[PATCH] arm64: compat: Expose offset to registers in sigframes

[Mark Salyzyn]

From: Kevin Brodsky <kevin.brodsky at arm.com>

This will be needed to provide unwinding information in compat
sigreturn trampolines, part of the future compat vDSO. There is no
obvious header the compat_sig* struct's should be moved to, so let's
put them in signal32.h.

Also fix minor style issues reported by checkpatch.

Signed-off-by: Kevin Brodsky <kevin.brodsky at arm.com>
Signed-off-by: Mark Salyzyn <salyzyn at android.com>

NB:
Basically unchanged as part of a vDSO32 effort through 4 revisions,
Resubmitted as a standalone change for quciker approval.

---
 arch/arm64/include/asm/signal32.h | 46 +++++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/asm-offsets.c   | 13 +++++++++++
 arch/arm64/kernel/signal32.c      | 46 ---------------------------------------
 3 files changed, 59 insertions(+), 46 deletions(-)

diff --git a/arch/arm64/include/asm/signal32.h b/arch/arm64/include/asm/signal32.h
index 81abea0b7650..612d4ba76fcd 100644
--- a/arch/arm64/include/asm/signal32.h
+++ b/arch/arm64/include/asm/signal32.h
@@ -22,6 +22,52 @@
 
 #define AARCH32_KERN_SIGRET_CODE_OFFSET	0x500
 
+struct compat_sigcontext {
+	/* We always set these two fields to 0 */
+	compat_ulong_t			trap_no;
+	compat_ulong_t			error_code;
+
+	compat_ulong_t			oldmask;
+	compat_ulong_t			arm_r0;
+	compat_ulong_t			arm_r1;
+	compat_ulong_t			arm_r2;
+	compat_ulong_t			arm_r3;
+	compat_ulong_t			arm_r4;
+	compat_ulong_t			arm_r5;
+	compat_ulong_t			arm_r6;
+	compat_ulong_t			arm_r7;
+	compat_ulong_t			arm_r8;
+	compat_ulong_t			arm_r9;
+	compat_ulong_t			arm_r10;
+	compat_ulong_t			arm_fp;
+	compat_ulong_t			arm_ip;
+	compat_ulong_t			arm_sp;
+	compat_ulong_t			arm_lr;
+	compat_ulong_t			arm_pc;
+	compat_ulong_t			arm_cpsr;
+	compat_ulong_t			fault_address;
+};
+
+struct compat_ucontext {
+	compat_ulong_t			uc_flags;
+	compat_uptr_t			uc_link;
+	compat_stack_t			uc_stack;
+	struct compat_sigcontext	uc_mcontext;
+	compat_sigset_t			uc_sigmask;
+	int __unused[32 - (sizeof(compat_sigset_t) / sizeof(int))];
+	compat_ulong_t			uc_regspace[128] __aligned(8);
+};
+
+struct compat_sigframe {
+	struct compat_ucontext		uc;
+	compat_ulong_t			retcode[2];
+};
+
+struct compat_rt_sigframe {
+	struct compat_siginfo		info;
+	struct compat_sigframe		sig;
+};
+
 int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set,
 		       struct pt_regs *regs);
 int compat_setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index db5b305806b7..804072fa695f 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -26,6 +26,7 @@
 #include <asm/cpufeature.h>
 #include <asm/thread_info.h>
 #include <asm/memory.h>
+#include <asm/signal32.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>
 #include <asm/vdso_datapage.h>
@@ -78,6 +79,18 @@ int main(void)
   DEFINE(S_STACKFRAME,		offsetof(struct pt_regs, stackframe));
   DEFINE(S_FRAME_SIZE,		sizeof(struct pt_regs));
   BLANK();
+#ifdef CONFIG_COMPAT
+  DEFINE(COMPAT_SIGFRAME_REGS_OFFSET,
+				offsetof(struct compat_sigframe, uc) +
+				offsetof(struct compat_ucontext, uc_mcontext) +
+				offsetof(struct compat_sigcontext, arm_r0));
+  DEFINE(COMPAT_RT_SIGFRAME_REGS_OFFSET,
+				offsetof(struct compat_rt_sigframe, sig) +
+				offsetof(struct compat_sigframe, uc) +
+				offsetof(struct compat_ucontext, uc_mcontext) +
+				offsetof(struct compat_sigcontext, arm_r0));
+  BLANK();
+#endif
   DEFINE(MM_CONTEXT_ID,		offsetof(struct mm_struct, context.id.counter));
   BLANK();
   DEFINE(VMA_VM_MM,		offsetof(struct vm_area_struct, vm_mm));
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index e09bf5d15606..b69acad2d93c 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -29,42 +29,6 @@
 #include <linux/uaccess.h>
 #include <asm/unistd.h>
 
-struct compat_sigcontext {
-	/* We always set these two fields to 0 */
-	compat_ulong_t			trap_no;
-	compat_ulong_t			error_code;
-
-	compat_ulong_t			oldmask;
-	compat_ulong_t			arm_r0;
-	compat_ulong_t			arm_r1;
-	compat_ulong_t			arm_r2;
-	compat_ulong_t			arm_r3;
-	compat_ulong_t			arm_r4;
-	compat_ulong_t			arm_r5;
-	compat_ulong_t			arm_r6;
-	compat_ulong_t			arm_r7;
-	compat_ulong_t			arm_r8;
-	compat_ulong_t			arm_r9;
-	compat_ulong_t			arm_r10;
-	compat_ulong_t			arm_fp;
-	compat_ulong_t			arm_ip;
-	compat_ulong_t			arm_sp;
-	compat_ulong_t			arm_lr;
-	compat_ulong_t			arm_pc;
-	compat_ulong_t			arm_cpsr;
-	compat_ulong_t			fault_address;
-};
-
-struct compat_ucontext {
-	compat_ulong_t			uc_flags;
-	compat_uptr_t			uc_link;
-	compat_stack_t			uc_stack;
-	struct compat_sigcontext	uc_mcontext;
-	compat_sigset_t			uc_sigmask;
-	int		__unused[32 - (sizeof (compat_sigset_t) / sizeof (int))];
-	compat_ulong_t	uc_regspace[128] __attribute__((__aligned__(8)));
-};
-
 struct compat_vfp_sigframe {
 	compat_ulong_t	magic;
 	compat_ulong_t	size;
@@ -91,16 +55,6 @@ struct compat_aux_sigframe {
 	unsigned long			end_magic;
 } __attribute__((__aligned__(8)));
 
-struct compat_sigframe {
-	struct compat_ucontext	uc;
-	compat_ulong_t		retcode[2];
-};
-
-struct compat_rt_sigframe {
-	struct compat_siginfo info;
-	struct compat_sigframe sig;
-};
-
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
 static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set)
-- 
2.15.0.rc0.271.g36b669edcc-goog