Thread (49 messages) 49 messages, 6 authors, 2014-07-01

[PATCH 03/24] ARM64: Change some CONFIG_COMPAT over to use CONFIG_AARCH32_EL0 instead.

From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2014-06-17 15:15:45
Also in: lkml

On Sat, May 24, 2014 at 12:01:58AM -0700, Andrew Pinski wrote:
This patch changes CONFIG_COMPAT checks inside the arm64 which are AARCH32 specific.
Please state what it is changed to. I guess CONFIG_AARCH32_EL0. Longer
commit log is always better.
quoted hunk ↗ jump to hunk
--- a/arch/arm64/include/asm/signal32.h
+++ b/arch/arm64/include/asm/signal32.h
@@ -20,6 +20,7 @@
 #ifdef CONFIG_COMPAT
 #include <linux/compat.h>
 
+#ifdef CONFIG_AARCH32_EL0
 #define AARCH32_KERN_SIGRET_CODE_OFFSET	0x500
Do we still need the top CONFIG_COMPAT for signal32.h? We don't use the
signal32 infrastructure for ILP32.
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/include/asm/stat.h b/arch/arm64/include/asm/stat.h
index 15e3559..af04276 100644
--- a/arch/arm64/include/asm/stat.h
+++ b/arch/arm64/include/asm/stat.h
@@ -22,6 +22,7 @@
 
 #include <asm/compat.h>
 
+#ifdef CONFIG_AARCH32_EL0
Same here, we have another #ifdef CONFIG_COMPAT above the #include.
quoted hunk ↗ jump to hunk
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
[...]
quoted hunk ↗ jump to hunk
@@ -1041,11 +1041,28 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 
 	return ret;
 }
-#endif /* CONFIG_COMPAT */
+#else /* !CONFIG_AARCH32_EL0 */
+long compat_a32_arch_ptrace(struct task_struct *child, compat_long_t request,
+			    compat_ulong_t caddr, compat_ulong_t cdata)
+{
+	return -1;
+}
+#endif /* !CONFIG_AARCH32_EL0 */
Can you return an appropriate error code here?
+
+#ifdef CONFIG_COMPAT
+long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
+			compat_ulong_t caddr, compat_ulong_t cdata)
+{
+	if (is_compat_task())
+		return compat_a32_arch_ptrace(child, request, caddr, cdata);
+	return compat_ptrace_request(child, request, caddr, cdata);
+}
+#endif
So for ILP32, will we route ptrace calls via compat_arch_ptrace? Some
explanation for this code would help as it doesn't look like a simple
CONFIG_COMPAT conversion.
quoted hunk ↗ jump to hunk
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -417,3 +417,16 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
 		tracehook_notify_resume(regs);
 	}
 }
+
+/* Some functions are needed for compat ptrace but we don't define
+   them if we don't have AARCH32 support compiled in */
As per the kernel coding style, the multi-line comment should be:

/*
 * Some functions are needed for compat ptrace but we don't define
 * them if we don't have AARCH32 support compiled in.
 */
+#if defined CONFIG_COMPAT && !defined CONFIG_AARCH32_EL0
+int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
+{
+	return -EFAULT;
+}
+int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
+{
+	return -EFAULT;
+}
+#endif
Maybe it gets clearer in subsequent patches on how this interacts with
ptrace. But at this stage in the series, COMPAT cannot be defined
without CONFIG_AARCH32_EL0, so the above could be removed.

-- 
Catalin
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