linux-kernel - [PATCH 2/7] take fdpic-related parts of elf

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Message-Id: <20200630044108.615673-2-viro@ZenIV.linux.org.uk>
Date:   Tue, 30 Jun 2020 05:41:03 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org,
        "Eric W . Biederman" <ebiederm@...ssion.com>,
        David Howells <dhowells@...hat.com>,
        Nicolas Pitre <nico@...xnic.net>
Subject: [PATCH 2/7] take fdpic-related parts of elf_prstatus out

From: Al Viro <viro@...iv.linux.org.uk>

The only architecture where we might end up using both is arm,
and there we definitely don't want fdpic-related fields in
elf_prstatus - coredump layout of ELF binaries should not
depend upon having the kernel built with the support of ELF_FDPIC
ones.  Just move the fdpic-modified variant into binfmt_elf_fdpic.c
(and call it elf_prstatus_fdpic there)

[name stolen from nico]

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/binfmt_elf_fdpic.c          | 32 +++++++++++++++++++++++++++++---
 include/linux/elfcore-compat.h |  4 ----
 include/linux/elfcore.h        | 10 ----------
 3 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 0f45521b237c..6e13d8bea32d 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1189,6 +1189,32 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
  */
 #ifdef CONFIG_ELF_CORE
 
+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 */
+	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
+	 * fields (below) used to communicate this information are placed
+	 * immediately after ``pr_reg'', so that the loadmap addresses may
+	 * be viewed as part of the register set if so desired.
+	 */
+	unsigned long pr_exec_fdpic_loadmap;
+	unsigned long pr_interp_fdpic_loadmap;
+	int pr_fpvalid;		/* True if math co-processor being used.  */
+};
+
 /*
  * Decide whether a segment is worth dumping; default is yes to be
  * sure (missing info is worse than too much; etc).
@@ -1345,7 +1371,7 @@ 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 *prstatus,
+static void fill_prstatus(struct elf_prstatus_fdpic *prstatus,
 			  struct task_struct *p, long signr)
 {
 	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
@@ -1428,7 +1454,7 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
 struct elf_thread_status
 {
 	struct list_head list;
-	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
+	struct elf_prstatus_fdpic prstatus;	/* NT_PRSTATUS */
 	elf_fpregset_t fpu;		/* NT_PRFPREG */
 	struct task_struct *thread;
 #ifdef ELF_CORE_COPY_XFPREGS
@@ -1562,7 +1588,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 	loff_t offset = 0, dataoff;
 	int numnote;
 	struct memelfnote *notes = NULL;
-	struct elf_prstatus *prstatus = NULL;	/* NT_PRSTATUS */
+	struct elf_prstatus_fdpic *prstatus = NULL;	/* NT_PRSTATUS */
 	struct elf_prpsinfo *psinfo = NULL;	/* NT_PRPSINFO */
  	LIST_HEAD(thread_list);
  	struct list_head *t;
diff --git a/include/linux/elfcore-compat.h b/include/linux/elfcore-compat.h
index 7a37f4ce9fd2..10485f0c9740 100644
--- a/include/linux/elfcore-compat.h
+++ b/include/linux/elfcore-compat.h
@@ -32,10 +32,6 @@ struct compat_elf_prstatus
 	struct old_timeval32		pr_cutime;
 	struct old_timeval32		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;
 };
 
diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h
index 96ab215dad2d..adb8ee89f3fd 100644
--- a/include/linux/elfcore.h
+++ b/include/linux/elfcore.h
@@ -44,16 +44,6 @@ struct elf_prstatus
 	struct __kernel_old_timeval pr_cutime;	/* Cumulative user time */
 	struct __kernel_old_timeval pr_cstime;	/* Cumulative system time */
 	elf_gregset_t pr_reg;	/* GP registers */
-#ifdef CONFIG_BINFMT_ELF_FDPIC
-	/* When using FDPIC, the loadmap addresses need to be communicated
-	 * to GDB in order for GDB to do the necessary relocations.  The
-	 * fields (below) used to communicate this information are placed
-	 * immediately after ``pr_reg'', so that the loadmap addresses may
-	 * be viewed as part of the register set if so desired.
-	 */
-	unsigned long pr_exec_fdpic_loadmap;
-	unsigned long pr_interp_fdpic_loadmap;
-#endif
 	int pr_fpvalid;		/* True if math co-processor being used.  */
 };
 
-- 
2.11.0