On 1/8/24 00:22, del...@kernel.org wrote:
From: Helge Deller <del...@gmx.de>

The value of unwind_breg may reference register %r0, but we need to avoid
accessing gr0 directly and use the value 0 instead.

At runtime I've seen unwind_breg being zero with the Linux kernel when
rfi is used to jump to smp_callin().

Signed-off-by: Helge Deller <del...@gmx.de>
---
  target/hppa/mem_helper.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/hppa/mem_helper.c b/target/hppa/mem_helper.c
index 011b192406..42bd0063c0 100644
--- a/target/hppa/mem_helper.c
+++ b/target/hppa/mem_helper.c
@@ -335,7 +335,7 @@ raise_exception_with_ior(CPUHPPAState *env, int excp, 
uintptr_t retaddr,
cpu_restore_state(cs, retaddr); - b = env->gr[env->unwind_breg];
+                b = env->unwind_breg ? env->gr[env->unwind_breg] : 0;
                  b >>= (env->psw & PSW_W ? 62 : 30);
                  env->cr[CR_IOR] |= b << 62;

Reviewed-by: Richard Henderson <richard.hender...@linaro.org>


r~

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