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s390: introduce nospec_uses_trampoline() 

and replace all of the "__is_defined(CC_USING_EXPOLINE) && !nospec_disable"
occurrences.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Sven Schnelle 2021-10-04 08:51:06 +02:00 committed by Vasily Gorbik
parent 26c21aa485
commit 5d17d4ed7e
4 changed files with 10 additions and 5 deletions
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5
arch/s390/include/asm/nospec-branch.h
View File

@ -12,6 +12,11 @@ void nospec_init_branches(void);
void nospec_auto_detect(void);
void nospec_revert(s32 *start, s32 *end);
static inline bool nospec_uses_trampoline(void)
{
return __is_defined(CC_USING_EXPOLINE) && !nospec_disable;
}
#endif /* __ASSEMBLY__ */
#endif /* _ASM_S390_EXPOLINE_H */

2
arch/s390/kernel/nospec-branch.c
View File

@ -38,7 +38,7 @@ static int __init nospec_report(void)
{
if (test_facility(156))
pr_info("Spectre V2 mitigation: etokens\n");
if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable)
if (nospec_uses_trampoline())
pr_info("Spectre V2 mitigation: execute trampolines\n");
if (__test_facility(82, alt_stfle_fac_list))
pr_info("Spectre V2 mitigation: limited branch prediction\n");

2
arch/s390/kernel/nospec-sysfs.c
View File

@ -15,7 +15,7 @@ ssize_t cpu_show_spectre_v2(struct device *dev,
{
if (test_facility(156))
return sprintf(buf, "Mitigation: etokens\n");
if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable)
if (nospec_uses_trampoline())
return sprintf(buf, "Mitigation: execute trampolines\n");
if (__test_facility(82, alt_stfle_fac_list))
return sprintf(buf, "Mitigation: limited branch prediction\n");

6
arch/s390/net/bpf_jit_comp.c
View File

@ -567,7 +567,7 @@ static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth)
EMIT4(0xb9040000, REG_2, BPF_REG_0);
/* Restore registers */
save_restore_regs(jit, REGS_RESTORE, stack_depth);
if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable) {
if (nospec_uses_trampoline()) {
jit->r14_thunk_ip = jit->prg;
/* Generate __s390_indirect_jump_r14 thunk */
if (test_facility(35)) {
@ -585,7 +585,7 @@ static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth)
/* br %r14 */
_EMIT2(0x07fe);
if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable &&
if ((nospec_uses_trampoline()) &&
(is_first_pass(jit) || (jit->seen & SEEN_FUNC))) {
jit->r1_thunk_ip = jit->prg;
/* Generate __s390_indirect_jump_r1 thunk */
@ -1332,7 +1332,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
jit->seen |= SEEN_FUNC;
/* lgrl %w1,func */
EMIT6_PCREL_RILB(0xc4080000, REG_W1, _EMIT_CONST_U64(func));
if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable) {
if (nospec_uses_trampoline()) {
/* brasl %r14,__s390_indirect_jump_r1 */
EMIT6_PCREL_RILB(0xc0050000, REG_14, jit->r1_thunk_ip);
} else {