From: Josh Poimboeuf Associate an .sframe section with its mm by adding it to a per-mm maple tree which is indexed by the corresponding text address range. A single .sframe section can be associated with multiple text ranges. [ Jens Remus: Minor cleanups. Reword commit subject/message. ] Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (Google) Reviewed-by: Indu Bhagat Signed-off-by: Jens Remus --- Notes (jremus): Changes in v16: - Move SRCU definitions from patch "unwind_user/sframe: Add support for reading .sframe contents" here. (Sashiko AI) Changes in v15: - Fix text section end passed to mtree_insert_range() to be inclusive. (Sashiko AI) - sframe_remove_section(): Add guard(srcu) to guard access to sec->sframe_start. This also guards access to sec->filename in __sframe_remove_section(). (Sashiko AI) - Use GFP_KERNEL_ACCOUNT instead of GFP_KERNEL (see memory-allocation.rst, section "Get Free Page flags"). (Sashiko AI) arch/x86/include/asm/mmu.h | 2 +- include/linux/mm_types.h | 3 ++ include/linux/sframe.h | 18 ++++++++++ kernel/fork.c | 10 ++++++ kernel/unwind/sframe.c | 68 ++++++++++++++++++++++++++++++++++++-- mm/init-mm.c | 2 ++ 6 files changed, 99 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 0fe9c569d171..227a32899a59 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -87,7 +87,7 @@ typedef struct { .context = { \ .ctx_id = 1, \ .lock = __MUTEX_INITIALIZER(mm.context.lock), \ - } + }, void leave_mm(void); #define leave_mm leave_mm diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index a308e2c23b82..c1505356b6fc 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1424,6 +1424,9 @@ struct mm_struct { #ifdef CONFIG_MM_ID mm_id_t mm_id; #endif /* CONFIG_MM_ID */ +#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME + struct maple_tree sframe_mt; +#endif } __randomize_layout; /* diff --git a/include/linux/sframe.h b/include/linux/sframe.h index 0642595534f9..38047760e252 100644 --- a/include/linux/sframe.h +++ b/include/linux/sframe.h @@ -2,9 +2,14 @@ #ifndef _LINUX_SFRAME_H #define _LINUX_SFRAME_H +#include +#include + #ifdef CONFIG_HAVE_UNWIND_USER_SFRAME struct sframe_section { + struct rcu_head rcu; + unsigned long sframe_start; unsigned long sframe_end; unsigned long text_start; @@ -19,18 +24,31 @@ struct sframe_section { signed char fp_off; }; +#define INIT_MM_SFRAME .sframe_mt = MTREE_INIT(sframe_mt, 0), +extern void sframe_free_mm(struct mm_struct *mm); + extern int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end, unsigned long text_start, unsigned long text_end); extern int sframe_remove_section(unsigned long sframe_addr); +static inline bool current_has_sframe(void) +{ + struct mm_struct *mm = current->mm; + + return mm && !mtree_empty(&mm->sframe_mt); +} + #else /* !CONFIG_HAVE_UNWIND_USER_SFRAME */ +#define INIT_MM_SFRAME +static inline void sframe_free_mm(struct mm_struct *mm) {} static inline int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end, unsigned long text_start, unsigned long text_end) { return -ENOSYS; } static inline int sframe_remove_section(unsigned long sframe_addr) { return -ENOSYS; } +static inline bool current_has_sframe(void) { return false; } #endif /* CONFIG_HAVE_UNWIND_USER_SFRAME */ diff --git a/kernel/fork.c b/kernel/fork.c index 5f3fdfdb14c7..8d8195561c95 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -110,6 +110,7 @@ #include #include #include +#include #include #include @@ -735,6 +736,7 @@ void __mmdrop(struct mm_struct *mm) mm_pasid_drop(mm); mm_destroy_cid(mm); percpu_counter_destroy_many(mm->rss_stat, NR_MM_COUNTERS); + sframe_free_mm(mm); free_mm(mm); } @@ -1072,6 +1074,13 @@ static void mmap_init_lock(struct mm_struct *mm) #endif } +static void mm_init_sframe(struct mm_struct *mm) +{ +#ifdef CONFIG_HAVE_UNWIND_USER_SFRAME + mt_init(&mm->sframe_mt); +#endif +} + static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, struct user_namespace *user_ns) { @@ -1100,6 +1109,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm->pmd_huge_pte = NULL; #endif mm_init_uprobes_state(mm); + mm_init_sframe(mm); hugetlb_count_init(mm); mm_flags_clear_all(mm); diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index d24e9d4f8bef..46dba3cb016d 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -19,6 +19,8 @@ #define dbg(fmt, ...) \ pr_debug("%s (%d): " fmt, current->comm, current->pid, ##__VA_ARGS__) +DEFINE_STATIC_SRCU(sframe_srcu); + static void free_section(struct sframe_section *sec) { kfree(sec); @@ -81,6 +83,7 @@ static int sframe_read_header(struct sframe_section *sec) int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end, unsigned long text_start, unsigned long text_end) { + struct maple_tree *sframe_mt = ¤t->mm->sframe_mt; struct vm_area_struct *sframe_vma, *text_vma; struct mm_struct *mm = current->mm; struct sframe_section *sec; @@ -122,15 +125,74 @@ int sframe_add_section(unsigned long sframe_start, unsigned long sframe_end, if (ret) goto err_free; - /* TODO nowhere to store it yet - just free it and return an error */ - ret = -ENOSYS; + ret = mtree_insert_range(sframe_mt, sec->text_start, sec->text_end - 1, + sec, GFP_KERNEL_ACCOUNT); + if (ret) { + dbg("mtree_insert_range failed: text=%lx-%lx\n", + sec->text_start, sec->text_end); + goto err_free; + } + + return 0; err_free: free_section(sec); return ret; } +static void sframe_free_srcu(struct rcu_head *rcu) +{ + struct sframe_section *sec = container_of(rcu, struct sframe_section, rcu); + + free_section(sec); +} + +static int __sframe_remove_section(struct mm_struct *mm, + struct sframe_section *sec) +{ + if (!mtree_erase(&mm->sframe_mt, sec->text_start)) { + dbg("mtree_erase failed: text=%lx\n", sec->text_start); + return -EINVAL; + } + + call_srcu(&sframe_srcu, &sec->rcu, sframe_free_srcu); + + return 0; +} + int sframe_remove_section(unsigned long sframe_start) { - return -ENOSYS; + struct mm_struct *mm = current->mm; + struct sframe_section *sec; + unsigned long index = 0; + bool found = false; + int ret = 0; + + guard(srcu)(&sframe_srcu); + + mt_for_each(&mm->sframe_mt, sec, index, ULONG_MAX) { + if (sec->sframe_start == sframe_start) { + found = true; + ret |= __sframe_remove_section(mm, sec); + } + } + + if (!found || ret) + return -EINVAL; + + return 0; +} + +void sframe_free_mm(struct mm_struct *mm) +{ + struct sframe_section *sec; + unsigned long index = 0; + + if (!mm) + return; + + mt_for_each(&mm->sframe_mt, sec, index, ULONG_MAX) + free_section(sec); + + mtree_destroy(&mm->sframe_mt); } diff --git a/mm/init-mm.c b/mm/init-mm.c index c5556bb9d5f0..77909139162e 100644 --- a/mm/init-mm.c +++ b/mm/init-mm.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #ifndef INIT_MM_CONTEXT @@ -49,6 +50,7 @@ struct mm_struct init_mm = { #endif .flexible_array = MM_STRUCT_FLEXIBLE_ARRAY_INIT, INIT_MM_CONTEXT(init_mm) + INIT_MM_SFRAME }; void setup_initial_init_mm(void *start_code, void *end_code, -- 2.51.0