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Merge branch 'x86/debug' into core/urgent 

Pick up the two pending objtool patches as the next round of objtool fixes
depend on them.
This commit is contained in:
Thomas Gleixner 2019-07-18 20:50:48 +02:00
parent cac9b9a4b0 e55a73251d
commit 54f698f31e
3 changed files with 26 additions and 9 deletions
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5
include/linux/compiler.h
View File

@ -116,9 +116,14 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
".pushsection .discard.unreachable\n\t" \
".long 999b - .\n\t" \
".popsection\n\t"
/* Annotate a C jump table to allow objtool to follow the code flow */
#define __annotate_jump_table __section(".rodata..c_jump_table")
#else
#define annotate_reachable()
#define annotate_unreachable()
#define __annotate_jump_table
#endif
#ifndef ASM_UNREACHABLE

3
kernel/bpf/core.c
View File

@ -1299,7 +1299,7 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
{
#define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y
#define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
static const void *jumptable[256] = {
static const void * const jumptable[256] __annotate_jump_table = {
[0 ... 255] = &&default_label,
/* Now overwrite non-defaults ... */
BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
@ -1558,7 +1558,6 @@ static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
BUG_ON(1);
return 0;
}
STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */
#define PROG_NAME(stack_size) __bpf_prog_run##stack_size
#define DEFINE_BPF_PROG_RUN(stack_size) \

27
tools/objtool/check.c
View File

@ -18,6 +18,8 @@
#define FAKE_JUMP_OFFSET -1
#define C_JUMP_TABLE_SECTION ".rodata..c_jump_table"
struct alternative {
struct list_head list;
struct instruction *insn;
@ -1035,9 +1037,15 @@ static struct rela *find_switch_table(struct objtool_file *file,
/*
* Make sure the .rodata address isn't associated with a
* symbol. gcc jump tables are anonymous data.
* symbol. GCC jump tables are anonymous data.
*
* Also support C jump tables which are in the same format as
* switch jump tables. For objtool to recognize them, they
* need to be placed in the C_JUMP_TABLE_SECTION section. They
* have symbols associated with them.
*/
if (find_symbol_containing(rodata_sec, table_offset))
if (find_symbol_containing(rodata_sec, table_offset) &&
strcmp(rodata_sec->name, C_JUMP_TABLE_SECTION))
continue;
rodata_rela = find_rela_by_dest(rodata_sec, table_offset);
@ -1277,13 +1285,18 @@ static void mark_rodata(struct objtool_file *file)
bool found = false;
/*
* This searches for the .rodata section or multiple .rodata.func_name
* sections if -fdata-sections is being used. The .str.1.1 and .str.1.8
* rodata sections are ignored as they don't contain jump tables.
* Search for the following rodata sections, each of which can
* potentially contain jump tables:
*
* - .rodata: can contain GCC switch tables
* - .rodata.<func>: same, if -fdata-sections is being used
* - .rodata..c_jump_table: contains C annotated jump tables
*
* .rodata.str1.* sections are ignored; they don't contain jump tables.
*/
for_each_sec(file, sec) {
if (!strncmp(sec->name, ".rodata", 7) &&
!strstr(sec->name, ".str1.")) {
if ((!strncmp(sec->name, ".rodata", 7) && !strstr(sec->name, ".str1.")) ||
!strcmp(sec->name, C_JUMP_TABLE_SECTION)) {
sec->rodata = true;
found = true;
}