Merge branch 'sh/dwarf-unwinder'

Conflicts:
	arch/sh/kernel/dwarf.c

1 files changed, 135 insertions, 50 deletions

diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index 03b3616c80a5..c274039e9c8d 100644
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -529,7 +529,18 @@ static int dwarf_cfa_execute_insns(unsigned char *insn_start,
 }
 
 /**
- *      dwarf_unwind_stack - recursively unwind the stack
+ *      dwarf_free_frame - free the memory allocated for @frame
+ *      @frame: the frame to free
+ */
+void dwarf_free_frame(struct dwarf_frame *frame)
+{
+        dwarf_frame_free_regs(frame);
+        mempool_free(frame, dwarf_frame_pool);
+}
+
+/**
+ *      dwarf_unwind_stack - unwind the stack
+ *
  *      @pc: address of the function to unwind
  *      @prev: struct dwarf_frame of the previous stackframe on the callstack
  *
@@ -547,9 +558,9 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc,
         unsigned long addr;
 
         /*
-         * If this is the first invocation of this recursive function we
-         * need get the contents of a physical register to get the CFA
-         * in order to begin the virtual unwinding of the stack.
+         * If we're starting at the top of the stack we need get the
+         * contents of a physical register to get the CFA in order to
+         * begin the virtual unwinding of the stack.
          *
          * NOTE: the return address is guaranteed to be setup by the
          * time this function makes its first function call.
@@ -571,9 +582,8 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc,
         fde = dwarf_lookup_fde(pc);
         if (!fde) {
                 /*
-                 * This is our normal exit path - the one that stops the
-                 * recursion. There's two reasons why we might exit
-                 * here,
+                 * This is our normal exit path. There are two reasons
+                 * why we might exit here,
                  *
                  *      a) pc has no asscociated DWARF frame info and so
                  *      we don't know how to unwind this frame. This is
@@ -615,10 +625,10 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc,
 
                 } else {
                         /*
-                         * Again, this is the first invocation of this
-                         * recurisve function. We need to physically
-                         * read the contents of a register in order to
-                         * get the Canonical Frame Address for this
+                         * Again, we're starting from the top of the
+                         * stack. We need to physically read
+                         * the contents of a register in order to get
+                         * the Canonical Frame Address for this
                          * function.
                          */
                         frame->cfa = dwarf_read_arch_reg(frame->cfa_register);
@@ -648,13 +658,12 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc,
         return frame;
 
 bail:
-        dwarf_frame_free_regs(frame);
-        mempool_free(frame, dwarf_frame_pool);
+        dwarf_free_frame(frame);
         return NULL;
 }
 
 static int dwarf_parse_cie(void *entry, void *p, unsigned long len,
-                           unsigned char *end)
+                           unsigned char *end, struct module *mod)
 {
         struct dwarf_cie *cie;
         unsigned long flags;
@@ -750,6 +759,8 @@ static int dwarf_parse_cie(void *entry, void *p, unsigned long len,
         cie->initial_instructions = p;
         cie->instructions_end = end;
 
+        cie->mod = mod;
+
         /* Add to list */
         spin_lock_irqsave(&dwarf_cie_lock, flags);
         list_add_tail(&cie->link, &dwarf_cie_list);
@@ -760,7 +771,7 @@ static int dwarf_parse_cie(void *entry, void *p, unsigned long len,
 
 static int dwarf_parse_fde(void *entry, u32 entry_type,
                            void *start, unsigned long len,
-                           unsigned char *end)
+                           unsigned char *end, struct module *mod)
 {
         struct dwarf_fde *fde;
         struct dwarf_cie *cie;
@@ -809,6 +820,8 @@ static int dwarf_parse_fde(void *entry, u32 entry_type,
         fde->instructions = p;
         fde->end = end;
 
+        fde->mod = mod;
+
         /* Add to list. */
         spin_lock_irqsave(&dwarf_fde_lock, flags);
         list_add_tail(&fde->link, &dwarf_fde_list);
@@ -832,10 +845,8 @@ static void dwarf_unwinder_dump(struct task_struct *task,
         while (1) {
                 frame = dwarf_unwind_stack(return_addr, _frame);
 
-                if (_frame) {
-                        dwarf_frame_free_regs(_frame);
-                        mempool_free(_frame, dwarf_frame_pool);
-                }
+                if (_frame)
+                        dwarf_free_frame(_frame);
 
                 _frame = frame;
 
@@ -845,6 +856,9 @@ static void dwarf_unwinder_dump(struct task_struct *task,
                 return_addr = frame->return_addr;
                 ops->address(data, return_addr, 1);
         }
+
+        if (frame)
+                dwarf_free_frame(frame);
 }
 
 static struct unwinder dwarf_unwinder = {
@@ -874,15 +888,15 @@ static void dwarf_unwinder_cleanup(void)
 }
 
 /**
- *      dwarf_unwinder_init - initialise the dwarf unwinder
+ *      dwarf_parse_section - parse DWARF section
+ *      @eh_frame_start: start address of the .eh_frame section
+ *      @eh_frame_end: end address of the .eh_frame section
+ *      @mod: the kernel module containing the .eh_frame section
  *
- *      Build the data structures describing the .dwarf_frame section to
- *      make it easier to lookup CIE and FDE entries. Because the
- *      .eh_frame section is packed as tightly as possible it is not
- *      easy to lookup the FDE for a given PC, so we build a list of FDE
- *      and CIE entries that make it easier.
+ *      Parse the information in a .eh_frame section.
  */
-static int __init dwarf_unwinder_init(void)
+int dwarf_parse_section(char *eh_frame_start, char *eh_frame_end,
+                        struct module *mod)
 {
         u32 entry_type;
         void *p, *entry;
@@ -890,32 +904,12 @@ static int __init dwarf_unwinder_init(void)
         unsigned long len;
         unsigned int c_entries, f_entries;
         unsigned char *end;
-        INIT_LIST_HEAD(&dwarf_cie_list);
-        INIT_LIST_HEAD(&dwarf_fde_list);
 
         c_entries = 0;
         f_entries = 0;
-        entry = &__start_eh_frame;
-
-        dwarf_frame_cachep = kmem_cache_create("dwarf_frames",
-                        sizeof(struct dwarf_frame), 0,
-                        SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL);
-
-        dwarf_reg_cachep = kmem_cache_create("dwarf_regs",
-                        sizeof(struct dwarf_reg), 0,
-                        SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL);
-
-        dwarf_frame_pool = mempool_create(DWARF_FRAME_MIN_REQ,
-                                          mempool_alloc_slab,
-                                          mempool_free_slab,
-                                          dwarf_frame_cachep);
+        entry = eh_frame_start;
 
-        dwarf_reg_pool = mempool_create(DWARF_REG_MIN_REQ,
-                                         mempool_alloc_slab,
-                                         mempool_free_slab,
-                                         dwarf_reg_cachep);
-
-        while ((char *)entry < __stop_eh_frame) {
+        while ((char *)entry < eh_frame_end) {
                 p = entry;
 
                 count = dwarf_entry_len(p, &len);
@@ -927,6 +921,7 @@ static int __init dwarf_unwinder_init(void)
                          * entry and move to the next one because 'len'
                          * tells us where our next entry is.
                          */
+                        err = -EINVAL;
                         goto out;
                 } else
                         p += count;
@@ -938,13 +933,14 @@ static int __init dwarf_unwinder_init(void)
                 p += 4;
 
                 if (entry_type == DW_EH_FRAME_CIE) {
-                        err = dwarf_parse_cie(entry, p, len, end);
+                        err = dwarf_parse_cie(entry, p, len, end, mod);
                         if (err < 0)
                                 goto out;
                         else
                                 c_entries++;
                 } else {
-                        err = dwarf_parse_fde(entry, entry_type, p, len, end);
+                        err = dwarf_parse_fde(entry, entry_type, p, len,
+                                              end, mod);
                         if (err < 0)
                                 goto out;
                         else
@@ -957,6 +953,95 @@ static int __init dwarf_unwinder_init(void)
         printk(KERN_INFO "DWARF unwinder initialised: read %u CIEs, %u FDEs\n",
                c_entries, f_entries);
 
+        return 0;
+
+out:
+        return err;
+}
+
+/**
+ *      dwarf_module_unload - remove FDE/CIEs associated with @mod
+ *      @mod: the module that is being unloaded
+ *
+ *      Remove any FDEs and CIEs from the global lists that came from
+ *      @mod's .eh_frame section because @mod is being unloaded.
+ */
+void dwarf_module_unload(struct module *mod)
+{
+        struct dwarf_fde *fde;
+        struct dwarf_cie *cie;
+        unsigned long flags;
+
+        spin_lock_irqsave(&dwarf_cie_lock, flags);
+
+again_cie:
+        list_for_each_entry(cie, &dwarf_cie_list, link) {
+                if (cie->mod == mod)
+                        break;
+        }
+
+        if (&cie->link != &dwarf_cie_list) {
+                list_del(&cie->link);
+                kfree(cie);
+                goto again_cie;
+        }
+
+        spin_unlock_irqrestore(&dwarf_cie_lock, flags);
+
+        spin_lock_irqsave(&dwarf_fde_lock, flags);
+
+again_fde:
+        list_for_each_entry(fde, &dwarf_fde_list, link) {
+                if (fde->mod == mod)
+                        break;
+        }
+
+        if (&fde->link != &dwarf_fde_list) {
+                list_del(&fde->link);
+                kfree(fde);
+                goto again_fde;
+        }
+
+        spin_unlock_irqrestore(&dwarf_fde_lock, flags);
+}
+
+/**
+ *      dwarf_unwinder_init - initialise the dwarf unwinder
+ *
+ *      Build the data structures describing the .dwarf_frame section to
+ *      make it easier to lookup CIE and FDE entries. Because the
+ *      .eh_frame section is packed as tightly as possible it is not
+ *      easy to lookup the FDE for a given PC, so we build a list of FDE
+ *      and CIE entries that make it easier.
+ */
+static int __init dwarf_unwinder_init(void)
+{
+        int err;
+        INIT_LIST_HEAD(&dwarf_cie_list);
+        INIT_LIST_HEAD(&dwarf_fde_list);
+
+        dwarf_frame_cachep = kmem_cache_create("dwarf_frames",
+                        sizeof(struct dwarf_frame), 0,
+                        SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL);
+
+        dwarf_reg_cachep = kmem_cache_create("dwarf_regs",
+                        sizeof(struct dwarf_reg), 0,
+                        SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL);
+
+        dwarf_frame_pool = mempool_create(DWARF_FRAME_MIN_REQ,
+                                          mempool_alloc_slab,
+                                          mempool_free_slab,
+                                          dwarf_frame_cachep);
+
+        dwarf_reg_pool = mempool_create(DWARF_REG_MIN_REQ,
+                                         mempool_alloc_slab,
+                                         mempool_free_slab,
+                                         dwarf_reg_cachep);
+
+        err = dwarf_parse_section(__start_eh_frame, __stop_eh_frame, NULL);
+        if (err)
+                goto out;
+
         err = unwinder_register(&dwarf_unwinder);
         if (err)
                 goto out;