From: Andrew Pinski <apin...@cavium.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.

Signed-off-by: Philipp Tomsich <philipp.toms...@theobroma-systems.com>
Signed-off-by: Christoph Muellner <christoph.muell...@theobroma-systems.com>
Signed-off-by: Yury Norov <yno...@caviumnetworks.com>
Signed-off-by: Andrew Pinski <andrew.pin...@caviumnetworks.com>
Reviewed-by: David Daney <david.da...@cavium.com>
---
 arch/arm64/include/asm/elf.h | 87 ++++++++++++++++++++++++++++++++++++++------
 arch/arm64/kernel/ptrace.c   | 12 +++---
 arch/arm64/kernel/vdso.c     |  8 ++++
 3 files changed, 89 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 01e032c..8f13dac 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -134,7 +134,11 @@ 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 {                                                                   \
@@ -166,12 +170,15 @@ 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
@@ -179,24 +186,80 @@ 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_SET_PERSONALITY(ex)
-#define COMPAT_ARCH_DLINFO
+#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;
+#define PR_REG_SIZE(S)                 (is_a32_compat_task() ? 72 : 272)
+#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 d2e428c..22d0d5e 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -854,8 +854,8 @@ 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
        },
@@ -946,7 +946,7 @@ 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);
@@ -967,7 +967,7 @@ 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);
@@ -1130,7 +1130,7 @@ 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;
 
@@ -1138,7 +1138,7 @@ 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;
 
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 26352a6..b239b9b 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -107,6 +107,14 @@ int aarch32_setup_vectors_page(struct linux_binprm *bprm, 
int uses_interp)
 
        return PTR_ERR_OR_ZERO(ret);
 }
+#else
+int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
+{
+       (void) bprm;
+       (void) uses_interp;
+
+       return -EINVAL;
+}
 #endif /* CONFIG_AARCH32_EL0 */
 
 static struct vm_special_mapping vdso_spec[2];
-- 
2.1.4

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