target/riscv: avoid integer overflow in next_page PC check

If the PC is in the last page of the address space, next_page_start
overflows to 0. Fix it.

Reported-by: Richard Henderson <richard.henderson@linaro.org>
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Michael Clark <mjc@sifive.com>
Acked-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Michael Clark <mjc@sifive.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Emilio G. Cota 2018-04-10 11:11:04 -04:00 committed by Richard Henderson
parent e5cd695266
commit 33572269a5

View File

@ -1850,11 +1850,11 @@ void gen_intermediate_code(CPUState *cs, TranslationBlock *tb)
CPURISCVState *env = cs->env_ptr;
DisasContext ctx;
target_ulong pc_start;
target_ulong next_page_start;
target_ulong page_start;
int num_insns;
int max_insns;
pc_start = tb->pc;
next_page_start = (pc_start & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE;
page_start = pc_start & TARGET_PAGE_MASK;
ctx.pc = pc_start;
/* once we have GDB, the rest of the translate.c implementation should be
@ -1904,7 +1904,7 @@ void gen_intermediate_code(CPUState *cs, TranslationBlock *tb)
if (cs->singlestep_enabled) {
break;
}
if (ctx.pc >= next_page_start) {
if (ctx.pc - page_start >= TARGET_PAGE_SIZE) {
break;
}
if (tcg_op_buf_full()) {