Merge branch 'sh/dwarf-unwinder'

Conflicts:
	arch/sh/kernel/dwarf.c

diff --git a/arch/sh/include/asm/dwarf.h b/arch/sh/include/asm/dwarf.h
index ced6795891a6f06977e54b9f3da239da0fdd71ae..fc51e66f2380b3097ba6c43b87f0a1177906e072 100644 (file)
--- a/arch/sh/include/asm/dwarf.h
+++ b/arch/sh/include/asm/dwarf.h
@@ -241,6 +241,12 @@ struct dwarf_cie {
 
        unsigned long flags;
 #define DWARF_CIE_Z_AUGMENTATION       (1 << 0)
+
+       /*
+        * 'mod' will be non-NULL if this CIE came from a module's
+        * .eh_frame section.
+        */
+       struct module *mod;
 };
 
 /**
@@ -255,6 +261,12 @@ struct dwarf_fde {
        unsigned char *instructions;
        unsigned char *end;
        struct list_head link;
+
+       /*
+        * 'mod' will be non-NULL if this FDE came from a module's
+        * .eh_frame section.
+        */
+       struct module *mod;
 };
 
 /**
@@ -364,6 +376,10 @@ static inline unsigned int DW_CFA_operand(unsigned long insn)
 
 extern struct dwarf_frame *dwarf_unwind_stack(unsigned long,
                                              struct dwarf_frame *);
+extern void dwarf_free_frame(struct dwarf_frame *);
+extern int dwarf_parse_section(char *, char *, struct module *);
+extern void dwarf_module_unload(struct module *);
+
 #endif /* !__ASSEMBLY__ */
 
 #define CFI_STARTPROC  .cfi_startproc

diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index 03b3616c80a5e164502b0d4d4a77e35831348de3..c274039e9c8d6a2f3d5683bef5f3c3143bcd141a 100644 (file)
--- 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;

diff --git a/arch/sh/kernel/module.c b/arch/sh/kernel/module.c
index c2efdcde266f7e91f196aaa3a1aa942e86c558f6..d297a148d16c69b581604595496cf3ff873b7333 100644 (file)
--- a/arch/sh/kernel/module.c
+++ b/arch/sh/kernel/module.c
@@ -32,6 +32,7 @@
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <asm/unaligned.h>
+#include <asm/dwarf.h>
 
 void *module_alloc(unsigned long size)
 {
@@ -145,10 +146,41 @@ int module_finalize(const Elf_Ehdr *hdr,
                    const Elf_Shdr *sechdrs,
                    struct module *me)
 {
+#ifdef CONFIG_DWARF_UNWINDER
+       unsigned int i, err;
+       unsigned long start, end;
+       char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+
+       start = end = 0;
+
+       for (i = 1; i < hdr->e_shnum; i++) {
+               /* Alloc bit cleared means "ignore it." */
+               if ((sechdrs[i].sh_flags & SHF_ALLOC)
+                   && !strcmp(secstrings+sechdrs[i].sh_name, ".eh_frame")) {
+                       start = sechdrs[i].sh_addr;
+                       end = start + sechdrs[i].sh_size;
+                       break;
+               }
+       }
+
+       /* Did we find the .eh_frame section? */
+       if (i != hdr->e_shnum) {
+               err = dwarf_parse_section((char *)start, (char *)end, me);
+               if (err)
+                       printk(KERN_WARNING "%s: failed to parse DWARF info\n",
+                              me->name);
+       }
+
+#endif /* CONFIG_DWARF_UNWINDER */
+
        return module_bug_finalize(hdr, sechdrs, me);
 }
 
 void module_arch_cleanup(struct module *mod)
 {
        module_bug_cleanup(mod);
+
+#ifdef CONFIG_DWARF_UNWINDER
+       dwarf_module_unload(mod);
+#endif /* CONFIG_DWARF_UNWINDER */
 }