[PATCH 3/4] powerpc: TRAP_IS_SYSCALL helper to hide syscall trap number

[Nicholas Piggin]

A new system call interrupt will be added with a new trap number.
Hide the explicit 0xc00 test behind an accessor to reduce churn
in callers.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 arch/powerpc/include/asm/ptrace.h  | 2 ++
 arch/powerpc/include/asm/syscall.h | 5 ++++-
 arch/powerpc/kernel/process.c      | 2 +-
 arch/powerpc/kernel/signal.c       | 2 +-
 arch/powerpc/xmon/xmon.c           | 2 +-
 5 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 7eaa2ecfd0b7..5eb249c725bd 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -180,6 +180,8 @@ extern int ptrace_put_reg(struct task_struct *task, int regno,
 #define current_pt_regs() \
 	((struct pt_regs *)((unsigned long)task_stack_page(current) + THREAD_SIZE) - 1)
 
+#define TRAP_IS_SYSCALL(regs)	(TRAP(regs) == 0xc00)
+
 #ifdef __powerpc64__
 #ifdef CONFIG_PPC_BOOK3S
 #define TRAP(regs)		((regs)->trap)
diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index 38d62acfdce7..1e0446d6ba45 100644
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -26,7 +26,10 @@ static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
 	 * This is important for seccomp so that compat tasks can set r0 = -1
 	 * to reject the syscall.
 	 */
-	return TRAP(regs) == 0xc00 ? regs->gpr[0] : -1;
+	if (TRAP_IS_SYSCALL(regs))
+		return regs->gpr[0];
+	else
+		return -1;
 }
 
 static inline void syscall_rollback(struct task_struct *task,
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 6599a3099d10..0dce642ca39d 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1412,7 +1412,7 @@ void show_regs(struct pt_regs * regs)
 	print_msr_bits(regs->msr);
 	pr_cont("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
 	trap = TRAP(regs);
-	if ((TRAP(regs) != 0xc00) && cpu_has_feature(CPU_FTR_CFAR))
+	if (!TRAP_IS_SYSCALL(regs) && cpu_has_feature(CPU_FTR_CFAR))
 		pr_cont("CFAR: "REG" ", regs->orig_gpr3);
 	if (trap == 0x200 || trap == 0x300 || trap == 0x600)
 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index a264989626fd..4b74eef1d881 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -198,7 +198,7 @@ static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
 	int restart = 1;
 
 	/* syscall ? */
-	if (TRAP(regs) != 0x0C00)
+	if (!TRAP_IS_SYSCALL(regs))
 		return;
 
 	/* error signalled ? */
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 20c1fc08819b..8da771e025fa 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1776,7 +1776,7 @@ static void prregs(struct pt_regs *fp)
 #endif
 	printf("pc  = ");
 	xmon_print_symbol(fp->nip, " ", "\n");
-	if (TRAP(fp) != 0xc00 && cpu_has_feature(CPU_FTR_CFAR)) {
+	if (!TRAP_IS_SYSCALL(fp) && cpu_has_feature(CPU_FTR_CFAR)) {
 		printf("cfar= ");
 		xmon_print_symbol(fp->orig_gpr3, " ", "\n");
 	}
-- 
2.23.0