Commit 8640de0d authored by Rohan McLure's avatar Rohan McLure Committed by Michael Ellerman
Browse files

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: default avatarRohan McLure <rmclure@linux.ibm.com>
Reviewed-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220921065605.1051927-19-rmclure@linux.ibm.com
parent 39859aea

arch/powerpc/include/asm/syscall.h

+5 −2
Original line number Diff line number Diff line
@@ -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)

{

arch/powerpc/include/asm/syscalls.h

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/powerpc/kernel/syscall.c

+0 −2
Original line number Diff line number Diff line
@@ -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,

arch/powerpc/kernel/systbl.c

+8 −3
Original line number Diff line number Diff line
@@ -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 */

arch/powerpc/kernel/vdso.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

	}

}