[PATCH 02/10] elf_prstatus: collect the common part (everything before pr_reg) into a struct

Al Viro
2020-12-03T21:47:40Z

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

Preparations to doing i386 compat elf_prstatus sanely - rather than duplicating
the beginning of compat_elf_prstatus, take these fields into a separate
structure (compat_elf_prstatus_common), so that it could be reused. Due to
the incestous relationship between binfmt_elf.c and compat_binfmt_elf.c we
need the same shape change done to native struct elf_prstatus, gathering the
fields prior to pr_reg into a new structure (struct elf_prstatus_common).

Fortunately, offset of pr_reg is always a multiple of 16 with no padding
right before it, so it's possible to turn all the stuff prior to it into
a single member without disturbing the layout.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/ia64/kernel/crash.c | 2 +-
arch/mips/kernel/binfmt_elfn32.c | 7 ++++++-
arch/mips/kernel/binfmt_elfo32.c | 6 +++++-
arch/powerpc/platforms/powernv/opal-core.c | 6 +++---
arch/s390/kernel/crash_dump.c | 2 +-
fs/binfmt_elf.c | 6 +++---
fs/binfmt_elf_fdpic.c | 22 +++++-----------------
fs/compat_binfmt_elf.c | 1 +
include/linux/elfcore-compat.h | 7 ++++++-
include/linux/elfcore.h | 7 ++++++-
kernel/kexec_core.c | 2 +-
11 files changed, 38 insertions(+), 30 deletions(-)

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/kernel/binfmt_elfn32.c b/arch/mips/kernel/binfmt_elfn32.c
index 6ee3f7218c67..136dc0c9300d 100644
--- a/arch/mips/kernel/binfmt_elfn32.c
+++ b/arch/mips/kernel/binfmt_elfn32.c
@@ -44,7 +44,8 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
#include <linux/math64.h>

#define elf_prstatus elf_prstatus32
-struct elf_prstatus32
+#define elf_prstatus_common elf_prstatus32_common
+struct elf_prstatus32_common
{
struct elf_siginfo pr_info; /* Info associated with signal */
short pr_cursig; /* Current signal */
@@ -58,6 +59,10 @@ struct elf_prstatus32
struct old_timeval32 pr_stime; /* System time */
struct old_timeval32 pr_cutime;/* Cumulative user time */
struct old_timeval32 pr_cstime;/* Cumulative system time */
+};
+struct elf_prstatus32
+{
+ struct elf_prstatus32_common common:
elf_gregset_t pr_reg; /* GP registers */
int pr_fpvalid; /* True if math co-processor being used. */
};
diff --git a/arch/mips/kernel/binfmt_elfo32.c b/arch/mips/kernel/binfmt_elfo32.c
index 6dd103d3cebb..b1f4b8f1dee7 100644
--- a/arch/mips/kernel/binfmt_elfo32.c
+++ b/arch/mips/kernel/binfmt_elfo32.c
@@ -49,7 +49,7 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
#include <linux/math64.h>

#define elf_prstatus elf_prstatus32
-struct elf_prstatus32
+struct elf_prstatus32_common
{
struct elf_siginfo pr_info; /* Info associated with signal */
short pr_cursig; /* Current signal */
@@ -63,6 +63,10 @@ struct elf_prstatus32
struct old_timeval32 pr_stime; /* System time */
struct old_timeval32 pr_cutime;/* Cumulative user time */
struct old_timeval32 pr_cstime;/* Cumulative system time */
+};
+struct elf_prstatus32
+{
+ struct elf_prstatus32_common common:
elf_gregset_t pr_reg; /* GP registers */
int pr_fpvalid; /* True if math co-processor being used. */
};
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/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/fs/binfmt_elf.c b/fs/binfmt_elf.c
index f066882bd270..c76324f647ae 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;
@@ -1736,7 +1736,7 @@ 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);
+ fill_prstatus(&t->prstatus.common, t->task, signr);
regset_get(t->task, &view->regsets[0],
sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);

@@ -1958,7 +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),
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 13cd78773700..a40df32acff5 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
diff --git a/include/linux/elfcore-compat.h b/include/linux/elfcore-compat.h
index 10485f0c9740..4aeda5f1f038 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;
@@ -31,6 +31,11 @@ struct compat_elf_prstatus
struct old_timeval32 pr_stime;
struct old_timeval32 pr_cutime;
struct old_timeval32 pr_cstime;
+};
+
+struct compat_elf_prstatus
+{
+ struct compat_elf_prstatus_common common;
compat_elf_gregset_t pr_reg;
compat_int_t pr_fpvalid;
};
diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h
index 46c3d691f677..641a9041182d 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 8798a8183974..e61ab826ab18 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -1077,7 +1077,7 @@ 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));
--
2.11.0