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-rw-r--r--arch/um/include/asm/unwind.h8
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/Kconfig.debug25
-rw-r--r--arch/x86/include/asm/module.h9
-rw-r--r--arch/x86/include/asm/orc_lookup.h46
-rw-r--r--arch/x86/include/asm/orc_types.h2
-rw-r--r--arch/x86/include/asm/unwind.h76
-rw-r--r--arch/x86/kernel/Makefile8
-rw-r--r--arch/x86/kernel/module.c11
-rw-r--r--arch/x86/kernel/setup.c3
-rw-r--r--arch/x86/kernel/unwind_frame.c39
-rw-r--r--arch/x86/kernel/unwind_guess.c5
-rw-r--r--arch/x86/kernel/unwind_orc.c582
-rw-r--r--arch/x86/kernel/vmlinux.lds.S3
14 files changed, 759 insertions, 59 deletions
diff --git a/arch/um/include/asm/unwind.h b/arch/um/include/asm/unwind.h
new file mode 100644
index 000000000000..7ffa5437b761
--- /dev/null
+++ b/arch/um/include/asm/unwind.h
@@ -0,0 +1,8 @@
+#ifndef _ASM_UML_UNWIND_H
+#define _ASM_UML_UNWIND_H
+
+static inline void
+unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
+ void *orc, size_t orc_size) {}
+
+#endif /* _ASM_UML_UNWIND_H */
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 781521b7cf9e..7ccf26a427cb 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -157,6 +157,7 @@ config X86
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
select HAVE_MIXED_BREAKPOINTS_REGS
+ select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
select HAVE_OPROFILE
select HAVE_OPTPROBES
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 353ed09f5fba..dc10ec6ead6e 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -355,4 +355,29 @@ config PUNIT_ATOM_DEBUG
The current power state can be read from
/sys/kernel/debug/punit_atom/dev_power_state
+config ORC_UNWINDER
+ bool "ORC unwinder"
+ depends on X86_64
+ select STACK_VALIDATION
+ ---help---
+ This option enables the ORC (Oops Rewind Capability) unwinder for
+ unwinding kernel stack traces. It uses a custom data format which is
+ a simplified version of the DWARF Call Frame Information standard.
+
+ This unwinder is more accurate across interrupt entry frames than the
+ frame pointer unwinder. It can also enable a 5-10% performance
+ improvement across the entire kernel if CONFIG_FRAME_POINTER is
+ disabled.
+
+ Enabling this option will increase the kernel's runtime memory usage
+ by roughly 2-4MB, depending on your kernel config.
+
+config FRAME_POINTER_UNWINDER
+ def_bool y
+ depends on !ORC_UNWINDER && FRAME_POINTER
+
+config GUESS_UNWINDER
+ def_bool y
+ depends on !ORC_UNWINDER && !FRAME_POINTER
+
endmenu
diff --git a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h
index e3b7819caeef..9eb7c718aaf8 100644
--- a/arch/x86/include/asm/module.h
+++ b/arch/x86/include/asm/module.h
@@ -2,6 +2,15 @@
#define _ASM_X86_MODULE_H
#include <asm-generic/module.h>
+#include <asm/orc_types.h>
+
+struct mod_arch_specific {
+#ifdef CONFIG_ORC_UNWINDER
+ unsigned int num_orcs;
+ int *orc_unwind_ip;
+ struct orc_entry *orc_unwind;
+#endif
+};
#ifdef CONFIG_X86_64
/* X86_64 does not define MODULE_PROC_FAMILY */
diff --git a/arch/x86/include/asm/orc_lookup.h b/arch/x86/include/asm/orc_lookup.h
new file mode 100644
index 000000000000..91c8d868424d
--- /dev/null
+++ b/arch/x86/include/asm/orc_lookup.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _ORC_LOOKUP_H
+#define _ORC_LOOKUP_H
+
+/*
+ * This is a lookup table for speeding up access to the .orc_unwind table.
+ * Given an input address offset, the corresponding lookup table entry
+ * specifies a subset of the .orc_unwind table to search.
+ *
+ * Each block represents the end of the previous range and the start of the
+ * next range. An extra block is added to give the last range an end.
+ *
+ * The block size should be a power of 2 to avoid a costly 'div' instruction.
+ *
+ * A block size of 256 was chosen because it roughly doubles unwinder
+ * performance while only adding ~5% to the ORC data footprint.
+ */
+#define LOOKUP_BLOCK_ORDER 8
+#define LOOKUP_BLOCK_SIZE (1 << LOOKUP_BLOCK_ORDER)
+
+#ifndef LINKER_SCRIPT
+
+extern unsigned int orc_lookup[];
+extern unsigned int orc_lookup_end[];
+
+#define LOOKUP_START_IP (unsigned long)_stext
+#define LOOKUP_STOP_IP (unsigned long)_etext
+
+#endif /* LINKER_SCRIPT */
+
+#endif /* _ORC_LOOKUP_H */
diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h
index 7dc777a6cb40..9c9dc579bd7d 100644
--- a/arch/x86/include/asm/orc_types.h
+++ b/arch/x86/include/asm/orc_types.h
@@ -88,7 +88,7 @@ struct orc_entry {
unsigned sp_reg:4;
unsigned bp_reg:4;
unsigned type:2;
-};
+} __packed;
/*
* This struct is used by asm and inline asm code to manually annotate the
diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h
index e6676495b125..25b8d31a007d 100644
--- a/arch/x86/include/asm/unwind.h
+++ b/arch/x86/include/asm/unwind.h
@@ -12,11 +12,14 @@ struct unwind_state {
struct task_struct *task;
int graph_idx;
bool error;
-#ifdef CONFIG_FRAME_POINTER
+#if defined(CONFIG_ORC_UNWINDER)
+ bool signal, full_regs;
+ unsigned long sp, bp, ip;
+ struct pt_regs *regs;
+#elif defined(CONFIG_FRAME_POINTER)
bool got_irq;
- unsigned long *bp, *orig_sp;
+ unsigned long *bp, *orig_sp, ip;
struct pt_regs *regs;
- unsigned long ip;
#else
unsigned long *sp;
#endif
@@ -24,41 +27,30 @@ struct unwind_state {
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame);
-
bool unwind_next_frame(struct unwind_state *state);
-
unsigned long unwind_get_return_address(struct unwind_state *state);
+unsigned long *unwind_get_return_address_ptr(struct unwind_state *state);
static inline bool unwind_done(struct unwind_state *state)
{
return state->stack_info.type == STACK_TYPE_UNKNOWN;
}
-static inline
-void unwind_start(struct unwind_state *state, struct task_struct *task,
- struct pt_regs *regs, unsigned long *first_frame)
-{
- first_frame = first_frame ? : get_stack_pointer(task, regs);
-
- __unwind_start(state, task, regs, first_frame);
-}
-
static inline bool unwind_error(struct unwind_state *state)
{
return state->error;
}
-#ifdef CONFIG_FRAME_POINTER
-
static inline
-unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
+void unwind_start(struct unwind_state *state, struct task_struct *task,
+ struct pt_regs *regs, unsigned long *first_frame)
{
- if (unwind_done(state))
- return NULL;
+ first_frame = first_frame ? : get_stack_pointer(task, regs);
- return state->regs ? &state->regs->ip : state->bp + 1;
+ __unwind_start(state, task, regs, first_frame);
}
+#if defined(CONFIG_ORC_UNWINDER) || defined(CONFIG_FRAME_POINTER)
static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
{
if (unwind_done(state))
@@ -66,20 +58,46 @@ static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
return state->regs;
}
-
-#else /* !CONFIG_FRAME_POINTER */
-
-static inline
-unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
+#else
+static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
{
return NULL;
}
+#endif
-static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
+#ifdef CONFIG_ORC_UNWINDER
+void unwind_init(void);
+void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
+ void *orc, size_t orc_size);
+#else
+static inline void unwind_init(void) {}
+static inline
+void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size,
+ void *orc, size_t orc_size) {}
+#endif
+
+/*
+ * This disables KASAN checking when reading a value from another task's stack,
+ * since the other task could be running on another CPU and could have poisoned
+ * the stack in the meantime.
+ */
+#define READ_ONCE_TASK_STACK(task, x) \
+({ \
+ unsigned long val; \
+ if (task == current) \
+ val = READ_ONCE(x); \
+ else \
+ val = READ_ONCE_NOCHECK(x); \
+ val; \
+})
+
+static inline bool task_on_another_cpu(struct task_struct *task)
{
- return NULL;
+#ifdef CONFIG_SMP
+ return task != current && task->on_cpu;
+#else
+ return false;
+#endif
}
-#endif /* CONFIG_FRAME_POINTER */
-
#endif /* _ASM_X86_UNWIND_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index a01892bdd61a..287eac7d207f 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -126,11 +126,9 @@ obj-$(CONFIG_PERF_EVENTS) += perf_regs.o
obj-$(CONFIG_TRACING) += tracepoint.o
obj-$(CONFIG_SCHED_MC_PRIO) += itmt.o
-ifdef CONFIG_FRAME_POINTER
-obj-y += unwind_frame.o
-else
-obj-y += unwind_guess.o
-endif
+obj-$(CONFIG_ORC_UNWINDER) += unwind_orc.o
+obj-$(CONFIG_FRAME_POINTER_UNWINDER) += unwind_frame.o
+obj-$(CONFIG_GUESS_UNWINDER) += unwind_guess.o
###
# 64 bit specific files
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index f67bd3205df7..62e7d70aadd5 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -35,6 +35,7 @@
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/setup.h>
+#include <asm/unwind.h>
#if 0
#define DEBUGP(fmt, ...) \
@@ -213,7 +214,7 @@ int module_finalize(const Elf_Ehdr *hdr,
struct module *me)
{
const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
- *para = NULL;
+ *para = NULL, *orc = NULL, *orc_ip = NULL;
char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
@@ -225,6 +226,10 @@ int module_finalize(const Elf_Ehdr *hdr,
locks = s;
if (!strcmp(".parainstructions", secstrings + s->sh_name))
para = s;
+ if (!strcmp(".orc_unwind", secstrings + s->sh_name))
+ orc = s;
+ if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
+ orc_ip = s;
}
if (alt) {
@@ -248,6 +253,10 @@ int module_finalize(const Elf_Ehdr *hdr,
/* make jump label nops */
jump_label_apply_nops(me);
+ if (orc && orc_ip)
+ unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
+ (void *)orc->sh_addr, orc->sh_size);
+
return 0;
}
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 3486d0498800..ecab32282f0f 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -115,6 +115,7 @@
#include <asm/microcode.h>
#include <asm/mmu_context.h>
#include <asm/kaslr.h>
+#include <asm/unwind.h>
/*
* max_low_pfn_mapped: highest direct mapped pfn under 4GB
@@ -1310,6 +1311,8 @@ void __init setup_arch(char **cmdline_p)
if (efi_enabled(EFI_BOOT))
efi_apply_memmap_quirks();
#endif
+
+ unwind_init();
}
#ifdef CONFIG_X86_32
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index b9389d72b2f7..7574ef5f16ec 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -10,20 +10,22 @@
#define FRAME_HEADER_SIZE (sizeof(long) * 2)
-/*
- * This disables KASAN checking when reading a value from another task's stack,
- * since the other task could be running on another CPU and could have poisoned
- * the stack in the meantime.
- */
-#define READ_ONCE_TASK_STACK(task, x) \
-({ \
- unsigned long val; \
- if (task == current) \
- val = READ_ONCE(x); \
- else \
- val = READ_ONCE_NOCHECK(x); \
- val; \
-})
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+ if (unwind_done(state))
+ return 0;
+
+ return __kernel_text_address(state->ip) ? state->ip : 0;
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
+unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
+{
+ if (unwind_done(state))
+ return NULL;
+
+ return state->regs ? &state->regs->ip : state->bp + 1;
+}
static void unwind_dump(struct unwind_state *state)
{
@@ -66,15 +68,6 @@ static void unwind_dump(struct unwind_state *state)
}
}
-unsigned long unwind_get_return_address(struct unwind_state *state)
-{
- if (unwind_done(state))
- return 0;
-
- return __kernel_text_address(state->ip) ? state->ip : 0;
-}
-EXPORT_SYMBOL_GPL(unwind_get_return_address);
-
static size_t regs_size(struct pt_regs *regs)
{
/* x86_32 regs from kernel mode are two words shorter: */
diff --git a/arch/x86/kernel/unwind_guess.c b/arch/x86/kernel/unwind_guess.c
index 039f36738e49..4f0e17b90463 100644
--- a/arch/x86/kernel/unwind_guess.c
+++ b/arch/x86/kernel/unwind_guess.c
@@ -19,6 +19,11 @@ unsigned long unwind_get_return_address(struct unwind_state *state)
}
EXPORT_SYMBOL_GPL(unwind_get_return_address);
+unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
+{
+ return NULL;
+}
+
bool unwind_next_frame(struct unwind_state *state)
{
struct stack_info *info = &state->stack_info;
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
new file mode 100644
index 000000000000..570b70d3f604
--- /dev/null
+++ b/arch/x86/kernel/unwind_orc.c
@@ -0,0 +1,582 @@
+#include <linux/module.h>
+#include <linux/sort.h>
+#include <asm/ptrace.h>
+#include <asm/stacktrace.h>
+#include <asm/unwind.h>
+#include <asm/orc_types.h>
+#include <asm/orc_lookup.h>
+#include <asm/sections.h>
+
+#define orc_warn(fmt, ...) \
+ printk_deferred_once(KERN_WARNING pr_fmt("WARNING: " fmt), ##__VA_ARGS__)
+
+extern int __start_orc_unwind_ip[];
+extern int __stop_orc_unwind_ip[];
+extern struct orc_entry __start_orc_unwind[];
+extern struct orc_entry __stop_orc_unwind[];
+
+static DEFINE_MUTEX(sort_mutex);
+int *cur_orc_ip_table = __start_orc_unwind_ip;
+struct orc_entry *cur_orc_table = __start_orc_unwind;
+
+unsigned int lookup_num_blocks;
+bool orc_init;
+
+static inline unsigned long orc_ip(const int *ip)
+{
+ return (unsigned long)ip + *ip;
+}
+
+static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table,
+ unsigned int num_entries, unsigned long ip)
+{
+ int *first = ip_table;
+ int *last = ip_table + num_entries - 1;
+ int *mid = first, *found = first;
+
+ if (!num_entries)
+ return NULL;
+
+ /*
+ * Do a binary range search to find the rightmost duplicate of a given
+ * starting address. Some entries are section terminators which are
+ * "weak" entries for ensuring there are no gaps. They should be
+ * ignored when they conflict with a real entry.
+ */
+ while (first <= last) {
+ mid = first + ((last - first) / 2);
+
+ if (orc_ip(mid) <= ip) {
+ found = mid;
+ first = mid + 1;
+ } else
+ last = mid - 1;
+ }
+
+ return u_table + (found - ip_table);
+}
+
+#ifdef CONFIG_MODULES
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+ struct module *mod;
+
+ mod = __module_address(ip);
+ if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip)
+ return NULL;
+ return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind,
+ mod->arch.num_orcs, ip);
+}
+#else
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+ return NULL;
+}
+#endif
+
+static struct orc_entry *orc_find(unsigned long ip)
+{
+ if (!orc_init)
+ return NULL;
+
+ /* For non-init vmlinux addresses, use the fast lookup table: */
+ if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) {
+ unsigned int idx, start, stop;
+
+ idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE;
+
+ if (unlikely((idx >= lookup_num_blocks-1))) {
+ orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%lx\n",
+ idx, lookup_num_blocks, ip);
+ return NULL;
+ }
+
+ start = orc_lookup[idx];
+ stop = orc_lookup[idx + 1] + 1;
+
+ if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) ||
+ (__start_orc_unwind + stop > __stop_orc_unwind))) {
+ orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%lx\n",
+ idx, lookup_num_blocks, start, stop, ip);
+ return NULL;
+ }
+
+ return __orc_find(__start_orc_unwind_ip + start,
+ __start_orc_unwind + start, stop - start, ip);
+ }
+
+ /* vmlinux .init slow lookup: */
+ if (ip >= (unsigned long)_sinittext && ip < (unsigned long)_einittext)
+ return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+ __stop_orc_unwind_ip - __start_orc_unwind_ip, ip);
+
+ /* Module lookup: */
+ return orc_module_find(ip);
+}
+
+static void orc_sort_swap(void *_a, void *_b, int size)
+{
+ struct orc_entry *orc_a, *orc_b;
+ struct orc_entry orc_tmp;
+ int *a = _a, *b = _b, tmp;
+ int delta = _b - _a;
+
+ /* Swap the .orc_unwind_ip entries: */
+ tmp = *a;
+ *a = *b + delta;
+ *b = tmp - delta;
+
+ /* Swap the corresponding .orc_unwind entries: */
+ orc_a = cur_orc_table + (a - cur_orc_ip_table);
+ orc_b = cur_orc_table + (b - cur_orc_ip_table);
+ orc_tmp = *orc_a;
+ *orc_a = *orc_b;
+ *orc_b = orc_tmp;
+}
+
+static int orc_sort_cmp(const void *_a, const void *_b)
+{
+ struct orc_entry *orc_a;
+ const int *a = _a, *b = _b;
+ unsigned long a_val = orc_ip(a);
+ unsigned long b_val = orc_ip(b);
+
+ if (a_val > b_val)
+ return 1;
+ if (a_val < b_val)
+ return -1;
+
+ /*
+ * The "weak" section terminator entries need to always be on the left
+ * to ensure the lookup code skips them in favor of real entries.
+ * These terminator entries exist to handle any gaps created by
+ * whitelisted .o files which didn't get objtool generation.
+ */
+ orc_a = cur_orc_table + (a - cur_orc_ip_table);
+ return orc_a->sp_reg == ORC_REG_UNDEFINED ? -1 : 1;
+}
+
+#ifdef CONFIG_MODULES
+void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
+ void *_orc, size_t orc_size)
+{
+ int *orc_ip = _orc_ip;
+ struct orc_entry *orc = _orc;
+ unsigned int num_entries = orc_ip_size / sizeof(int);
+
+ WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 ||
+ orc_size % sizeof(*orc) != 0 ||
+ num_entries != orc_size / sizeof(*orc));
+
+ /*
+ * The 'cur_orc_*' globals allow the orc_sort_swap() callback to
+ * associate an .orc_unwind_ip table entry with its corresponding
+ * .orc_unwind entry so they can both be swapped.
+ */
+ mutex_lock(&sort_mutex);
+ cur_orc_ip_table = orc_ip;
+ cur_orc_table = orc;
+ sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap);
+ mutex_unlock(&sort_mutex);
+
+ mod->arch.orc_unwind_ip = orc_ip;
+ mod->arch.orc_unwind = orc;
+ mod->arch.num_orcs = num_entries;
+}
+#endif
+
+void __init unwind_init(void)
+{
+ size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip;
+ size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind;
+ size_t num_entries = orc_ip_size / sizeof(int);
+ struct orc_entry *orc;
+ int i;
+
+ if (!num_entries || orc_ip_size % sizeof(int) != 0 ||
+ orc_size % sizeof(struct orc_entry) != 0 ||
+ num_entries != orc_size / sizeof(struct orc_entry)) {
+ orc_warn("WARNING: Bad or missing .orc_unwind table. Disabling unwinder.\n");
+ return;
+ }
+
+ /* Sort the .orc_unwind and .orc_unwind_ip tables: */
+ sort(__start_orc_unwind_ip, num_entries, sizeof(int), orc_sort_cmp,
+ orc_sort_swap);
+
+ /* Initialize the fast lookup table: */
+ lookup_num_blocks = orc_lookup_end - orc_lookup;
+ for (i = 0; i < lookup_num_blocks-1; i++) {
+ orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+ num_entries,
+ LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i));
+ if (!orc) {
+ orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
+ return;
+ }
+
+ orc_lookup[i] = orc - __start_orc_unwind;
+ }
+
+ /* Initialize the ending block: */
+ orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries,
+ LOOKUP_STOP_IP);
+ if (!orc) {
+ orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
+ return;
+ }
+ orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind;
+
+ orc_init = true;
+}
+
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+ if (unwind_done(state))
+ return 0;
+
+ return __kernel_text_address(state->ip) ? state->ip : 0;
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
+unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
+{
+ if (unwind_done(state))
+ return NULL;
+
+ if (state->regs)
+ return &state->regs->ip;
+
+ if (state->sp)
+ return (unsigned long *)state->sp - 1;
+
+ return NULL;
+}
+
+static bool stack_access_ok(struct unwind_state *state, unsigned long addr,
+ size_t len)
+{
+ struct stack_info *info = &state->stack_info;
+
+ /*
+ * If the address isn't on the current stack, switch to the next one.
+ *
+ * We may have to traverse multiple stacks to deal with the possibility
+ * that info->next_sp could point to an empty stack and the address
+ * could be on a subsequent stack.
+ */
+ while (!on_stack(info, (void *)addr, len))
+ if (get_stack_info(info->next_sp, state->task, info,
+ &state->stack_mask))
+ return false;
+
+ return true;
+}
+
+static bool deref_stack_reg(struct unwind_state *state, unsigned long addr,
+ unsigned long *val)
+{
+ if (!stack_access_ok(state, addr, sizeof(long)))
+ return false;
+
+ *val = READ_ONCE_TASK_STACK(state->task, *(unsigned long *)addr);
+ return true;
+}
+
+#define REGS_SIZE (sizeof(struct pt_regs))
+#define SP_OFFSET (offsetof(struct pt_regs, sp))
+#define IRET_REGS_SIZE (REGS_SIZE - offsetof(struct pt_regs, ip))
+#define IRET_SP_OFFSET (SP_OFFSET - offsetof(struct pt_regs, ip))
+
+static bool deref_stack_regs(struct unwind_state *state, unsigned long addr,
+ unsigned long *ip, unsigned long *sp, bool full)
+{
+ size_t regs_size = full ? REGS_SIZE : IRET_REGS_SIZE;
+ size_t sp_offset = full ? SP_OFFSET : IRET_SP_OFFSET;
+ struct pt_regs *regs = (struct pt_regs *)(addr + regs_size - REGS_SIZE);
+
+ if (IS_ENABLED(CONFIG_X86_64)) {
+ if (!stack_access_ok(state, addr, regs_size))
+ return false;
+
+ *ip = regs->ip;
+ *sp = regs->sp;
+
+ return true;
+ }
+
+ if (!stack_access_ok(state, addr, sp_offset))
+ return false;
+
+ *ip = regs->ip;
+
+ if (user_mode(regs)) {
+ if (!stack_access_ok(state, addr + sp_offset,
+ REGS_SIZE - SP_OFFSET))
+ return false;
+
+ *sp = regs->sp;
+ } else
+ *sp = (unsigned long)&regs->sp;
+
+ return true;
+}
+
+bool unwind_next_frame(struct unwind_state *state)
+{
+ unsigned long ip_p, sp, orig_ip, prev_sp = state->sp;
+ enum stack_type prev_type = state->stack_info.type;
+ struct orc_entry *orc;
+ struct pt_regs *ptregs;
+ bool indirect = false;
+
+ if (unwind_done(state))
+ return false;
+
+ /* Don't let modules unload while we're reading their ORC data. */
+ preempt_disable();
+
+ /* Have we reached the end? */
+ if (state->regs && user_mode(state->regs))
+ goto done;
+
+ /*
+ * Find the orc_entry associated with the text address.
+ *
+ * Decrement call return addresses by one so they work for sibling
+ * calls and calls to noreturn functions.
+ */
+ orc = orc_find(state->signal ? state->ip : state->ip - 1);
+ if (!orc || orc->sp_reg == ORC_REG_UNDEFINED)
+ goto done;
+ orig_ip = state->ip;
+
+ /* Find the previous frame's stack: */
+ switch (orc->sp_reg) {
+ case ORC_REG_SP:
+ sp = state->sp + orc->sp_offset;
+ break;
+
+ case ORC_REG_BP:
+ sp = state->bp + orc->sp_offset;
+ break;
+
+ case ORC_REG_SP_INDIRECT:
+ sp = state->sp + orc->sp_offset;
+ indirect = true;
+ break;
+
+ case ORC_REG_BP_INDIRECT:
+ sp = state->bp + orc->sp_offset;
+ indirect = true;
+ break;
+
+ case ORC_REG_R10:
+ if (!state->regs || !state->full_regs) {
+ orc_warn("missing regs for base reg R10 at ip %p\n",
+ (void *)state->ip);
+ goto done;
+ }
+ sp = state->regs->r10;
+ break;
+
+ case ORC_REG_R13:
+ if (!state->regs || !state->full_regs) {
+ orc_warn("missing regs for base reg R13 at ip %p\n",
+ (void *)state->ip);
+ goto done;
+ }
+ sp = state->regs->r13;
+ break;
+
+ case ORC_REG_DI:
+ if (!state->regs || !state->full_regs) {
+ orc_warn("missing regs for base reg DI at ip %p\n",
+ (void *)state->ip);
+ goto done;
+ }
+ sp = state->regs->di;
+ break;
+
+ case ORC_REG_DX:
+ if (!state->regs || !state->full_regs) {
+ orc_warn("missing regs for base reg DX at ip %p\n",
+ (void *)state->ip);
+ goto done;
+ }
+ sp = state->regs->dx;
+ break;
+
+ default:
+ orc_warn("unknown SP base reg %d for ip %p\n",
+ orc->sp_reg, (void *)state->ip);
+ goto done;
+ }
+
+ if (indirect) {
+ if (!deref_stack_reg(state, sp, &sp))
+ goto done;
+ }
+
+ /* Find IP, SP and possibly regs: */
+ switch (orc->type) {
+ case ORC_TYPE_CALL:
+ ip_p = sp - sizeof(long);
+
+ if (!deref_stack_reg(state, ip_p, &state->ip))
+ goto done;
+
+ state->ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
+ state->ip, (void *)ip_p);
+
+ state->sp = sp;
+ state->regs = NULL;
+ state->signal = false;
+ break;
+
+ case ORC_TYPE_REGS:
+ if (!deref_stack_regs(state, sp, &state->ip, &state->sp, true)) {
+ orc_warn("can't dereference registers at %p for ip %p\n",
+ (void *)sp, (void *)orig_ip);
+ goto done;
+ }
+
+ state->regs = (struct pt_regs *)sp;
+ state->full_regs = true;
+ state->signal = true;
+ break;
+
+ case ORC_TYPE_REGS_IRET:
+ if (!deref_stack_regs(state, sp, &state->ip, &state->sp, false)) {
+ orc_warn("can't dereference iret registers at %p for ip %p\n",
+ (void *)sp, (void *)orig_ip);
+ goto done;
+ }
+
+ ptregs = container_of((void *)sp, struct pt_regs, ip);
+ if ((unsigned long)ptregs >= prev_sp &&
+ on_stack(&state->stack_info, ptregs, REGS_SIZE)) {
+ state->regs = ptregs;
+ state->full_regs = false;
+ } else
+ state->regs = NULL;
+
+ state->signal = true;
+ break;
+
+ default:
+ orc_warn("unknown .orc_unwind entry type %d\n", orc->type);
+ break;
+ }
+
+ /* Find BP: */
+ switch (orc->bp_reg) {
+ case ORC_REG_UNDEFINED:
+ if (state->regs && state->full_regs)
+ state->bp = state->regs->bp;
+ break;
+
+ case ORC_REG_PREV_SP:
+ if (!deref_stack_reg(state, sp + orc->bp_offset, &state->bp))
+ goto done;
+ break;
+
+ case ORC_REG_BP:
+ if (!deref_stack_reg(state, state->bp + orc->bp_offset, &state->bp))
+ goto done;
+ break;
+
+ default:
+ orc_warn("unknown BP base reg %d for ip %p\n",
+ orc->bp_reg, (void *)orig_ip);
+ goto done;
+ }
+
+ /* Prevent a recursive loop due to bad ORC data: */
+ if (state->stack_info.type == prev_type &&
+ on_stack(&state->stack_info, (void *)state->sp, sizeof(long)) &&
+ state->sp <= prev_sp) {
+ orc_warn("stack going in the wrong direction? ip=%p\n",
+ (void *)orig_ip);
+ goto done;
+ }
+
+ preempt_enable();
+ return true;
+
+done:
+ preempt_enable();
+ state->stack_info.type = STACK_TYPE_UNKNOWN;
+ return false;
+}
+EXPORT_SYMBOL_GPL(unwind_next_frame);
+
+void __unwind_start(struct unwind_state *state, struct task_struct *task,
+ struct pt_regs *regs, unsigned long *first_frame)
+{
+ memset(state, 0, sizeof(*state));
+ state->task = task;
+
+ /*
+ * Refuse to unwind the stack of a task while it's executing on another
+ * CPU. This check is racy, but that's ok: the unwinder has other
+ * checks to prevent it from going off the rails.
+ */
+ if (task_on_another_cpu(task))
+ goto done;
+
+ if (regs) {
+ if (user_mode(regs))
+ goto done;
+
+ state->ip = regs->ip;
+ state->sp = kernel_stack_pointer(regs);
+ state->bp = regs->bp;
+ state->regs = regs;
+ state->full_regs = true;
+ state->signal = true;
+
+ } else if (task == current) {
+ asm volatile("lea (%%rip), %0\n\t"
+ "mov %%rsp, %1\n\t"
+ "mov %%rbp, %2\n\t"
+ : "=r" (state->ip), "=r" (state->sp),
+ "=r" (state->bp));
+
+ } else {
+ struct inactive_task_frame *frame = (void *)task->thread.sp;
+
+ state->sp = task->thread.sp;
+ state->bp = READ_ONCE_NOCHECK(frame->bp);
+ state->ip = READ_ONCE_NOCHECK(frame->ret_addr);
+ }
+
+ if (get_stack_info((unsigned long *)state->sp, state->task,
+ &state->stack_info, &state->stack_mask))
+ return;
+
+ /*
+ * The caller can provide the address of the first frame directly
+ * (first_frame) or indirectly (regs->sp) to indicate which stack frame
+ * to start unwinding at. Skip ahead until we reach it.
+ */
+
+ /* When starting from regs, skip the regs frame: */
+ if (regs) {
+ unwind_next_frame(state);
+ return;
+ }
+
+ /* Otherwise, skip ahead to the user-specified starting frame: */
+ while (!unwind_done(state) &&
+ (!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
+ state->sp <= (unsigned long)first_frame))
+ unwind_next_frame(state);
+
+ return;
+
+done:
+ state->stack_info.type = STACK_TYPE_UNKNOWN;
+ return;
+}
+EXPORT_SYMBOL_GPL(__unwind_start);
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index c8a3b61be0aa..f05f00acac89 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -24,6 +24,7 @@
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page_types.h>
+#include <asm/orc_lookup.h>
#include <asm/cache.h>
#include <asm/boot.h>
@@ -148,6 +149,8 @@ SECTIONS
BUG_TABLE
+ ORC_UNWIND_TABLE
+
. = ALIGN(PAGE_SIZE);
__vvar_page = .;
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-20 14:28:14 +0300