[PATCH v6 18/25] powerpc: Use common syscall handler type
From: Rohan McLure <hidden>
Date: 2022-09-21 07:09:30
Subsystem:
cell broadband engine architecture, linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 <redacted>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
---
V2: New patch.
V3: Remove unnecessary cast from const syscall_fn to syscall_fn
V5: Update patch desctiption.
V6: Remove syscall_fn typedef in syscall.c. Comment void* cast.
---
arch/powerpc/include/asm/syscall.h | 7 +++++--
arch/powerpc/include/asm/syscalls.h | 1 +
arch/powerpc/kernel/syscall.c | 2 --
arch/powerpc/kernel/systbl.c | 11 ++++++++---
arch/powerpc/kernel/vdso.c | 4 ++--
arch/powerpc/platforms/cell/spu_callbacks.c | 6 +++---
6 files changed, 19 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index 25fc8ad9a27a..d2a8dfd5de33 100644
--- 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 5d106acf7906..cc87168d6ecb 100644
--- 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 64102a64fd84..9875486f6168 100644
--- 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 ce52bd2ec292..d64dfafc2e5e 100644
--- 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 bf9574ec26ce..fcca06d200d3 100644
--- 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 fe0d8797a00a..e780c14c5733 100644
--- 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);
--
2.34.1