diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/sysreg.h | 11 | ||||
| -rw-r--r-- | arch/arm64/kernel/entry-common.c | 8 |
2 files changed, 15 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 6455db1b54fd..c231d2a3e515 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -1220,10 +1220,19 @@ __val; \ }) +/* + * The "Z" constraint combined with the "%x0" template should be enough + * to force XZR generation if (v) is a constant 0 value but LLVM does not + * yet understand that modifier/constraint combo so a conditional is required + * to nudge the compiler into using XZR as a source for a 0 constant value. + */ #define write_sysreg_s(v, r) do { \ u64 __val = (u64)(v); \ u32 __maybe_unused __check_r = (u32)(r); \ - asm volatile(__msr_s(r, "%x0") : : "rZ" (__val)); \ + if (__builtin_constant_p(__val) && __val == 0) \ + asm volatile(__msr_s(r, "xzr")); \ + else \ + asm volatile(__msr_s(r, "%x0") : : "r" (__val)); \ } while (0) /* diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index f546a914f041..a9c81715ce59 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -697,6 +697,8 @@ static void noinstr el0_breakpt(struct pt_regs *regs, unsigned long esr) static void noinstr el0_softstp(struct pt_regs *regs, unsigned long esr) { + bool step_done; + if (!is_ttbr0_addr(regs->pc)) arm64_apply_bp_hardening(); @@ -707,10 +709,10 @@ static void noinstr el0_softstp(struct pt_regs *regs, unsigned long esr) * If we are stepping a suspended breakpoint there's nothing more to do: * the single-step is complete. */ - if (!try_step_suspended_breakpoints(regs)) { - local_daif_restore(DAIF_PROCCTX); + step_done = try_step_suspended_breakpoints(regs); + local_daif_restore(DAIF_PROCCTX); + if (!step_done) do_el0_softstep(esr, regs); - } arm64_exit_to_user_mode(regs); } |