powerpc: Remove direct call to mmap2 syscall handlers

Syscall handlers should not be invoked internally by their symbol names,
as these symbols defined by the architecture-defined SYSCALL_DEFINE
macro. Move the compatibility syscall definition for mmap2 to
syscalls.c, so that all mmap implementations can share a helper function.

Remove 'inline' on static mmap helper.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fix compat_sys_mmap2() prototype and offset handling]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220921065605.1051927-14-rmclure@linux.ibm.com

arch/powerpc/include/asm/syscalls.h

@@ -34,7 +34,7 @@ long ppc_fadvise64_64(int fd, int advice, u32 offset_high, u32 offset_low,
 		      u32 len_high, u32 len_low);
 
 #ifdef CONFIG_COMPAT
-unsigned long compat_sys_mmap2(unsigned long addr, size_t len,
+long compat_sys_mmap2(unsigned long addr, size_t len,
 			       unsigned long prot, unsigned long flags,
 			       unsigned long fd, unsigned long pgoff);
 

arch/powerpc/kernel/sys_ppc32.c

@@ -25,7 +25,6 @@
 #include <linux/poll.h>
 #include <linux/personality.h>
 #include <linux/stat.h>
-#include <linux/mman.h>
 #include <linux/in.h>
 #include <linux/syscalls.h>
 #include <linux/unistd.h>
@@ -48,14 +47,6 @@
 #include <asm/syscalls.h>
 #include <asm/switch_to.h>
 
-unsigned long compat_sys_mmap2(unsigned long addr, size_t len,
-			  unsigned long prot, unsigned long flags,
-			  unsigned long fd, unsigned long pgoff)
-{
-	/* This should remain 12 even if PAGE_SIZE changes */
-	return sys_mmap(addr, len, prot, flags, fd, pgoff << 12);
-}
-
 compat_ssize_t compat_sys_pread64(unsigned int fd, char __user *ubuf, compat_size_t count,
 			     u32 reg6, u32 pos1, u32 pos2)
 {

arch/powerpc/kernel/syscalls.c

@@ -36,9 +36,9 @@
 #include <asm/time.h>
 #include <asm/unistd.h>
 
-static inline long do_mmap2(unsigned long addr, size_t len,
-			unsigned long prot, unsigned long flags,
-			unsigned long fd, unsigned long off, int shift)
+static long do_mmap2(unsigned long addr, size_t len,
+		     unsigned long prot, unsigned long flags,
+		     unsigned long fd, unsigned long off, int shift)
 {
 	if (!arch_validate_prot(prot, addr))
 		return -EINVAL;
@@ -56,6 +56,16 @@ SYSCALL_DEFINE6(mmap2, unsigned long, addr, size_t, len,
 	return do_mmap2(addr, len, prot, flags, fd, pgoff, PAGE_SHIFT-12);
 }
 
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE6(mmap2,
+		       unsigned long, addr, size_t, len,
+		       unsigned long, prot, unsigned long, flags,
+		       unsigned long, fd, unsigned long, off_4k)
+{
+	return do_mmap2(addr, len, prot, flags, fd, off_4k, PAGE_SHIFT-12);
+}
+#endif
+
 SYSCALL_DEFINE6(mmap, unsigned long, addr, size_t, len,
 		unsigned long, prot, unsigned long, flags,
 		unsigned long, fd, off_t, offset)