RepoMirrors/kpatch
1
0
Fork 0
mirror of https://github.com/dynup/kpatch synced 2025-02-19 19:26:53 +00:00
Code Issues Packages Projects Releases Wiki Activity

Merge pull request #1315 from jpoimboe/static-call-fixes

Browse Source 
Static call fixes
This commit is contained in:
Josh Poimboeuf 2022-11-30 14:58:58 -06:00 committed by GitHub
commit 95f87659c9
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 213 additions and 132 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
kmod/patch/kpatch-macros.h
View File

@ -141,4 +141,15 @@ struct kpatch_post_unpatch_callback {
printk(_fmt, ## __VA_ARGS__); \
})
/*
* KPATCH_STATIC_CALL macro
*
* Replace usages of static_call() with this macro, when create-diff-object
* recommends it due to the original static call key living in a module.
*
* This converts the static call to a regular indirect call.
*/
#define KPATCH_STATIC_CALL(name) \
((typeof(STATIC_CALL_TRAMP(name))*)(STATIC_CALL_KEY(name).func))
#endif /* __KPATCH_MACROS_H_ */

330
kpatch-build/create-diff-object.c
View File

@ -56,7 +56,7 @@
#define DIFF_FATAL(format, ...) \
({ \
fprintf(stderr, "ERROR: %s: " format "\n", childobj, ##__VA_ARGS__); \
err(EXIT_STATUS_DIFF_FATAL, "unreconcilable difference"); \
errx(EXIT_STATUS_DIFF_FATAL, "unreconcilable difference"); \
})
char *childobj;
@ -71,6 +71,8 @@ enum loglevel loglevel = NORMAL;
bool KLP_ARCH;
int jump_label_errors, static_call_errors;
/*******************
* Data structures
* ****************/
@ -78,6 +80,9 @@ struct special_section {
char *name;
enum architecture arch;
int (*group_size)(struct kpatch_elf *kelf, int offset);
bool (*group_filter)(struct lookup_table *lookup,
struct section *relasec, unsigned int offset,
unsigned int size);
};
/*************
@ -2215,120 +2220,10 @@ static int fixup_group_size(struct kpatch_elf *kelf, int offset)
return (int)(rela->addend - offset);
}
static struct special_section special_sections[] = {
{
.name = "__bug_table",
.arch = X86_64 | PPC64 | S390,
.group_size = bug_table_group_size,
},
{
.name = ".fixup",
.arch = X86_64 | PPC64 | S390,
.group_size = fixup_group_size,
},
{
.name = "__ex_table", /* must come after .fixup */
.arch = X86_64 | PPC64 | S390,
.group_size = ex_table_group_size,
},
{
.name = "__jump_table",
.arch = X86_64 | PPC64 | S390,
.group_size = jump_table_group_size,
},
{
.name = ".printk_index",
.arch = X86_64 | PPC64 | S390,
.group_size = printk_index_group_size,
},
{
.name = ".smp_locks",
.arch = X86_64,
.group_size = smp_locks_group_size,
},
{
.name = ".parainstructions",
.arch = X86_64,
.group_size = parainstructions_group_size,
},
{
.name = ".altinstructions",
.arch = X86_64 | S390,
.group_size = altinstructions_group_size,
},
{
.name = ".static_call_sites",
.arch = X86_64,
.group_size = static_call_sites_group_size,
},
{
.name = ".retpoline_sites",
.arch = X86_64,
.group_size = retpoline_sites_group_size,
},
{
.name = ".return_sites",
.arch = X86_64,
.group_size = return_sites_group_size,
},
{
.name = "__ftr_fixup",
.arch = PPC64,
.group_size = fixup_entry_group_size,
},
{
.name = "__mmu_ftr_fixup",
.arch = PPC64,
.group_size = fixup_entry_group_size,
},
{
.name = "__fw_ftr_fixup",
.arch = PPC64,
.group_size = fixup_entry_group_size,
},
{
.name = "__lwsync_fixup",
.arch = PPC64,
.group_size = fixup_lwsync_group_size,
},
{
.name = "__barrier_nospec_fixup",
.arch = PPC64,
.group_size = fixup_barrier_nospec_group_size,
},
{
.name = ".s390_return_mem",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{
.name = ".s390_return_reg",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{
.name = ".s390_indirect_call",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{
.name = ".s390_indirect_branches",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{
.name = ".s390_indirect_jump",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{},
};
static bool should_keep_jump_label(struct lookup_table *lookup,
struct section *relasec,
unsigned int group_offset,
unsigned int group_size,
int *jump_labels_found)
static bool jump_table_group_filter(struct lookup_table *lookup,
struct section *relasec,
unsigned int group_offset,
unsigned int group_size)
{
struct rela *code = NULL, *key = NULL, *rela;
bool tracepoint = false, dynamic_debug = false;
@ -2378,7 +2273,7 @@ static bool should_keep_jump_label(struct lookup_table *lookup,
*/
log_normal("Found a jump label at %s()+0x%lx, using key %s. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.\n",
code->sym->name, code->addend, key->sym->name);
(*jump_labels_found)++;
jump_label_errors++;
return false;
}
@ -2403,12 +2298,12 @@ static bool should_keep_jump_label(struct lookup_table *lookup,
return false;
/*
* This will be upgraded to an error after all jump labels have
* been reported.
* This will be upgraded to an error after all jump label
* errors have been reported.
*/
log_normal("Found a jump label at %s()+0x%lx, using key %s, which is defined in a module. Use static_key_enabled() instead.\n",
code->sym->name, code->addend, key->sym->name);
(*jump_labels_found)++;
jump_label_errors++;
return false;
}
@ -2426,9 +2321,182 @@ static bool should_keep_jump_label(struct lookup_table *lookup,
return true;
}
static bool static_call_sites_group_filter(struct lookup_table *lookup,
struct section *relasec,
unsigned int group_offset,
unsigned int group_size)
{
struct rela *code = NULL, *key = NULL, *rela;
bool tracepoint = false;
struct lookup_result symbol;
int i = 0;
/*
* Here we hard-code knowledge about the contents of the jump_entry
* struct. It has three fields: code, target, and key. Each field has
* a relocation associated with it.
*/
list_for_each_entry(rela, &relasec->relas, list) {
if (rela->offset >= group_offset &&
rela->offset < group_offset + group_size) {
if (i == 0)
code = rela;
else if (i == 1)
key = rela;
i++;
}
}
if (i != 2 || !key || !code)
ERROR("BUG: .static_call_sites has an unexpected format");
if (!strncmp(key->sym->name, "__SCK__tp_func_", 15))
tracepoint = true;
/*
* Static calls are only supported in the case where the corresponding
* static call key lives in vmlinux (see explanation in
* jump_table_group_filter).
*/
if (lookup_symbol(lookup, key->sym, &symbol) &&
strcmp(symbol.objname, "vmlinux")) {
/* The key lives in a module -- not supported */
/* Inert tracepoints are harmless */
if (tracepoint)
return false;
/*
* This will be upgraded to an error after all static call
* errors have been reported.
*/
log_normal("Found a static call at %s()+0x%lx, using key %s, which is defined in a module. Use KPATCH_STATIC_CALL() instead.\n",
code->sym->name, code->addend, key->sym->name);
static_call_errors++;
return false;
}
/* The key lives in vmlinux or the patch module itself */
return true;
}
static struct special_section special_sections[] = {
{
.name = "__bug_table",
.arch = X86_64 | PPC64 | S390,
.group_size = bug_table_group_size,
},
{
.name = ".fixup",
.arch = X86_64 | PPC64 | S390,
.group_size = fixup_group_size,
},
{
.name = "__ex_table", /* must come after .fixup */
.arch = X86_64 | PPC64 | S390,
.group_size = ex_table_group_size,
},
{
.name = "__jump_table",
.arch = X86_64 | PPC64 | S390,
.group_size = jump_table_group_size,
.group_filter = jump_table_group_filter,
},
{
.name = ".printk_index",
.arch = X86_64 | PPC64 | S390,
.group_size = printk_index_group_size,
},
{
.name = ".smp_locks",
.arch = X86_64,
.group_size = smp_locks_group_size,
},
{
.name = ".parainstructions",
.arch = X86_64,
.group_size = parainstructions_group_size,
},
{
.name = ".altinstructions",
.arch = X86_64 | S390,
.group_size = altinstructions_group_size,
},
{
.name = ".static_call_sites",
.arch = X86_64,
.group_size = static_call_sites_group_size,
.group_filter = static_call_sites_group_filter,
},
{
.name = ".retpoline_sites",
.arch = X86_64,
.group_size = retpoline_sites_group_size,
},
{
.name = ".return_sites",
.arch = X86_64,
.group_size = return_sites_group_size,
},
{
.name = "__ftr_fixup",
.arch = PPC64,
.group_size = fixup_entry_group_size,
},
{
.name = "__mmu_ftr_fixup",
.arch = PPC64,
.group_size = fixup_entry_group_size,
},
{
.name = "__fw_ftr_fixup",
.arch = PPC64,
.group_size = fixup_entry_group_size,
},
{
.name = "__lwsync_fixup",
.arch = PPC64,
.group_size = fixup_lwsync_group_size,
},
{
.name = "__barrier_nospec_fixup",
.arch = PPC64,
.group_size = fixup_barrier_nospec_group_size,
},
{
.name = ".s390_return_mem",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{
.name = ".s390_return_reg",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{
.name = ".s390_indirect_call",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{
.name = ".s390_indirect_branches",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{
.name = ".s390_indirect_jump",
.arch = S390,
.group_size = s390_expolines_group_size,
},
{},
};
static bool should_keep_rela_group(struct lookup_table *lookup,
struct section *relasec, unsigned int offset,
unsigned int size, int *jump_labels_found)
unsigned int size)
{
struct rela *rela;
bool found = false;
@ -2448,10 +2516,6 @@ static bool should_keep_rela_group(struct lookup_table *lookup,
if (!found)
return false;
if (!strcmp(relasec->name, ".rela__jump_table"))
return should_keep_jump_label(lookup, relasec, offset, size,
jump_labels_found);
return true;
}
@ -2488,7 +2552,6 @@ static void kpatch_regenerate_special_section(struct kpatch_elf *kelf,
struct rela *rela, *safe;
char *src, *dest;
unsigned int group_size, src_offset, dest_offset;
int jump_labels_found = 0;
LIST_HEAD(newrelas);
@ -2523,8 +2586,11 @@ static void kpatch_regenerate_special_section(struct kpatch_elf *kelf,
if (src_offset + group_size > relasec->base->sh.sh_size)
group_size = (unsigned int)(relasec->base->sh.sh_size - src_offset);
if (!should_keep_rela_group(lookup, relasec, src_offset, group_size,
&jump_labels_found))
if (!should_keep_rela_group(lookup, relasec, src_offset, group_size))
continue;
if (special->group_filter &&
!special->group_filter(lookup, relasec, src_offset, group_size))
continue;
/*
@ -2557,9 +2623,13 @@ static void kpatch_regenerate_special_section(struct kpatch_elf *kelf,
dest_offset += group_size;
}
if (jump_labels_found)
ERROR("Found %d jump label(s) in the patched code. Jump labels aren't currently supported. Use static_key_enabled() instead.",
jump_labels_found);
if (jump_label_errors)
ERROR("Found %d unsupported jump label(s) in the patched code. Use static_key_enabled() instead.",
jump_label_errors);
if (static_call_errors)
ERROR("Found %d unsupported static call(s) in the patched code. Use KPATCH_STATIC_CALL() instead.",
static_call_errors);
if (!dest_offset) {
/* no changed or global functions referenced */

2
kpatch-build/log.h
View File

@ -9,7 +9,7 @@ extern enum loglevel loglevel;
extern char *childobj;
#define ERROR(format, ...) \
err(EXIT_STATUS_ERROR, "ERROR: %s: %s: %d: " format, childobj, __FUNCTION__, __LINE__, ##__VA_ARGS__)
errx(EXIT_STATUS_ERROR, "ERROR: %s: %s: %d: " format, childobj, __FUNCTION__, __LINE__, ##__VA_ARGS__)
#define log_debug(format, ...) log(DEBUG, format, ##__VA_ARGS__)
#define log_normal(format, ...) log(NORMAL, "%s: " format, childobj, ##__VA_ARGS__)

2
test/unit/objs

@ -1 +1 @@
Subproject commit 6485a329826b7299859b246e2f9850ea19f52e77
Subproject commit b1b6cc3c03f7093cfff042574594418125678d8c