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powerpc: Use common syscall handler type

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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
This commit is contained in:
Rohan McLure 2022-09-21 16:55:58 +10:00 committed by Michael Ellerman
parent 39859aea41
commit 8640de0dee
6 changed files with 19 additions and 12 deletions
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7
arch/powerpc/include/asm/syscall.h
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@ -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)
{

1
arch/powerpc/include/asm/syscalls.h
View File

@ -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

2
arch/powerpc/kernel/syscall.c
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@ -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,

11
arch/powerpc/kernel/systbl.c
View File

@ -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 */

4
arch/powerpc/kernel/vdso.c
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@ -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);
}
}

6
arch/powerpc/platforms/cell/spu_callbacks.c
View File

@ -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);