powerpc: Use common syscall handler type

Cause syscall handlers to be typed as follows when called indirectly
throughout the kernel. This is to allow for better type checking.

typedef long (*syscall_fn)(unsigned long, unsigned long, unsigned long,
                           unsigned long, unsigned long, unsigned long);

Since both 32 and 64-bit abis allow for at least the first six
machine-word length parameters to a function to be passed by registers,
even handlers which admit fewer than six parameters may be viewed as
having the above type.

Coercing syscalls to syscall_fn requires a cast to void* to avoid
-Wcast-function-type.

Fixup comparisons in VDSO to avoid pointer-integer comparison. Introduce
explicit cast on systems with SPUs.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220921065605.1051927-19-rmclure@linux.ibm.com

diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index 25fc8ad9a27afaba9b17b8cc74b82fb7caa3c5f8..d2a8dfd5de33925e7bc8bb9a74fa43a6385874d1 100644 (file)
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -14,9 +14,12 @@
 #include <linux/sched.h>
 #include <linux/thread_info.h>
 
+typedef long (*syscall_fn)(unsigned long, unsigned long, unsigned long,
+                          unsigned long, unsigned long, unsigned long);
+
 /* ftrace syscalls requires exporting the sys_call_table */
-extern const unsigned long sys_call_table[];
-extern const unsigned long compat_sys_call_table[];
+extern const syscall_fn sys_call_table[];
+extern const syscall_fn compat_sys_call_table[];
 
 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
 {

diff --git a/arch/powerpc/include/asm/syscalls.h b/arch/powerpc/include/asm/syscalls.h
index 7911738ad4a981e925dc9b4b3c28217ff8a413a5..211bb8393dee25dc726883a1933c90c74a6bc939 100644 (file)
--- a/arch/powerpc/include/asm/syscalls.h
+++ b/arch/powerpc/include/asm/syscalls.h
@@ -8,6 +8,7 @@
 #include <linux/types.h>
 #include <linux/compat.h>
 
+#include <asm/syscall.h>
 #ifdef CONFIG_PPC64
 #include <asm/syscalls_32.h>
 #endif

diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c
index 64102a64fd84104ea90396c1bb9aa87257947395..9875486f616811ad3b48073fc53567e6e6614550 100644 (file)
--- a/arch/powerpc/kernel/syscall.c
+++ b/arch/powerpc/kernel/syscall.c
@@ -12,8 +12,6 @@
 #include <asm/unistd.h>
 
 
-typedef long (*syscall_fn)(long, long, long, long, long, long);
-
 /* Has to run notrace because it is entered not completely "reconciled" */
 notrace long system_call_exception(long r3, long r4, long r5,
                                   long r6, long r7, long r8,

diff --git a/arch/powerpc/kernel/systbl.c b/arch/powerpc/kernel/systbl.c
index ce52bd2ec292354fdede10148fdc1593b52d86e1..d64dfafc2e5ecdfd598cde38c7fd00606101ca2f 100644 (file)
--- a/arch/powerpc/kernel/systbl.c
+++ b/arch/powerpc/kernel/systbl.c
@@ -16,9 +16,14 @@
 #include <asm/syscalls.h>
 
 #define __SYSCALL_WITH_COMPAT(nr, entry, compat) __SYSCALL(nr, entry)
-#define __SYSCALL(nr, entry) [nr] = (unsigned long) &entry,
 
-const unsigned long sys_call_table[] = {
+/*
+ * Coerce syscall handlers with arbitrary parameters to common type
+ * requires cast to void* to avoid -Wcast-function-type.
+ */
+#define __SYSCALL(nr, entry) [nr] = (void *) entry,
+
+const syscall_fn sys_call_table[] = {
 #ifdef CONFIG_PPC64
 #include <asm/syscall_table_64.h>
 #else
@@ -29,7 +34,7 @@ const unsigned long sys_call_table[] = {
 #ifdef CONFIG_COMPAT
 #undef __SYSCALL_WITH_COMPAT
 #define __SYSCALL_WITH_COMPAT(nr, native, compat)      __SYSCALL(nr, compat)
-const unsigned long compat_sys_call_table[] = {
+const syscall_fn compat_sys_call_table[] = {
 #include <asm/syscall_table_32.h>
 };
 #endif /* CONFIG_COMPAT */

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index bf9574ec26ce86b2570edf01e2793dbc62ae6b2f..fcca06d200d368d2800222f2e8cdc32b4587606f 100644 (file)
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -304,10 +304,10 @@ static void __init vdso_setup_syscall_map(void)
        unsigned int i;
 
        for (i = 0; i < NR_syscalls; i++) {
-               if (sys_call_table[i] != (unsigned long)&sys_ni_syscall)
+               if (sys_call_table[i] != (void *)&sys_ni_syscall)
                        vdso_data->syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
                if (IS_ENABLED(CONFIG_COMPAT) &&
-                   compat_sys_call_table[i] != (unsigned long)&sys_ni_syscall)
+                   compat_sys_call_table[i] != (void *)&sys_ni_syscall)
                        vdso_data->compat_syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
        }
 }

diff --git a/arch/powerpc/platforms/cell/spu_callbacks.c b/arch/powerpc/platforms/cell/spu_callbacks.c
index fe0d8797a00a3bd40082a5133b0cc82839392ebf..e780c14c5733cb21b2b5f3f19141d886706f5002 100644 (file)
--- a/arch/powerpc/platforms/cell/spu_callbacks.c
+++ b/arch/powerpc/platforms/cell/spu_callbacks.c
@@ -34,15 +34,15 @@
  *     mbind, mq_open, ipc, ...
  */
 
-static void *spu_syscall_table[] = {
+static const syscall_fn spu_syscall_table[] = {
 #define __SYSCALL_WITH_COMPAT(nr, entry, compat) __SYSCALL(nr, entry)
-#define __SYSCALL(nr, entry) [nr] = entry,
+#define __SYSCALL(nr, entry) [nr] = (void *) entry,
 #include <asm/syscall_table_spu.h>
 };
 
 long spu_sys_callback(struct spu_syscall_block *s)
 {
-       long (*syscall)(u64 a1, u64 a2, u64 a3, u64 a4, u64 a5, u64 a6);
+       syscall_fn syscall;
 
        if (s->nr_ret >= ARRAY_SIZE(spu_syscall_table)) {
                pr_debug("%s: invalid syscall #%lld", __func__, s->nr_ret);