[PATCH 2/3] arm64/ptrace: introduce PTRACE_O_ARM64_RAW_REGS

@@ -109,6 +109,10 @@ struct user_hwdebug_state {
 	}		dbg_regs[16];
 };
 
+#define PTRACE_O_ARM64_RAW_REGS	(1 << 28)
+
+#define _PTRACE_O_ARCH_OPTIONS PTRACE_O_ARM64_RAW_REGS
+
 /* SVE/FP/SIMD state (NT_ARM_SVE) */
 
 struct user_sve_header {

@@ -565,21 +565,23 @@ static int gpr_get(struct task_struct *target,
 	unsigned long saved_reg;
 	int ret;
 
-	/*
-	 * We have some ABI weirdness here in the way that we handle syscall
-	 * exit stops because we indicate whether or not the stop has been
-	 * signalled from syscall entry or syscall exit by clobbering the general
-	 * purpose register x7.
-	 */
 	saved_reg = uregs->regs[7];
 
-	switch (target->ptrace_message) {
-	case PTRACE_EVENTMSG_SYSCALL_ENTRY:
-		uregs->regs[7] = PTRACE_SYSCALL_ENTER;
-		break;
-	case PTRACE_EVENTMSG_SYSCALL_EXIT:
-		uregs->regs[7] = PTRACE_SYSCALL_EXIT;
-		break;
+	if (!(target->ptrace & PT_ARM64_RAW_REGS)) {
+		/*
+		 * We have some ABI weirdness here in the way that we handle
+		 * syscall exit stops because we indicate whether or not the
+		 * stop has been signalled from syscall entry or syscall exit
+		 * by clobbering the general purpose register x7.
+		 */
+		switch (target->ptrace_message) {
+		case PTRACE_EVENTMSG_SYSCALL_ENTRY:
+			uregs->regs[7] = PTRACE_SYSCALL_ENTER;
+			break;
+		case PTRACE_EVENTMSG_SYSCALL_EXIT:
+			uregs->regs[7] = PTRACE_SYSCALL_EXIT;
+			break;
+		}
 	}
 
 	ret =  membuf_write(&to, uregs, sizeof(*uregs));

@@ -600,15 +602,17 @@ static int gpr_set(struct task_struct *target, const struct user_regset *regset,
 	if (ret)
 		return ret;
 
-	/*
-	 * Historically, x7 can't be changed if the stop has been signalled
-	 * from syscall-enter of syscall-exit.
-	 */
-	switch (target->ptrace_message) {
-	case PTRACE_EVENTMSG_SYSCALL_ENTRY:
-	case PTRACE_EVENTMSG_SYSCALL_EXIT:
-		newregs.regs[7] = task_pt_regs(target)->regs[7];
-		break;
+	if (!(target->ptrace & PT_ARM64_RAW_REGS)) {
+		/*
+		 * Historically, x7 can't be changed if the stop has been
+		 * signalled from syscall-enter of syscall-exit.
+		 */
+		switch (target->ptrace_message) {
+		case PTRACE_EVENTMSG_SYSCALL_ENTRY:
+		case PTRACE_EVENTMSG_SYSCALL_EXIT:
+			newregs.regs[7] = task_pt_regs(target)->regs[7];
+			break;
+		}
 	}
 
 	if (!valid_user_regs(&newregs, target))

@@ -1243,6 +1247,8 @@ static inline compat_ulong_t compat_get_user_reg(struct task_struct *task, int i
 
 	switch (idx) {
 	case 12:
+		if (task->ptrace & PT_ARM64_RAW_REGS)
+			return regs->regs[idx];
 		/*
 		 * We have some ABI weirdness here in the way that we handle
 		 * syscall exit stops because we indicate whether or not the

@@ -1332,15 +1338,17 @@ static int compat_gpr_set(struct task_struct *target,
 
 	}
 
-	/*
-	 * Historically, x12 can't be changed if the stop has been signalled
-	 * from syscall-enter of syscall-exit.
-	 */
-	switch (target->ptrace_message) {
-	case PTRACE_EVENTMSG_SYSCALL_ENTRY:
-	case PTRACE_EVENTMSG_SYSCALL_EXIT:
-		newregs.regs[12] = task_pt_regs(target)->regs[12];
-		break;
+	if (!(target->ptrace & PT_ARM64_RAW_REGS)) {
+		/*
+		 * Historically, r12 can't be changed if the stop has been
+		 * signalled from syscall-enter of syscall-exit.
+		 */
+		switch (target->ptrace_message) {
+		case PTRACE_EVENTMSG_SYSCALL_ENTRY:
+		case PTRACE_EVENTMSG_SYSCALL_EXIT:
+			newregs.regs[12] = task_pt_regs(target)->regs[12];
+			break;
+		}
 	}
 
 	if (valid_user_regs(&newregs.user_regs, target))

@@ -46,6 +46,7 @@ extern int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
 
 #define PT_EXITKILL		(PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT)
 #define PT_SUSPEND_SECCOMP	(PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT)
+#define PT_ARM64_RAW_REGS	(PTRACE_O_ARM64_RAW_REGS << PT_OPT_FLAG_SHIFT)
 
 /* single stepping state bits (used on ARM and PA-RISC) */
 #define PT_SINGLESTEP_BIT	31

@@ -7,6 +7,7 @@
 /* has the defines to get at the registers. */
 
 #include <linux/types.h>
+#include <asm/ptrace.h>
 
 #define PTRACE_TRACEME		   0
 #define PTRACE_PEEKTEXT		   1

@@ -137,8 +138,14 @@ struct ptrace_syscall_info {
 #define PTRACE_O_EXITKILL		(1 << 20)
 #define PTRACE_O_SUSPEND_SECCOMP	(1 << 21)
 
+/* (1<<28) is reserved for arch specific options. */
+#ifndef _PTRACE_O_ARCH_OPTIONS
+#define _PTRACE_O_ARCH_OPTIONS 0
+#endif
+
 #define PTRACE_O_MASK		(\
-	0x000000ff | PTRACE_O_EXITKILL | PTRACE_O_SUSPEND_SECCOMP)
+	0x000000ff | PTRACE_O_EXITKILL | \
+	PTRACE_O_SUSPEND_SECCOMP | _PTRACE_O_ARCH_OPTIONS)
 
 #include <asm/ptrace.h>