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>

3 files changed, 43 insertions, 16 deletions

diff --git a/arch/parisc/include/uapi/asm/mman.h b/arch/parisc/include/uapi/asm/mman.h
index 22133a6a506e..68c44f99bc93 100644
--- a/arch/parisc/include/uapi/asm/mman.h
+++ b/arch/parisc/include/uapi/asm/mman.h
@@ -49,6 +49,19 @@
 #define MADV_DONTFORK	10		/* don't inherit across fork */
 #define MADV_DOFORK	11		/* do inherit across fork */
 
+#define MADV_MERGEABLE   12		/* KSM may merge identical pages */
+#define MADV_UNMERGEABLE 13		/* KSM may not merge identical pages */
+
+#define MADV_HUGEPAGE	14		/* Worth backing with hugepages */
+#define MADV_NOHUGEPAGE 15		/* Not worth backing with hugepages */
+
+#define MADV_DONTDUMP   16		/* Explicity exclude from the core dump,
+					   overrides the coredump filter bits */
+#define MADV_DODUMP	17		/* Clear the MADV_NODUMP flag */
+
+#define MADV_WIPEONFORK 18		/* Zero memory on fork, child only */
+#define MADV_KEEPONFORK 19		/* Undo MADV_WIPEONFORK */
+
 #define MADV_COLD	20		/* deactivate these pages */
 #define MADV_PAGEOUT	21		/* reclaim these pages */
 
@@ -57,27 +70,13 @@
 
 #define MADV_DONTNEED_LOCKED	24	/* like DONTNEED, but drop locked pages too */
 
-#define MADV_MERGEABLE   65		/* KSM may merge identical pages */
-#define MADV_UNMERGEABLE 66		/* KSM may not merge identical pages */
-
-#define MADV_HUGEPAGE	67		/* Worth backing with hugepages */
-#define MADV_NOHUGEPAGE	68		/* Not worth backing with hugepages */
-
-#define MADV_DONTDUMP   69		/* Explicity exclude from the core dump,
-					   overrides the coredump filter bits */
-#define MADV_DODUMP	70		/* Clear the MADV_NODUMP flag */
-
-#define MADV_WIPEONFORK 71		/* Zero memory on fork, child only */
-#define MADV_KEEPONFORK 72		/* Undo MADV_WIPEONFORK */
-
-#define MADV_COLLAPSE	73		/* Synchronous hugepage collapse */
+#define MADV_COLLAPSE	25		/* Synchronous hugepage collapse */
 
 #define MADV_HWPOISON     100		/* poison a page for testing */
 #define MADV_SOFT_OFFLINE 101		/* soft offline page for testing */
 
 /* compatibility flags */
 #define MAP_FILE	0
-#define MAP_VARIABLE	0
 
 #define PKEY_DISABLE_ACCESS	0x1
 #define PKEY_DISABLE_WRITE	0x2
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);
+}
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 8a99c998da9b..0e42fceb2d5e 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -131,7 +131,7 @@
 116	common	sysinfo			sys_sysinfo			compat_sys_sysinfo
 117	common	shutdown		sys_shutdown
 118	common	fsync			sys_fsync
-119	common	madvise			sys_madvise
+119	common	madvise			parisc_madvise
 120	common	clone			sys_clone_wrapper
 121	common	setdomainname		sys_setdomainname
 122	common	sendfile		sys_sendfile			compat_sys_sendfile