parisc: Align parisc MADV_XXX constants with all other architectures

Adjust some MADV_XXX constants to be in sync what their values are on
all other platforms. There is currently no reason to have an own
numbering on parisc, but it requires workarounds in many userspace
sources (e.g. glibc, qemu, ...) - which are often forgotten and thus
introduce bugs and different behaviour on parisc.

A wrapper avoids an ABI breakage for existing userspace applications by
translating any old values to the new ones, so this change allows us to
move over all programs to the new ABI over time.

Signed-off-by: Helge Deller <deller@gmx.de>

1 files changed, 28 insertions, 0 deletions

diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index 848b0702005d..09a34b07f02e 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -465,3 +465,31 @@ asmlinkage long parisc_inotify_init1(int flags)
 	flags = FIX_O_NONBLOCK(flags);
 	return sys_inotify_init1(flags);
 }
+
+/*
+ * madvise() wrapper
+ *
+ * Up to kernel v6.1 parisc has different values than all other
+ * platforms for the MADV_xxx flags listed below.
+ * To keep binary compatibility with existing userspace programs
+ * translate the former values to the new values.
+ *
+ * XXX: Remove this wrapper in year 2025 (or later)
+ */
+
+asmlinkage notrace long parisc_madvise(unsigned long start, size_t len_in, int behavior)
+{
+	switch (behavior) {
+	case 65: behavior = MADV_MERGEABLE;	break;
+	case 66: behavior = MADV_UNMERGEABLE;	break;
+	case 67: behavior = MADV_HUGEPAGE;	break;
+	case 68: behavior = MADV_NOHUGEPAGE;	break;
+	case 69: behavior = MADV_DONTDUMP;	break;
+	case 70: behavior = MADV_DODUMP;	break;
+	case 71: behavior = MADV_WIPEONFORK;	break;
+	case 72: behavior = MADV_KEEPONFORK;	break;
+	case 73: behavior = MADV_COLLAPSE;	break;
+	}
+
+	return sys_madvise(start, len_in, behavior);
+}