percpu, module: implement and use is_kernel/module_percpu_address()
lockdep has custom code to check whether a pointer belongs to static percpu area which is somewhat broken. Implement proper is_kernel/module_percpu_address() and replace the custom code. On UP, percpu variables are regular static variables and can't be distinguished from them. Always return %false on UP. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com>
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5 changed files with 77 additions and 16 deletions
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@ -395,6 +395,7 @@ static inline int module_is_live(struct module *mod)
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struct module *__module_text_address(unsigned long addr);
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struct module *__module_address(unsigned long addr);
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bool is_module_address(unsigned long addr);
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bool is_module_percpu_address(unsigned long addr);
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bool is_module_text_address(unsigned long addr);
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static inline int within_module_core(unsigned long addr, struct module *mod)
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@ -137,6 +137,7 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size,
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extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
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extern void __percpu *__alloc_percpu(size_t size, size_t align);
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extern void free_percpu(void __percpu *__pdata);
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extern bool is_kernel_percpu_address(unsigned long addr);
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extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
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#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
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@ -163,6 +164,12 @@ static inline void free_percpu(void __percpu *p)
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kfree(p);
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}
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/* can't distinguish from other static vars, always false */
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static inline bool is_kernel_percpu_address(unsigned long addr)
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{
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return false;
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}
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static inline phys_addr_t per_cpu_ptr_to_phys(void *addr)
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{
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return __pa(addr);
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@ -582,9 +582,6 @@ static int static_obj(void *obj)
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unsigned long start = (unsigned long) &_stext,
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end = (unsigned long) &_end,
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addr = (unsigned long) obj;
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#ifdef CONFIG_SMP
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int i;
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#endif
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/*
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* static variable?
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@ -595,24 +592,16 @@ static int static_obj(void *obj)
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if (arch_is_kernel_data(addr))
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return 1;
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#ifdef CONFIG_SMP
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/*
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* percpu var?
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* in-kernel percpu var?
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*/
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for_each_possible_cpu(i) {
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start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
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end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
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+ per_cpu_offset(i);
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if ((addr >= start) && (addr < end))
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if (is_kernel_percpu_address(addr))
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return 1;
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}
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#endif
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/*
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* module var?
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* module static or percpu var?
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*/
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return is_module_address(addr);
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return is_module_address(addr) || is_module_percpu_address(addr);
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}
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/*
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@ -415,6 +415,40 @@ static void percpu_modcopy(struct module *mod,
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memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
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}
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/**
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* is_module_percpu_address - test whether address is from module static percpu
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* @addr: address to test
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*
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* Test whether @addr belongs to module static percpu area.
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*
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* RETURNS:
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* %true if @addr is from module static percpu area
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*/
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bool is_module_percpu_address(unsigned long addr)
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{
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struct module *mod;
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unsigned int cpu;
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preempt_disable();
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list_for_each_entry_rcu(mod, &modules, list) {
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if (!mod->percpu_size)
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continue;
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for_each_possible_cpu(cpu) {
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void *start = per_cpu_ptr(mod->percpu, cpu);
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if ((void *)addr >= start &&
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(void *)addr < start + mod->percpu_size) {
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preempt_enable();
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return true;
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}
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}
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}
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preempt_enable();
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return false;
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}
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#else /* ... !CONFIG_SMP */
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static inline void __percpu *mod_percpu(struct module *mod)
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@ -441,6 +475,10 @@ static inline void percpu_modcopy(struct module *mod,
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/* pcpusec should be 0, and size of that section should be 0. */
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BUG_ON(size != 0);
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}
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bool is_module_percpu_address(unsigned long addr)
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{
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return false;
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}
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#endif /* CONFIG_SMP */
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26
mm/percpu.c
26
mm/percpu.c
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@ -1303,6 +1303,32 @@ void free_percpu(void __percpu *ptr)
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}
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EXPORT_SYMBOL_GPL(free_percpu);
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/**
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* is_kernel_percpu_address - test whether address is from static percpu area
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* @addr: address to test
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*
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* Test whether @addr belongs to in-kernel static percpu area. Module
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* static percpu areas are not considered. For those, use
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* is_module_percpu_address().
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*
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* RETURNS:
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* %true if @addr is from in-kernel static percpu area, %false otherwise.
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*/
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bool is_kernel_percpu_address(unsigned long addr)
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{
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const size_t static_size = __per_cpu_end - __per_cpu_start;
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void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
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unsigned int cpu;
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for_each_possible_cpu(cpu) {
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void *start = per_cpu_ptr(base, cpu);
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if ((void *)addr >= start && (void *)addr < start + static_size)
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return true;
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}
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return false;
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}
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/**
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* per_cpu_ptr_to_phys - convert translated percpu address to physical address
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* @addr: the address to be converted to physical address
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