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author | David Smith <dsmith@redhat.com> | 2008-06-23 12:41:45 -0500 |
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committer | David Smith <dsmith@redhat.com> | 2008-06-23 12:43:23 -0500 |
commit | a21d81ec8b00571cb5987fe04ce74a3fe873351c (patch) | |
tree | d38eae80a5cfaf3cb5bdf0a8da6cbe0b8b98cd88 /runtime/task_finder_vma.c | |
parent | b857a3649c0f8e4e2d8a7209424f23c5d55adac7 (diff) | |
download | systemtap-steved-a21d81ec8b00571cb5987fe04ce74a3fe873351c.tar.gz systemtap-steved-a21d81ec8b00571cb5987fe04ce74a3fe873351c.tar.xz systemtap-steved-a21d81ec8b00571cb5987fe04ce74a3fe873351c.zip |
Major update to memory map change notification code.
2008-06-23 David Smith <dsmith@redhat.com>
* tapsets.cxx (utrace_derived_probe_group::emit_probe_decl):
Handles UDPF_NONE value.
(utrace_derived_probe_group::emit_vm_callback_probe_decl): New
function.
(utrace_derived_probe_group::emit_module_decls): Calls
emit_vm_callback_probe_decl() to set up vm_callbacks.
2008-06-23 David Smith <dsmith@redhat.com>
* task_finder.c (__stp_tf_vm_cb): New function.
(stap_register_task_finder_target): Sets up syscall entry and
syscall exit handlers.
(__stp_find_file_based_vma): New function.
(__stp_utrace_task_finder_target_syscall_entry): New function.
Saves vma information off at syscall entry.
(__stp_target_call_vm_callback): New function.
(__stp_utrace_task_finder_target_syscall_exit): New function.
Handles changes to memory maps based on information saved at
syscall entry.
* syscall.h: New file containing syscall function.
* task_finder_vma.c: New file containing saved vma information
handling functions.
Diffstat (limited to 'runtime/task_finder_vma.c')
-rw-r--r-- | runtime/task_finder_vma.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/runtime/task_finder_vma.c b/runtime/task_finder_vma.c new file mode 100644 index 00000000..c849f187 --- /dev/null +++ b/runtime/task_finder_vma.c @@ -0,0 +1,112 @@ +#include <linux/list.h> +#include <linux/jhash.h> +#include <linux/mutex.h> + +// __stp_tf_vma_mutex protects the hash table. +static DEFINE_MUTEX(__stp_tf_vma_mutex); + +#define __STP_TF_HASH_BITS 4 +#define __STP_TF_TABLE_SIZE (1 << __STP_TF_HASH_BITS) + +struct __stp_tf_vma_entry { + struct hlist_node hlist; + + pid_t pid; + unsigned long addr; + unsigned long vm_start; + unsigned long vm_end; + unsigned long vm_pgoff; + // Is that enough? Should we store a dcookie for vm_file? +}; + +static struct hlist_head __stp_tf_vma_table[__STP_TF_TABLE_SIZE]; + +static inline u32 +__stp_tf_vma_hash(struct task_struct *tsk, unsigned long addr) +{ +#if (__SIZEOF_LONG__ == 8) + return (jhash_3words(tsk->pid, (u32)addr, (u32)(addr >> 32), 0) + & (__STP_TF_TABLE_SIZE - 1)); +#else + return (jhash_2words(tsk->pid, addr, 0) & (__STP_TF_TABLE_SIZE - 1)); +#endif +} + + +// Get vma_entry if the vma is present in the vma hash table. +// Returns NULL if not present. +static struct __stp_tf_vma_entry * +__stp_tf_get_vma_entry(struct task_struct *tsk, unsigned long addr) +{ + struct hlist_head *head; + struct hlist_node *node; + struct __stp_tf_vma_entry *entry; + + mutex_lock(&__stp_tf_vma_mutex); + head = &__stp_tf_vma_table[__stp_tf_vma_hash(tsk, addr)]; + hlist_for_each_entry(entry, node, head, hlist) { + if (tsk->pid == entry->pid + && addr == entry->addr) { + mutex_unlock(&__stp_tf_vma_mutex); + return entry; + } + } + mutex_unlock(&__stp_tf_vma_mutex); + return NULL; +} + +// Add the vma info to the vma hash table. +static int +__stp_tf_add_vma(struct task_struct *tsk, unsigned long addr, + struct vm_area_struct *vma) +{ + struct hlist_head *head; + struct hlist_node *node; + struct __stp_tf_vma_entry *entry; + + mutex_lock(&__stp_tf_vma_mutex); + head = &__stp_tf_vma_table[__stp_tf_vma_hash(tsk, addr)]; + hlist_for_each_entry(entry, node, head, hlist) { + if (tsk->pid == entry->pid + && addr == entry->addr) { + printk(KERN_NOTICE + "vma (pid: %d, vm_start: 0x%lx) present?\n", + tsk->pid, vma->vm_start); + mutex_unlock(&__stp_tf_vma_mutex); + return -EBUSY; /* Already there */ + } + } + + // Using kmalloc here to allocate an element. Could cause some + // memory fragmentation if overused. + entry = kmalloc(sizeof(struct __stp_tf_vma_entry), GFP_KERNEL); + if (!entry) { + mutex_unlock(&__stp_tf_vma_mutex); + return -ENOMEM; + } + entry->pid = tsk->pid; + entry->addr = addr; + entry->vm_start = vma->vm_start; + entry->vm_end = vma->vm_end; + entry->vm_pgoff = vma->vm_pgoff; + hlist_add_head(&entry->hlist, head); + mutex_unlock(&__stp_tf_vma_mutex); + return 0; +} + +// Remove the vma entry from the vma hash table. +static int +__stp_tf_remove_vma_entry(struct __stp_tf_vma_entry *entry) +{ + struct hlist_head *head; + struct hlist_node *node; + int found = 0; + + if (entry != NULL) { + mutex_lock(&__stp_tf_vma_mutex); + hlist_del(&entry->hlist); + kfree(entry); + mutex_unlock(&__stp_tf_vma_mutex); + } + return 0; +} |