf_gregset_t pr_reg;	/* GP registers */
 	/* When using FDPIC, the loadmap addresses need to be communicated
 	 * to GDB in order for GDB to do the necessary relocations.  The
@@ -1301,7 +1290,7 @@ static inline void fill_note(struct memelfnote *note, const char *name, int type
  * fill up all the fields in prstatus from the given task struct, except
  * registers which need to be filled up separately.
  */
-static void fill_prstatus(struct elf_prstatus_fdpic *prstatus,
+static void fill_prstatus(struct elf_prstatus_common *prstatus,
 			  struct task_struct *p, long signr)
 {
 	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
@@ -1332,9 +1321,6 @@ static void fill_prstatus(struct elf_prstatus_fdpic *prstatus,
 	}
 	prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
 	prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
-
-	prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
-	prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
 }
 
 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
@@ -1405,7 +1391,9 @@ static struct elf_thread_status *elf_dump_thread_status(long signr, struct task_
 	if (!t)
 		return t;
 
-	fill_prstatus(&t->prstatus, p, signr);
+	fill_prstatus(&t->prstatus.common, p, signr);
+	t->prstatus.pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
+	t->prstatus.pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
 	regset_get(p, &view->regsets[0],
 		   sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
 
diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c
index 2c557229696a..95e72d271b95 100644
--- a/fs/compat_binfmt_elf.c
+++ b/fs/compat_binfmt_elf.c
@@ -50,6 +50,7 @@
  * which requires asm/elf.h to define compat_elf_gregset_t et al.
  */
 #define elf_prstatus	compat_elf_prstatus
+#define elf_prstatus_common	compat_elf_prstatus_common
 #define elf_prpsinfo	compat_elf_prpsinfo
 
 #undef ns_to_kernel_old_timeval
@@ -61,7 +62,6 @@
  * differ from the native ones, or omitted when they match.
  */
 
-#undef	ELF_ARCH
 #undef	elf_check_arch
 #define	elf_check_arch	compat_elf_check_arch
 
@@ -90,11 +90,6 @@
 #define	ELF_ET_DYN_BASE		COMPAT_ELF_ET_DYN_BASE
 #endif
 
-#ifdef COMPAT_ELF_EXEC_PAGESIZE
-#undef	ELF_EXEC_PAGESIZE
-#define	ELF_EXEC_PAGESIZE	COMPAT_ELF_EXEC_PAGESIZE
-#endif
-
 #ifdef	COMPAT_ELF_PLAT_INIT
 #undef	ELF_PLAT_INIT
 #define	ELF_PLAT_INIT		COMPAT_ELF_PLAT_INIT
diff --git a/include/linux/elfcore-compat.h b/include/linux/elfcore-compat.h
index 10485f0c9740..e272c3d452ce 100644
--- a/include/linux/elfcore-compat.h
+++ b/include/linux/elfcore-compat.h
@@ -17,7 +17,7 @@ struct compat_elf_siginfo
 	compat_int_t			si_errno;
 };
 
-struct compat_elf_prstatus
+struct compat_elf_prstatus_common
 {
 	struct compat_elf_siginfo	pr_info;
 	short				pr_cursig;
@@ -31,8 +31,6 @@ struct compat_elf_prstatus
 	struct old_timeval32		pr_stime;
 	struct old_timeval32		pr_cutime;
 	struct old_timeval32		pr_cstime;
-	compat_elf_gregset_t		pr_reg;
-	compat_int_t			pr_fpvalid;
 };
 
 struct compat_elf_prpsinfo
@@ -49,4 +47,15 @@ struct compat_elf_prpsinfo
 	char				pr_psargs[ELF_PRARGSZ];
 };
 
+#ifdef CONFIG_ARCH_HAS_ELFCORE_COMPAT
+#include <asm/elfcore-compat.h>
+#endif
+
+struct compat_elf_prstatus
+{
+	struct compat_elf_prstatus_common	common;
+	compat_elf_gregset_t		pr_reg;
+	compat_int_t			pr_fpvalid;
+};
+
 #endif /* _LINUX_ELFCORE_COMPAT_H */
diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h
index de51c1bef27d..2aaa15779d50 100644
--- a/include/linux/elfcore.h
+++ b/include/linux/elfcore.h
@@ -29,7 +29,7 @@ struct elf_siginfo
  * the SVR4 structure, but more Linuxy, with things that Linux does
  * not support and which gdb doesn't really use excluded.
  */
-struct elf_prstatus
+struct elf_prstatus_common
 {
 	struct elf_siginfo pr_info;	/* Info associated with signal */
 	short	pr_cursig;		/* Current signal */
@@ -43,6 +43,11 @@ struct elf_prstatus
 	struct __kernel_old_timeval pr_stime;	/* System time */
 	struct __kernel_old_timeval pr_cutime;	/* Cumulative user time */
 	struct __kernel_old_timeval pr_cstime;	/* Cumulative system time */
+};
+
+struct elf_prstatus
+{
+	struct elf_prstatus_common common;
 	elf_gregset_t pr_reg;	/* GP registers */
 	int pr_fpvalid;		/* True if math co-processor being used.  */
 };
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index aa919585c24b..a0b6780740c8 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -1076,7 +1076,7 @@ void crash_save_cpu(struct pt_regs *regs, int cpu)
 	if (!buf)
 		return;
 	memset(&prstatus, 0, sizeof(prstatus));
-	prstatus.pr_pid = current->pid;
+	prstatus.common.pr_pid = current->pid;
 	elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
 	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
 			      &prstatus, sizeof(prstatus));