From 68d9102f76de7a923fb81c8b6de4764f8f50ed17 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Thu, 1 Sep 2005 12:37:13 +0100 Subject: [PATCH] [ARM] 2865/2: fix fadvise64_64 syscall argument passing Patch from Nicolas Pitre The prototype for sys_fadvise64_64() is: long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) The argument list is therefore as follows on legacy ABI: fd: type int (r0) offset: type long long (r1-r2) len: type long long (r3-sp[0]) advice: type int (sp[4]) With EABI this becomes: fd: type int (r0) offset: type long long (r2-r3) len: type long long (sp[0]-sp[4]) advice: type int (sp[8]) Not only do we have ABI differences here, but the EABI version requires one additional word on the syscall stack. To avoid the ABI mismatch and the extra stack space required with EABI this syscall is now defined with a different argument ordering on ARM as follows: long sys_arm_fadvise64_64(int fd, int advice, loff_t offset, loff_t len) This gives us the following ABI independent argument distribution: fd: type int (r0) advice: type int (r1) offset: type long long (r2-r3) len: type long long (sp[0]-sp[4]) Now, since the syscall entry code takes care of 5 registers only by default including the store of r4 to the stack, we need a wrapper to store r5 to the stack as well. Because that wrapper was missing and was always required this means that sys_fadvise64_64 never worked on ARM and therefore we can safely reuse its syscall number for our new sys_arm_fadvise64_64 interface. Signed-off-by: Nicolas Pitre Signed-off-by: Russell King --- arch/arm/kernel/calls.S | 2 +- arch/arm/kernel/entry-common.S | 4 ++++ arch/arm/kernel/sys_arm.c | 10 ++++++++++ include/asm-arm/unistd.h | 2 +- 4 files changed, 16 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S index 2b6b4c786e..db07ce42b3 100644 --- a/arch/arm/kernel/calls.S +++ b/arch/arm/kernel/calls.S @@ -284,7 +284,7 @@ __syscall_start: .long sys_fstatfs64 .long sys_tgkill .long sys_utimes -/* 270 */ .long sys_fadvise64_64 +/* 270 */ .long sys_arm_fadvise64_64_wrapper .long sys_pciconfig_iobase .long sys_pciconfig_read .long sys_pciconfig_write diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 3f8d0e3aef..6281d488ac 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -265,6 +265,10 @@ sys_futex_wrapper: str r5, [sp, #4] @ push sixth arg b sys_futex +sys_arm_fadvise64_64_wrapper: + str r5, [sp, #4] @ push r5 to stack + b sys_arm_fadvise64_64 + /* * Note: off_4k (r5) is always units of 4K. If we can't do the requested * offset, we return EINVAL. diff --git a/arch/arm/kernel/sys_arm.c b/arch/arm/kernel/sys_arm.c index f897ce2ccf..42629ff84f 100644 --- a/arch/arm/kernel/sys_arm.c +++ b/arch/arm/kernel/sys_arm.c @@ -311,3 +311,13 @@ long execve(const char *filename, char **argv, char **envp) return ret; } EXPORT_SYMBOL(execve); + +/* + * Since loff_t is a 64 bit type we avoid a lot of ABI hastle + * with a different argument ordering. + */ +asmlinkage long sys_arm_fadvise64_64(int fd, int advice, + loff_t offset, loff_t len) +{ + return sys_fadvise64_64(fd, offset, len, advice); +} diff --git a/include/asm-arm/unistd.h b/include/asm-arm/unistd.h index 94619ccee7..278de61224 100644 --- a/include/asm-arm/unistd.h +++ b/include/asm-arm/unistd.h @@ -295,7 +295,7 @@ #define __NR_fstatfs64 (__NR_SYSCALL_BASE+267) #define __NR_tgkill (__NR_SYSCALL_BASE+268) #define __NR_utimes (__NR_SYSCALL_BASE+269) -#define __NR_fadvise64_64 (__NR_SYSCALL_BASE+270) +#define __NR_arm_fadvise64_64 (__NR_SYSCALL_BASE+270) #define __NR_pciconfig_iobase (__NR_SYSCALL_BASE+271) #define __NR_pciconfig_read (__NR_SYSCALL_BASE+272) #define __NR_pciconfig_write (__NR_SYSCALL_BASE+273) -- 2.39.5