diff options
| -rw-r--r-- | fs/binfmt_elf.c | 10 | ||||
| -rw-r--r-- | include/linux/regset.h | 67 |
2 files changed, 65 insertions, 12 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 73b01e474fdc..c697882b3aba 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1699,7 +1699,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, long signr, size_t *total) { unsigned int i; - unsigned int regset_size = view->regsets[0].n * view->regsets[0].size; + unsigned int regset0_size = regset_size(t->task, &view->regsets[0]); /* * NT_PRSTATUS is the one special case, because the regset data @@ -1708,11 +1708,11 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, * We assume that regset 0 is NT_PRSTATUS. */ fill_prstatus(&t->prstatus, t->task, signr); - (void) view->regsets[0].get(t->task, &view->regsets[0], 0, regset_size, + (void) view->regsets[0].get(t->task, &view->regsets[0], 0, regset0_size, &t->prstatus.pr_reg, NULL); fill_note(&t->notes[0], "CORE", NT_PRSTATUS, - PRSTATUS_SIZE(t->prstatus, regset_size), &t->prstatus); + PRSTATUS_SIZE(t->prstatus, regset0_size), &t->prstatus); *total += notesize(&t->notes[0]); do_thread_regset_writeback(t->task, &view->regsets[0]); @@ -1728,7 +1728,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, if (regset->core_note_type && regset->get && (!regset->active || regset->active(t->task, regset))) { int ret; - size_t size = regset->n * regset->size; + size_t size = regset_size(t->task, regset); void *data = kmalloc(size, GFP_KERNEL); if (unlikely(!data)) return 0; @@ -1743,7 +1743,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, size, data); else { SET_PR_FPVALID(&t->prstatus, - 1, regset_size); + 1, regset0_size); fill_note(&t->notes[i], "CORE", NT_PRFPREG, size, data); } diff --git a/include/linux/regset.h b/include/linux/regset.h index 8e0c9febf495..494cedaafdf2 100644 --- a/include/linux/regset.h +++ b/include/linux/regset.h @@ -107,6 +107,28 @@ typedef int user_regset_writeback_fn(struct task_struct *target, int immediate); /** + * user_regset_get_size_fn - type of @get_size function in &struct user_regset + * @target: thread being examined + * @regset: regset being examined + * + * This call is optional; usually the pointer is %NULL. + * + * When provided, this function must return the current size of regset + * data, as observed by the @get function in &struct user_regset. The + * value returned must be a multiple of @size. The returned size is + * required to be valid only until the next time (if any) @regset is + * modified for @target. + * + * This function is intended for dynamically sized regsets. A regset + * that is statically sized does not need to implement it. + * + * This function should not be called directly: instead, callers should + * call regset_size() to determine the current size of a regset. + */ +typedef unsigned int user_regset_get_size_fn(struct task_struct *target, + const struct user_regset *regset); + +/** * struct user_regset - accessible thread CPU state * @n: Number of slots (registers). * @size: Size in bytes of a slot (register). @@ -117,19 +139,33 @@ typedef int user_regset_writeback_fn(struct task_struct *target, * @set: Function to store values. * @active: Function to report if regset is active, or %NULL. * @writeback: Function to write data back to user memory, or %NULL. + * @get_size: Function to return the regset's size, or %NULL. * * This data structure describes a machine resource we call a register set. * This is part of the state of an individual thread, not necessarily * actual CPU registers per se. A register set consists of a number of * similar slots, given by @n. Each slot is @size bytes, and aligned to - * @align bytes (which is at least @size). + * @align bytes (which is at least @size). For dynamically-sized + * regsets, @n must contain the maximum possible number of slots for the + * regset, and @get_size must point to a function that returns the + * current regset size. * - * These functions must be called only on the current thread or on a - * thread that is in %TASK_STOPPED or %TASK_TRACED state, that we are - * guaranteed will not be woken up and return to user mode, and that we - * have called wait_task_inactive() on. (The target thread always might - * wake up for SIGKILL while these functions are working, in which case - * that thread's user_regset state might be scrambled.) + * Callers that need to know only the current size of the regset and do + * not care about its internal structure should call regset_size() + * instead of inspecting @n or calling @get_size. + * + * For backward compatibility, the @get and @set methods must pad to, or + * accept, @n * @size bytes, even if the current regset size is smaller. + * The precise semantics of these operations depend on the regset being + * accessed. + * + * The functions to which &struct user_regset members point must be + * called only on the current thread or on a thread that is in + * %TASK_STOPPED or %TASK_TRACED state, that we are guaranteed will not + * be woken up and return to user mode, and that we have called + * wait_task_inactive() on. (The target thread always might wake up for + * SIGKILL while these functions are working, in which case that + * thread's user_regset state might be scrambled.) * * The @pos argument must be aligned according to @align; the @count * argument must be a multiple of @size. These functions are not @@ -156,6 +192,7 @@ struct user_regset { user_regset_set_fn *set; user_regset_active_fn *active; user_regset_writeback_fn *writeback; + user_regset_get_size_fn *get_size; unsigned int n; unsigned int size; unsigned int align; @@ -371,5 +408,21 @@ static inline int copy_regset_from_user(struct task_struct *target, return regset->set(target, regset, offset, size, NULL, data); } +/** + * regset_size - determine the current size of a regset + * @target: thread to be examined + * @regset: regset to be examined + * + * Note that the returned size is valid only until the next time + * (if any) @regset is modified for @target. + */ +static inline unsigned int regset_size(struct task_struct *target, + const struct user_regset *regset) +{ + if (!regset->get_size) + return regset->n * regset->size; + else + return regset->get_size(target, regset); +} #endif /* <linux/regset.h> */ |