[S390] 64-bit register support for 31-bit processes

From: Heiko Carstens <heiko.carstens@de.ibm.com>
From: Martin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

7 files changed, 148 insertions, 4 deletions

diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h
index 74d0bbb7d955..e885442c1dfe 100644
--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -92,6 +92,18 @@
 /* Keep this the last entry.  */
 #define R_390_NUM       61
 
+/* Bits present in AT_HWCAP. */
+#define HWCAP_S390_ESAN3        1
+#define HWCAP_S390_ZARCH        2
+#define HWCAP_S390_STFLE        4
+#define HWCAP_S390_MSA          8
+#define HWCAP_S390_LDISP        16
+#define HWCAP_S390_EIMM         32
+#define HWCAP_S390_DFP          64
+#define HWCAP_S390_HPAGE        128
+#define HWCAP_S390_ETF3EH       256
+#define HWCAP_S390_HIGH_GPRS    512
+
 /*
  * These are used to set parameters in the core dumps.
  */
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index 539263fc9ab9..95dcf183a28d 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -311,6 +311,10 @@ typedef struct
         __u32           orig_gpr2;
 } s390_compat_regs;
 
+typedef struct
+{
+        __u32           gprs_high[NUM_GPRS];
+} s390_compat_regs_high;
 
 #ifdef __KERNEL__
 
diff --git a/arch/s390/include/asm/ucontext.h b/arch/s390/include/asm/ucontext.h
index d69bec0b03f5..cfb874e66c9a 100644
--- a/arch/s390/include/asm/ucontext.h
+++ b/arch/s390/include/asm/ucontext.h
@@ -9,6 +9,21 @@
 #ifndef _ASM_S390_UCONTEXT_H
 #define _ASM_S390_UCONTEXT_H
 
+#define UC_EXTENDED     0x00000001
+
+#ifndef __s390x__
+
+struct ucontext_extended {
+        unsigned long     uc_flags;
+        struct ucontext  *uc_link;
+        stack_t           uc_stack;
+        _sigregs          uc_mcontext;
+        unsigned long     uc_sigmask[2];
+        unsigned long     uc_gprs_high[16];
+};
+
+#endif
+
 struct ucontext {
         unsigned long     uc_flags;
         struct ucontext  *uc_link;
diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index b537cb0e9b55..eee999853a7c 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -39,6 +39,7 @@ typedef struct
         struct sigcontext32 sc;
         _sigregs32 sregs;
         int signo;
+        __u32 gprs_high[NUM_GPRS];
         __u8 retcode[S390_SYSCALL_SIZE];
 } sigframe32;
 
@@ -48,6 +49,7 @@ typedef struct
         __u8 retcode[S390_SYSCALL_SIZE];
         compat_siginfo_t info;
         struct ucontext32 uc;
+        __u32 gprs_high[NUM_GPRS];
 } rt_sigframe32;
 
 int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
@@ -344,6 +346,30 @@ static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
         return 0;
 }
 
+static int save_sigregs_gprs_high(struct pt_regs *regs, __u32 __user *uregs)
+{
+        __u32 gprs_high[NUM_GPRS];
+        int i;
+
+        for (i = 0; i < NUM_GPRS; i++)
+                gprs_high[i] = regs->gprs[i] >> 32;
+
+        return __copy_to_user(uregs, &gprs_high, sizeof(gprs_high));
+}
+
+static int restore_sigregs_gprs_high(struct pt_regs *regs, __u32 __user *uregs)
+{
+        __u32 gprs_high[NUM_GPRS];
+        int err, i;
+
+        err = __copy_from_user(&gprs_high, uregs, sizeof(gprs_high));
+        if (err)
+                return err;
+        for (i = 0; i < NUM_GPRS; i++)
+                *(__u32 *)&regs->gprs[i] = gprs_high[i];
+        return 0;
+}
+
 asmlinkage long sys32_sigreturn(void)
 {
         struct pt_regs *regs = task_pt_regs(current);
@@ -363,6 +389,8 @@ asmlinkage long sys32_sigreturn(void)
 
         if (restore_sigregs32(regs, &frame->sregs))
                 goto badframe;
+        if (restore_sigregs_gprs_high(regs, frame->gprs_high))
+                goto badframe;
 
         return regs->gprs[2];
 
@@ -394,6 +422,8 @@ asmlinkage long sys32_rt_sigreturn(void)
 
         if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
                 goto badframe;
+        if (restore_sigregs_gprs_high(regs, frame->gprs_high))
+                goto badframe;
 
         err = __get_user(ss_sp, &frame->uc.uc_stack.ss_sp);
         st.ss_sp = compat_ptr(ss_sp);
@@ -474,6 +504,8 @@ static int setup_frame32(int sig, struct k_sigaction *ka,
 
         if (save_sigregs32(regs, &frame->sregs))
                 goto give_sigsegv;
+        if (save_sigregs_gprs_high(regs, frame->gprs_high))
+                goto give_sigsegv;
         if (__put_user((unsigned long) &frame->sregs, &frame->sc.sregs))
                 goto give_sigsegv;
 
@@ -529,13 +561,14 @@ static int setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,
                 goto give_sigsegv;
 
         /* Create the ucontext.  */
-        err |= __put_user(0, &frame->uc.uc_flags);
+        err |= __put_user(UC_EXTENDED, &frame->uc.uc_flags);
         err |= __put_user(0, &frame->uc.uc_link);
         err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
         err |= __put_user(sas_ss_flags(regs->gprs[15]),
                           &frame->uc.uc_stack.ss_flags);
         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
         err |= save_sigregs32(regs, &frame->uc.uc_mcontext);
+        err |= save_sigregs_gprs_high(regs, frame->gprs_high);
         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
         if (err)
                 goto give_sigsegv;
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index a8738676b26c..653c6a178740 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -57,6 +57,7 @@
 enum s390_regset {
         REGSET_GENERAL,
         REGSET_FP,
+        REGSET_GENERAL_EXTENDED,
 };
 
 static void
@@ -879,6 +880,67 @@ static int s390_compat_regs_set(struct task_struct *target,
         return rc;
 }
 
+static int s390_compat_regs_high_get(struct task_struct *target,
+                                     const struct user_regset *regset,
+                                     unsigned int pos, unsigned int count,
+                                     void *kbuf, void __user *ubuf)
+{
+        compat_ulong_t *gprs_high;
+
+        gprs_high = (compat_ulong_t *)
+                &task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
+        if (kbuf) {
+                compat_ulong_t *k = kbuf;
+                while (count > 0) {
+                        *k++ = *gprs_high;
+                        gprs_high += 2;
+                        count -= sizeof(*k);
+                }
+        } else {
+                compat_ulong_t __user *u = ubuf;
+                while (count > 0) {
+                        if (__put_user(*gprs_high, u++))
+                                return -EFAULT;
+                        gprs_high += 2;
+                        count -= sizeof(*u);
+                }
+        }
+        return 0;
+}
+
+static int s390_compat_regs_high_set(struct task_struct *target,
+                                     const struct user_regset *regset,
+                                     unsigned int pos, unsigned int count,
+                                     const void *kbuf, const void __user *ubuf)
+{
+        compat_ulong_t *gprs_high;
+        int rc = 0;
+
+        gprs_high = (compat_ulong_t *)
+                &task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
+        if (kbuf) {
+                const compat_ulong_t *k = kbuf;
+                while (count > 0) {
+                        *gprs_high = *k++;
+                        *gprs_high += 2;
+                        count -= sizeof(*k);
+                }
+        } else {
+                const compat_ulong_t  __user *u = ubuf;
+                while (count > 0 && !rc) {
+                        unsigned long word;
+                        rc = __get_user(word, u++);
+                        if (rc)
+                                break;
+                        *gprs_high = word;
+                        *gprs_high += 2;
+                        count -= sizeof(*u);
+                }
+        }
+
+        return rc;
+}
+
 static const struct user_regset s390_compat_regsets[] = {
         [REGSET_GENERAL] = {
                 .core_note_type = NT_PRSTATUS,
@@ -896,6 +958,14 @@ static const struct user_regset s390_compat_regsets[] = {
                 .get = s390_fpregs_get,
                 .set = s390_fpregs_set,
         },
+        [REGSET_GENERAL_EXTENDED] = {
+                .core_note_type = NT_PRXSTATUS,
+                .n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
+                .size = sizeof(compat_long_t),
+                .align = sizeof(compat_long_t),
+                .get = s390_compat_regs_high_get,
+                .set = s390_compat_regs_high_set,
+        },
 };
 
 static const struct user_regset_view user_s390_compat_view = {
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 9ed13a1ed376..061479ff029f 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -729,7 +729,7 @@ static void __init setup_hwcaps(void)
 
         if ((facility_list & (1UL << (31 - 22)))
             && (facility_list & (1UL << (31 - 30))))
-                elf_hwcap |= 1UL << 8;
+                elf_hwcap |= HWCAP_S390_ETF3EH;
 
         /*
          * Check for additional facilities with store-facility-list-extended.
@@ -748,11 +748,20 @@ static void __init setup_hwcaps(void)
             __stfle(&facility_list_extended, 1) > 0) {
                 if ((facility_list_extended & (1ULL << (63 - 42)))
                     && (facility_list_extended & (1ULL << (63 - 44))))
-                        elf_hwcap |= 1UL << 6;
+                        elf_hwcap |= HWCAP_S390_DFP;
         }
 
+        /*
+         * Huge page support HWCAP_S390_HPAGE is bit 7.
+         */
         if (MACHINE_HAS_HPAGE)
-                elf_hwcap |= 1UL << 7;
+                elf_hwcap |= HWCAP_S390_HPAGE;
+
+        /*
+         * 64-bit register support for 31-bit processes
+         * HWCAP_S390_HIGH_GPRS is bit 9.
+         */
+        elf_hwcap |= HWCAP_S390_HIGH_GPRS;
 
         switch (S390_lowcore.cpu_id.machine) {
         case 0x9672:
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 45a937be6d38..90a4ed0ea0e5 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -361,6 +361,7 @@ typedef struct elf64_shdr {
 #define NT_PPC_VSX      0x102           /* PowerPC VSX registers */
 #define NT_386_TLS      0x200           /* i386 TLS slots (struct user_desc) */
 #define NT_386_IOPERM   0x201           /* x86 io permission bitmap (1=deny) */
+#define NT_PRXSTATUS    0x300           /* s390 upper register halves */
 
 
 /* Note header in a PT_NOTE section */