/* DEBUGCTLMSR bits (others vary by model): */
#define DEBUGCTLMSR_LBR (1UL << 0) /* last branch recording */
+#define DEBUGCTLMSR_BTF_SHIFT 1
#define DEBUGCTLMSR_BTF (1UL << 1) /* single-step on branches */
#define DEBUGCTLMSR_TR (1UL << 6)
#define DEBUGCTLMSR_BTS (1UL << 7)
propagate_user_return_notify(prev_p, next_p);
- if ((tifp ^ tifn) & _TIF_BLOCKSTEP) {
- unsigned long debugctl = get_debugctlmsr();
+ if ((tifp & _TIF_BLOCKSTEP || tifn & _TIF_BLOCKSTEP) &&
+ arch_has_block_step()) {
+ unsigned long debugctl, msk;
+ rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
debugctl &= ~DEBUGCTLMSR_BTF;
- if (tifn & _TIF_BLOCKSTEP)
- debugctl |= DEBUGCTLMSR_BTF;
- update_debugctlmsr(debugctl);
+ msk = tifn & _TIF_BLOCKSTEP;
+ debugctl |= (msk >> TIF_BLOCKSTEP) << DEBUGCTLMSR_BTF_SHIFT;
+ wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
}
if ((tifp ^ tifn) & _TIF_NOTSC) {