Re: [PATCH 16/23] arm64: ilp32: introduce binfmt_ilp32.c

From: Zhangjian (Bamvor)
Date: Thu May 26 2016 - 09:50:43 EST


Hi, yury

The coredump is usable in our platform. It miss the following definition:
+#define compat_elf_greg_t elf_greg_t
+#define compat_elf_gregset_t elf_gregset_t

And it leads to the wrong register save in core dump. After apply this patch,
gdb could debug core dump files.

Here is the full patch:
From 102624840aa5dacdd1bbfe3b390290f52f530ea2 Mon Sep 17 00:00:00 2001
From: Bamvor Jian Zhang <bamvor.zhangjian@xxxxxxxxxx>
Date: Thu, 26 May 2016 21:00:16 +0800
Subject: [PATCH hulk-4.1-next] arm64: ilp32: fix coredump issue

ILP32 use aarch64 register and 32bit signal struct which means it
could not make use of the existing compat_elf_prstatus/elf_prstatus
and compat_elf_prpsinfo/elf_prpsinfo.

This patch fix this issue by introducing the different
compat_elf_greg_t, compat_elf_gregset_t for aarch64 ilp32 and aarch32
el0.

Tested pass on huawei's hardware in bigendian.

Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@xxxxxxxxxx>
---
arch/arm64/include/asm/elf.h | 14 +++++++-------
arch/arm64/kernel/binfmt_elf32.c | 3 +++
arch/arm64/kernel/binfmt_ilp32.c | 8 +++++++-
arch/arm64/kernel/ptrace.c | 20 ++++++++++----------
4 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 0106d18..9019441 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -154,18 +154,18 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm,
int uses_interp);

/* 1GB of VA */
-#define STACK_RND_MASK (is_compat_task() ? \
- 0x7ff >> (PAGE_SHIFT - 12) : \
- 0x3ffff >> (PAGE_SHIFT - 12))
+#define STACK_RND_MASK (is_compat_task() ? \
+ 0x7ff >> (PAGE_SHIFT - 12) : \
+ 0x3ffff >> (PAGE_SHIFT - 12))

#ifdef CONFIG_COMPAT

-#define COMPAT_ELF_ET_DYN_BASE (2 * TASK_SIZE_32 / 3)
+#define COMPAT_ELF_ET_DYN_BASE (2 * TASK_SIZE_32 / 3)

/* AArch32 registers. */
-#define COMPAT_ELF_NGREG 18
-typedef unsigned int compat_elf_greg_t;
-typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG];
+#define COMPAT_ELF_NGREG 18
+typedef unsigned int compat_a32_elf_greg_t;
+typedef compat_a32_elf_greg_t compat_a32_elf_gregset_t[COMPAT_ELF_NGREG];

#endif /* CONFIG_COMPAT */

diff --git a/arch/arm64/kernel/binfmt_elf32.c b/arch/arm64/kernel/binfmt_elf32.c
index 7b9b445..f75253c 100644
--- a/arch/arm64/kernel/binfmt_elf32.c
+++ b/arch/arm64/kernel/binfmt_elf32.c
@@ -31,4 +31,7 @@ struct linux_binprm;
extern int aarch32_setup_vectors_page(struct linux_binprm *bprm,
int uses_interp);

+#define compat_elf_greg_t compat_a32_elf_greg_t
+#define compat_elf_gregset_t compat_a32_elf_gregset_t
+
#include "../../../fs/compat_binfmt_elf.c"
diff --git a/arch/arm64/kernel/binfmt_ilp32.c b/arch/arm64/kernel/binfmt_ilp32.c
index b827a9a..01baf83 100644
--- a/arch/arm64/kernel/binfmt_ilp32.c
+++ b/arch/arm64/kernel/binfmt_ilp32.c
@@ -2,7 +2,9 @@
* Support for ILP32 Linux/aarch64 ELF binaries.
*/

-#include <linux/elfcore-compat.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/compat.h>
#include <linux/time.h>

#undef ELF_CLASS
@@ -30,9 +32,13 @@
* The machine-dependent core note format types are defined in elfcore-compat.h,
* which requires asm/elf.h to define compat_elf_gregset_t et al.
*/
+#define compat_elf_greg_t elf_greg_t
+#define compat_elf_gregset_t elf_gregset_t
#define elf_prstatus compat_elf_prstatus
#define elf_prpsinfo compat_elf_prpsinfo

+#include <linux/elfcore-compat.h>
+
/*
* Compat version of cputime_to_compat_timeval, perhaps this
* should be an inline in <linux/compat.h>.
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 5c86135..9784c77 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -913,8 +913,8 @@ static const struct user_regset aarch32_regsets[] = {
[REGSET_COMPAT_GPR] = {
.core_note_type = NT_PRSTATUS,
.n = COMPAT_ELF_NGREG,
- .size = sizeof(compat_elf_greg_t),
- .align = sizeof(compat_elf_greg_t),
+ .size = sizeof(compat_a32_elf_greg_t),
+ .align = sizeof(compat_a32_elf_greg_t),
.get = compat_gpr_get,
.set = compat_gpr_set
},
@@ -947,7 +947,7 @@ static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off,
tmp = tsk->mm->start_data;
else if (off == COMPAT_PT_TEXT_END_ADDR)
tmp = tsk->mm->end_code;
- else if (off < sizeof(compat_elf_gregset_t))
+ else if (off < sizeof(compat_a32_elf_gregset_t))
return copy_regset_to_user(tsk, &user_aarch32_view,
REGSET_COMPAT_GPR, off,
sizeof(compat_ulong_t), ret);
@@ -968,7 +968,7 @@ static int compat_ptrace_write_user(struct task_struct *tsk, compat_ulong_t off,
if (off & 3 || off >= COMPAT_USER_SZ)
return -EIO;

- if (off >= sizeof(compat_elf_gregset_t))
+ if (off >= sizeof(compat_a32_elf_gregset_t))
return 0;

set_fs(KERNEL_DS);
@@ -1116,9 +1116,11 @@ static long compat_a32_ptrace(struct task_struct *child, compat_long_t request,
unsigned long addr = caddr;
unsigned long data = cdata;
void __user *datap = compat_ptr(data);
+ unsigned int pr_reg_size = sizeof(compat_a32_elf_gregset_t);
int ret;

switch (request) {
+
case PTRACE_PEEKUSR:
ret = compat_ptrace_read_user(child, addr, datap);
break;
@@ -1130,17 +1132,15 @@ static long compat_a32_ptrace(struct task_struct *child, compat_long_t request,
case COMPAT_PTRACE_GETREGS:
ret = copy_regset_to_user(child,
&user_aarch32_view,
- REGSET_COMPAT_GPR,
- 0, sizeof(compat_elf_gregset_t),
- datap);
+ REGSET_COMPAT_GPR, 0,
+ pr_reg_size, datap);
break;

case COMPAT_PTRACE_SETREGS:
ret = copy_regset_from_user(child,
&user_aarch32_view,
- REGSET_COMPAT_GPR,
- 0, sizeof(compat_elf_gregset_t),
- datap);
+ REGSET_COMPAT_GPR, 0,
+ pr_reg_size, datap);
break;

case COMPAT_PTRACE_GET_THREAD_AREA:
--
1.8.4.5


On 2016/5/24 8:04, Yury Norov wrote:
to handle ILP32 binaries

Signed-off-by: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/Makefile | 1 +
arch/arm64/kernel/binfmt_ilp32.c | 91 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 92 insertions(+)
create mode 100644 arch/arm64/kernel/binfmt_ilp32.c

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 6bc9738..9dfdf86 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -28,6 +28,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
arm64-obj-$(CONFIG_AARCH32_EL0) += sys32.o kuser32.o signal32.o \
sys_compat.o entry32.o \
../../arm/kernel/opcodes.o binfmt_elf32.o
+arm64-obj-$(CONFIG_ARM64_ILP32) += binfmt_ilp32.o
arm64-obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o
arm64-obj-$(CONFIG_MODULES) += arm64ksyms.o module.o
arm64-obj-$(CONFIG_ARM64_MODULE_PLTS) += module-plts.o
diff --git a/arch/arm64/kernel/binfmt_ilp32.c b/arch/arm64/kernel/binfmt_ilp32.c
new file mode 100644
index 0000000..a934fd4
--- /dev/null
+++ b/arch/arm64/kernel/binfmt_ilp32.c
@@ -0,0 +1,91 @@
+/*
+ * Support for ILP32 Linux/aarch64 ELF binaries.
+ */
+
+#include <linux/elfcore-compat.h>
+#include <linux/time.h>
+
+#undef ELF_CLASS
+#define ELF_CLASS ELFCLASS32
+
+#undef elfhdr
+#undef elf_phdr
+#undef elf_shdr
+#undef elf_note
+#undef elf_addr_t
+#define elfhdr elf32_hdr
+#define elf_phdr elf32_phdr
+#define elf_shdr elf32_shdr
+#define elf_note elf32_note
+#define elf_addr_t Elf32_Addr
+
+/*
+ * 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_user copy_siginfo_to_user32
+
+/*
+ * The machine-dependent core note format types are defined in elfcore-compat.h,
+ * which requires asm/elf.h to define compat_elf_gregset_t et al.
+ */
+#define elf_prstatus compat_elf_prstatus
+#define elf_prpsinfo compat_elf_prpsinfo
+
+/*
+ * Compat version of cputime_to_compat_timeval, perhaps this
+ * should be an inline in <linux/compat.h>.
+ */
+static void cputime_to_compat_timeval(const cputime_t cputime,
+ struct compat_timeval *value)
+{
+ struct timeval tv;
+ cputime_to_timeval(cputime, &tv);
+ value->tv_sec = tv.tv_sec;
+ value->tv_usec = tv.tv_usec;
+}
+
+#undef cputime_to_timeval
+#define cputime_to_timeval cputime_to_compat_timeval
+
+/* AARCH64 ILP32 EABI. */
+#undef elf_check_arch
+#define elf_check_arch(x) (((x)->e_machine == EM_AARCH64) \
+ && (x)->e_ident[EI_CLASS] == ELFCLASS32)
+
+#undef SET_PERSONALITY
+#define SET_PERSONALITY(ex) \
+do { \
+ set_thread_flag(TIF_32BIT_AARCH64); \
+ clear_thread_flag(TIF_32BIT); \
+} while (0)
+
+#undef ARCH_DLINFO
+#define ARCH_DLINFO \
+do { \
+ NEW_AUX_ENT(AT_SYSINFO_EHDR, \
+ (elf_addr_t)(long)current->mm->context.vdso); \
+} while (0)
+
+#ifdef __AARCH64EB__
+#define COMPAT_ELF_PLATFORM ("aarch64_be:ilp32")
+#else
+#define COMPAT_ELF_PLATFORM ("aarch64:ilp32")
+#endif
+
+#undef ELF_HWCAP
+#undef ELF_HWCAP2
+#define ELF_HWCAP ((u32) elf_hwcap)
+#define ELF_HWCAP2 ((u32) (elf_hwcap >> 32))
+
+/*
+ * Rename a few of the symbols that binfmt_elf.c will define.
+ * These are all local so the names don't really matter, but it
+ * might make some debugging less confusing not to duplicate them.
+ */
+#define elf_format compat_elf_format
+#define init_elf_binfmt init_compat_elf_binfmt
+#define exit_elf_binfmt exit_compat_elf_binfmt
+
+#include "../../../fs/binfmt_elf.c"