mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-25 22:05:23 +07:00
f14bf6a350
Now that the orc_unwind and orc_unwind_ip tables are sorted at build time, remove the boot time sorting pass. No change in functionality. [ mingo: Rewrote the changelog and code comments. ] Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kbuild@vger.kernel.org Link: https://lkml.kernel.org/r/20191204004633.88660-8-shile.zhang@linux.alibaba.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
663 lines
16 KiB
C
663 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/module.h>
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#include <linux/sort.h>
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#include <asm/ptrace.h>
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#include <asm/stacktrace.h>
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#include <asm/unwind.h>
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#include <asm/orc_types.h>
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#include <asm/orc_lookup.h>
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#define orc_warn(fmt, ...) \
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printk_deferred_once(KERN_WARNING pr_fmt("WARNING: " fmt), ##__VA_ARGS__)
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extern int __start_orc_unwind_ip[];
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extern int __stop_orc_unwind_ip[];
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extern struct orc_entry __start_orc_unwind[];
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extern struct orc_entry __stop_orc_unwind[];
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static DEFINE_MUTEX(sort_mutex);
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int *cur_orc_ip_table = __start_orc_unwind_ip;
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struct orc_entry *cur_orc_table = __start_orc_unwind;
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unsigned int lookup_num_blocks;
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bool orc_init;
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static inline unsigned long orc_ip(const int *ip)
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{
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return (unsigned long)ip + *ip;
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}
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static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table,
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unsigned int num_entries, unsigned long ip)
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{
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int *first = ip_table;
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int *last = ip_table + num_entries - 1;
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int *mid = first, *found = first;
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if (!num_entries)
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return NULL;
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/*
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* Do a binary range search to find the rightmost duplicate of a given
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* starting address. Some entries are section terminators which are
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* "weak" entries for ensuring there are no gaps. They should be
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* ignored when they conflict with a real entry.
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*/
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while (first <= last) {
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mid = first + ((last - first) / 2);
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if (orc_ip(mid) <= ip) {
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found = mid;
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first = mid + 1;
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} else
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last = mid - 1;
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}
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return u_table + (found - ip_table);
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}
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#ifdef CONFIG_MODULES
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static struct orc_entry *orc_module_find(unsigned long ip)
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{
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struct module *mod;
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mod = __module_address(ip);
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if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip)
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return NULL;
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return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind,
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mod->arch.num_orcs, ip);
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}
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#else
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static struct orc_entry *orc_module_find(unsigned long ip)
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{
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return NULL;
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}
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#endif
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#ifdef CONFIG_DYNAMIC_FTRACE
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static struct orc_entry *orc_find(unsigned long ip);
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/*
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* Ftrace dynamic trampolines do not have orc entries of their own.
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* But they are copies of the ftrace entries that are static and
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* defined in ftrace_*.S, which do have orc entries.
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*
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* If the unwinder comes across a ftrace trampoline, then find the
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* ftrace function that was used to create it, and use that ftrace
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* function's orc entry, as the placement of the return code in
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* the stack will be identical.
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*/
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static struct orc_entry *orc_ftrace_find(unsigned long ip)
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{
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struct ftrace_ops *ops;
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unsigned long caller;
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ops = ftrace_ops_trampoline(ip);
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if (!ops)
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return NULL;
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if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
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caller = (unsigned long)ftrace_regs_call;
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else
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caller = (unsigned long)ftrace_call;
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/* Prevent unlikely recursion */
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if (ip == caller)
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return NULL;
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return orc_find(caller);
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}
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#else
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static struct orc_entry *orc_ftrace_find(unsigned long ip)
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{
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return NULL;
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}
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#endif
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/*
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* If we crash with IP==0, the last successfully executed instruction
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* was probably an indirect function call with a NULL function pointer,
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* and we don't have unwind information for NULL.
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* This hardcoded ORC entry for IP==0 allows us to unwind from a NULL function
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* pointer into its parent and then continue normally from there.
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*/
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static struct orc_entry null_orc_entry = {
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.sp_offset = sizeof(long),
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.sp_reg = ORC_REG_SP,
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.bp_reg = ORC_REG_UNDEFINED,
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.type = ORC_TYPE_CALL
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};
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/* Fake frame pointer entry -- used as a fallback for generated code */
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static struct orc_entry orc_fp_entry = {
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.type = ORC_TYPE_CALL,
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.sp_reg = ORC_REG_BP,
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.sp_offset = 16,
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.bp_reg = ORC_REG_PREV_SP,
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.bp_offset = -16,
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.end = 0,
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};
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static struct orc_entry *orc_find(unsigned long ip)
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{
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static struct orc_entry *orc;
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if (!orc_init)
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return NULL;
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if (ip == 0)
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return &null_orc_entry;
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/* For non-init vmlinux addresses, use the fast lookup table: */
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if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) {
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unsigned int idx, start, stop;
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idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE;
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if (unlikely((idx >= lookup_num_blocks-1))) {
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orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%pB\n",
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idx, lookup_num_blocks, (void *)ip);
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return NULL;
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}
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start = orc_lookup[idx];
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stop = orc_lookup[idx + 1] + 1;
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if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) ||
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(__start_orc_unwind + stop > __stop_orc_unwind))) {
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orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%pB\n",
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idx, lookup_num_blocks, start, stop, (void *)ip);
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return NULL;
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}
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return __orc_find(__start_orc_unwind_ip + start,
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__start_orc_unwind + start, stop - start, ip);
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}
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/* vmlinux .init slow lookup: */
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if (init_kernel_text(ip))
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return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
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__stop_orc_unwind_ip - __start_orc_unwind_ip, ip);
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/* Module lookup: */
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orc = orc_module_find(ip);
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if (orc)
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return orc;
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return orc_ftrace_find(ip);
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}
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static void orc_sort_swap(void *_a, void *_b, int size)
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{
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struct orc_entry *orc_a, *orc_b;
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struct orc_entry orc_tmp;
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int *a = _a, *b = _b, tmp;
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int delta = _b - _a;
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/* Swap the .orc_unwind_ip entries: */
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tmp = *a;
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*a = *b + delta;
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*b = tmp - delta;
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/* Swap the corresponding .orc_unwind entries: */
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orc_a = cur_orc_table + (a - cur_orc_ip_table);
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orc_b = cur_orc_table + (b - cur_orc_ip_table);
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orc_tmp = *orc_a;
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*orc_a = *orc_b;
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*orc_b = orc_tmp;
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}
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static int orc_sort_cmp(const void *_a, const void *_b)
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{
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struct orc_entry *orc_a;
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const int *a = _a, *b = _b;
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unsigned long a_val = orc_ip(a);
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unsigned long b_val = orc_ip(b);
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if (a_val > b_val)
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return 1;
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if (a_val < b_val)
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return -1;
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/*
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* The "weak" section terminator entries need to always be on the left
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* to ensure the lookup code skips them in favor of real entries.
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* These terminator entries exist to handle any gaps created by
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* whitelisted .o files which didn't get objtool generation.
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*/
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orc_a = cur_orc_table + (a - cur_orc_ip_table);
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return orc_a->sp_reg == ORC_REG_UNDEFINED && !orc_a->end ? -1 : 1;
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}
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#ifdef CONFIG_MODULES
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void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
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void *_orc, size_t orc_size)
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{
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int *orc_ip = _orc_ip;
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struct orc_entry *orc = _orc;
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unsigned int num_entries = orc_ip_size / sizeof(int);
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WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 ||
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orc_size % sizeof(*orc) != 0 ||
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num_entries != orc_size / sizeof(*orc));
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/*
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* The 'cur_orc_*' globals allow the orc_sort_swap() callback to
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* associate an .orc_unwind_ip table entry with its corresponding
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* .orc_unwind entry so they can both be swapped.
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*/
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mutex_lock(&sort_mutex);
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cur_orc_ip_table = orc_ip;
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cur_orc_table = orc;
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sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap);
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mutex_unlock(&sort_mutex);
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mod->arch.orc_unwind_ip = orc_ip;
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mod->arch.orc_unwind = orc;
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mod->arch.num_orcs = num_entries;
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}
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#endif
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void __init unwind_init(void)
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{
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size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip;
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size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind;
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size_t num_entries = orc_ip_size / sizeof(int);
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struct orc_entry *orc;
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int i;
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if (!num_entries || orc_ip_size % sizeof(int) != 0 ||
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orc_size % sizeof(struct orc_entry) != 0 ||
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num_entries != orc_size / sizeof(struct orc_entry)) {
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orc_warn("WARNING: Bad or missing .orc_unwind table. Disabling unwinder.\n");
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return;
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}
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/*
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* Note, the orc_unwind and orc_unwind_ip tables were already
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* sorted at build time via the 'sorttable' tool.
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* It's ready for binary search straight away, no need to sort it.
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*/
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/* Initialize the fast lookup table: */
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lookup_num_blocks = orc_lookup_end - orc_lookup;
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for (i = 0; i < lookup_num_blocks-1; i++) {
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orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
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num_entries,
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LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i));
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if (!orc) {
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orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
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return;
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}
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orc_lookup[i] = orc - __start_orc_unwind;
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}
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/* Initialize the ending block: */
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orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries,
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LOOKUP_STOP_IP);
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if (!orc) {
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orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
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return;
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}
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orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind;
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orc_init = true;
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}
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unsigned long unwind_get_return_address(struct unwind_state *state)
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{
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if (unwind_done(state))
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return 0;
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return __kernel_text_address(state->ip) ? state->ip : 0;
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}
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EXPORT_SYMBOL_GPL(unwind_get_return_address);
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unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
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{
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if (unwind_done(state))
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return NULL;
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if (state->regs)
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return &state->regs->ip;
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if (state->sp)
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return (unsigned long *)state->sp - 1;
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return NULL;
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}
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static bool stack_access_ok(struct unwind_state *state, unsigned long _addr,
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size_t len)
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{
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struct stack_info *info = &state->stack_info;
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void *addr = (void *)_addr;
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if (!on_stack(info, addr, len) &&
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(get_stack_info(addr, state->task, info, &state->stack_mask)))
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return false;
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return true;
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}
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static bool deref_stack_reg(struct unwind_state *state, unsigned long addr,
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unsigned long *val)
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{
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if (!stack_access_ok(state, addr, sizeof(long)))
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return false;
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*val = READ_ONCE_NOCHECK(*(unsigned long *)addr);
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return true;
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}
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static bool deref_stack_regs(struct unwind_state *state, unsigned long addr,
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unsigned long *ip, unsigned long *sp)
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{
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struct pt_regs *regs = (struct pt_regs *)addr;
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/* x86-32 support will be more complicated due to the ®s->sp hack */
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BUILD_BUG_ON(IS_ENABLED(CONFIG_X86_32));
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if (!stack_access_ok(state, addr, sizeof(struct pt_regs)))
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return false;
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*ip = regs->ip;
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*sp = regs->sp;
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return true;
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}
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static bool deref_stack_iret_regs(struct unwind_state *state, unsigned long addr,
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unsigned long *ip, unsigned long *sp)
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{
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struct pt_regs *regs = (void *)addr - IRET_FRAME_OFFSET;
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if (!stack_access_ok(state, addr, IRET_FRAME_SIZE))
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return false;
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*ip = regs->ip;
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*sp = regs->sp;
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return true;
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}
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bool unwind_next_frame(struct unwind_state *state)
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{
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unsigned long ip_p, sp, orig_ip = state->ip, prev_sp = state->sp;
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enum stack_type prev_type = state->stack_info.type;
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struct orc_entry *orc;
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bool indirect = false;
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if (unwind_done(state))
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return false;
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/* Don't let modules unload while we're reading their ORC data. */
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preempt_disable();
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/* End-of-stack check for user tasks: */
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if (state->regs && user_mode(state->regs))
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goto the_end;
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/*
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* Find the orc_entry associated with the text address.
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*
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* Decrement call return addresses by one so they work for sibling
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* calls and calls to noreturn functions.
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*/
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orc = orc_find(state->signal ? state->ip : state->ip - 1);
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if (!orc) {
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/*
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* As a fallback, try to assume this code uses a frame pointer.
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* This is useful for generated code, like BPF, which ORC
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* doesn't know about. This is just a guess, so the rest of
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* the unwind is no longer considered reliable.
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*/
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orc = &orc_fp_entry;
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state->error = true;
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}
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/* End-of-stack check for kernel threads: */
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if (orc->sp_reg == ORC_REG_UNDEFINED) {
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if (!orc->end)
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goto err;
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goto the_end;
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}
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/* Find the previous frame's stack: */
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switch (orc->sp_reg) {
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case ORC_REG_SP:
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sp = state->sp + orc->sp_offset;
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break;
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case ORC_REG_BP:
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sp = state->bp + orc->sp_offset;
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break;
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case ORC_REG_SP_INDIRECT:
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sp = state->sp + orc->sp_offset;
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indirect = true;
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break;
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case ORC_REG_BP_INDIRECT:
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sp = state->bp + orc->sp_offset;
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indirect = true;
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break;
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case ORC_REG_R10:
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if (!state->regs || !state->full_regs) {
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orc_warn("missing regs for base reg R10 at ip %pB\n",
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(void *)state->ip);
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goto err;
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}
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sp = state->regs->r10;
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break;
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case ORC_REG_R13:
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if (!state->regs || !state->full_regs) {
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orc_warn("missing regs for base reg R13 at ip %pB\n",
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(void *)state->ip);
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goto err;
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}
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sp = state->regs->r13;
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break;
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case ORC_REG_DI:
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if (!state->regs || !state->full_regs) {
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orc_warn("missing regs for base reg DI at ip %pB\n",
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(void *)state->ip);
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goto err;
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}
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sp = state->regs->di;
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break;
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case ORC_REG_DX:
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if (!state->regs || !state->full_regs) {
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orc_warn("missing regs for base reg DX at ip %pB\n",
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(void *)state->ip);
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goto err;
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}
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sp = state->regs->dx;
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break;
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default:
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orc_warn("unknown SP base reg %d for ip %pB\n",
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orc->sp_reg, (void *)state->ip);
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goto err;
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}
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if (indirect) {
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if (!deref_stack_reg(state, sp, &sp))
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goto err;
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}
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/* Find IP, SP and possibly regs: */
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switch (orc->type) {
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case ORC_TYPE_CALL:
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ip_p = sp - sizeof(long);
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if (!deref_stack_reg(state, ip_p, &state->ip))
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goto err;
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|
|
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)) {
|
|
orc_warn("can't dereference registers at %p for ip %pB\n",
|
|
(void *)sp, (void *)orig_ip);
|
|
goto err;
|
|
}
|
|
|
|
state->regs = (struct pt_regs *)sp;
|
|
state->full_regs = true;
|
|
state->signal = true;
|
|
break;
|
|
|
|
case ORC_TYPE_REGS_IRET:
|
|
if (!deref_stack_iret_regs(state, sp, &state->ip, &state->sp)) {
|
|
orc_warn("can't dereference iret registers at %p for ip %pB\n",
|
|
(void *)sp, (void *)orig_ip);
|
|
goto err;
|
|
}
|
|
|
|
state->regs = (void *)sp - IRET_FRAME_OFFSET;
|
|
state->full_regs = false;
|
|
state->signal = true;
|
|
break;
|
|
|
|
default:
|
|
orc_warn("unknown .orc_unwind entry type %d for ip %pB\n",
|
|
orc->type, (void *)orig_ip);
|
|
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 err;
|
|
break;
|
|
|
|
case ORC_REG_BP:
|
|
if (!deref_stack_reg(state, state->bp + orc->bp_offset, &state->bp))
|
|
goto err;
|
|
break;
|
|
|
|
default:
|
|
orc_warn("unknown BP base reg %d for ip %pB\n",
|
|
orc->bp_reg, (void *)orig_ip);
|
|
goto err;
|
|
}
|
|
|
|
/* 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=%pB\n",
|
|
(void *)orig_ip);
|
|
goto err;
|
|
}
|
|
|
|
preempt_enable();
|
|
return true;
|
|
|
|
err:
|
|
state->error = true;
|
|
|
|
the_end:
|
|
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 = regs->sp;
|
|
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)) {
|
|
/*
|
|
* We weren't on a valid stack. It's possible that
|
|
* we overflowed a valid stack into a guard page.
|
|
* See if the next page up is valid so that we can
|
|
* generate some kind of backtrace if this happens.
|
|
*/
|
|
void *next_page = (void *)PAGE_ALIGN((unsigned long)state->sp);
|
|
if (get_stack_info(next_page, 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);
|