This prevents a load reservation from being placed in one context/process,
then being used in another, resulting in an SC succeeding incorrectly and
breaking atomics.
Signed-off-by: Joel Sing <joel@sing.id.au>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
env->pc = env->resetvec;
#endif
cs->exception_index = EXCP_NONE;
+ env->load_res = -1;
set_default_nan_mode(1, &env->fp_status);
}
}
/* tlb_flush is unnecessary as mode is contained in mmu_idx */
env->priv = newpriv;
+
+ /*
+ * Clear the load reservation - otherwise a reservation placed in one
+ * context/process can be used by another, resulting in an SC succeeding
+ * incorrectly. Version 2.2 of the ISA specification explicitly requires
+ * this behaviour, while later revisions say that the kernel "should" use
+ * an SC instruction to force the yielding of a load reservation on a
+ * preemptive context switch. As a result, do both.
+ */
+ env->load_res = -1;
}
/* get_physical_address - get the physical address for this virtual address
gen_set_label(l1);
/*
- * Address comparion failure. However, we still need to
+ * Address comparison failure. However, we still need to
* provide the memory barrier implied by AQ/RL.
*/
tcg_gen_mb(TCG_MO_ALL + a->aq * TCG_BAR_LDAQ + a->rl * TCG_BAR_STRL);
gen_set_gpr(a->rd, dat);
gen_set_label(l2);
+ /*
+ * Clear the load reservation, since an SC must fail if there is
+ * an SC to any address, in between an LR and SC pair.
+ */
+ tcg_gen_movi_tl(load_res, -1);
+
tcg_temp_free(dat);
tcg_temp_free(src1);
tcg_temp_free(src2);