From 3cfc348bf90ffaa777c188652aa297f04eb94de8 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 26 Sep 2006 10:52:28 +0200 Subject: [PATCH] x86: Add portable getcpu call For NUMA optimization and some other algorithms it is useful to have a fast to get the current CPU and node numbers in user space. x86-64 added a fast way to do this in a vsyscall. This adds a generic syscall for other architectures to make it a generic portable facility. I expect some of them will also implement it as a faster vsyscall. The cache is an optimization for the x86-64 vsyscall optimization. Since what the syscall returns is an approximation anyways and user space often wants very fast results it can be cached for some time. The norma methods to get this information in user space are relatively slow The vsyscall is in a better position to manage the cache because it has direct access to a fast time stamp (jiffies). For the generic syscall optimization it doesn't help much, but enforce a valid argument to keep programs portable I only added an i386 syscall entry for now. Other architectures can follow as needed. AK: Also added some cleanups from Andrew Morton Signed-off-by: Andi Kleen --- kernel/sys.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index e236f98f7ec5..3f894775488d 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -2062,3 +2063,33 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3, } return error; } + +asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep, + struct getcpu_cache __user *cache) +{ + int err = 0; + int cpu = raw_smp_processor_id(); + if (cpup) + err |= put_user(cpu, cpup); + if (nodep) + err |= put_user(cpu_to_node(cpu), nodep); + if (cache) { + /* + * The cache is not needed for this implementation, + * but make sure user programs pass something + * valid. vsyscall implementations can instead make + * good use of the cache. Only use t0 and t1 because + * these are available in both 32bit and 64bit ABI (no + * need for a compat_getcpu). 32bit has enough + * padding + */ + unsigned long t0, t1; + get_user(t0, &cache->t0); + get_user(t1, &cache->t1); + t0++; + t1++; + put_user(t0, &cache->t0); + put_user(t1, &cache->t1); + } + return err ? -EFAULT : 0; +} -- cgit v1.2.3 From c9472e0f28cd2f0695a0ac3a0b4bd33f21714a7e Mon Sep 17 00:00:00 2001 From: Cal Peake Date: Fri, 29 Sep 2006 02:00:47 -0700 Subject: [PATCH] kill extraneous printk in kernel_restart() Get rid of an extraneous printk in kernel_restart(). Signed-off-by: Cal Peake Acked-by: Eric W. Biederman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sys.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index 3f894775488d..8647061c084a 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -612,7 +612,6 @@ void kernel_restart(char *cmd) } else { printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); } - printk(".\n"); machine_restart(cmd); } EXPORT_SYMBOL_GPL(kernel_restart); -- cgit v1.2.3 From 34596dc9e59d7bece16fe5aba08116b49465da26 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 30 Sep 2006 01:47:55 +0200 Subject: [PATCH] Define vsyscall cache as blob to make clearer that user space shouldn't use it Signed-off-by: Andi Kleen --- kernel/sys.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index 8647061c084a..b88806c66244 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2083,12 +2083,12 @@ asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep, * padding */ unsigned long t0, t1; - get_user(t0, &cache->t0); - get_user(t1, &cache->t1); + get_user(t0, &cache->blob[0]); + get_user(t1, &cache->blob[1]); t0++; t1++; - put_user(t0, &cache->t0); - put_user(t1, &cache->t1); + put_user(t0, &cache->blob[0]); + put_user(t1, &cache->blob[1]); } return err ? -EFAULT : 0; } -- cgit v1.2.3 From 756184b7d771992f4fb1998d62aebcaf3e028076 Mon Sep 17 00:00:00 2001 From: Cal Peake Date: Sat, 30 Sep 2006 23:27:24 -0700 Subject: [PATCH] CodingStyle cleanup for kernel/sys.c Fix up kernel/sys.c to be consistent with CodingStyle and the rest of the file. Signed-off-by: Cal Peake Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sys.c | 80 +++++++++++++++++++++++------------------------------------- 1 file changed, 30 insertions(+), 50 deletions(-) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index b88806c66244..2460581c928c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -607,11 +607,10 @@ static void kernel_restart_prepare(char *cmd) void kernel_restart(char *cmd) { kernel_restart_prepare(cmd); - if (!cmd) { + if (!cmd) printk(KERN_EMERG "Restarting system.\n"); - } else { + else printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); - } machine_restart(cmd); } EXPORT_SYMBOL_GPL(kernel_restart); @@ -627,9 +626,8 @@ static void kernel_kexec(void) #ifdef CONFIG_KEXEC struct kimage *image; image = xchg(&kexec_image, NULL); - if (!image) { + if (!image) return; - } kernel_restart_prepare(NULL); printk(KERN_EMERG "Starting new kernel\n"); machine_shutdown(); @@ -823,12 +821,10 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid) (current->sgid == egid) || capable(CAP_SETGID)) new_egid = egid; - else { + else return -EPERM; - } } - if (new_egid != old_egid) - { + if (new_egid != old_egid) { current->mm->dumpable = suid_dumpable; smp_wmb(); } @@ -857,19 +853,14 @@ asmlinkage long sys_setgid(gid_t gid) if (retval) return retval; - if (capable(CAP_SETGID)) - { - if(old_egid != gid) - { + if (capable(CAP_SETGID)) { + if (old_egid != gid) { current->mm->dumpable = suid_dumpable; smp_wmb(); } current->gid = current->egid = current->sgid = current->fsgid = gid; - } - else if ((gid == current->gid) || (gid == current->sgid)) - { - if(old_egid != gid) - { + } else if ((gid == current->gid) || (gid == current->sgid)) { + if (old_egid != gid) { current->mm->dumpable = suid_dumpable; smp_wmb(); } @@ -900,8 +891,7 @@ static int set_user(uid_t new_ruid, int dumpclear) switch_uid(new_user); - if(dumpclear) - { + if (dumpclear) { current->mm->dumpable = suid_dumpable; smp_wmb(); } @@ -957,8 +947,7 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid) if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0) return -EAGAIN; - if (new_euid != old_euid) - { + if (new_euid != old_euid) { current->mm->dumpable = suid_dumpable; smp_wmb(); } @@ -1008,8 +997,7 @@ asmlinkage long sys_setuid(uid_t uid) } else if ((uid != current->uid) && (uid != new_suid)) return -EPERM; - if (old_euid != uid) - { + if (old_euid != uid) { current->mm->dumpable = suid_dumpable; smp_wmb(); } @@ -1054,8 +1042,7 @@ asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) return -EAGAIN; } if (euid != (uid_t) -1) { - if (euid != current->euid) - { + if (euid != current->euid) { current->mm->dumpable = suid_dumpable; smp_wmb(); } @@ -1105,8 +1092,7 @@ asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) return -EPERM; } if (egid != (gid_t) -1) { - if (egid != current->egid) - { + if (egid != current->egid) { current->mm->dumpable = suid_dumpable; smp_wmb(); } @@ -1151,10 +1137,8 @@ asmlinkage long sys_setfsuid(uid_t uid) if (uid == current->uid || uid == current->euid || uid == current->suid || uid == current->fsuid || - capable(CAP_SETUID)) - { - if (uid != old_fsuid) - { + capable(CAP_SETUID)) { + if (uid != old_fsuid) { current->mm->dumpable = suid_dumpable; smp_wmb(); } @@ -1182,10 +1166,8 @@ asmlinkage long sys_setfsgid(gid_t gid) if (gid == current->gid || gid == current->egid || gid == current->sgid || gid == current->fsgid || - capable(CAP_SETGID)) - { - if (gid != old_fsgid) - { + capable(CAP_SETGID)) { + if (gid != old_fsgid) { current->mm->dumpable = suid_dumpable; smp_wmb(); } @@ -1321,9 +1303,9 @@ out: asmlinkage long sys_getpgid(pid_t pid) { - if (!pid) { + if (!pid) return process_group(current); - } else { + else { int retval; struct task_struct *p; @@ -1353,9 +1335,9 @@ asmlinkage long sys_getpgrp(void) asmlinkage long sys_getsid(pid_t pid) { - if (!pid) { + if (!pid) return current->signal->session; - } else { + else { int retval; struct task_struct *p; @@ -1363,7 +1345,7 @@ asmlinkage long sys_getsid(pid_t pid) p = find_task_by_pid(pid); retval = -ESRCH; - if(p) { + if (p) { retval = security_task_getsid(p); if (!retval) retval = p->signal->session; @@ -1431,9 +1413,9 @@ struct group_info *groups_alloc(int gidsetsize) group_info->nblocks = nblocks; atomic_set(&group_info->usage, 1); - if (gidsetsize <= NGROUPS_SMALL) { + if (gidsetsize <= NGROUPS_SMALL) group_info->blocks[0] = group_info->small_block; - } else { + else { for (i = 0; i < nblocks; i++) { gid_t *b; b = (void *)__get_free_page(GFP_USER); @@ -1489,7 +1471,7 @@ static int groups_to_user(gid_t __user *grouplist, /* fill a group_info from a user-space array - it must be allocated already */ static int groups_from_user(struct group_info *group_info, gid_t __user *grouplist) - { +{ int i; int count = group_info->ngroups; @@ -1647,9 +1629,8 @@ asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist) int in_group_p(gid_t grp) { int retval = 1; - if (grp != current->fsgid) { + if (grp != current->fsgid) retval = groups_search(current->group_info, grp); - } return retval; } @@ -1658,9 +1639,8 @@ EXPORT_SYMBOL(in_group_p); int in_egroup_p(gid_t grp) { int retval = 1; - if (grp != current->egid) { + if (grp != current->egid) retval = groups_search(current->group_info, grp); - } return retval; } @@ -1775,9 +1755,9 @@ asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *r task_lock(current->group_leader); x = current->signal->rlim[resource]; task_unlock(current->group_leader); - if(x.rlim_cur > 0x7FFFFFFF) + if (x.rlim_cur > 0x7FFFFFFF) x.rlim_cur = 0x7FFFFFFF; - if(x.rlim_max > 0x7FFFFFFF) + if (x.rlim_max > 0x7FFFFFFF) x.rlim_max = 0x7FFFFFFF; return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0; } -- cgit v1.2.3