[PATCH] Add linux/elfcore-compat.h

[PATCH] Add linux/elfcore-compat.h

[Roland McGrath]

This adds the linux/elfcore-compat.h header file, which is the
CONFIG_COMPAT analog of the linux/elfcore.h header.  Each arch
that needs to fake out fs/binfmt_elf.c for its compat code can
use this header to replace the hand-copied definitions of the
compat variants of struct elf_prstatus et al.  Only the pr_reg
field varies by arch, so asm/{compat,elf}.h must define
compat_elf_gregset_t before linux/elfcore-compat.h can be used.

Signed-off-by: Roland McGrath <roland@redhat.com>
---
 include/linux/elfcore-compat.h |   55 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 55 insertions(+), 0 deletions(-)
 create mode 100644 include/linux/elfcore-compat.h

diff --git a/include/linux/elfcore-compat.h b/include/linux/elfcore-compat.h
new file mode 100644
index 0000000..532d13a
--- /dev/null
+++ b/include/linux/elfcore-compat.h
@@ -0,0 +1,55 @@
+#ifndef _LINUX_ELFCORE_COMPAT_H
+#define _LINUX_ELFCORE_COMPAT_H
+
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/compat.h>
+
+/*
+ * Make sure these layouts match the linux/elfcore.h native definitions.
+ */
+
+struct compat_elf_siginfo
+{
+	compat_int_t			si_signo;
+	compat_int_t			si_code;
+	compat_int_t			si_errno;
+};
+
+struct compat_elf_prstatus
+{
+	struct compat_elf_siginfo	pr_info;
+	short				pr_cursig;
+	compat_ulong_t			pr_sigpend;
+	compat_ulong_t			pr_sighold;
+	compat_pid_t			pr_pid;
+	compat_pid_t			pr_ppid;
+	compat_pid_t			pr_pgrp;
+	compat_pid_t			pr_sid;
+	struct compat_timeval		pr_utime;
+	struct compat_timeval		pr_stime;
+	struct compat_timeval		pr_cutime;
+	struct compat_timeval		pr_cstime;
+	compat_elf_gregset_t		pr_reg;
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+	compat_ulong_t			pr_exec_fdpic_loadmap;
+	compat_ulong_t			pr_interp_fdpic_loadmap;
+#endif
+	compat_int_t			pr_fpvalid;
+};
+
+struct compat_elf_prpsinfo
+{
+	char				pr_state;
+	char				pr_sname;
+	char				pr_zomb;
+	char				pr_nice;
+	compat_ulong_t			pr_flag;
+	compat_uid_t			pr_uid;
+	compat_gid_t			pr_gid;
+	compat_pid_t			pr_pid, pr_ppid, pr_pgrp, pr_sid;
+	char				pr_fname[16];
+	char				pr_psargs[ELF_PRARGSZ];
+};
+
+#endif /* _LINUX_ELFCORE_COMPAT_H */

[PATCH] x86_64: Use linux/elfcore-compat.h

[Roland McGrath]

This makes x86-64's ia32 code use the new linux/elfcore-compat.h,
reducing some hand-copied duplication.

Signed-off-by: Roland McGrath <roland@redhat.com>
---
 arch/x86_64/ia32/ia32_binfmt.c |  123 +++++++++++++++-------------------------
 include/asm-x86_64/compat.h    |    6 ++
 2 files changed, 51 insertions(+), 78 deletions(-)

diff --git a/arch/x86_64/ia32/ia32_binfmt.c b/arch/x86_64/ia32/ia32_binfmt.c
index 90b37fc..57de329 100644
--- a/arch/x86_64/ia32/ia32_binfmt.c
+++ b/arch/x86_64/ia32/ia32_binfmt.c
@@ -5,10 +5,6 @@
  * This tricks binfmt_elf.c into loading 32bit binaries using lots
  * of ugly preprocessor tricks. Talk about very very poor man's inheritance.
  */
-#define __ASM_X86_64_ELF_H 1
-
-#undef ELF_CLASS
-#define ELF_CLASS ELFCLASS32
 
 #include <linux/types.h>
 #include <linux/stddef.h>
@@ -19,6 +15,7 @@
 #include <linux/binfmts.h>
 #include <linux/mm.h>
 #include <linux/security.h>
+#include <linux/elfcore-compat.h>
 
 #include <asm/segment.h>
 #include <asm/ptrace.h>
@@ -31,6 +28,20 @@
 #include <asm/ia32.h>
 #include <asm/vsyscall32.h>
 
+#undef	ELF_ARCH
+#undef	ELF_CLASS
+#define ELF_CLASS	ELFCLASS32
+#define ELF_ARCH	EM_386
+
+#undef	elfhdr
+#undef	elf_phdr
+#undef	elf_note
+#undef	elf_addr_t
+#define elfhdr		elf32_hdr
+#define elf_phdr	elf32_phdr
+#define elf_note	elf32_note
+#define elf_addr_t	Elf32_Off
+
 #define ELF_NAME "elf/i386"
 
 #define AT_SYSINFO 32
@@ -48,70 +59,14 @@ int sysctl_vsyscall32 = 1;
 } while(0)
 
 struct file;
-struct elf_phdr;
 
 #define IA32_EMULATOR 1
 
+#undef	ELF_ET_DYN_BASE
 #define ELF_ET_DYN_BASE		(TASK_UNMAPPED_BASE + 0x1000000)
 
-#undef ELF_ARCH
-#define ELF_ARCH EM_386
-
-#define ELF_DATA	ELFDATA2LSB
-
-#define USE_ELF_CORE_DUMP 1
-
-/* Override elfcore.h */
-#define _LINUX_ELFCORE_H 1
-typedef unsigned int elf_greg_t;
-
-#define ELF_NGREG (sizeof (struct user_regs_struct32) / sizeof(elf_greg_t))
-typedef elf_greg_t elf_gregset_t[ELF_NGREG];
-
-struct elf_siginfo
-{
-	int	si_signo;			/* signal number */
-	int	si_code;			/* extra code */
-	int	si_errno;			/* errno */
-};
-
 #define jiffies_to_timeval(a,b) do { (b)->tv_usec = 0; (b)->tv_sec = (a)/HZ; }while(0)
 
-struct elf_prstatus
-{
-	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 compat_timeval pr_utime;	/* User time */
-	struct compat_timeval pr_stime;	/* System time */
-	struct compat_timeval pr_cutime;	/* Cumulative user time */
-	struct compat_timeval pr_cstime;	/* Cumulative system time */
-	elf_gregset_t pr_reg;	/* GP registers */
-	int pr_fpvalid;		/* True if math co-processor being used.  */
-};
-
-#define ELF_PRARGSZ	(80)	/* Number of chars for args */
-
-struct elf_prpsinfo
-{
-	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 */
-	__u16	pr_uid;
-	__u16	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 __STR(x) #x
 #define STR(x) __STR(x)
 
@@ -119,6 +74,7 @@ struct elf_prpsinfo
 	({ __u32 seg; asm("movl %%" STR(x) ",%0" : "=r"(seg)); seg; })
 
 /* Assumes current==process to be dumped */
+#undef	ELF_CORE_COPY_REGS
 #define ELF_CORE_COPY_REGS(pr_reg, regs)       		\
 	pr_reg[0] = regs->rbx;				\
 	pr_reg[1] = regs->rcx;				\
@@ -138,36 +94,41 @@ struct elf_prpsinfo
 	pr_reg[15] = regs->rsp;				\
 	pr_reg[16] = regs->ss;
 
-#define user user32
+
+#define elf_prstatus	compat_elf_prstatus
+#define elf_prpsinfo	compat_elf_prpsinfo
+#define elf_fpregset_t	struct user_i387_ia32_struct
+#define	elf_fpxregset_t	struct user32_fxsr_struct
+#define user		user32
 
 #undef elf_read_implies_exec
 #define elf_read_implies_exec(ex, executable_stack)     (executable_stack != EXSTACK_DISABLE_X)
-//#include <asm/ia32.h>
-#include <linux/elf.h>
-
-typedef struct user_i387_ia32_struct elf_fpregset_t;
-typedef struct user32_fxsr_struct elf_fpxregset_t;
-
 
-static inline void elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs)
+#define elf_core_copy_regs		elf32_core_copy_regs
+static inline void elf32_core_copy_regs(compat_elf_gregset_t *elfregs,
+					struct pt_regs *regs)
 {
-	ELF_CORE_COPY_REGS((*elfregs), regs)
+	ELF_CORE_COPY_REGS((&elfregs->ebx), regs)
 }
 
-static inline int elf_core_copy_task_regs(struct task_struct *t, elf_gregset_t* elfregs)
+#define elf_core_copy_task_regs		elf32_core_copy_task_regs
+static inline int elf32_core_copy_task_regs(struct task_struct *t,
+					    compat_elf_gregset_t* elfregs)
 {
 	struct pt_regs *pp = task_pt_regs(t);
-	ELF_CORE_COPY_REGS((*elfregs), pp);
+	ELF_CORE_COPY_REGS((&elfregs->ebx), pp);
 	/* fix wrong segments */
-	(*elfregs)[7] = t->thread.ds;
-	(*elfregs)[9] = t->thread.fsindex;
-	(*elfregs)[10] = t->thread.gsindex;
-	(*elfregs)[8] = t->thread.es;
+	elfregs->ds = t->thread.ds;
+	elfregs->fs = t->thread.fsindex;
+	elfregs->gs = t->thread.gsindex;
+	elfregs->es = t->thread.es;
 	return 1;
 }
 
+#define elf_core_copy_task_fpregs	elf32_core_copy_task_fpregs
 static inline int
-elf_core_copy_task_fpregs(struct task_struct *tsk, struct pt_regs *regs, elf_fpregset_t *fpu)
+elf32_core_copy_task_fpregs(struct task_struct *tsk, struct pt_regs *regs,
+			    elf_fpregset_t *fpu)
 {
 	struct _fpstate_ia32 *fpstate = (void*)fpu;
 	mm_segment_t oldfs = get_fs();
@@ -188,8 +149,9 @@ elf_core_copy_task_fpregs(struct task_struct *tsk, struct pt_regs *regs, elf_fpr
 }
 
 #define ELF_CORE_COPY_XFPREGS 1
+#define elf_core_copy_task_xfpregs	elf32_core_copy_task_xfpregs
 static inline int
-elf_core_copy_task_xfpregs(struct task_struct *t, elf_fpxregset_t *xfpu)
+elf32_core_copy_task_xfpregs(struct task_struct *t, elf_fpxregset_t *xfpu)
 {
 	struct pt_regs *regs = task_pt_regs(t);
 	if (!tsk_used_math(t))
@@ -208,6 +170,10 @@ elf_core_copy_task_xfpregs(struct task_struct *t, elf_fpxregset_t *xfpu)
 
 extern int force_personality32;
 
+#undef	ELF_EXEC_PAGESIZE
+#undef	ELF_HWCAP
+#undef	ELF_PLATFORM
+#undef	SET_PERSONALITY
 #define ELF_EXEC_PAGESIZE PAGE_SIZE
 #define ELF_HWCAP (boot_cpu_data.x86_capability[0])
 #define ELF_PLATFORM  ("i686")
@@ -233,6 +199,7 @@ do {							\
 
 #define load_elf_binary load_elf32_binary
 
+#undef	ELF_PLAT_INIT
 #define ELF_PLAT_INIT(r, load_addr)	elf32_init(r)
 
 #undef start_thread
diff --git a/include/asm-x86_64/compat.h b/include/asm-x86_64/compat.h
index 53cb96b..a250546 100644
--- a/include/asm-x86_64/compat.h
+++ b/include/asm-x86_64/compat.h
@@ -6,6 +6,7 @@
  */
 #include <linux/types.h>
 #include <linux/sched.h>
+#include <asm/user32.h>
 
 #define COMPAT_USER_HZ	100
 
@@ -181,6 +182,11 @@ struct compat_shmid64_ds {
 };
 
 /*
+ * The type of struct elf_prstatus.pr_reg in compatible core dumps.
+ */
+typedef struct user_regs_struct32 compat_elf_gregset_t;
+
+/*
  * A pointer passed in from user mode. This should not
  * be used for syscall parameters, just declare them
  * as pointers because the syscall entry code will have

[PATCH] powerpc: Use linux/elfcore-compat.h

[Roland McGrath]

This makes powerpc64's compat code use the new linux/elfcore-compat.h,
reducing some hand-copied duplication.

Signed-off-by: Roland McGrath <roland@redhat.com>
---
 arch/powerpc/kernel/binfmt_elf32.c |   67 ++++++++++++++++-------------------
 include/asm-powerpc/elf.h          |   38 +++++++++++----------
 2 files changed, 51 insertions(+), 54 deletions(-)

diff --git a/arch/powerpc/kernel/binfmt_elf32.c b/arch/powerpc/kernel/binfmt_elf32.c
index 5cb5875..1d45d77 100644
--- a/arch/powerpc/kernel/binfmt_elf32.c
+++ b/arch/powerpc/kernel/binfmt_elf32.c
@@ -13,49 +13,44 @@
  * 2 of the License, or (at your option) any later version.
  */
 
-#define ELF_ARCH		EM_PPC
-#define ELF_CLASS		ELFCLASS32
-#define ELF_DATA		ELFDATA2MSB;
-
 #include <asm/processor.h>
 #include <linux/module.h>
-#include <linux/elfcore.h>
 #include <linux/compat.h>
+#include <linux/elfcore-compat.h>
+
+#undef	ELF_ARCH
+#undef	ELF_CLASS
+#define ELF_CLASS	ELFCLASS32
+#define ELF_ARCH	EM_PPC
+
+#undef	elfhdr
+#undef	elf_phdr
+#undef	elf_note
+#undef	elf_addr_t
+#define elfhdr		elf32_hdr
+#define elf_phdr	elf32_phdr
+#define elf_note	elf32_note
+#define elf_addr_t	Elf32_Off
 
-#define elf_prstatus elf_prstatus32
-struct elf_prstatus32
+#define elf_prstatus	compat_elf_prstatus
+#define elf_prpsinfo	compat_elf_prpsinfo
+
+#define elf_core_copy_regs compat_elf_core_copy_regs
+static inline void compat_elf_core_copy_regs(compat_elf_gregset_t *elf_regs,
+					     struct pt_regs *regs)
 {
-	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 compat_timeval pr_utime;	/* User time */
-	struct compat_timeval pr_stime;	/* System time */
-	struct compat_timeval pr_cutime;	/* Cumulative user time */
-	struct compat_timeval pr_cstime;	/* Cumulative system time */
-	elf_gregset_t pr_reg;		/* General purpose registers. */
-	int pr_fpvalid;		/* True if math co-processor being used. */
-};
+	PPC_ELF_CORE_COPY_REGS((*elf_regs), regs);
+}
 
-#define elf_prpsinfo elf_prpsinfo32
-struct elf_prpsinfo32
+#define elf_core_copy_task_regs compat_elf_core_copy_task_regs
+static int compat_elf_core_copy_task_regs(struct task_struct *tsk,
+					  compat_elf_gregset_t *elf_regs)
 {
-	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 */
-	u32	pr_uid;
-	u32	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 */
-};
+	struct pt_regs *regs = tsk->thread.regs;
+	if (regs)
+		compat_elf_core_copy_regs(elf_regs, regs);
+	return 1;
+}
 
 #include <linux/time.h>
 
diff --git a/include/asm-powerpc/elf.h b/include/asm-powerpc/elf.h
index de50799..b6a1aef 100644
--- a/include/asm-powerpc/elf.h
+++ b/include/asm-powerpc/elf.h
@@ -101,6 +101,7 @@ typedef elf_greg_t64 elf_gregset_t64[ELF_NGREG];
 
 typedef unsigned int elf_greg_t32;
 typedef elf_greg_t32 elf_gregset_t32[ELF_NGREG];
+typedef elf_gregset_t32 compat_elf_gregset_t;
 
 /*
  * ELF_ARCH, CLASS, and DATA are used to set parameters in the core dumps.
@@ -175,26 +176,27 @@ typedef elf_vrreg_t elf_vrregset_t32[ELF_NVRREG32];
 
 #define ELF_ET_DYN_BASE         (0x20000000)
 
-/* Common routine for both 32-bit and 64-bit processes */
+/*
+ * Our registers are always unsigned longs, whether we're a 32 bit
+ * process or 64 bit, on either a 64 bit or 32 bit kernel.
+ *
+ * This macro relies on elf_regs[i] having the right type to truncate to,
+ * either u32 or u64.  It defines the body of the elf_core_copy_regs
+ * function, either the native one with elf_gregset_t elf_regs or
+ * the 32-bit one with elf_gregset_t32 elf_regs.
+ */
+#define PPC_ELF_CORE_COPY_REGS(elf_regs, regs) \
+	int i, nregs = min(sizeof(*regs) / sizeof(unsigned long), \
+			   (size_t)ELF_NGREG);			  \
+	for (i = 0; i < nregs; i++) \
+		elf_regs[i] = ((unsigned long *) regs)[i]; \
+	memset(&elf_regs[i], 0, (ELF_NGREG - i) * sizeof(elf_regs[0]))
+
+/* Common routine for both 32-bit and 64-bit native processes */
 static inline void ppc_elf_core_copy_regs(elf_gregset_t elf_regs,
-					    struct pt_regs *regs)
+					  struct pt_regs *regs)
 {
-	int i, nregs;
-
-	memset((void *)elf_regs, 0, sizeof(elf_gregset_t));
-
-	/* Our registers are always unsigned longs, whether we're a 32 bit
-	 * process or 64 bit, on either a 64 bit or 32 bit kernel.
-	 * Don't use ELF_GREG_TYPE here. */
-	nregs = sizeof(struct pt_regs) / sizeof(unsigned long);
-	if (nregs > ELF_NGREG)
-		nregs = ELF_NGREG;
-
-	for (i = 0; i < nregs; i++) {
-		/* This will correctly truncate 64 bit registers to 32 bits
-		 * for a 32 bit process on a 64 bit kernel. */
-		elf_regs[i] = (elf_greg_t)((ELF_GREG_TYPE *)regs)[i];
-	}
+	PPC_ELF_CORE_COPY_REGS(elf_regs, regs);
 }
 #define ELF_CORE_COPY_REGS(gregs, regs) ppc_elf_core_copy_regs(gregs, regs);
 

Re: [PATCH] Add linux/elfcore-compat.h

[Andrew Morton]

On Fri,  3 Aug 2007 16:21:21 -0700 (PDT)
Roland McGrath <roland@redhat.com> wrote:

> This adds the linux/elfcore-compat.h header file, which is the
> CONFIG_COMPAT analog of the linux/elfcore.h header.  Each arch
> that needs to fake out fs/binfmt_elf.c for its compat code can
> use this header to replace the hand-copied definitions of the
> compat variants of struct elf_prstatus et al.  Only the pr_reg
> field varies by arch, so asm/{compat,elf}.h must define
> compat_elf_gregset_t before linux/elfcore-compat.h can be used.
> 

Should ia64 be using this too?

Re: [PATCH] Add linux/elfcore-compat.h

[Roland McGrath]

> Should ia64 be using this too?

It's a clean-up that every arch with compat core dumping code can benefit from.
I only touched the ones I have handy to test at home.  Doing the same for
each other arch should be straightforward, and I'm happy to offer tips.


Thanks,
Roland

Re: [PATCH] powerpc: Use linux/elfcore-compat.h

[Arnd Bergmann]

On Saturday 04 August 2007, Roland McGrath wrote:
> 
> This makes powerpc64's compat code use the new linux/elfcore-compat.h,
> reducing some hand-copied duplication.

There is hardly anything interesting remaining in 
arch/powerpc/kernel/binfmt_elf32.c after your patch.

Do you think it's reasonable to go one step further and
turn the file into a completely generic fs/binfmt_elf32.c
that can be used by all 32/64 compat architectures?

I tried that in the past, but failed because I don't
really understand enough of the ELF loader to know
which architectures do it right and which don't -- I only
saw them all being very different in this file ;-)

	Arnd <><

Re: [PATCH] powerpc: Use linux/elfcore-compat.h

[Roland McGrath]

> There is hardly anything interesting remaining in 
> arch/powerpc/kernel/binfmt_elf32.c after your patch.
> 
> Do you think it's reasonable to go one step further and
> turn the file into a completely generic fs/binfmt_elf32.c
> that can be used by all 32/64 compat architectures?

There is certainly more cleanup that can be done.  
This was just an easy incremental step.

It's not going to get quite to "completely generic".  On other machines the
32/64 flavors are not quite as similar as on powerpc, so there is some more
code required there.  There will have to be a lot of per-arch macros and
functions, even if they are unified to compat_* names.


Thanks,
Roland