[PATCH v6 11/20] arm64:ilp32: support core dump generation for ILP32

Yury Norov
2015-12-15T21:48:41Z

From: Andrew Pinski <Andrew.Pinski@caviumnetworks.com>

This patch supports core dumping on ILP32.
We need a few extra macros (COMPAT_PR_REG_SIZE and COMPAT_PRSTATUS_SIZE) due
to size differences of the register sets.

Reviewed-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Andrew Pinski <Andrew.Pinski@caviumnetworks.com>
---
arch/arm64/include/asm/elf.h | 104 ++++++++++++++++++++++++++++++++++++++-----
arch/arm64/kernel/ptrace.c | 12 ++---
2 files changed, 100 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 8786ca5..4e2e3c0 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -135,7 +135,11 @@ typedef struct user_fpsimd_state elf_fpregset_t;
*/
#define ELF_PLAT_INIT(_r, load_addr) (_r)->regs[0] = 0

-#define SET_PERSONALITY(ex) clear_thread_flag(TIF_32BIT);
+#define SET_PERSONALITY(ex) \
+do { \
+ clear_thread_flag(TIF_32BIT_AARCH64); \
+ clear_thread_flag(TIF_32BIT); \
+} while (0)

#define ARCH_DLINFO \
do { \
@@ -167,12 +171,15 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm,

#define COMPAT_ELF_ET_DYN_BASE (2 * TASK_SIZE_32 / 3)

+extern int aarch32_setup_vectors_page(struct linux_binprm *bprm,
+ int uses_interp);
+
#ifdef CONFIG_AARCH32_EL0

/* AArch32 registers. */
#define COMPAT_A32_ELF_NGREG 18
-typedef unsigned int compat_elf_greg_t;
-typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_A32_ELF_NGREG];
+typedef unsigned int compat_a32_elf_greg_t;
+typedef compat_a32_elf_greg_t compat_a32_elf_gregset_t[COMPAT_A32_ELF_NGREG];

/* AArch32 EABI. */
#define EF_ARM_EABI_MASK 0xff000000
@@ -180,15 +187,92 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_A32_ELF_NGREG];
((x)->e_flags & EF_ARM_EABI_MASK))

#define compat_start_thread compat_start_thread
-#define COMPAT_SET_PERSONALITY(ex) set_thread_flag(TIF_32BIT);
-#define COMPAT_ARCH_DLINFO
-extern int aarch32_setup_vectors_page(struct linux_binprm *bprm,
- int uses_interp);
-#define compat_arch_setup_additional_pages \
- aarch32_setup_vectors_page
+#define COMPAT_A32_SET_PERSONALITY(ex) \
+do { \
+ clear_thread_flag(TIF_32BIT_AARCH64); \
+ set_thread_flag(TIF_32BIT); \
+} while (0)
+#define COMPAT_A32_ARCH_DLINFO do {} while (0)
+
+#else
+
+typedef elf_greg_t compat_elf_greg_t;
+typedef elf_gregset_t compat_elf_gregset_t;
+#define compat_a32_elf_check_arch(x) 0
+#define COMPAT_A32_SET_PERSONALITY(ex) do {} while (0)
+#define COMPAT_A32_ARCH_DLINFO do {} while (0)
+#endif
+
+/*
+ * If ILP32 is turned on, we want to define the compat_elf_greg_t to the non compat
+ * one and define PR_REG_SIZE/PRSTATUS_SIZE/SET_PR_FPVALID so we pick up the correct
+ * ones for AARCH32. Note also the definition of the macros have to be correct for
+ * LP64 as this file is included in the standard binfmt_elf.c.
+ */
+#ifdef CONFIG_ARM64_ILP32
+typedef elf_greg_t compat_elf_greg_t;
+typedef elf_gregset_t compat_elf_gregset_t;
+#ifdef CONFIG_AARCH32_EL0
+#define PR_REG_SIZE(S) (is_a32_compat_task() \
+ ? sizeof(compat_a32_elf_gregset_t) \
+ : sizeof(elf_gregset_t))
+#endif
+
+/*
+ * struct elf_prstatus is defined in include/uapi/linux/elfcore.h,
+ * and has different sise for supported ABIs
+ */
+#define PRSTATUS_SIZE(S) (is_a32_compat_task() ? 124 : (is_ilp32_compat_task() ? 352 : 392))
+
+#define SET_PR_FPVALID(S, V) \
+do { \
+ *(int *) (((void *) &((S)->pr_reg)) + PR_REG_SIZE((S)->pr_reg)) = (V); \
+} while (0)
+#else
+typedef compat_a32_elf_greg_t compat_elf_greg_t;
+typedef compat_a32_elf_gregset_t compat_elf_gregset_t;
+#endif
+
+#ifdef CONFIG_ARM64_ILP32
+#define compat_ilp32_elf_check_arch(x) ((x)->e_machine == EM_AARCH64)
+#define COMPAT_ILP32_SET_PERSONALITY(ex) \
+do { \
+ set_thread_flag(TIF_32BIT_AARCH64); \
+ clear_thread_flag(TIF_32BIT); \
+} while (0)
+#define COMPAT_ILP32_ARCH_DLINFO \
+do { \
+ NEW_AUX_ENT(AT_SYSINFO_EHDR, \
+ (elf_addr_t)(long)current->mm->context.vdso); \
+} while (0)
+#else
+#define compat_ilp32_elf_check_arch(x) 0
+#define COMPAT_ILP32_SET_PERSONALITY(ex) do {} while (0)
+#define COMPAT_ILP32_ARCH_DLINFO do {} while (0)
#endif

-#define compat_elf_check_arch(x) compat_a32_elf_check_arch(x)
+#define compat_elf_check_arch(x) (compat_a32_elf_check_arch(x) || compat_ilp32_elf_check_arch(x))
+#define COMPAT_SET_PERSONALITY(ex) \
+do { \
+ if (compat_a32_elf_check_arch(&ex)) \
+ COMPAT_A32_SET_PERSONALITY(ex); \
+ else \
+ COMPAT_ILP32_SET_PERSONALITY(ex); \
+} while (0)
+
+/* ILP32 uses the "LP64-like" vdso pages */
+#define compat_arch_setup_additional_pages \
+ (is_a32_compat_task() \
+ ? &aarch32_setup_vectors_page \
+ : &(arch_setup_additional_pages))
+
+#define COMPAT_ARCH_DLINFO \
+do { \
+ if (is_a32_compat_task()) \
+ COMPAT_A32_ARCH_DLINFO; \
+ else \
+ COMPAT_ILP32_ARCH_DLINFO; \
+} while (0)

#endif /* CONFIG_COMPAT */

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 816b432..a9d07a9 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -853,8 +853,8 @@ static const struct user_regset aarch32_regsets[] = {
[REGSET_COMPAT_GPR] = {
.core_note_type = NT_PRSTATUS,
.n = COMPAT_A32_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
},
@@ -945,7 +945,7 @@ 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);
@@ -966,7 +966,7 @@ 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);
@@ -1129,7 +1129,7 @@ long compat_a32_arch_ptrace(struct task_struct *child, compat_long_t request,
ret = copy_regset_to_user(child,
&user_aarch32_view,
REGSET_COMPAT_GPR,
- 0, sizeof(compat_elf_gregset_t),
+ 0, sizeof(compat_a32_elf_gregset_t),
datap);
break;

@@ -1137,7 +1137,7 @@ long compat_a32_arch_ptrace(struct task_struct *child, compat_long_t request,
ret = copy_regset_from_user(child,
&user_aarch32_view,
REGSET_COMPAT_GPR,
- 0, sizeof(compat_elf_gregset_t),
+ 0, sizeof(compat_a32_elf_gregset_t),
datap);
break;

--
2.5.0