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qemu/linux-user/ppc/signal.c
Richard Henderson fa97e38eed linux-user/ppc: Implement swapcontext syscall 
This allows the tests generated by debian-powerpc-user-cross
to function properly, especially tests/test-coroutine.

Technically this syscall is available to both ppc32 and ppc64,
but only ppc32 glibc actually uses it.  Thus the ppc64 path is
untested.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20180718200648.22529-1-richard.henderson@linaro.org>
2018-07-22 21:33:45 +02:00

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/*
* Emulation of Linux signals
*
* Copyright (c) 2003 Fabrice Bellard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu.h"
#include "signal-common.h"
#include "linux-user/trace.h"
/* Size of dummy stack frame allocated when calling signal handler.
See arch/powerpc/include/asm/ptrace.h. */
#if defined(TARGET_PPC64)
#define SIGNAL_FRAMESIZE 128
#else
#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];
#if defined(TARGET_PPC64)
/* Pointer to the vector regs */
target_ulong v_regs;
#else
target_ulong mc_pad[2];
#endif
/* 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.
We also need to account for the VSX registers on PPC64
*/
#if defined(TARGET_PPC64)
#define QEMU_NVRREG (34 + 16)
/* On ppc64, this mcontext structure is naturally *unaligned*,
* or rather it is aligned on a 8 bytes boundary but not on
* a 16 bytes one. This pad fixes it up. This is also why the
* vector regs are referenced by the v_regs pointer above so
* any amount of padding can be added here
*/
target_ulong pad;
#else
/* On ppc32, we are already aligned to 16 bytes */
#define QEMU_NVRREG 33
#endif
/* We cannot use ppc_avr_t here as we do *not* want the implied
* 16-bytes alignment that would result from it. This would have
* the effect of making the whole struct target_mcontext aligned
* which breaks the layout of struct target_ucontext on ppc64.
*/
uint64_t altivec[QEMU_NVRREG][2];
#undef QEMU_NVRREG
} mc_vregs;
};
/* See arch/powerpc/include/asm/sigcontext.h. */
struct target_sigcontext {
target_ulong _unused[4];
int32_t signal;
#if defined(TARGET_PPC64)
int32_t pad0;
#endif
target_ulong handler;
target_ulong oldmask;
target_ulong regs; /* struct pt_regs __user * */
#if defined(TARGET_PPC64)
struct target_mcontext mcontext;
#endif
};
/* Indices for target_mcontext.mc_gregs, below.
See arch/powerpc/include/asm/ptrace.h for details. */
enum {
TARGET_PT_R0 = 0,
TARGET_PT_R1 = 1,
TARGET_PT_R2 = 2,
TARGET_PT_R3 = 3,
TARGET_PT_R4 = 4,
TARGET_PT_R5 = 5,
TARGET_PT_R6 = 6,
TARGET_PT_R7 = 7,
TARGET_PT_R8 = 8,
TARGET_PT_R9 = 9,
TARGET_PT_R10 = 10,
TARGET_PT_R11 = 11,
TARGET_PT_R12 = 12,
TARGET_PT_R13 = 13,
TARGET_PT_R14 = 14,
TARGET_PT_R15 = 15,
TARGET_PT_R16 = 16,
TARGET_PT_R17 = 17,
TARGET_PT_R18 = 18,
TARGET_PT_R19 = 19,
TARGET_PT_R20 = 20,
TARGET_PT_R21 = 21,
TARGET_PT_R22 = 22,
TARGET_PT_R23 = 23,
TARGET_PT_R24 = 24,
TARGET_PT_R25 = 25,
TARGET_PT_R26 = 26,
TARGET_PT_R27 = 27,
TARGET_PT_R28 = 28,
TARGET_PT_R29 = 29,
TARGET_PT_R30 = 30,
TARGET_PT_R31 = 31,
TARGET_PT_NIP = 32,
TARGET_PT_MSR = 33,
TARGET_PT_ORIG_R3 = 34,
TARGET_PT_CTR = 35,
TARGET_PT_LNK = 36,
TARGET_PT_XER = 37,
TARGET_PT_CCR = 38,
/* Yes, there are two registers with #39. One is 64-bit only. */
TARGET_PT_MQ = 39,
TARGET_PT_SOFTE = 39,
TARGET_PT_TRAP = 40,
TARGET_PT_DAR = 41,
TARGET_PT_DSISR = 42,
TARGET_PT_RESULT = 43,
TARGET_PT_REGS_COUNT = 44
};
struct target_ucontext {
target_ulong tuc_flags;
target_ulong tuc_link; /* ucontext_t __user * */
struct target_sigaltstack tuc_stack;
#if !defined(TARGET_PPC64)
int32_t tuc_pad[7];
target_ulong tuc_regs; /* struct mcontext __user *
points to uc_mcontext field */
#endif
target_sigset_t tuc_sigmask;
#if defined(TARGET_PPC64)
target_sigset_t unused[15]; /* Allow for uc_sigmask growth */
struct target_sigcontext tuc_sigcontext;
#else
int32_t tuc_maskext[30];
int32_t tuc_pad2[3];
struct target_mcontext tuc_mcontext;
#endif
};
/* See arch/powerpc/kernel/signal_32.c. */
struct target_sigframe {
struct target_sigcontext sctx;
struct target_mcontext mctx;
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
#if defined(TARGET_PPC64)
struct target_func_ptr {
target_ulong entry;
target_ulong toc;
};
#endif
/* We use the mc_pad field for the signal return trampoline. */
#define tramp mc_pad
/* See arch/powerpc/kernel/signal.c. */
static target_ulong get_sigframe(struct target_sigaction *ka,
CPUPPCState *env,
int frame_size)
{
target_ulong oldsp;
oldsp = target_sigsp(get_sp_from_cpustate(env), ka);
return (oldsp - frame_size) & ~0xFUL;
}
#if ((defined(TARGET_WORDS_BIGENDIAN) && defined(HOST_WORDS_BIGENDIAN)) || \
(!defined(HOST_WORDS_BIGENDIAN) && !defined(TARGET_WORDS_BIGENDIAN)))
#define PPC_VEC_HI 0
#define PPC_VEC_LO 1
#else
#define PPC_VEC_HI 1
#define PPC_VEC_LO 0
#endif
static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame)
{
target_ulong msr = env->msr;
int i;
target_ulong ccr = 0;
/* In general, the kernel attempts to be intelligent about what it
needs to save for Altivec/FP/SPE registers. We don't care that
much, so we just go ahead and save everything. */
/* Save general registers. */
for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
__put_user(env->gpr[i], &frame->mc_gregs[i]);
}
__put_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
__put_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
__put_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
__put_user(env->xer, &frame->mc_gregs[TARGET_PT_XER]);
for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
ccr |= env->crf[i] << (32 - ((i + 1) * 4));
}
__put_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
/* Save Altivec registers if necessary. */
if (env->insns_flags & PPC_ALTIVEC) {
uint32_t *vrsave;
for (i = 0; i < ARRAY_SIZE(env->avr); i++) {
ppc_avr_t *avr = &env->avr[i];
ppc_avr_t *vreg = (ppc_avr_t *)&frame->mc_vregs.altivec[i];
__put_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
__put_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
}
/* Set MSR_VR in the saved MSR value to indicate that
frame->mc_vregs contains valid data. */
msr |= MSR_VR;
#if defined(TARGET_PPC64)
vrsave = (uint32_t *)&frame->mc_vregs.altivec[33];
/* 64-bit needs to put a pointer to the vectors in the frame */
__put_user(h2g(frame->mc_vregs.altivec), &frame->v_regs);
#else
vrsave = (uint32_t *)&frame->mc_vregs.altivec[32];
#endif
__put_user((uint32_t)env->spr[SPR_VRSAVE], vrsave);
}
/* Save VSX second halves */
if (env->insns_flags2 & PPC2_VSX) {
uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
for (i = 0; i < ARRAY_SIZE(env->vsr); i++) {
__put_user(env->vsr[i], &vsregs[i]);
}
}
/* Save floating point registers. */
if (env->insns_flags & PPC_FLOAT) {
for (i = 0; i < ARRAY_SIZE(env->fpr); i++) {
__put_user(env->fpr[i], &frame->mc_fregs[i]);
}
__put_user((uint64_t) env->fpscr, &frame->mc_fregs[32]);
}
/* Save SPE registers. The kernel only saves the high half. */
if (env->insns_flags & PPC_SPE) {
#if defined(TARGET_PPC64)
for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
__put_user(env->gpr[i] >> 32, &frame->mc_vregs.spe[i]);
}
#else
for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
__put_user(env->gprh[i], &frame->mc_vregs.spe[i]);
}
#endif
/* Set MSR_SPE in the saved MSR value to indicate that
frame->mc_vregs contains valid data. */
msr |= MSR_SPE;
__put_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
}
/* Store MSR. */
__put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
}
static void encode_trampoline(int sigret, uint32_t *tramp)
{
/* Set up the sigreturn trampoline: li r0,sigret; sc. */
if (sigret) {
__put_user(0x38000000 | sigret, &tramp[0]);
__put_user(0x44000002, &tramp[1]);
}
}
static void restore_user_regs(CPUPPCState *env,
struct target_mcontext *frame, int sig)
{
target_ulong save_r2 = 0;
target_ulong msr;
target_ulong ccr;
int i;
if (!sig) {
save_r2 = env->gpr[2];
}
/* Restore general registers. */
for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
__get_user(env->gpr[i], &frame->mc_gregs[i]);
}
__get_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
__get_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
__get_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
__get_user(env->xer, &frame->mc_gregs[TARGET_PT_XER]);
__get_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
env->crf[i] = (ccr >> (32 - ((i + 1) * 4))) & 0xf;
}
if (!sig) {
env->gpr[2] = save_r2;
}
/* Restore MSR. */
__get_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
/* If doing signal return, restore the previous little-endian mode. */
if (sig)
env->msr = (env->msr & ~(1ull << MSR_LE)) | (msr & (1ull << MSR_LE));
/* Restore Altivec registers if necessary. */
if (env->insns_flags & PPC_ALTIVEC) {
ppc_avr_t *v_regs;
uint32_t *vrsave;
#if defined(TARGET_PPC64)
uint64_t v_addr;
/* 64-bit needs to recover the pointer to the vectors from the frame */
__get_user(v_addr, &frame->v_regs);
v_regs = g2h(v_addr);
#else
v_regs = (ppc_avr_t *)frame->mc_vregs.altivec;
#endif
for (i = 0; i < ARRAY_SIZE(env->avr); i++) {
ppc_avr_t *avr = &env->avr[i];
ppc_avr_t *vreg = &v_regs[i];
__get_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
__get_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
}
/* Set MSR_VEC in the saved MSR value to indicate that
frame->mc_vregs contains valid data. */
#if defined(TARGET_PPC64)
vrsave = (uint32_t *)&v_regs[33];
#else
vrsave = (uint32_t *)&v_regs[32];
#endif
__get_user(env->spr[SPR_VRSAVE], vrsave);
}
/* Restore VSX second halves */
if (env->insns_flags2 & PPC2_VSX) {
uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
for (i = 0; i < ARRAY_SIZE(env->vsr); i++) {
__get_user(env->vsr[i], &vsregs[i]);
}
}
/* Restore floating point registers. */
if (env->insns_flags & PPC_FLOAT) {
uint64_t fpscr;
for (i = 0; i < ARRAY_SIZE(env->fpr); i++) {
__get_user(env->fpr[i], &frame->mc_fregs[i]);
}
__get_user(fpscr, &frame->mc_fregs[32]);
env->fpscr = (uint32_t) fpscr;
}
/* Save SPE registers. The kernel only saves the high half. */
if (env->insns_flags & PPC_SPE) {
#if defined(TARGET_PPC64)
for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
uint32_t hi;
__get_user(hi, &frame->mc_vregs.spe[i]);
env->gpr[i] = ((uint64_t)hi << 32) | ((uint32_t) env->gpr[i]);
}
#else
for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
__get_user(env->gprh[i], &frame->mc_vregs.spe[i]);
}
#endif
__get_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
}
}
#if !defined(TARGET_PPC64)
void setup_frame(int sig, struct target_sigaction *ka,
target_sigset_t *set, CPUPPCState *env)
{
struct target_sigframe *frame;
struct target_sigcontext *sc;
target_ulong frame_addr, newsp;
int err = 0;
frame_addr = get_sigframe(ka, env, sizeof(*frame));
trace_user_setup_frame(env, frame_addr);
if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 1))
goto sigsegv;
sc = &frame->sctx;
__put_user(ka->_sa_handler, &sc->handler);
__put_user(set->sig[0], &sc->oldmask);
__put_user(set->sig[1], &sc->_unused[3]);
__put_user(h2g(&frame->mctx), &sc->regs);
__put_user(sig, &sc->signal);
/* Save user regs. */
save_user_regs(env, &frame->mctx);
/* Construct the trampoline code on the stack. */
encode_trampoline(TARGET_NR_sigreturn, (uint32_t *)&frame->mctx.tramp);
/* 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->mctx.tramp);
/* Turn off all fp exceptions. */
env->fpscr = 0;
/* Create a stack frame for the caller of the handler. */
newsp = frame_addr - SIGNAL_FRAMESIZE;
err |= put_user(env->gpr[1], newsp, target_ulong);
if (err)
goto sigsegv;
/* Set up registers for signal handler. */
env->gpr[1] = newsp;
env->gpr[3] = sig;
env->gpr[4] = frame_addr + offsetof(struct target_sigframe, sctx);
env->nip = (target_ulong) ka->_sa_handler;
/* Signal handlers are entered in big-endian mode. */
env->msr &= ~(1ull << MSR_LE);
unlock_user_struct(frame, frame_addr, 1);
return;
sigsegv:
unlock_user_struct(frame, frame_addr, 1);
force_sigsegv(sig);
}
#endif /* !defined(TARGET_PPC64) */
void setup_rt_frame(int sig, struct target_sigaction *ka,
target_siginfo_t *info,
target_sigset_t *set, CPUPPCState *env)
{
struct target_rt_sigframe *rt_sf;
uint32_t *trampptr = 0;
struct target_mcontext *mctx = 0;
target_ulong rt_sf_addr, newsp = 0;
int i, err = 0;
#if defined(TARGET_PPC64)
struct target_sigcontext *sc = 0;
struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
#endif
rt_sf_addr = get_sigframe(ka, env, sizeof(*rt_sf));
if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
goto sigsegv;
tswap_siginfo(&rt_sf->info, info);
__put_user(0, &rt_sf->uc.tuc_flags);
__put_user(0, &rt_sf->uc.tuc_link);
target_save_altstack(&rt_sf->uc.tuc_stack, env);
#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]);
}
#if defined(TARGET_PPC64)
mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
trampptr = &rt_sf->trampoline[0];
sc = &rt_sf->uc.tuc_sigcontext;
__put_user(h2g(mctx), &sc->regs);
__put_user(sig, &sc->signal);
#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(trampptr);
/* Turn off all fp exceptions. */
env->fpscr = 0;
/* Create a stack frame for the caller of the handler. */
newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + 16);
err |= put_user(env->gpr[1], newsp, target_ulong);
if (err)
goto sigsegv;
/* Set up registers for signal handler. */
env->gpr[1] = newsp;
env->gpr[3] = (target_ulong) sig;
env->gpr[4] = (target_ulong) h2g(&rt_sf->info);
env->gpr[5] = (target_ulong) h2g(&rt_sf->uc);
env->gpr[6] = (target_ulong) h2g(rt_sf);
#if defined(TARGET_PPC64)
if (get_ppc64_abi(image) < 2) {
/* ELFv1 PPC64 function pointers are pointers to OPD entries. */
struct target_func_ptr *handler =
(struct target_func_ptr *)g2h(ka->_sa_handler);
env->nip = tswapl(handler->entry);
env->gpr[2] = tswapl(handler->toc);
} else {
/* ELFv2 PPC64 function pointers are entry points, but R12
* must also be set */
env->nip = tswapl((target_ulong) ka->_sa_handler);
env->gpr[12] = env->nip;
}
#else
env->nip = (target_ulong) ka->_sa_handler;
#endif
/* Signal handlers are entered in big-endian mode. */
env->msr &= ~(1ull << MSR_LE);
unlock_user_struct(rt_sf, rt_sf_addr, 1);
return;
sigsegv:
unlock_user_struct(rt_sf, rt_sf_addr, 1);
force_sigsegv(sig);
}
#if !defined(TARGET_PPC64)
long do_sigreturn(CPUPPCState *env)
{
struct target_sigcontext *sc = NULL;
struct target_mcontext *sr = NULL;
target_ulong sr_addr = 0, sc_addr;
sigset_t blocked;
target_sigset_t set;
sc_addr = env->gpr[1] + SIGNAL_FRAMESIZE;
if (!lock_user_struct(VERIFY_READ, sc, sc_addr, 1))
goto sigsegv;
#if defined(TARGET_PPC64)
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]);
#endif
target_to_host_sigset_internal(&blocked, &set);
set_sigmask(&blocked);
__get_user(sr_addr, &sc->regs);
if (!lock_user_struct(VERIFY_READ, sr, sr_addr, 1))
goto sigsegv;
restore_user_regs(env, sr, 1);
unlock_user_struct(sr, sr_addr, 1);
unlock_user_struct(sc, sc_addr, 1);
return -TARGET_QEMU_ESIGRETURN;
sigsegv:
unlock_user_struct(sr, sr_addr, 1);
unlock_user_struct(sc, sc_addr, 1);
force_sig(TARGET_SIGSEGV);
return -TARGET_QEMU_ESIGRETURN;
}
#endif /* !defined(TARGET_PPC64) */
/* See arch/powerpc/kernel/signal_32.c. */
static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
{
struct target_mcontext *mcp;
target_ulong mcp_addr;
sigset_t blocked;
target_sigset_t set;
if (copy_from_user(&set, h2g(ucp) + offsetof(struct target_ucontext, tuc_sigmask),
sizeof (set)))
return 1;
#if defined(TARGET_PPC64)
mcp_addr = h2g(ucp) +
offsetof(struct target_ucontext, tuc_sigcontext.mcontext);
#else
__get_user(mcp_addr, &ucp->tuc_regs);
#endif
if (!lock_user_struct(VERIFY_READ, mcp, mcp_addr, 1))
return 1;
target_to_host_sigset_internal(&blocked, &set);
set_sigmask(&blocked);
restore_user_regs(env, mcp, sig);
unlock_user_struct(mcp, mcp_addr, 1);
return 0;
}
long do_rt_sigreturn(CPUPPCState *env)
{
struct target_rt_sigframe *rt_sf = NULL;
target_ulong rt_sf_addr;
rt_sf_addr = env->gpr[1] + SIGNAL_FRAMESIZE + 16;
if (!lock_user_struct(VERIFY_READ, rt_sf, rt_sf_addr, 1))
goto sigsegv;
if (do_setcontext(&rt_sf->uc, env, 1))
goto sigsegv;
do_sigaltstack(rt_sf_addr
+ offsetof(struct target_rt_sigframe, uc.tuc_stack),
0, env->gpr[1]);
unlock_user_struct(rt_sf, rt_sf_addr, 1);
return -TARGET_QEMU_ESIGRETURN;
sigsegv:
unlock_user_struct(rt_sf, rt_sf_addr, 1);
force_sig(TARGET_SIGSEGV);
return -TARGET_QEMU_ESIGRETURN;
}
/* This syscall implements {get,set,swap}context for userland. */
abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,
abi_ulong unew_ctx, abi_long ctx_size)
{
struct target_ucontext *uctx;
struct target_mcontext *mctx;
/* For ppc32, ctx_size is "reserved for future use".
* For ppc64, we do not yet support the VSX extension.
*/
if (ctx_size < sizeof(struct target_ucontext)) {
return -TARGET_EINVAL;
}
if (uold_ctx) {
TaskState *ts = (TaskState *)thread_cpu->opaque;
if (!lock_user_struct(VERIFY_WRITE, uctx, uold_ctx, 1)) {
return -TARGET_EFAULT;
}
#ifdef TARGET_PPC64
mctx = &uctx->tuc_sigcontext.mcontext;
#else
/* ??? The kernel aligns the pointer down here into padding, but
* in setup_rt_frame we don't. Be self-compatible for now.
*/
mctx = &uctx->tuc_mcontext;
__put_user(h2g(mctx), &uctx->tuc_regs);
#endif
save_user_regs(env, mctx);
host_to_target_sigset(&uctx->tuc_sigmask, &ts->signal_mask);
unlock_user_struct(uctx, uold_ctx, 1);
}
if (unew_ctx) {
int err;
if (!lock_user_struct(VERIFY_READ, uctx, unew_ctx, 1)) {
return -TARGET_EFAULT;
}
err = do_setcontext(uctx, env, 0);
unlock_user_struct(uctx, unew_ctx, 1);
if (err) {
/* We cannot return to a partially updated context. */
force_sig(TARGET_SIGSEGV);
}
return -TARGET_QEMU_ESIGRETURN;
}
return 0;
}
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