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linux-user: Fix MIPS ISA transitions during signal handling

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Processors supporting the MIPS16 or microMIPS ISAs set bit 0 in target
addresses to indicate that the target is written using a compressed ISA.

During signal handling, when jumping to or returning from a signal
handler, bit 0 of the destination PC is inspected and MIPS_HFLAG_M16 in
hflags cleared or set accordingly.  Bit 0 of the PC is then cleared.

Signed-off-by: Kwok Cheung Yeung <kcy@codesourcery.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Kwok Cheung Yeung 2013-05-17 14:51:20 -07:00 committed by Aurelien Jarno
parent d8992825ae
commit ea3164aafc
1 changed files with 13 additions and 0 deletions
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13
linux-user/signal.c
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@ -2620,6 +2620,15 @@ get_sigframe(struct target_sigaction *ka, CPUMIPSState *regs, size_t frame_size)
return (sp - frame_size) & ~7;
}
static void mips_set_hflags_isa_mode_from_pc(CPUMIPSState *env)
{
if (env->insn_flags & (ASE_MIPS16 | ASE_MICROMIPS)) {
env->hflags &= ~MIPS_HFLAG_M16;
env->hflags |= (env->active_tc.PC & 1) << MIPS_HFLAG_M16_SHIFT;
env->active_tc.PC &= ~(target_ulong) 1;
}
}
# if defined(TARGET_ABI_MIPSO32)
/* compare linux/arch/mips/kernel/signal.c:setup_frame() */
static void setup_frame(int sig, struct target_sigaction * ka,
@ -2662,6 +2671,7 @@ static void setup_frame(int sig, struct target_sigaction * ka,
* since it returns to userland using eret
* we cannot do this here, and we must set PC directly */
regs->active_tc.PC = regs->active_tc.gpr[25] = ka->_sa_handler;
mips_set_hflags_isa_mode_from_pc(regs);
unlock_user_struct(frame, frame_addr, 1);
return;
@ -2709,6 +2719,7 @@ long do_sigreturn(CPUMIPSState *regs)
#endif
regs->active_tc.PC = regs->CP0_EPC;
mips_set_hflags_isa_mode_from_pc(regs);
/* I am not sure this is right, but it seems to work
* maybe a problem with nested signals ? */
regs->CP0_EPC = 0;
@ -2771,6 +2782,7 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
* since it returns to userland using eret
* we cannot do this here, and we must set PC directly */
env->active_tc.PC = env->active_tc.gpr[25] = ka->_sa_handler;
mips_set_hflags_isa_mode_from_pc(env);
unlock_user_struct(frame, frame_addr, 1);
return;
@ -2804,6 +2816,7 @@ long do_rt_sigreturn(CPUMIPSState *env)
goto badframe;
env->active_tc.PC = env->CP0_EPC;
mips_set_hflags_isa_mode_from_pc(env);
/* I am not sure this is right, but it seems to work
* maybe a problem with nested signals ? */
env->CP0_EPC = 0;