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linux-user: Enable Signal Handlers on PPC64
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Enable the 64-bit PowerPC signal handling code that was previously
disabled via #ifdefs.  Specifically:

  - Move the target_mcontext (register save area) structure and
    append it to the 64-bit target_sigcontext structure.  This
    provides the space on the stack for saving and restoring
    context.
  - Define the target_rt_sigframe for 64-bit.
  - Adjust the setup_frame and setup_rt_frame routines to properly
    select the target_mcontext area and trampoline within the stack
    frame; tthis is different for 32-bit and 64-bit implementations.
  - Adjust the do_setcontext stub for 64-bit so that it compiles
    without warnings.

The 64-bit signal handling code is still not functional after this
change; but the 32-bit code is.  Subsequent changes will address
specific issues with the 64-bit code.

Signed-off-by: Tom Musta <tommusta@gmail.com>
[agraf: fix build on 32bit hosts, ppc64abi32]
Signed-off-by: Alexander Graf <agraf@suse.de>
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@agraf
Tom Musta authored and agraf committed Sep 8, 2014
1 parent 7678108 commit 61e75fe
Showing 1 changed file with 73 additions and 48 deletions.
121 changes: 73 additions & 48 deletions linux-user/signal.c
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Expand Up @@ -4325,15 +4325,7 @@ long do_rt_sigreturn(CPUS390XState *env)
return 0;
}

#elif defined(TARGET_PPC) && !defined(TARGET_PPC64)

/* FIXME: Many of the structures are defined for both PPC and PPC64, but
the signal handling is different enough that we haven't implemented
support for PPC64 yet. Hence the restriction above.
There are various #if'd blocks for code for TARGET_PPC64. These
blocks should go away so that we can successfully run 32-bit and
64-bit binaries on a QEMU configured for PPC64. */
#elif defined(TARGET_PPC)

/* Size of dummy stack frame allocated when calling signal handler.
See arch/powerpc/include/asm/ptrace.h. */
Expand All @@ -4343,6 +4335,33 @@ long do_rt_sigreturn(CPUS390XState *env)
#define SIGNAL_FRAMESIZE 64
#endif

/* See arch/powerpc/include/asm/ucontext.h. Only used for 32-bit PPC;
on 64-bit PPC, sigcontext and mcontext are one and the same. */
struct target_mcontext {
target_ulong mc_gregs[48];
/* Includes fpscr. */
uint64_t mc_fregs[33];
target_ulong mc_pad[2];
/* We need to handle Altivec and SPE at the same time, which no
kernel needs to do. Fortunately, the kernel defines this bit to
be Altivec-register-large all the time, rather than trying to
twiddle it based on the specific platform. */
union {
/* SPE vector registers. One extra for SPEFSCR. */
uint32_t spe[33];
/* Altivec vector registers. The packing of VSCR and VRSAVE
varies depending on whether we're PPC64 or not: PPC64 splits
them apart; PPC32 stuffs them together. */
#if defined(TARGET_PPC64)
#define QEMU_NVRREG 34
#else
#define QEMU_NVRREG 33
#endif
ppc_avr_t altivec[QEMU_NVRREG];
#undef QEMU_NVRREG
} mc_vregs __attribute__((__aligned__(16)));
};

/* See arch/powerpc/include/asm/sigcontext.h. */
struct target_sigcontext {
target_ulong _unused[4];
Expand All @@ -4353,7 +4372,9 @@ struct target_sigcontext {
target_ulong handler;
target_ulong oldmask;
target_ulong regs; /* struct pt_regs __user * */
/* TODO: PPC64 includes extra bits here. */
#if defined(TARGET_PPC64)
struct target_mcontext mcontext;
#endif
};

/* Indices for target_mcontext.mc_gregs, below.
Expand Down Expand Up @@ -4408,32 +4429,6 @@ enum {
TARGET_PT_REGS_COUNT = 44
};

/* See arch/powerpc/include/asm/ucontext.h. Only used for 32-bit PPC;
on 64-bit PPC, sigcontext and mcontext are one and the same. */
struct target_mcontext {
target_ulong mc_gregs[48];
/* Includes fpscr. */
uint64_t mc_fregs[33];
target_ulong mc_pad[2];
/* We need to handle Altivec and SPE at the same time, which no
kernel needs to do. Fortunately, the kernel defines this bit to
be Altivec-register-large all the time, rather than trying to
twiddle it based on the specific platform. */
union {
/* SPE vector registers. One extra for SPEFSCR. */
uint32_t spe[33];
/* Altivec vector registers. The packing of VSCR and VRSAVE
varies depending on whether we're PPC64 or not: PPC64 splits
them apart; PPC32 stuffs them together. */
#if defined(TARGET_PPC64)
#define QEMU_NVRREG 34
#else
#define QEMU_NVRREG 33
#endif
ppc_avr_t altivec[QEMU_NVRREG];
#undef QEMU_NVRREG
} mc_vregs __attribute__((__aligned__(16)));
};

struct target_ucontext {
target_ulong tuc_flags;
Expand All @@ -4447,7 +4442,7 @@ struct target_ucontext {
target_sigset_t tuc_sigmask;
#if defined(TARGET_PPC64)
target_sigset_t unused[15]; /* Allow for uc_sigmask growth */
struct target_sigcontext tuc_mcontext;
struct target_sigcontext tuc_sigcontext;
#else
int32_t tuc_maskext[30];
int32_t tuc_pad2[3];
Expand All @@ -4462,12 +4457,32 @@ struct target_sigframe {
int32_t abigap[56];
};

#if defined(TARGET_PPC64)

#define TARGET_TRAMP_SIZE 6

struct target_rt_sigframe {
/* sys_rt_sigreturn requires the ucontext be the first field */
struct target_ucontext uc;
target_ulong _unused[2];
uint32_t trampoline[TARGET_TRAMP_SIZE];
target_ulong pinfo; /* struct siginfo __user * */
target_ulong puc; /* void __user * */
struct target_siginfo info;
/* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
char abigap[288];
} __attribute__((aligned(16)));

#else

struct target_rt_sigframe {
struct target_siginfo info;
struct target_ucontext uc;
int32_t abigap[56];
};

#endif

/* We use the mc_pad field for the signal return trampoline. */
#define tramp mc_pad

Expand Down Expand Up @@ -4667,7 +4682,7 @@ static void setup_frame(int sig, struct target_sigaction *ka,

__put_user(ka->_sa_handler, &sc->handler);
__put_user(set->sig[0], &sc->oldmask);
#if defined(TARGET_PPC64)
#if TARGET_ABI_BITS == 64
__put_user(set->sig[0] >> 32, &sc->_unused[3]);
#else
__put_user(set->sig[1], &sc->_unused[3]);
Expand Down Expand Up @@ -4717,7 +4732,8 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
target_sigset_t *set, CPUPPCState *env)
{
struct target_rt_sigframe *rt_sf;
struct target_mcontext *frame;
uint32_t *trampptr = 0;
struct target_mcontext *mctx = 0;
target_ulong rt_sf_addr, newsp = 0;
int i, err = 0;
int signal;
Expand All @@ -4738,19 +4754,28 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
&rt_sf->uc.tuc_stack.ss_flags);
__put_user(target_sigaltstack_used.ss_size,
&rt_sf->uc.tuc_stack.ss_size);
#if !defined(TARGET_PPC64)
__put_user(h2g (&rt_sf->uc.tuc_mcontext),
&rt_sf->uc.tuc_regs);
#endif
for(i = 0; i < TARGET_NSIG_WORDS; i++) {
__put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
}

frame = &rt_sf->uc.tuc_mcontext;
save_user_regs(env, frame);
encode_trampoline(TARGET_NR_rt_sigreturn, (uint32_t *)&frame->tramp);
#if defined(TARGET_PPC64)
mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
trampptr = &rt_sf->trampoline[0];
#else
mctx = &rt_sf->uc.tuc_mcontext;
trampptr = (uint32_t *)&rt_sf->uc.tuc_mcontext.tramp;
#endif

save_user_regs(env, mctx);
encode_trampoline(TARGET_NR_rt_sigreturn, trampptr);

/* The kernel checks for the presence of a VDSO here. We don't
emulate a vdso, so use a sigreturn system call. */
env->lr = (target_ulong) h2g(frame->tramp);
env->lr = (target_ulong) h2g(trampptr);

/* Turn off all fp exceptions. */
env->fpscr = 0;
Expand Down Expand Up @@ -4795,7 +4820,7 @@ long do_sigreturn(CPUPPCState *env)
goto sigsegv;

#if defined(TARGET_PPC64)
set.sig[0] = sc->oldmask + ((long)(sc->_unused[3]) << 32);
set.sig[0] = sc->oldmask + ((uint64_t)(sc->_unused[3]) << 32);
#else
__get_user(set.sig[0], &sc->oldmask);
__get_user(set.sig[1], &sc->_unused[3]);
Expand Down Expand Up @@ -4823,6 +4848,10 @@ long do_sigreturn(CPUPPCState *env)
/* See arch/powerpc/kernel/signal_32.c. */
static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
{
#if defined(TARGET_PPC64)
fprintf(stderr, "do_setcontext: not implemented\n");
return 0;
#else
struct target_mcontext *mcp;
target_ulong mcp_addr;
sigset_t blocked;
Expand All @@ -4832,10 +4861,6 @@ static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
sizeof (set)))
return 1;

#if defined(TARGET_PPC64)
fprintf (stderr, "do_setcontext: not implemented\n");
return 0;
#else
__get_user(mcp_addr, &ucp->tuc_regs);

if (!lock_user_struct(VERIFY_READ, mcp, mcp_addr, 1))
Expand Down

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