[ARM] 3270/1: ARM EABI: fix sigreturn and rt_sigreturn

Patch from Nicolas Pitre

The signal return path consists of user code provided by the kernel.
Since a syscall is used, it has to be updated to work with EABI.

Noticed by Daniel Jacobowitz.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 19 insertions, 12 deletions

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 765922bcf9e7..a0cd0a90a10d 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -30,15 +30,21 @@
 #define SWI_SYS_RT_SIGRETURN    (0xef000000|(__NR_rt_sigreturn))
 
 /*
+ * With EABI, the syscall number has to be loaded into r7.
+ */
+#define MOV_R7_NR_SIGRETURN     (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
+#define MOV_R7_NR_RT_SIGRETURN  (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
+
+/*
  * For Thumb syscalls, we pass the syscall number via r7.  We therefore
  * need two 16-bit instructions.
  */
 #define SWI_THUMB_SIGRETURN     (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
 #define SWI_THUMB_RT_SIGRETURN  (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
 
-const unsigned long sigreturn_codes[4] = {
-        SWI_SYS_SIGRETURN,      SWI_THUMB_SIGRETURN,
-        SWI_SYS_RT_SIGRETURN,   SWI_THUMB_RT_SIGRETURN
+const unsigned long sigreturn_codes[7] = {
+        MOV_R7_NR_SIGRETURN,    SWI_SYS_SIGRETURN,    SWI_THUMB_SIGRETURN,
+        MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
 };
 
 static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
@@ -189,7 +195,7 @@ struct aux_sigframe {
 struct sigframe {
         struct sigcontext sc;
         unsigned long extramask[_NSIG_WORDS-1];
-        unsigned long retcode;
+        unsigned long retcode[2];
         struct aux_sigframe aux __attribute__((aligned(8)));
 };
 
@@ -198,7 +204,7 @@ struct rt_sigframe {
         void __user *puc;
         struct siginfo info;
         struct ucontext uc;
-        unsigned long retcode;
+        unsigned long retcode[2];
         struct aux_sigframe aux __attribute__((aligned(8)));
 };
 
@@ -436,12 +442,13 @@ setup_return(struct pt_regs *regs, struct k_sigaction *ka,
         if (ka->sa.sa_flags & SA_RESTORER) {
                 retcode = (unsigned long)ka->sa.sa_restorer;
         } else {
-                unsigned int idx = thumb;
+                unsigned int idx = thumb << 1;
 
                 if (ka->sa.sa_flags & SA_SIGINFO)
-                        idx += 2;
+                        idx += 3;
 
-                if (__put_user(sigreturn_codes[idx], rc))
+                if (__put_user(sigreturn_codes[idx],   rc) ||
+                    __put_user(sigreturn_codes[idx+1], rc+1))
                         return 1;
 
                 if (cpsr & MODE32_BIT) {
@@ -456,7 +463,7 @@ setup_return(struct pt_regs *regs, struct k_sigaction *ka,
                          * the return code written onto the stack.
                          */
                         flush_icache_range((unsigned long)rc,
-                                           (unsigned long)(rc + 1));
+                                           (unsigned long)(rc + 2));
 
                         retcode = ((unsigned long)rc) + thumb;
                 }
@@ -488,7 +495,7 @@ setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *reg
         }
 
         if (err == 0)
-                err = setup_return(regs, ka, &frame->retcode, frame, usig);
+                err = setup_return(regs, ka, frame->retcode, frame, usig);
 
         return err;
 }
@@ -522,7 +529,7 @@ setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 
         if (err == 0)
-                err = setup_return(regs, ka, &frame->retcode, frame, usig);
+                err = setup_return(regs, ka, frame->retcode, frame, usig);
 
         if (err == 0) {
                 /*
diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h
index 91d26faca62b..9991049c522d 100644
--- a/arch/arm/kernel/signal.h
+++ b/arch/arm/kernel/signal.h
@@ -9,4 +9,4 @@
  */
 #define KERN_SIGRETURN_CODE     0xffff0500
 
-extern const unsigned long sigreturn_codes[4];
+extern const unsigned long sigreturn_codes[7];