From: James Hogan <[email protected]>
Commit 01f728857941 ("target-mips: Status.UX/SX/KX enable 32-bit address
wrapping") added a new hflag MIPS_HFLAG_AWRAP, which indicates that
64-bit addressing is disallowed in the current mode, so hflag users
don't need to worry about the complexities of working that out, for
example checking both MIPS_HFLAG_KSU and MIPS_HFLAG_UX.
However when exceptions are taken outside of exception level,
mips_cpu_do_interrupt() manipulates the env->hflags directly rather than
using compute_hflags() to update them, and this code wasn't updated
accordingly. As a result, when UX is cleared, MIPS_HFLAG_AWRAP is set,
but it doesn't get cleared on entry back into kernel mode due to an
exception. Kernel mode then cannot access the 64-bit segments resulting
in a nested exception loop. The same applies to errors and debug
exceptions.
Fix by updating mips_cpu_do_interrupt() to clear the MIPS_HFLAG_WRAP
flag when necessary, according to compute_hflags().
Fixes: 01f728857941 ("target-mips: Status.UX/SX/KX enable 32-bit...")
Signed-off-by: James Hogan <[email protected]>
Cc: Leon Alrae <[email protected]>
Cc: Aurelien Jarno <[email protected]>
Reviewed-by: Leon Alrae <[email protected]>
Signed-off-by: Leon Alrae <[email protected]>
---
target-mips/helper.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/target-mips/helper.c b/target-mips/helper.c
index b3fe816..118072a 100644
--- a/target-mips/helper.c
+++ b/target-mips/helper.c
@@ -524,6 +524,10 @@ void mips_cpu_do_interrupt(CPUState *cs)
enter_debug_mode:
if (env->insn_flags & ISA_MIPS3) {
env->hflags |= MIPS_HFLAG_64;
+ if (!(env->insn_flags & ISA_MIPS64R6) ||
+ env->CP0_Status & (1 << CP0St_KX)) {
+ env->hflags &= ~MIPS_HFLAG_AWRAP;
+ }
}
env->hflags |= MIPS_HFLAG_DM | MIPS_HFLAG_CP0;
env->hflags &= ~(MIPS_HFLAG_KSU);
@@ -548,6 +552,10 @@ void mips_cpu_do_interrupt(CPUState *cs)
env->CP0_Status |= (1 << CP0St_ERL) | (1 << CP0St_BEV);
if (env->insn_flags & ISA_MIPS3) {
env->hflags |= MIPS_HFLAG_64;
+ if (!(env->insn_flags & ISA_MIPS64R6) ||
+ env->CP0_Status & (1 << CP0St_KX)) {
+ env->hflags &= ~MIPS_HFLAG_AWRAP;
+ }
}
env->hflags |= MIPS_HFLAG_CP0;
env->hflags &= ~(MIPS_HFLAG_KSU);
@@ -725,6 +733,10 @@ void mips_cpu_do_interrupt(CPUState *cs)
env->CP0_Status |= (1 << CP0St_EXL);
if (env->insn_flags & ISA_MIPS3) {
env->hflags |= MIPS_HFLAG_64;
+ if (!(env->insn_flags & ISA_MIPS64R6) ||
+ env->CP0_Status & (1 << CP0St_KX)) {
+ env->hflags &= ~MIPS_HFLAG_AWRAP;
+ }
}
env->hflags |= MIPS_HFLAG_CP0;
env->hflags &= ~(MIPS_HFLAG_KSU);
--
2.1.0
